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Complications of Light Coagulation Therapy*
EYE AND PSYCHIATRIC DISORDER we can anticipate the period of depression, denial of reality, hopes for miraculous cures and spectacular operations, schizophreniclike symptoms and attitudes of bitterness or self pity. We may find well-meaning relatives sup porting the patient's false hopes and even pro moting them. The stage of shock and the stage of subsequent reaction are in many ways akin to the reaction to a bereavement. To me it
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would seem that within certain limits they are a necessary part of the adjustment and ought not to be viewed as evidence of a poor prognosis from a psychiatric point of view. Given time and support, most patients will be willing to start anew when they are "good and ready." 500 Newton Road.
REFESENCES
1. Diagnostic and Statistical Manual, Mental Disorders. Washington, D.C., American Psychiatric As sociation, 1952. 2. Hoch, P. H.: Biosocial aspects of anxiety. In Anxiety. (Edited by P. H. Hoch and J. Zubin.) New York, Grune and Stratton, 1950. 3. Tourney, G.: Evil eye in myth and schizophrenia. Psychiat. Quart., 28:478-495 (July) 1954. 4. Schlaegel, T. F.: Psychosomatic Ophthalmology. Baltimore, Williams & Wilkins, 1957. 5. Grinker, R. R., et al.: The Phenomena of Depressions. New York, Hoeber, 1961. COMPLICATIONS O F LIGHT COAGULATION T H E R A P Y * BAYARD H. COLYEAR, JR., M.D.
AND DOHRMANN K. PISCHEL,
M.D.
San Francisco, California Light coagulation (photocoagulation) has become an established adjunct in the treat ment of some ocular diseases and, in particu lar, of those conditions involving the ret ina. It has been used by us satisfactorily in the treatment of retinal tears unassociated with separation of the retina, in postopera tive cases of retinal detachment in which further chorioretinal adhesion was advisable and as a prophylactic measure to help pre vent the occurrence of a retinal detachment (most especially in areas where there is "lat tice degeneration" of the retina). In addi tion, it has been very helpful in the manage ment of cases of von Hippel's disease, Leber's miliary aneurysms and retinoblastoma. As in the case of any other medical instru ment or drug, complications arising from the use of light coagulation may occur. We have been using this method of treatment at Chil dren's Hospital in San Francisco since July, 1958, and during this period of time we have had occasion to witness, either primarily or * Presented before the Section on the Eye at the 91st annual session of the California Medical Association, San Francisco, April, 1962.
secondarily, some of the difficulties attendant on its use. These difficulties, fortunately, are infrequent and should not dissuade others from adopting this method of treatment. A problem involved in this treatment is not at all directly connected to the procedure itself but rather to the hopeful expectancies of the patient. Having heard of this method and not infrequently having been told by the referring physician that this might suffice, the patient is often convinced that surgery will be avoidable. It is, therefore, necessary to explain carefully to the patient and his family that photocoagulation is effective only under certain circumstances and that surgery is frequently the more conservative and less time-consuming alternative. ANESTHESIA
The majority of patients treated by photo coagulation are given a retrobulbar injection of Novocaine or Xylocaine in addition to premedication with Demerol, Phenergan, and topical Dorsacaine. The more mobile the eye, the easier it is to position it so that one can treat an area satisfactorily. In practice, how-
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BAYARD H. COLYEAR, JR. AND DOHRMANN K. PISCHEL
ever, most patients require a retrobulbar in jection, which reduces the discomfort due to glare and heat, while partially or totally im mobilizing the eye. If the treatment is per formed very shortly after the retrobulbar in jection (about three minutes), the anesthesia is good but the paralysis of the ocular mus cles is not complete. Approximately half of our treatments are performed with a retro bulbar injection, many of the patients being able to undergo treatment without any retro bulbar injection on the second or third oc casion. In 1,012 consecutive retrobulbar injec tions, a retrobulbar hemorrhage occurred in 16 cases, an incidence of between one and two percent. In a few of these patients, the hemorrhage was so swift and the globe so totally immovable that little or no light co agulation could be performed properly. Un der these circumstances, all one can do is to wait a few days until the eye is more com fortable and then proceed with the treatment, usually trying initially to avoid another in jection. However, in the majority of cases the proptosis helped. Anesthesia for this procedure, as already indicated, is invariably local, except in the case of infants. We routinely use Demerol and Phenergan and, occasionally, a patient will react to the Phenergan by a fall in blood pressure. Time enough should be allowed for the premedication to assert itself, as before a cataract operation, but occasionally, when several patients are being treated in succes sion, this may be neglected and the patient may be quite aware of the discomfort in volved. Another factor to remember is that there is a frequent, transient loss of vision after a retrobulbar injection of Novocaine or of Xylocaine. Usually, when this injection is given for other treatments, the patient's eye sight is already so diminished that the result ant decrease in vision is not appreciated by the patient. However, patients who undergo photocoagulation usually have quite good cen tral visual acuity. The operator should re
member to tell the patient that a marked re duction in vision may follow the injection. It is not unusual for the patient's vision to fall precipitously to no light perception or very poor light perception. The first time this happened, neither the patient nor we were prepared and all of us were dismayed. A retrobulbar injection should be preceded by a warning of probable decrease in vi sion. In young children and infants, general an esthesia is preferable. These cases should be done close to the operating room, inasmuch as suction may be necessary. In addition, many children who are in need of light co agulation have other (especially cardiac) de fects which may necessitate immediate care (oxygen, cardiac massage, defibrillation). In spite of adequate local anesthesia, there may be considerable discomfort if the limbus, and especially the limbus at the hori zontal meridian, is photocoagulated. The more tangential the beam of light from the machine, the more likely that the limbus will be struck. By cutting down the width of the light aperture, much of this difficulty can be avoided. Often glare is noticeable to the eye not be ing treated. Under these circumstances, topi cal anesthetic drops, or a patch, may reduce the amount of "squinting" on the part of the patient. Movement of the eye just as the full power of the machine is triggered is one complica tion to fear for the macula may be struck inadvertently. This has never occurred in our experience. Any movements of the eye are immediately noticeable to the operator, who has adequate time to release the pressure on the trigger of the machine, immediately shuting off an amount of light that might in jure the interior of the eye. If the retrobulbar injection has failed to paralyze the muscle sufficiently and the eye continues to stray, or if paralysis is so great that the eye cannot move at all, fixation for ceps placed adjacent to the limbus will be of great help in positioning the globe.
COMPLICATIONS OF LIGHT COAGULATION POSITION OF PATIENT
One difficulty in treatment with photocoagulation is to achieve the proper position of the patient in relation to the machine. The area to be treated should be in line with the long axis of the "trunk" of the machine. Thus, if an area at the 12-o'clock position in the left eye is to be treated, the patient's body should be in the same axis as the ex tended arm of the machine, the head toward the machine, the left eye under the ophthal moscope handle. This assures the greatest amount of mobility. Another means of pro viding freedom of motion, is to have the pa tient on a stretcher, all four wheels of which can rotate and which can be elevated or low ered as desired. We have also had the two front wheels of our machine changed so that they, too, rotate, as do the rear wheels. This makes repositioning of the heavy machine much easier. Being able and willing to move the patient and/or the machine frequently makes most of the applications easier and more rapid; within reason, the more easily the applications can be made, the more ade quately can the lesion be treated. OVERTREATMENT
Many difficulties experienced with photocoagulation result from overtreatment. The amount of light energy striking the eye is controlled by the basic input of power (which can be increased gradually in eight steps), by a diaphragm which "cones" down the bundle of rays emitted from the machine, by an aperture which varies the breadth of the beam impinging on the retina and by the length of exposure permitted. The more clear the media (cornea, aqueous, lens, vitreous), the more centrally (toward the posterior pole) one is treating and the more pigmented the choroid and pigmented layer of the retina, the quicker the response to photocoagulation at any given setting. In addition, the less refractive error there is, the more rapidly does the chorioretinal burn occur.
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For example, in a young Negro with clear ocular media, an immediate response to photocoagulation can be witnessed after a very low input, with the diaphragm only slightly opened and an exposure time of less than a second. In such a case, the response is immediate almost regardless of how periph eral the treatment. On the other hand, in a patient with considerable nuclear sclerosis or with posterior subcapsular opacities, the basic input has to be increased considerably and the diaphragm has to be wide open in order to obtain any appreciable response in the retina from the equator on out toward the ora serrata. To avoid overheating and damage to the cornea, iris and vitreous, the basic power input should always be increased to achieve a result rather than the exposure time extended beyond one and one-half seconds to two seconds. It is safer to have a higher basic input setting for a one-second exposure than to leave the basic input low and allow the ex posure to run to three or four seconds. It is with longer exposure that most operators come to grief ; that is, corneal damage and clouding of the vitreous. Although high refractive errors may offer some difficulties, they are surprisingly few. The machine is equipped with a set of plus and minus contact lenses of various powers. However, in practice we get satisfactory treatment response in aphakic and highly myopic patients without the use of a contact lens. In aphakic patients, the basic input usu ally has to be a "green I I I " ; however, the chorioretinal response is usually adequate. If the reaction is not sufficient and one decides to use a contact lens, the basic power input should be set back to "green I " before pro ceeding, or a very severe burn of the retina may result. In highly myopic patients treated without a contact lens, the areas usually are relatively far in the periphery, where the myopic error is much less and often of no conse quence. Therefore, the intensity of light
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necessary to obtain a good reaction is less the basic input raised to "overload I or II," than might be expected. the media are probably too cloudy. Treat The contact lenses accompanying the ment should then be postponed, certainly for machine are rather thick and the fluid easily that day. Not all cases are suitable for escapes from under them. Under such photocoagulation. It is better to stop than to circumstances, if one is not careful, the run the risk of corneal, iris and vitreous underlying cornea becomes dry and can be damage. Often vitreous haze resulting from burned easily, sometimes with permanent vitreous hemorrhage occurring at the onset scarring. We, therefore, use one of two of a retinal tear, or vitreous haze resulting corneal lenses of the Tuohy type, a plus 10 from recent surgery, will prevent adequate and minus 10. These are easily applied and, response to treatment. We usually let these if a bubble of air gets under them, it can be patients rest with binocular bandages a few squeezed out easily. more days, prescribing topical steroids and One habit that is a good one to adopt is often oral steroids. This usually clears the to handle the ophthalmoscope "trigger" with vitreous haze; then the intended photocoag one hand, while controlling the knob on the ulation can be adequately and safely per diaphragm with the other hand. In this formed. manner a considerable amount of variation It is often easier to judge the photocoagu in intensity of light can be obtained from lation response at the time the machine is in one "shot" to the next, adjustment in inten use, rather than five minutes later with either sity and exposure depending on the immedi the direct or indirect ophthalmoscope. Even ately apparent visual results. the bright light of the indirect ophthalmo Danger may be encountered in treating scope cannot be compared to the brilliance aphakic patients. On occasion, even with of the photocoagulator when it is "opened" relatively low intensity treatment, the cornea for treatment. It is better to be guided by may become edematous. The cornea in what is seen while treating. After several aphakic patients should be checked from days, as the exudative response increases and time to time during treatment, to avoid such pigmentation occurs, other means of ophan occurrence. Too often this early edema is thalmoscopy may be used to observe the not recognized by the operator if he con effects. tinues to look at the eye through the oph COMPLICATIONS thalmoscope and not directly with side illumination. In our experience, this has As mentioned earlier, corneal damage can occurred several times. The edema has be caused by heavy exposure or drying of resolved after a few days with rest and the cornea (with or without a contact lens). topical steroids. Severe corneal damage has, It may occur in some aphakic patients, prob however, been reported. ably because of endothelial changes already Another way to avoid corneal damage, in present. In addition the cornea may be addition to avoiding overexposure, is the damaged when the machine is used to make constant moistening of the corneal surface or to enlarge a pupil. For this, a separate head with normal saline or one of the various is used. The light emerging from this head is salt solutions. For this, the operator should not parallel but comes to a focus on either always have an assistant, usually a nurse, the iris or the cornea, thus greatly increas stationed right beside the patient. In this ing the amount of heat absorbed by the an way the cornea can be kept moist. Often the terior segment. To help overcome this, the nurse may recognize early corneal edema treatment is performed with a water-bath before the operator becomes aware of it. over the cornea. However, often the iris is of If there is no chorioretinal response with the bombé type and the heat generated in it,
COMPLICATIONS OF LIGHT COAGULATION
so close to the cornea, may produce a perma nent corneal burn. If care is used, there should be little, if any, damage to the iris while the fundus is being treated. Maximum dilatation of the pupil is advised (we use 0.2-percent scopol amine and 10-percent neosynephrine eyedrops) . When the treatment is done close to the eye and relatively centrally, the beam of light only rarely hits the iris. However, the farther away from the eye the ophthalmo scope is and the more peripheral in the fundus the area being treated, the greater the chance that the iris will be hit. Under these circumstances, it is wise to cut down the aperture, thus producing a narrower bundle of rays so that fewer of them will strike outside the pupillary limits. We have not treated any pigmented lesions of the iris, preferring to excise them for histologie study. Our treatment with lesions of the iris has been confined solely to the reformation of pupils. This has been suc cessful only if there are few if any lens rests behind the iris, for lens rests negate the possibility of a desirable pupillary open ing. If the media behind the iris are clear, our experience in making new pupillary openings has been satisfactory. Treatment of this sort requires an assistant who must make sure that the beam of light is properly directed and the water-bath kept filled to avoid corneal damage. In such treatment, one must be careful to avoid hitting any iris vessels; they are quite friable and tend to bleed easily. Since anterior uveitis fre quently follows this type of treatment, topical or subconjunctival steroids and cycloplegics should be started immediately. In retinal detachment patients with small pupils, it is possible to improve the visibility first by enlarging the pupil, and then later operate on the detachment. This problem often occurs in patients suffering from Marian's syndrome or with aphakia, a small pupil and retinal detachment. The iris sphincter may be burned on several occa sions to help enlarge the pupil, and then
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surgery undertaken when the eye quiets down. In such cases, iritis is almost inevi table and must be combated with vigor. Unless the anterior segment is being treated, photocoagulation rarely damages the lens. When it does, a small anterior subcapsular opacity, which is. usually not progressive, results. We have not used photocoagulation to perform an iridectomy in narrow-angle glaucoma because of poor results obtained by others. DIFFICULTIES
When the lens is cataractous, it can create some difficulties by scattering the rays of light which, naturally, cuts down the in tensity of light hitting the retina, usually scattering the rays ineffectively about in the periphery. If one wishes to treat prophylactically a weakened area of retina, and if the lens is sufficiently cataractous, it is prob ably better to do the cataract extraction ini tially. Later the photocoagulation can be per formed through clear media, sometimes as soon as 10 days after cataract surgery. If a lens is subluxated, the great and sudden differences in refractive powers are annoying, as one photocoagulates first through a portion of lens and then through an aphakic portion of the pupil. It is best to treat such patients slowly and on many occa sions, settling for a few well-placed applica tions at each session and avoiding overtreatment of the anterior segment of the eye. The vitreous itself offers problems, as already mentioned, if there is residual hemorrhage or haze from recent surgery. As to what damage can be done to the vitreous by photocoagulation, it is difficult to say. Surely, vitreous must absorb some of the heat of the rays of light passing through it and, to avoid this, the globe must be kept cool and not treated too heavily. As with diathermy, the vitreous response may be quite variable. There seem to be patients who develop massive vitreous retraction following surgery in which little diathermy was used. We have had occasional clouding
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BAYARD H. COLYEAR, JR. AND DOHRMANN K. PISCHEL
of the vitreous following photocoagulation but nothing that we considerd to be massive vitreous retraction. It is certainly possible that, following photocoagulation, new adhérences of the recently coagulated vitreous and retina may occur, leading eventually to a new tear. We have seen new tears following light coagula tion. Often they are immediately adjacent to previous areas of treatment, suggesting that either the retina had shrunken a little here or, because of retinal shrinkage, more vitreous tension had been placed upon the retina. Certainly the incidence of new tears following photocoagulation has been no greater than it was following partially pene trating diathermy. CARE DURING TREATMENT
While treating the retina, visual control is essential to regulation of the intensity of light. A very light blanching effect is most desirable, since it will excite a good choroidal reaction and produce minimal shrinkage of the retina. On occasion, while treating next to a large tear in a flat retina, one can see the tear become even larger as its margins slowly begin to shrink. It must be remem bered that the retina anterior to the tear (on the ora serrata side) should also be sealed off, if at all possible. This is usually not too difficult, even with breaks that are far ante rior, if one uses scierai indentation. We have found that a cotton applicator will give a broad and perfectly satisfactory indentation, without the risk of putting more localized pressure on a weak area of retina. Care must be taken in the treatment of highly myopic eyes, or in eyes which for other reasons have little pigmentation. There will be, understandably, less reaction im mediately visible in these patients, and an er ror can be committed by treating longer, or more heavily, in an effort to obtain the "usual" visual result. Sometimes it is better to place a few applications in more normally pigmented portions of the retina to find out what setting is adequate and then use the
same setting to treat the desired regions. Not much reaction will be seen at the time because of the lack of contrast between a blanched retina and a darker choroid. A few days later good exudate is usually seen. Not infrequently, a week or so later, there will be a nice, although fine, pigmented re action. Although it is natural to avoid hitting a large retinal vein or arteriole, it is surpris ing how often this may occur without hemor rhage. We have seen at least a hundred vessels of this caliber suddenly narrow be cause of treatment too close to them, with out a subsequent hemorrhage. We have not had a single hemorrhage of any significance that was due to damage to one of the retinal vessels. Nevertheless, we have always been so afraid that this might happen that prob ably we have been most discrete in placing applications between vessels and have thus avoided serious hemorrhage. In treating a case which might need ret inal surgery later, if the chorioretinal re sponse is poor, it is better to stop attempts at photocoagulation and save the choroid in the hope that it will respond better to later surgical treatment. RETINAL DETACHMENT
In the postoperative care of retinal de tachment patients, light coagulation certainly has been of great help. However, many of the causes of failure in retinal detachment surgery are not eliminated by photocoagulation which should not be anxiously at tempted when the proper solution is further surgery. If the tear is flat but not adequately treated, photocoagulation is simple and easy. If a new tear develops but the retina is not elevated, photocoagulation is of great help, as it also is in the presence of other degenera tive (especially lattice) changes in the retina. Many detachments recur, however, be cause another tear was not discovered, and certainly light coagulation will not discover tears. Often, during the early postoperative course, the tear will be open and surrounded
COMPLICATIONS OF LIGHT COAGULATION by elevated retina. This circumstance, which appears within the first two weeks following surgery, usually is not suitable for photoco agulation. Formerly, we operated again and usually obtained a good result with a little more subretinal drainage and partially penetrating diathermy. Too often nowadays it is hoped that photocoagulation will close an elevated, open break in the retina. This can be accomplished on rare occasions, by gradually moving in upon the tear from its peripheral, less elevated margins. As exudate forms, the retina gradually flattens, permit ting the operator to treat areas closer to the edges of the tear. This is not usual, however, and reoperation most often is the better choice. Under certain circumstances, photocoagu lation may be used with success following retinal detachment surgery. Sometimes, im mediately following surgery, the cornea and vitreous are hazy, reducing the chances of any appreciable effect from the light. Also, the retina may not be absolutely flat against the choroid, and this thin film of fluid will be sufficient to prohibit the response de sired. Very often the retinal tear causing the de tachment is located in the region of a vortex vein (most usually the one under the inser tion of the superior oblique muscle). If it is difficult to place diathermy safely about the tear and around the ampulla of the vortex vein, photocoagulation may be used in that region immediately following surgery, if the retina in that region is flat. PROPHYLAXIS
Photocoagulation may be used immediately following surgery in the prophylactic treat ment of the other eye. This can most often be accomplished without difficulty, and cer tainly without discomfort or hazard to the patient. A retinal tear without an associated de tachment is the ideal case for photocoagula tion treatment. Use of the slitlamp and the contact lens of Goldmann probably provides
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the most accurate way of determining whether there is a true hole in the retina and whether or not the retina is elevated. Having confirmed the presence of the retinal break, the amount and extent of ret inal elevation, if any, can be determined. If the elevation is minimal, photocoagula tion may help. In addition to finding out whether the elevation is minimal, it is neces sary to consider the area of the elevation. By minimal elevation is meant an elevation that is difficult to perceive by either direct or by binocular indirect ophthalmoscopy, but which can be made out with the slitlamp or the binocular ophthalmoscope manufactured by Bausch and Lomb. Concerning the ex tent or area of the elevation, if the detach ment spreads two disc diameters from the margins of the tear, the chances of per manently sealing the tear by photocoagula tion alone are, perhaps, 75 percent. If the area of the elevation extends three to four disc diameters from the margins of the tear, and if the elevation is easily discernible by direct or by binocular indirect ophthal moscopy, the chances of a cure by photoco agulation drop to about 25 percent. After a few applications of light, the ex tent of any retinal elevation surrounding the tear can be confirmed. Ideally, the aver age tear without detachment should be per manently sealed by a double barrage around its margins, and sometimes by less. When it becomes necessary to go much farther centrally, one should consider diathermy and discrete subretinal drainage to close the tear more securely. The treatment of tears in the retina with a freed operculum floating in front of them on the posterior "face" of the vitreous is really no problem. More dangerous is the treatment of atrophie, round holes situated along a line of obliterated, white, vascular twigs at or near the equator. In the treat ment of these cases, if the photocoagulation is brought too close to the region, new tears can be provoked through shrinkage of the retina. It is necessary, therefore, to sur-
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BAYARD H. COLYEAR, JR. AND DOHRMANN K. PISCHEL
The postphotocoagulation management of round these areas, not to treat them directly ; to insulate them from the remaining retina these latter cases should be similar to that with a single barrage of treatment no closer following partially penetrating diathermy ; it than a disc diameter to the degenerated is more conservative than that following area. Later the lesion can be treated directly. photocoagulation of a tear without a detach Large retinal tears, with a flap of retina ment. Once the retina has been detached, pulled into the vitreous, can be most hazard even if it settles remarkably well, separation ous. The presence of a large tear and flap from its pigmentary layer may easily recur is ample evidence of an expansive attach with rotation of the eye during the early ment of the vitreous to the retina, and one days following surgery or photocoagulation. must be especially careful of any retinal or About on third of the patients, whose retinas vitreous shrinkage. This is particularly true settled with bedrest, and who underwent if the central margins of the tear are turned photocoagulation, have had a relapse of inward, denoting further traction upon the the detachment, necessitating either more tear in this area. photocoagulation or surgery. All of them, Prophylactic use of photocoagulation is fortunately, were ultimately cured. These relapses all occurred within three months of most warranted in the presence of areas of so-called "lattice degeneration." However, treatment, the period of the majority of as already mentioned, the operator must be recurrences, regardless of the type of sur careful to avoid hitting these patches of gery employed. weak retina directly and concentrate on OTHER USES placing the treatment completely around the lesion. Unwarranted prophylactic treatment We do not treat macular holes by photoshould be avoided, since the normal pig coagulation unless the vision is 20/200 or mentary degenerative changes that occur less, and only after high-magnification lenses with age do not lead to retinal detachment. have failed to improve vision. When mac When undertaking prophylactic treatment, it ular holes are treated, they usually can be probably is best not to treat more than one handled with two or three well-placed applica quadrant of retina at a single sitting; an tions, with the aperture made smaller so other treatment may be given within a day that the beam of light just barely touches or so. By doing this, the likelihood of dam the margins of the hole. In this manner, as age to the cornea, vitreous, and retina is much paramacular vision as possible is pre lessened. Obviously, it will be many years be served. A macular hole (which can be dif fore anyone will be able to estimate the in ferentiated from a macular cyst most readily fluence of photocoagulation in reducing the with the slitlamp) only infrequently leads to incidence of retinal detachment in the second the development of an extensive retinal eye. detachment. In our experience this has in variably occurred in patients with high In some patients, bedrest with binocular myopia (in the range of minus 15 to minus bandages will allow the retina to settle 25 diopters). In general, therefore, true markedly and, occasionally, completely. macular holes can be managed by observa These patients are good candidates for light tion, and photocoagulation used if the mar coagulation, if the operator bears in mind gins of the hole become elevated (to help that the retina about the tear must truly be prevent a larger central scotoma) or if the flat. If a retina has not settled sufficiently macular hole is in an eye with high myopia. after three days of quiet in bed, with both eyes bandaged, it probably never will settle completely enough for successful photoco agulation,
Treating such retinal vascular lesions as Leber's miliary aneurysms, Eales' disease, early stages of Coats' disease, and some
COMPLICATIONS OF LIGHT COAGULATION
cases of vascular abnormalities associated with the sickle-cell trait can lead to minor hemorrhages. However, in our experience there has never been a severe hemorrhage. Usually, the lesions respond well to gentle coagulation about the area, and gradually shrink. Of course, the cause of the abnor mality is not being treated, only a diseased vessel in an effort to close it off before it spontaneously hemorrhages into the vitreous. In these cases there must be routine check ups, since similar lesions may appear in the same or fellow eye at a later time. Treatment of a von Hippel aneurysm offers the greatest threat of massive hemorrhage. It is imperative that the large feeding ves sels be avoided. Initially, one or two applica tions are gently placed on the body of the tu mor ; no further treatment is then performed for perhaps a week. Gradually more light co agulation is placed about the margins of the mass. Carefully avoiding the major feeding vessels, the foci of treatment can be placed just on either side of them. The slow forma tion of glial tissue, as a result of the retinal burn, will usually, and gradually, pinch the vessels closed, without a resultant hemor rhage. These lesions often tend not only to be bilateral but may also recur in other por tions of the eye. A long-time routine followup is strongly urged. In the management of patients with vari ous vascular abnormalities, it must be re membered that the majority of them are young and have clear ocular media. There fore, treatment should be initiated with the lowest input of power, and with the dia phragm closed to at least one-half its di ameter. We think that retinoblastomas are best treated by an initial full course of irradia tion, frequently supplemented by intraarterial TEM. Following this, if some tumor
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remains, these areas may be treated with photocoagulation. The tumor should be sur rounded first in an effort to destroy the retinal vessels feeding it. With this procedure, good results can be expected. We have been dis appointed with photocoagulation alone. In each of nine cases irradiation was eventually necessary. A problem we have encountered with these patients may account for the poor results. Many parents seem to be apathetic about keeping their appointments so that the child can be followed closely with anesthetic examinations. We have had little experience with photocoagulation treatment of choroidal mela nomas. In four patients so treated, the lesion was dark, slightly elevated, had a serous de tachment of the retina overlying it and had been noted to grow in size. In each instance, the patient requested this form of treatment in preference to enucleation. The follow-up periods in these patients extend from six months to one and one-half years. All of the treated eyes look well at the present time. It will take many years before photocoagu lation in the treatment of this type of tumor can be fully evaluated. The procedure for treatment of choroidal melanomas is similar to that in retinoblastoma. An effort is first made to surround the tumor thoroughly and completely, thus di vesting it of its blood supply. A day or so later, applications are placed directly upon the body of the tumor, usually with considerable response due to the pigmentation of the mass. Treating highly elevated melanomas in this manner probably is not safe, since the depth of the tumor would prevent an ap preciable amount of reaction at the base. In addition, the debris produced by such ex tensive coagulation might lead to loss of the eye. 490 Post Street (2).
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would seem that within certain limits they are a necessary part of the adjustment and ought not to be viewed as evidence of a poor prognosis from a psychiatric point of view. Given time and support, most patients will be willing to start anew when they are "good and ready." 500 Newton Road.
REFESENCES
1. Diagnostic and Statistical Manual, Mental Disorders. Washington, D.C., American Psychiatric As sociation, 1952. 2. Hoch, P. H.: Biosocial aspects of anxiety. In Anxiety. (Edited by P. H. Hoch and J. Zubin.) New York, Grune and Stratton, 1950. 3. Tourney, G.: Evil eye in myth and schizophrenia. Psychiat. Quart., 28:478-495 (July) 1954. 4. Schlaegel, T. F.: Psychosomatic Ophthalmology. Baltimore, Williams & Wilkins, 1957. 5. Grinker, R. R., et al.: The Phenomena of Depressions. New York, Hoeber, 1961. COMPLICATIONS O F LIGHT COAGULATION T H E R A P Y * BAYARD H. COLYEAR, JR., M.D.
AND DOHRMANN K. PISCHEL,
M.D.
San Francisco, California Light coagulation (photocoagulation) has become an established adjunct in the treat ment of some ocular diseases and, in particu lar, of those conditions involving the ret ina. It has been used by us satisfactorily in the treatment of retinal tears unassociated with separation of the retina, in postopera tive cases of retinal detachment in which further chorioretinal adhesion was advisable and as a prophylactic measure to help pre vent the occurrence of a retinal detachment (most especially in areas where there is "lat tice degeneration" of the retina). In addi tion, it has been very helpful in the manage ment of cases of von Hippel's disease, Leber's miliary aneurysms and retinoblastoma. As in the case of any other medical instru ment or drug, complications arising from the use of light coagulation may occur. We have been using this method of treatment at Chil dren's Hospital in San Francisco since July, 1958, and during this period of time we have had occasion to witness, either primarily or * Presented before the Section on the Eye at the 91st annual session of the California Medical Association, San Francisco, April, 1962.
secondarily, some of the difficulties attendant on its use. These difficulties, fortunately, are infrequent and should not dissuade others from adopting this method of treatment. A problem involved in this treatment is not at all directly connected to the procedure itself but rather to the hopeful expectancies of the patient. Having heard of this method and not infrequently having been told by the referring physician that this might suffice, the patient is often convinced that surgery will be avoidable. It is, therefore, necessary to explain carefully to the patient and his family that photocoagulation is effective only under certain circumstances and that surgery is frequently the more conservative and less time-consuming alternative. ANESTHESIA
The majority of patients treated by photo coagulation are given a retrobulbar injection of Novocaine or Xylocaine in addition to premedication with Demerol, Phenergan, and topical Dorsacaine. The more mobile the eye, the easier it is to position it so that one can treat an area satisfactorily. In practice, how-
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ever, most patients require a retrobulbar in jection, which reduces the discomfort due to glare and heat, while partially or totally im mobilizing the eye. If the treatment is per formed very shortly after the retrobulbar in jection (about three minutes), the anesthesia is good but the paralysis of the ocular mus cles is not complete. Approximately half of our treatments are performed with a retro bulbar injection, many of the patients being able to undergo treatment without any retro bulbar injection on the second or third oc casion. In 1,012 consecutive retrobulbar injec tions, a retrobulbar hemorrhage occurred in 16 cases, an incidence of between one and two percent. In a few of these patients, the hemorrhage was so swift and the globe so totally immovable that little or no light co agulation could be performed properly. Un der these circumstances, all one can do is to wait a few days until the eye is more com fortable and then proceed with the treatment, usually trying initially to avoid another in jection. However, in the majority of cases the proptosis helped. Anesthesia for this procedure, as already indicated, is invariably local, except in the case of infants. We routinely use Demerol and Phenergan and, occasionally, a patient will react to the Phenergan by a fall in blood pressure. Time enough should be allowed for the premedication to assert itself, as before a cataract operation, but occasionally, when several patients are being treated in succes sion, this may be neglected and the patient may be quite aware of the discomfort in volved. Another factor to remember is that there is a frequent, transient loss of vision after a retrobulbar injection of Novocaine or of Xylocaine. Usually, when this injection is given for other treatments, the patient's eye sight is already so diminished that the result ant decrease in vision is not appreciated by the patient. However, patients who undergo photocoagulation usually have quite good cen tral visual acuity. The operator should re
member to tell the patient that a marked re duction in vision may follow the injection. It is not unusual for the patient's vision to fall precipitously to no light perception or very poor light perception. The first time this happened, neither the patient nor we were prepared and all of us were dismayed. A retrobulbar injection should be preceded by a warning of probable decrease in vi sion. In young children and infants, general an esthesia is preferable. These cases should be done close to the operating room, inasmuch as suction may be necessary. In addition, many children who are in need of light co agulation have other (especially cardiac) de fects which may necessitate immediate care (oxygen, cardiac massage, defibrillation). In spite of adequate local anesthesia, there may be considerable discomfort if the limbus, and especially the limbus at the hori zontal meridian, is photocoagulated. The more tangential the beam of light from the machine, the more likely that the limbus will be struck. By cutting down the width of the light aperture, much of this difficulty can be avoided. Often glare is noticeable to the eye not be ing treated. Under these circumstances, topi cal anesthetic drops, or a patch, may reduce the amount of "squinting" on the part of the patient. Movement of the eye just as the full power of the machine is triggered is one complica tion to fear for the macula may be struck inadvertently. This has never occurred in our experience. Any movements of the eye are immediately noticeable to the operator, who has adequate time to release the pressure on the trigger of the machine, immediately shuting off an amount of light that might in jure the interior of the eye. If the retrobulbar injection has failed to paralyze the muscle sufficiently and the eye continues to stray, or if paralysis is so great that the eye cannot move at all, fixation for ceps placed adjacent to the limbus will be of great help in positioning the globe.
COMPLICATIONS OF LIGHT COAGULATION POSITION OF PATIENT
One difficulty in treatment with photocoagulation is to achieve the proper position of the patient in relation to the machine. The area to be treated should be in line with the long axis of the "trunk" of the machine. Thus, if an area at the 12-o'clock position in the left eye is to be treated, the patient's body should be in the same axis as the ex tended arm of the machine, the head toward the machine, the left eye under the ophthal moscope handle. This assures the greatest amount of mobility. Another means of pro viding freedom of motion, is to have the pa tient on a stretcher, all four wheels of which can rotate and which can be elevated or low ered as desired. We have also had the two front wheels of our machine changed so that they, too, rotate, as do the rear wheels. This makes repositioning of the heavy machine much easier. Being able and willing to move the patient and/or the machine frequently makes most of the applications easier and more rapid; within reason, the more easily the applications can be made, the more ade quately can the lesion be treated. OVERTREATMENT
Many difficulties experienced with photocoagulation result from overtreatment. The amount of light energy striking the eye is controlled by the basic input of power (which can be increased gradually in eight steps), by a diaphragm which "cones" down the bundle of rays emitted from the machine, by an aperture which varies the breadth of the beam impinging on the retina and by the length of exposure permitted. The more clear the media (cornea, aqueous, lens, vitreous), the more centrally (toward the posterior pole) one is treating and the more pigmented the choroid and pigmented layer of the retina, the quicker the response to photocoagulation at any given setting. In addition, the less refractive error there is, the more rapidly does the chorioretinal burn occur.
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For example, in a young Negro with clear ocular media, an immediate response to photocoagulation can be witnessed after a very low input, with the diaphragm only slightly opened and an exposure time of less than a second. In such a case, the response is immediate almost regardless of how periph eral the treatment. On the other hand, in a patient with considerable nuclear sclerosis or with posterior subcapsular opacities, the basic input has to be increased considerably and the diaphragm has to be wide open in order to obtain any appreciable response in the retina from the equator on out toward the ora serrata. To avoid overheating and damage to the cornea, iris and vitreous, the basic power input should always be increased to achieve a result rather than the exposure time extended beyond one and one-half seconds to two seconds. It is safer to have a higher basic input setting for a one-second exposure than to leave the basic input low and allow the ex posure to run to three or four seconds. It is with longer exposure that most operators come to grief ; that is, corneal damage and clouding of the vitreous. Although high refractive errors may offer some difficulties, they are surprisingly few. The machine is equipped with a set of plus and minus contact lenses of various powers. However, in practice we get satisfactory treatment response in aphakic and highly myopic patients without the use of a contact lens. In aphakic patients, the basic input usu ally has to be a "green I I I " ; however, the chorioretinal response is usually adequate. If the reaction is not sufficient and one decides to use a contact lens, the basic power input should be set back to "green I " before pro ceeding, or a very severe burn of the retina may result. In highly myopic patients treated without a contact lens, the areas usually are relatively far in the periphery, where the myopic error is much less and often of no conse quence. Therefore, the intensity of light
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necessary to obtain a good reaction is less the basic input raised to "overload I or II," than might be expected. the media are probably too cloudy. Treat The contact lenses accompanying the ment should then be postponed, certainly for machine are rather thick and the fluid easily that day. Not all cases are suitable for escapes from under them. Under such photocoagulation. It is better to stop than to circumstances, if one is not careful, the run the risk of corneal, iris and vitreous underlying cornea becomes dry and can be damage. Often vitreous haze resulting from burned easily, sometimes with permanent vitreous hemorrhage occurring at the onset scarring. We, therefore, use one of two of a retinal tear, or vitreous haze resulting corneal lenses of the Tuohy type, a plus 10 from recent surgery, will prevent adequate and minus 10. These are easily applied and, response to treatment. We usually let these if a bubble of air gets under them, it can be patients rest with binocular bandages a few squeezed out easily. more days, prescribing topical steroids and One habit that is a good one to adopt is often oral steroids. This usually clears the to handle the ophthalmoscope "trigger" with vitreous haze; then the intended photocoag one hand, while controlling the knob on the ulation can be adequately and safely per diaphragm with the other hand. In this formed. manner a considerable amount of variation It is often easier to judge the photocoagu in intensity of light can be obtained from lation response at the time the machine is in one "shot" to the next, adjustment in inten use, rather than five minutes later with either sity and exposure depending on the immedi the direct or indirect ophthalmoscope. Even ately apparent visual results. the bright light of the indirect ophthalmo Danger may be encountered in treating scope cannot be compared to the brilliance aphakic patients. On occasion, even with of the photocoagulator when it is "opened" relatively low intensity treatment, the cornea for treatment. It is better to be guided by may become edematous. The cornea in what is seen while treating. After several aphakic patients should be checked from days, as the exudative response increases and time to time during treatment, to avoid such pigmentation occurs, other means of ophan occurrence. Too often this early edema is thalmoscopy may be used to observe the not recognized by the operator if he con effects. tinues to look at the eye through the oph COMPLICATIONS thalmoscope and not directly with side illumination. In our experience, this has As mentioned earlier, corneal damage can occurred several times. The edema has be caused by heavy exposure or drying of resolved after a few days with rest and the cornea (with or without a contact lens). topical steroids. Severe corneal damage has, It may occur in some aphakic patients, prob however, been reported. ably because of endothelial changes already Another way to avoid corneal damage, in present. In addition the cornea may be addition to avoiding overexposure, is the damaged when the machine is used to make constant moistening of the corneal surface or to enlarge a pupil. For this, a separate head with normal saline or one of the various is used. The light emerging from this head is salt solutions. For this, the operator should not parallel but comes to a focus on either always have an assistant, usually a nurse, the iris or the cornea, thus greatly increas stationed right beside the patient. In this ing the amount of heat absorbed by the an way the cornea can be kept moist. Often the terior segment. To help overcome this, the nurse may recognize early corneal edema treatment is performed with a water-bath before the operator becomes aware of it. over the cornea. However, often the iris is of If there is no chorioretinal response with the bombé type and the heat generated in it,
COMPLICATIONS OF LIGHT COAGULATION
so close to the cornea, may produce a perma nent corneal burn. If care is used, there should be little, if any, damage to the iris while the fundus is being treated. Maximum dilatation of the pupil is advised (we use 0.2-percent scopol amine and 10-percent neosynephrine eyedrops) . When the treatment is done close to the eye and relatively centrally, the beam of light only rarely hits the iris. However, the farther away from the eye the ophthalmo scope is and the more peripheral in the fundus the area being treated, the greater the chance that the iris will be hit. Under these circumstances, it is wise to cut down the aperture, thus producing a narrower bundle of rays so that fewer of them will strike outside the pupillary limits. We have not treated any pigmented lesions of the iris, preferring to excise them for histologie study. Our treatment with lesions of the iris has been confined solely to the reformation of pupils. This has been suc cessful only if there are few if any lens rests behind the iris, for lens rests negate the possibility of a desirable pupillary open ing. If the media behind the iris are clear, our experience in making new pupillary openings has been satisfactory. Treatment of this sort requires an assistant who must make sure that the beam of light is properly directed and the water-bath kept filled to avoid corneal damage. In such treatment, one must be careful to avoid hitting any iris vessels; they are quite friable and tend to bleed easily. Since anterior uveitis fre quently follows this type of treatment, topical or subconjunctival steroids and cycloplegics should be started immediately. In retinal detachment patients with small pupils, it is possible to improve the visibility first by enlarging the pupil, and then later operate on the detachment. This problem often occurs in patients suffering from Marian's syndrome or with aphakia, a small pupil and retinal detachment. The iris sphincter may be burned on several occa sions to help enlarge the pupil, and then
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surgery undertaken when the eye quiets down. In such cases, iritis is almost inevi table and must be combated with vigor. Unless the anterior segment is being treated, photocoagulation rarely damages the lens. When it does, a small anterior subcapsular opacity, which is. usually not progressive, results. We have not used photocoagulation to perform an iridectomy in narrow-angle glaucoma because of poor results obtained by others. DIFFICULTIES
When the lens is cataractous, it can create some difficulties by scattering the rays of light which, naturally, cuts down the in tensity of light hitting the retina, usually scattering the rays ineffectively about in the periphery. If one wishes to treat prophylactically a weakened area of retina, and if the lens is sufficiently cataractous, it is prob ably better to do the cataract extraction ini tially. Later the photocoagulation can be per formed through clear media, sometimes as soon as 10 days after cataract surgery. If a lens is subluxated, the great and sudden differences in refractive powers are annoying, as one photocoagulates first through a portion of lens and then through an aphakic portion of the pupil. It is best to treat such patients slowly and on many occa sions, settling for a few well-placed applica tions at each session and avoiding overtreatment of the anterior segment of the eye. The vitreous itself offers problems, as already mentioned, if there is residual hemorrhage or haze from recent surgery. As to what damage can be done to the vitreous by photocoagulation, it is difficult to say. Surely, vitreous must absorb some of the heat of the rays of light passing through it and, to avoid this, the globe must be kept cool and not treated too heavily. As with diathermy, the vitreous response may be quite variable. There seem to be patients who develop massive vitreous retraction following surgery in which little diathermy was used. We have had occasional clouding
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of the vitreous following photocoagulation but nothing that we considerd to be massive vitreous retraction. It is certainly possible that, following photocoagulation, new adhérences of the recently coagulated vitreous and retina may occur, leading eventually to a new tear. We have seen new tears following light coagula tion. Often they are immediately adjacent to previous areas of treatment, suggesting that either the retina had shrunken a little here or, because of retinal shrinkage, more vitreous tension had been placed upon the retina. Certainly the incidence of new tears following photocoagulation has been no greater than it was following partially pene trating diathermy. CARE DURING TREATMENT
While treating the retina, visual control is essential to regulation of the intensity of light. A very light blanching effect is most desirable, since it will excite a good choroidal reaction and produce minimal shrinkage of the retina. On occasion, while treating next to a large tear in a flat retina, one can see the tear become even larger as its margins slowly begin to shrink. It must be remem bered that the retina anterior to the tear (on the ora serrata side) should also be sealed off, if at all possible. This is usually not too difficult, even with breaks that are far ante rior, if one uses scierai indentation. We have found that a cotton applicator will give a broad and perfectly satisfactory indentation, without the risk of putting more localized pressure on a weak area of retina. Care must be taken in the treatment of highly myopic eyes, or in eyes which for other reasons have little pigmentation. There will be, understandably, less reaction im mediately visible in these patients, and an er ror can be committed by treating longer, or more heavily, in an effort to obtain the "usual" visual result. Sometimes it is better to place a few applications in more normally pigmented portions of the retina to find out what setting is adequate and then use the
same setting to treat the desired regions. Not much reaction will be seen at the time because of the lack of contrast between a blanched retina and a darker choroid. A few days later good exudate is usually seen. Not infrequently, a week or so later, there will be a nice, although fine, pigmented re action. Although it is natural to avoid hitting a large retinal vein or arteriole, it is surpris ing how often this may occur without hemor rhage. We have seen at least a hundred vessels of this caliber suddenly narrow be cause of treatment too close to them, with out a subsequent hemorrhage. We have not had a single hemorrhage of any significance that was due to damage to one of the retinal vessels. Nevertheless, we have always been so afraid that this might happen that prob ably we have been most discrete in placing applications between vessels and have thus avoided serious hemorrhage. In treating a case which might need ret inal surgery later, if the chorioretinal re sponse is poor, it is better to stop attempts at photocoagulation and save the choroid in the hope that it will respond better to later surgical treatment. RETINAL DETACHMENT
In the postoperative care of retinal de tachment patients, light coagulation certainly has been of great help. However, many of the causes of failure in retinal detachment surgery are not eliminated by photocoagulation which should not be anxiously at tempted when the proper solution is further surgery. If the tear is flat but not adequately treated, photocoagulation is simple and easy. If a new tear develops but the retina is not elevated, photocoagulation is of great help, as it also is in the presence of other degenera tive (especially lattice) changes in the retina. Many detachments recur, however, be cause another tear was not discovered, and certainly light coagulation will not discover tears. Often, during the early postoperative course, the tear will be open and surrounded
COMPLICATIONS OF LIGHT COAGULATION by elevated retina. This circumstance, which appears within the first two weeks following surgery, usually is not suitable for photoco agulation. Formerly, we operated again and usually obtained a good result with a little more subretinal drainage and partially penetrating diathermy. Too often nowadays it is hoped that photocoagulation will close an elevated, open break in the retina. This can be accomplished on rare occasions, by gradually moving in upon the tear from its peripheral, less elevated margins. As exudate forms, the retina gradually flattens, permit ting the operator to treat areas closer to the edges of the tear. This is not usual, however, and reoperation most often is the better choice. Under certain circumstances, photocoagu lation may be used with success following retinal detachment surgery. Sometimes, im mediately following surgery, the cornea and vitreous are hazy, reducing the chances of any appreciable effect from the light. Also, the retina may not be absolutely flat against the choroid, and this thin film of fluid will be sufficient to prohibit the response de sired. Very often the retinal tear causing the de tachment is located in the region of a vortex vein (most usually the one under the inser tion of the superior oblique muscle). If it is difficult to place diathermy safely about the tear and around the ampulla of the vortex vein, photocoagulation may be used in that region immediately following surgery, if the retina in that region is flat. PROPHYLAXIS
Photocoagulation may be used immediately following surgery in the prophylactic treat ment of the other eye. This can most often be accomplished without difficulty, and cer tainly without discomfort or hazard to the patient. A retinal tear without an associated de tachment is the ideal case for photocoagula tion treatment. Use of the slitlamp and the contact lens of Goldmann probably provides
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the most accurate way of determining whether there is a true hole in the retina and whether or not the retina is elevated. Having confirmed the presence of the retinal break, the amount and extent of ret inal elevation, if any, can be determined. If the elevation is minimal, photocoagula tion may help. In addition to finding out whether the elevation is minimal, it is neces sary to consider the area of the elevation. By minimal elevation is meant an elevation that is difficult to perceive by either direct or by binocular indirect ophthalmoscopy, but which can be made out with the slitlamp or the binocular ophthalmoscope manufactured by Bausch and Lomb. Concerning the ex tent or area of the elevation, if the detach ment spreads two disc diameters from the margins of the tear, the chances of per manently sealing the tear by photocoagula tion alone are, perhaps, 75 percent. If the area of the elevation extends three to four disc diameters from the margins of the tear, and if the elevation is easily discernible by direct or by binocular indirect ophthal moscopy, the chances of a cure by photoco agulation drop to about 25 percent. After a few applications of light, the ex tent of any retinal elevation surrounding the tear can be confirmed. Ideally, the aver age tear without detachment should be per manently sealed by a double barrage around its margins, and sometimes by less. When it becomes necessary to go much farther centrally, one should consider diathermy and discrete subretinal drainage to close the tear more securely. The treatment of tears in the retina with a freed operculum floating in front of them on the posterior "face" of the vitreous is really no problem. More dangerous is the treatment of atrophie, round holes situated along a line of obliterated, white, vascular twigs at or near the equator. In the treat ment of these cases, if the photocoagulation is brought too close to the region, new tears can be provoked through shrinkage of the retina. It is necessary, therefore, to sur-
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The postphotocoagulation management of round these areas, not to treat them directly ; to insulate them from the remaining retina these latter cases should be similar to that with a single barrage of treatment no closer following partially penetrating diathermy ; it than a disc diameter to the degenerated is more conservative than that following area. Later the lesion can be treated directly. photocoagulation of a tear without a detach Large retinal tears, with a flap of retina ment. Once the retina has been detached, pulled into the vitreous, can be most hazard even if it settles remarkably well, separation ous. The presence of a large tear and flap from its pigmentary layer may easily recur is ample evidence of an expansive attach with rotation of the eye during the early ment of the vitreous to the retina, and one days following surgery or photocoagulation. must be especially careful of any retinal or About on third of the patients, whose retinas vitreous shrinkage. This is particularly true settled with bedrest, and who underwent if the central margins of the tear are turned photocoagulation, have had a relapse of inward, denoting further traction upon the the detachment, necessitating either more tear in this area. photocoagulation or surgery. All of them, Prophylactic use of photocoagulation is fortunately, were ultimately cured. These relapses all occurred within three months of most warranted in the presence of areas of so-called "lattice degeneration." However, treatment, the period of the majority of as already mentioned, the operator must be recurrences, regardless of the type of sur careful to avoid hitting these patches of gery employed. weak retina directly and concentrate on OTHER USES placing the treatment completely around the lesion. Unwarranted prophylactic treatment We do not treat macular holes by photoshould be avoided, since the normal pig coagulation unless the vision is 20/200 or mentary degenerative changes that occur less, and only after high-magnification lenses with age do not lead to retinal detachment. have failed to improve vision. When mac When undertaking prophylactic treatment, it ular holes are treated, they usually can be probably is best not to treat more than one handled with two or three well-placed applica quadrant of retina at a single sitting; an tions, with the aperture made smaller so other treatment may be given within a day that the beam of light just barely touches or so. By doing this, the likelihood of dam the margins of the hole. In this manner, as age to the cornea, vitreous, and retina is much paramacular vision as possible is pre lessened. Obviously, it will be many years be served. A macular hole (which can be dif fore anyone will be able to estimate the in ferentiated from a macular cyst most readily fluence of photocoagulation in reducing the with the slitlamp) only infrequently leads to incidence of retinal detachment in the second the development of an extensive retinal eye. detachment. In our experience this has in variably occurred in patients with high In some patients, bedrest with binocular myopia (in the range of minus 15 to minus bandages will allow the retina to settle 25 diopters). In general, therefore, true markedly and, occasionally, completely. macular holes can be managed by observa These patients are good candidates for light tion, and photocoagulation used if the mar coagulation, if the operator bears in mind gins of the hole become elevated (to help that the retina about the tear must truly be prevent a larger central scotoma) or if the flat. If a retina has not settled sufficiently macular hole is in an eye with high myopia. after three days of quiet in bed, with both eyes bandaged, it probably never will settle completely enough for successful photoco agulation,
Treating such retinal vascular lesions as Leber's miliary aneurysms, Eales' disease, early stages of Coats' disease, and some
COMPLICATIONS OF LIGHT COAGULATION
cases of vascular abnormalities associated with the sickle-cell trait can lead to minor hemorrhages. However, in our experience there has never been a severe hemorrhage. Usually, the lesions respond well to gentle coagulation about the area, and gradually shrink. Of course, the cause of the abnor mality is not being treated, only a diseased vessel in an effort to close it off before it spontaneously hemorrhages into the vitreous. In these cases there must be routine check ups, since similar lesions may appear in the same or fellow eye at a later time. Treatment of a von Hippel aneurysm offers the greatest threat of massive hemorrhage. It is imperative that the large feeding ves sels be avoided. Initially, one or two applica tions are gently placed on the body of the tu mor ; no further treatment is then performed for perhaps a week. Gradually more light co agulation is placed about the margins of the mass. Carefully avoiding the major feeding vessels, the foci of treatment can be placed just on either side of them. The slow forma tion of glial tissue, as a result of the retinal burn, will usually, and gradually, pinch the vessels closed, without a resultant hemor rhage. These lesions often tend not only to be bilateral but may also recur in other por tions of the eye. A long-time routine followup is strongly urged. In the management of patients with vari ous vascular abnormalities, it must be re membered that the majority of them are young and have clear ocular media. There fore, treatment should be initiated with the lowest input of power, and with the dia phragm closed to at least one-half its di ameter. We think that retinoblastomas are best treated by an initial full course of irradia tion, frequently supplemented by intraarterial TEM. Following this, if some tumor
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remains, these areas may be treated with photocoagulation. The tumor should be sur rounded first in an effort to destroy the retinal vessels feeding it. With this procedure, good results can be expected. We have been dis appointed with photocoagulation alone. In each of nine cases irradiation was eventually necessary. A problem we have encountered with these patients may account for the poor results. Many parents seem to be apathetic about keeping their appointments so that the child can be followed closely with anesthetic examinations. We have had little experience with photocoagulation treatment of choroidal mela nomas. In four patients so treated, the lesion was dark, slightly elevated, had a serous de tachment of the retina overlying it and had been noted to grow in size. In each instance, the patient requested this form of treatment in preference to enucleation. The follow-up periods in these patients extend from six months to one and one-half years. All of the treated eyes look well at the present time. It will take many years before photocoagu lation in the treatment of this type of tumor can be fully evaluated. The procedure for treatment of choroidal melanomas is similar to that in retinoblastoma. An effort is first made to surround the tumor thoroughly and completely, thus di vesting it of its blood supply. A day or so later, applications are placed directly upon the body of the tumor, usually with considerable response due to the pigmentation of the mass. Treating highly elevated melanomas in this manner probably is not safe, since the depth of the tumor would prevent an ap preciable amount of reaction at the base. In addition, the debris produced by such ex tensive coagulation might lead to loss of the eye. 490 Post Street (2).