- Email: [email protected]
What’s new in ophthalmic surgery
WHAT’S NEW IN SURGERY
What’s New in Ophthalmic Surgery Douglas R Lazzaro, MD, FACS, FAAO “What’s New in Surgery” evolves from the contributions of leaders in each of the fields of surgery. In every instance the author has been designated by the appropriate Council from the American College of Surgeons’ Advisory Councils for the Surgical Specialties. This feature is now presented in issues of the Journal throughout the year.
designs. The method of removing the cataractous lens improved, as did the technology of IOLs. There has been a shift from intracapsular operation to extracapsular cataract extraction as the procedure of choice, but again the wounds were large and recovery often slow. Charles Kelman, an innovator in cataract surgery, began his work on ultrasonic dissolution of the lens in 1967, and refined it in the 1970s.1 Five generations of machines were developed in the 1970s and 1980s before the Series 10,000 machine was introduced in 1986. This machine introduced the ophthalmic community to commercially available ultrasonography. Phacoemulsification was the cornerstone that led the move to smallincision operations. The past 18 years have seen major improvements from the early phacoemulsification technology to what is available today. Better fluidics allow for greater control of the anterior chamber during operations, which is a great safeguard in this type of extremely delicate micronsensitive surgery. Ultrasonic machines continue to be manufactured by different companies, each of which has particular characteristics designed to most efficiently emulsify the cataract. Some surgeons prefer peristaltictype machines and others prefer Venturi-based mechanical platforms. The peristaltic systems work by building vacuum after occlusion of the port and the Venturi system builds vacuum even when the phaco tip is unoccluded. In an even newer machine, there is a way to use heated water pulses to emulsify a lens. This achieves dissolution of the lens without the use of ultrasonography energy. Its limitation may be with hard nuclei but its advantages with no ultrasonic energy may be considerable. The machines themselves offer a tremendous variety of settings, allowing the surgeon to customize his or her approach to a particular patient. There are many ways in which a lens can be removed through ultrasonography,
Ophthalmic surgery, like all surgical disciplines, has evolved tremendously over the past 50 years. Technologies improve, and so do the procedures that implement them. Ophthalmology is a field that continues to look for improved methodologies to remove cataracts, to change refractive errors, to remove retinal pathologies, and to decrease intraocular pressure more efficiently. In this review, I will break down the various subspecialty areas and elucidate how they have changed over the past 12 months and talk briefly of the new frontiers that relate to them. Cataract
Cataract surgery remains one of the most commonly performed operations in this country and worldwide. Opacification of the eye’s natural crystalline lens defines cataract and actually is a process that begins after birth when lens fiber architecture begins a lifelong process of change. Changes in the lens protein chemical properties over the years also contribute to clouding of the lens and development of visually notable cataracts. Ophthalmic microsurgery for cataract has progressed to an almost unfathomable level over the past 20 years or so. Cataract operations in the 1970s consisted of large, open wounds with chemical dissolution of zonules and subsequent cryoextraction of the lens in this intracapsular technique. Patients did not routinely receive intraocular lenses (IOLs) with these procedures and many were rendered aphakic, requiring use of visually limiting spectacles. IOLs were reintroduced after poor surgical outcomes were all too common with the early intraocular lens Funded in part by an unrestricted grant from Allergen, Inc. Received September 13, 2004; Accepted September 13, 2004. From the Department of Ophthalmology, SUNY Downstate, Brooklyn, NY. Correspondence address: Douglas R Lazzaro, MD, FACS, FAAO, Department of Ophthalmology, SUNY Downstate Medical Center, 451 Clarkson Ave, B5110, Brooklyn, NY 11203.
© 2005 by the American College of Surgeons Published by Elsevier Inc.
96
ISSN 1072-7515/05/$30.00 doi:10.1016/j.jamcollsurg.2004.09.038
Vol. 200, No. 1, January 2005
Abbreviations and Acronyms
IOLs ⫽ intraocular lens LASIK ⫽ laser-assisted in situ keratomileusis PDT ⫽ photodynamic therapy
and these may include such things as a high-vacuum, low-energy approach through cracking, chopping, or a combination of methods. The many ways to emulsify a nucleus are, in large part, surgeon preferences. Most of the present ultrasonography probes are ⬍ 3 mm in diameter, allowing for true small-incision operations. Over the past 12 months the probes have continued to decrease in size, contributing to extremely small wound sizes. These small wounds allow for shorter rehabilitation periods with almost astigmatically neutral incisions. Ultrasonography probes have improved from a technology standpoint. These high-efficiency small probes can combine ultrasonography with neosonic technology that helps to emulsify a lens very efficiently. These small probes allow for small wounds with tight seals, which contribute to a well-maintained anterior chamber intraoperatively. This improved fluidics system leads to a more controlled surgical environment. Ultrasonic needle sizes vary not only in size but configuration and angulation to help dissolve cataracts of different consistency. Instrumentation used to manipulate, crack, chop, and impale nuclei continues to change to facilitate the lens removal. The newer microincision operation is performed bimanually and is similar to the two-handed technique of cortical removal. The two instruments are separated for irrigation and aspiration allowing for very small incisions. The ultrasonography handpiece used for microincisional operations is ⬍ 1 mm in diameter. These incisions do need to be enlarged for intraocular lens implantation. Also there is a risk of thermal damage from these probes and an ideal incision size may be around 1.5 mm. Perhaps nothing has changed as dramatically in cataract surgery as the IOLs. They have changed dramatically since their early designs. In the early days of lens implantation, anterior chamber lenses were used regularly.2,3 The lenses were being used in Europe with success in the 1970s but the anterior chamber lenses manufactured in the US led to many problems. There was an
Lazzaro
What’s New in Ophthalmic Surgery
97
unacceptable incidence of chronic ocular inflammation leading to uveitis, glaucoma, and hyphema syndrome in some. Corneal decompensation also occurred in some patients. Lens warpage and rough edges led to poor surgical outcomes in many patients. A short time later, in the late 1970s and early 1980s, differently designed haptics, notably tubular in shape, were used on anterior chamber lenses. These also contributed to some poor results. Some doctors continued to leave patients aphakic to avoid the myriad of potential problems with these early phase lenses. Fortunately, there were some anterior chamber IOLs that were well designed and led to few problems. These included the Kelman Tripod and Quadriflex, the Choyce Mark VIII, and the Precision Cosmet lenses. In the 1980s, lenses were moved preferentially to the posterior chamber with great benefits. The preference is for in-the-bag insertion, but ciliary sulcus implantation still leads to excellent results in most patients. When extension of a capsulorrhexis tear occurs intraoperatively, implantation into the sulcus is an excellent option. Current IOLs have different chemical properties and shapes. Rigid polymethyl methacrylate, pliable polymethyl methacrylate (acrysof ), and silicone lenses are routinely used today. The shapes of the lens optics can be different from one lens to another, as design efforts are made to reduce incision size and the incidence of posterior capsule opacification. Unfortunately, even with newer designs of lenses that aim to increase optic-posterior capsule touch, the occurrence of posterior capsule opacification still exists. Although Yag laser capsulotomy is safe in the majority of patients, one must remember that there is a small percentage of patients who will have complications such as glaucoma, retinal detachment, hyphema, inflammation, and IOL pitting. In patients with weak zonules and particularly in cases of pseudoexfoliation syndrome, one can consider use of capsular tension rings to stabilize the bag. The use of these rings; careful surgical technique to lessen the stress on the zonules; and an IOL, possibly with a three-piece design, may reduce risk of IOL dislocation and capsular bag fibrosis in these patients. The US Food and Drug Administration has not yet approved certain rings that are most useful in cases of large zonular dialysis or diffusely weakened zonules. Lenses today can be made with multifocality and with
98
Lazzaro
What’s New in Ophthalmic Surgery
very compliant foldable designs. Foldable lenses are less than 20 years old! An even newer type of lens being used today is an accommodating or pseudoaccommodating lens that allows for some uncorrected reading ability postoperatively. All of these lenses are well suited for the small incision operations prevalent today. Most of the foldable lenses used today can be inserted between 2.0 and 2.5 mm. Injectors for these foldable lenses have also continued to evolve over the past 12 months. The injectors allow for a smaller incision than when one manually folds a lens. Certain lenses today are being manufactured with chromophore pigment in the lens material to filter certain wavelengths of light. These lenses may prove beneficial to the retinal pigment epithelium over the longterm but only time will tell. There is also a new prolate IOL designed for implantation that may improve contrast sensitivity. This lens is steeper centrally and flatter peripherally to offset the induced spherical aberration seen as we age. These lenses differ sharply from the routine spherical IOL used, which can induce spherical aberration even more and hence reduce contrast sensitivity. In the field of pediatric cataract surgery in 2004, the use of acrylic lenses predominates. Results have been very good using this lens.4 The two main problems associated with this operation remain posterior capsule opacification and glaucoma. Use of both anterior and posterior curvilinear capsulorrhexis is recommended by most pediatric surgeons. In the past year, work has continued with laser phacolysis and improvement has been seen. The laser system for lens removal allows for extremely small incisions— smaller than ultrasonography—but lens design has still not caught up with the reduced size of these wounds, necessitating enlargement of the surgical site. Energy delivery to the eye can be decreased with laser phacolysis, which should have a beneficial effect on the eye. This cataract removal system continues to evolve but still lags behind phacoemulsification in its ability to handle most cases. It is currently better suited for softer lenses. Refractive Surgery
Perhaps no field within ophthalmology has changed so dramatically than the still evolving subspecialty of refractive surgery. The roots of refractive surgery can be traced back well over 50 years to Jose Barraquer5 and others. Early work with keratomileusis laid the ground-
J Am Coll Surg
work for present-day laser-assisted in situ keratomileusis (LASIK). The instruments have been markedly improved and are still being modified. I will begin by talking briefly on the salient recent improvements in lasers and keratomes, and then mention on a broader range what is happening in the field in general. The excimer laser is the starting point for much of what is going on in this field. First used in1987, it has undergone great improvements.6 There are numerous manufacturers of these lasers, each with different operational platforms and treatment patterns. There are spot lasers and broader-beam lasers to go along with wavefront-capable machines.7 The wavefront analyzers in use today can be used to determine higher order aberrations that were not possible with older-type videokeratographers. These results can be subsequently translated to wavefront ablations. These custom and now “optimized” custom treatments are being used in an attempt to reduce higher-order aberrations and strive for “super vision.” Wavefront custom corneal ablative lasers likely will be the predominant way to modify the corneal refractive power as LASIK continues to progress. This method to reduce higher-order errors and make the cornea prolate will probably be around for some years to come. The microkeratomes used to generate the cornea flaps in LASIK have improved safety features and offer a fairly reproducible way to expose the stromal bed.8 There are both disposable and reusable microkeratomes used today. Although these are still used by the majority of laser centers, some surgeons are turning to laser creation of the flap with the Intralase system. The Intralase femtosecond laser is felt by some to be more reproducible, accurate, and safer than the present microkeratomes but the latter continue to improve as well. There are studies that favor microkeratomes over the Intralase system so there is no standard of care in this setting. I believe this should be the surgeon’s preference and there is no right or wrong when selecting either the microkeratome or the Intralase. For those patients with marginally thin corneas when ablative correction may lead to iatrogenic corneal ectasia, one must consider surface ablative procedures. Photorefractive keratectomy is being used more now than in recent years past, and laser epithelial keratomileusis is also getting consideration. There are different ways to peel off the epithelial layer in laser epithelial kerato-
Vol. 200, No. 1, January 2005
mileusis, but it this author’s opinion that this procedure has a limited scope in the range of cases that it can be used for. It is the combination of cataract operation and laser vision correction that brings us to the next exciting field within refractive surgery. Phakic IOLs are emerging as a procedure of choice for certain refractive ranges.9 One should consider phakic IOLs not only for certain refractive ranges but also in the settings of thin corneas and dry-eye patients. Currently, phakic IOLs are indicated for moderate and low myopia when the cornea is abnormally thin. They can correct astigmatism to some degree and can also be considered in higher myopes where residual stromal tissue post-LASIK may be a problem. There are anterior chamber, posterior chamber, and iris-fixated lenses used as phakic implants. Anterior implants must be placed with knowledge of the depth of the anterior chamber and one must be sure that there is adequate clearance between the optic and the endothelium. Most people agree that a 1.5-mm space between the optic and endothelium is sufficient. Posterior implants pose potential problems with cataract formation and are used infrequently. There is now a phakic foldable anterior chamber lens being tested in a European multicenter trial. This lens has a silicone haptic with polymethyl methacrylate haptics. The lens is used for myopia between 2 and 12 diopters. In initial studies of 21 eyes, no visual acuity was lost and 77% gained some visual acuity. The lens was very well tolerated but a larger study with followup longer than 6 months is needed. Refractive lens exchange to treat high myopic errors is being used by some surgeons today. There is a postoperative risk of retinal detachment in these high myopes that may or may not be higher than the natural course in high myopia. Also Yag capsulotomy may increase risk of retinal detachment in these postoperative patients as well. Refractive lens exchange comprises a standard meticulous phacoemulsification followed by IOL implantation. Most recently, development of a presbyopic phakic implant has occurred, but more work in this area is required. These lenses would allow patients to view near work without visual aids and would be ideal for the middle-aged patient. Conductive keratoplasty is one of the latest surgical treatments being used to treat presbyopia. This proce-
Lazzaro
What’s New in Ophthalmic Surgery
99
dure entails placement of one to three rings of eight symmetrical spots at the peripheral 6.0-mm, 7.0-mm, or 8.0-mm optical zone. The probe delivers radiofrequency energy through a small needle to shrink corneal collagen. Its aim is to produce a steepening of the cornea to produce a myopic shift and help offset the loss of accommodative potential. Patients best suited for conductive keratoplasty are middle-aged and close to emmetropia for distance. The procedure may not last beyond 5 years because of regression and may require retreatment. This would be in keeping with most other presbyopic surgical procedures used in the past that have also tended to regress over time. One of the problems seen with this treatment is induced astigmatism. The surgeon can test the light reflex and immediate postoperative keratometry values to check for this. An additional spot at the appropriate axis may offset the astigmatism. The currently approved guideline for the ViewPoint CK system is ⬍ 2 diopters of hyperopia and ⬍ 1 diopter of astigmatism. Glaucoma
Glaucoma operation remains an option for resistant glaucoma. With the emergence of the prostaglandin class of drugs and ␣-agonists to lower intraocular pressure, the rate of glaucoma surgical intervention has decreased. There remain cases when maximal medical therapy is not able to achieve a particular target pressure for a given patient and an operation is necessary. Standard laser trabeculoplasty remains an option for lowering pressure but response rates can vary among the different glaucomas and different patient populations. Over the past year, another effective way to decrease pressure by means of laser is selective trabeculoplasty.10 Selective laser trabeculoplasty is a means of more safely lasering the trabecular meshwork.11 This Yag laserbased procedure selectively treats the melanincontaining trabecular meshwork cells. Different studies have concluded the efficacy of this procedure both as a primary treatment and as a replacement therapy after failed medical attempts to control pressure. An attractive feature of this laser surgical procedure is the ability to repeat it because it does not cause thermal damage. A large US multicenter study is currently underway to evaluate its role as a primary therapy in glaucoma. Another advantage of this procedure is the short time it takes to perform—less than 5 minutes.
100
Lazzaro
What’s New in Ophthalmic Surgery
Trabeculectomy remains a very effective procedure for lowering intraocular pressure and can be used either with or without antimetabolites. Success rates of trabeculectomy compare well in some studies with glaucoma implants and a study is currently underway comparing the two modalities. Use of antimetabolites must be looked at from a risk-to-benefit ratio as in any surgical procedure. Their application will have a potentially greater pressure-lowering effect than without their use, but chemical properties of these antiscarring chemicals can also lead to some undesirable side effects.12 Clearly they must be used cautiously and mitomycin, when used, should be irrigated from the ocular surface. Careful application of the antimetabolite with filter paper may help to reduce complications with its use. A recent method developed to surgically reduce intraocular pressure involves placing a miniature glaucoma device under a scleral flap. The device is made of stainless steel and is 2.5 mm in length. The operation can be performed quite rapidly and is being reviewed for different glaucoma entities. A study from South Africa with the miniature glaucoma device looked at 24 eyes of 23 patients who had the device implanted with adjuvant mitomycin-C. The patients had a lowering effect of about 50%, with some complications such as hypotony, device iris touch, flat anterior chamber, and the formation of cystic blebs noted. Many patients did have lasting intraocular pressure lowering at 1 year followup. Another surgical technique being used for glaucoma management is nonpenetrating sclerectomy. In this technique, a scleral flap is created under which a partial sclerectomy is performed. The procedure can be difficult to perform, with inadvertent perforation occurring in some patients. A modification of this procedure using a CO2 laser for the sclerectomy is currently being tested. In an early study, some inflammation caused by the laser was responsible for a few failures. In a modified version of this procedure, mitomycin-C and subconjunctival steroid are used in an effort to reduce the undesirable inflammatory response secondary to the laser. Collagen implants can also be placed in conjunction with deep sclerectomy. In a recently published study of 105 patients, this procedure at 96 months followup showed very good results lowering intraocular pressure.13 There were few immediate postoperative complications noted. Deep sclerectomy with an acrylic implant has also
J Am Coll Surg
been performed recently with success.14 Results from this study compare favorably with viscocanulostomy, which is another effective means of surgically reducing intraocular pressure.15 Retina
Age-related macular degeneration continues to be a leading cause of blindness in our country. The dry form is not amenable to laser or standard surgical intervention. The wet form is currently treated by argon laser therapy, photodynamic therapy, and even subretinal operation. Argon laser therapy has been a mainstay of treatment for years and continues to be used today. The treatment is indicated mostly for lesions outside the fovea. The lesions in the juxtafoveal region can be lasered, with care not to encroach on the foveal avascular zone. Some retinologists recommend treatment of even subfoveal membranes with the argon laser when photodynamic therapy is unavailable. Argon laser therapy is considered better than no treatment at all. One of the main problems with argon laser treatment is recurrence of subretinal neovascularization, which is not uncommon within the first 18 months of treatment. These patients must be followed closely for development of both recurrent and new disease. Careful serial fluorescein and or indocyanin green angiography is important in detecting recurrent disease. Photodynamic therapy (PDT) is being used to treat subfoveal lesions.16,17 An average of three to five PDT treatments may be needed to retard choroidal neovascularization. There is some question about how close to the center of the avascular zone the choroidal neovascularization can be before disregarding the argon laser treatment option. Submacular surgery continues to be explored as a treatment option for some disorders unresponsive to more conventional approaches.18,19 For eyes that have failed PDT after a few attempts and possibly where steroids have not worked, this operation may be attempted. Eyes with better preoperative visual acuity tend to fare better with this intervention, as do eyes that have received fewer PDT treatments. Submacular surgery can be repeated for recurrences with possible success. Also, PDT can be used after a postsurgical recurrence. The vitreoretinal surgeon must be very comfortable with this treatment approach, as
Vol. 200, No. 1, January 2005
surgical complications can readily occur with inexperienced hands. Another interesting surgical procedure being performed today is pneumatic displacement of subretinal clots. Less invasive than the subretinal operation, this procedure tends to give better visual results than the operation and may be more stable longterm. Results are better when the clots are not thick. The pneumatic displacement may be combined with intravitreal tissue plasminogen activator.20 Macular translocation operation is still a relatively new procedure to treat patients with age-related macular degeneration. In a recent review of 39 patients, 33% had improved visual acuity, 46% were within three lines of acuity, and 21% showed a worsening of more than three lines.21 Proliferative vitreoretinopathy and diplopia were two main postoperative complications. In another study of macular translocation, mean near visual acuity was shown to be statistically significantly improved.22 A fascinating operation that holds some promise for retinitis pigmentosa patients is implantation of a silicon microchip in the subretinal space. In a study of six patients where one eye had the implant and the other eye served as the control, visual function was improved in all eyes.23 A larger study with longer followup is necessary to better evaluate the safety and efficacy of the procedure. Miscellaneous Topics Pterygium
Pterygium operations remain a concern with regard to recurrence after surgical removal. Excisional operation can be combined with conjunctival autografting, antimetabolites, and more recently with amniotic membrane transplantation, which has a variety of uses in ocular surface disease.24 It can be used for corneal thinning in the setting of inflammatory disease, for persistent epithelial defects, for conjunctival reconstruction, and for relief of pain in bullous keratopathy. For pterygium operation, the lesion is first removed and the amniotic membrane can be used to replace the resected conjunctiva. This technique can be most useful when there is a nasal and temporal pterygium on the same eye and when a previous operation on the eye has lead to conjunctival scarring. The success rate with this operation is high and the complication rate is low.
Lazzaro
What’s New in Ophthalmic Surgery
101
Oculoplastics
Oculoplastic surgery has had some new technologies available for use. One of the most important chemicals now in regular usage is Botulinum toxin type A for injection. Its main use has been for cosmetic reduction of wrinkles, and the oculoplastic and general plastic surgeon are using it regularly for this. Dermal fillers for cosmetic use are being used in increasing amounts by oculoplastic surgeons. Restylane can be injected in folds and creases and is better tolerated than the previously used bovine-derived products. This procedure will increase as more of the aging population looks to rejuvenating operations. Both hydroxyapatite and high-density porous polyethylene implants are being used in the anophthalmic socket. Both implants are well tolerated and can lead to good motility results. In a recent study comparing the two implants, the fibrovascular ingrowth rate was much more rapid in the hydroxyapatite group.25 Artificial cornea
Corneal transplantation has not changed considerably from a surgical standpoint in recent years. Immunomodulation with various drug regimens can help prevent allograft reactions in high-risk patients. There are some patients that require something different. These patients have multiple graft rejections and a poor prognosis for repeat keratoplasty. They may also be patients unable to tolerate antirejection drugs. A newer type of artificial cornea (keratoprosthesis) named AlphaCor has been used in international trials for 4 years. It has been implanted in the US mostly over the past year. This biocompatible device is inserted into the cornea in a two-stage procedure. The device is best used in patients without dry eye or stem cell deficiency and may give hope to many patients deemed unsuitable for standard corneal transplantation. Pediatric strabismus
Adjustable sutures have been used in strabismus for some years now. Many of today’s performed operations are with this technique. There are some who do not believe that the additional time and potential discomfort are needed in the nonrestrictive cases. In a recent comparative study, 88% of the nonadjustable operations were considered successful versus 81% of the adjustable cases.26 The authors concluded that there was inconclusive evidence to support the increasing trend toward adjustable operation.
102
Lazzaro
What’s New in Ophthalmic Surgery
A modified adjustable technique was described recently for both esotropia and exotropia.27 Sixty-one pediatric patients were treated for their strabismus using a standard adjustable procedure. Four to 6 hours later, an adjustment was made if necessary. Of 22 patients who required an adjustment, 20 were within 10 prism diopters of orthophoria at their final postoperative visit. Restrictive strabismus is an ideal procedure for adjustable suture technique. In a study of 12 patients with restrictive strabismus, a single-stage procedure was used to correct the deviation in this middle-aged group of patients.28 Ten of 12 patients had good alignment postoperatively. The 2 patients with poor alignment had thyroid disease with progressive overcorrection after inferior rectus recession. REFERENCES 1. Kelman CD. Phaco-emulsification and aspiration. Am J Ophthalmol 1967;64:23–35. 2. Jaffe NS. Current status of intraocular lenses. Eye Ear Nose Throat Mon 1972;52:290–296. 3. Binkhorst RD. The optic design of intra-ocular lens implants. Ophthalmic Surg 1975;6(3):17–31. 4. Raina UK, Mehta DK, Monga S, Arora R. Functional outcomes of acrylic intraocular lenses in pediatric cataract surgery. J Cataract Refract Surg 2004;30:1082–1091. 5. Nordan LT. Barraquer lecture. Jose Barraquer: father of modern refractive keratoplasty. J Refract Corneal Surg 1989;5:177–178. 6. Trokel S. Evolution of excimer laser corneal surgery. J Cataract Refract Surg 1989;15:373–383. 7. Reinstein DZ, Neal DR, Vogelsang H, et al. Optimized and wavefront guided corneal refractive surgery using the Carl Zeiss Meditec platform: the WASCA aberrometer, CRS-Master, and MEL80 excimer laser. Ophthalmol Clin North Am 2004;17: 191–210. 8. Barraquer Moner JI, Barraquer Granados JI. Intrastromal keratomileusis: complications associated with the microkeratome. In: Buratto L, Brint S, eds. LASIK principles and techniques. Thoroughfare, NJ: Slack Incorporated; 1998:365–370. 9. Alio JL. Advances in phakic intraocular lenses: indications, efficacy, safety, and new designs. Curr Opin Ophthalmol 2004;15: 350–357. 10. Melamed S, Ben Simon GJ, Levkovitch-Verbin H. Selective laser trabeculoplasty as a primary treatment for open angle glaucoma: a prospective, nonrandomized pilot study. Arch Ophthalmol 2003;121:957–960. 11. Martinez-de-la Casa JM, Garcia-Feijoo J, Castillo A, et al. Selective vs argon laser trabeculoplasty: hypotesive efficacy, anterior chamber inflammation, and postoperative pain. Eye 2004; 18:498–502.
J Am Coll Surg
12. Shu-Wen C. Early corneal edema following topical application of mitomycin-C. J Cataract Refract Surg 2004;30:1742–1750. 13. Shaarawy T, Mansouri K, Schnyder C, et al. Long term results of deep sclerectomy with collagen implant. J Cataract Refract Surg 2004;30:1225–1231. 14. Ates H, Uretman O, Andac K, Azarsiz SS. Deep sclerectomy with a nonabsorbable implant (T-Flux): preliminary results. Can J Ophthalmol 2003;38:482–488. 15. O’Brart DP, Shiew M, Edmunds B. A randomized, prospective study comparing trabeculectomy with viscocanalostomy with adjunctive antimetabolite usage for the management of open angle glaucoma uncontrolled by medical therapy. Br J Ophthalmol 2004;88:1012–1017. 16. Sharma S, Bakal J, Oliver-Fernandez A, Blair J. Photodynamic therapy with verteporfin for subfoveal choroidal neovascularization in age-related macular degeneration: results of an effectiveness study. Arch Ophthlmol 2004;122:853–856. 17. Bressler NM, Vam Study Writing Committee. Verteporfin therapy in age-related macular degeneration (VAM): an open label multicenter photodynamic therapy study of 4,435 patients. Retina 2004;24:512–520. 18. Joseph DP, Uemura A, Thomas MA. Subretinal surgery for juxtafoveal choroidal neovascularization. Retina 2003;23:463– 468. 19. Tennant MT, Borrillo JL, Regillo CD. Management of submacular hemorrhage. Ophthalmol Clin North Am 2002;15: 445–452. 20. Olivier S, Chow DR, Packo KH, et al. Subretinal recombinant tissue plasminogen activator injection and pneumatic displacement of thick submacular hemorrhage in age-related macular degeneration. Ophthalmology 2004;111:1201–1208. 21. Abdel-Meguid A, Lappas A, Hartmann K, et al. One year follow up of macular translocation with 360 degree retinotomy in patients with age related macular degeneration. Br J Ophthalmol 2003;87:615–621. 22. Toth CA, Lapolice DJ, Banks AD, Stinnett SS. Improvement in near visual function after macular translocation surgery with 360-degree peripheral retinotomy. Graefes Arch Clin Exp Ophthalmol 2004;242:541–548. 23. Chow AY, Chow VY, Packo KH, et al. The artificial silicon retina microchip for the treatment of vision loss from retinitis pigmentosa. Arch Ophthalmol 2004;122:460–469. 24. Dua HS, Gomes JA, King AJ, Majarajan VS. The amniotic membrane in ophthalmology. Surv Ophthalmol 2004;49: 51–77. 25. Pan MH, Wu YW, Yen RF, et al. Different fibrovascularization rates between coralline hydroxyapatite and high density porous polyethylene (Medpore) measured by 99mTc-MDP bone scintigraphy 6 months after intraorbital implantation. Nucl Med Commun 2003;24:1237–1241. 26. Bishop F, Doran RM. Adjustable and non-adjustable strabismus surgery: a retrospective case-matched study. Strabismus 2004; 12:3–11. 27. Engel JM, Rousta ST. Adjustable sutures in children using a modified technique. J AAPOS 2004;8:243–248. 28. Sharma P, Reinecke, RD. Single-stage adjustable strabismus surgery for restrictive strabismus. J AAPOS 2003;7:358–362.
What’s New in Ophthalmic Surgery Douglas R Lazzaro, MD, FACS, FAAO “What’s New in Surgery” evolves from the contributions of leaders in each of the fields of surgery. In every instance the author has been designated by the appropriate Council from the American College of Surgeons’ Advisory Councils for the Surgical Specialties. This feature is now presented in issues of the Journal throughout the year.
designs. The method of removing the cataractous lens improved, as did the technology of IOLs. There has been a shift from intracapsular operation to extracapsular cataract extraction as the procedure of choice, but again the wounds were large and recovery often slow. Charles Kelman, an innovator in cataract surgery, began his work on ultrasonic dissolution of the lens in 1967, and refined it in the 1970s.1 Five generations of machines were developed in the 1970s and 1980s before the Series 10,000 machine was introduced in 1986. This machine introduced the ophthalmic community to commercially available ultrasonography. Phacoemulsification was the cornerstone that led the move to smallincision operations. The past 18 years have seen major improvements from the early phacoemulsification technology to what is available today. Better fluidics allow for greater control of the anterior chamber during operations, which is a great safeguard in this type of extremely delicate micronsensitive surgery. Ultrasonic machines continue to be manufactured by different companies, each of which has particular characteristics designed to most efficiently emulsify the cataract. Some surgeons prefer peristaltictype machines and others prefer Venturi-based mechanical platforms. The peristaltic systems work by building vacuum after occlusion of the port and the Venturi system builds vacuum even when the phaco tip is unoccluded. In an even newer machine, there is a way to use heated water pulses to emulsify a lens. This achieves dissolution of the lens without the use of ultrasonography energy. Its limitation may be with hard nuclei but its advantages with no ultrasonic energy may be considerable. The machines themselves offer a tremendous variety of settings, allowing the surgeon to customize his or her approach to a particular patient. There are many ways in which a lens can be removed through ultrasonography,
Ophthalmic surgery, like all surgical disciplines, has evolved tremendously over the past 50 years. Technologies improve, and so do the procedures that implement them. Ophthalmology is a field that continues to look for improved methodologies to remove cataracts, to change refractive errors, to remove retinal pathologies, and to decrease intraocular pressure more efficiently. In this review, I will break down the various subspecialty areas and elucidate how they have changed over the past 12 months and talk briefly of the new frontiers that relate to them. Cataract
Cataract surgery remains one of the most commonly performed operations in this country and worldwide. Opacification of the eye’s natural crystalline lens defines cataract and actually is a process that begins after birth when lens fiber architecture begins a lifelong process of change. Changes in the lens protein chemical properties over the years also contribute to clouding of the lens and development of visually notable cataracts. Ophthalmic microsurgery for cataract has progressed to an almost unfathomable level over the past 20 years or so. Cataract operations in the 1970s consisted of large, open wounds with chemical dissolution of zonules and subsequent cryoextraction of the lens in this intracapsular technique. Patients did not routinely receive intraocular lenses (IOLs) with these procedures and many were rendered aphakic, requiring use of visually limiting spectacles. IOLs were reintroduced after poor surgical outcomes were all too common with the early intraocular lens Funded in part by an unrestricted grant from Allergen, Inc. Received September 13, 2004; Accepted September 13, 2004. From the Department of Ophthalmology, SUNY Downstate, Brooklyn, NY. Correspondence address: Douglas R Lazzaro, MD, FACS, FAAO, Department of Ophthalmology, SUNY Downstate Medical Center, 451 Clarkson Ave, B5110, Brooklyn, NY 11203.
© 2005 by the American College of Surgeons Published by Elsevier Inc.
96
ISSN 1072-7515/05/$30.00 doi:10.1016/j.jamcollsurg.2004.09.038
Vol. 200, No. 1, January 2005
Abbreviations and Acronyms
IOLs ⫽ intraocular lens LASIK ⫽ laser-assisted in situ keratomileusis PDT ⫽ photodynamic therapy
and these may include such things as a high-vacuum, low-energy approach through cracking, chopping, or a combination of methods. The many ways to emulsify a nucleus are, in large part, surgeon preferences. Most of the present ultrasonography probes are ⬍ 3 mm in diameter, allowing for true small-incision operations. Over the past 12 months the probes have continued to decrease in size, contributing to extremely small wound sizes. These small wounds allow for shorter rehabilitation periods with almost astigmatically neutral incisions. Ultrasonography probes have improved from a technology standpoint. These high-efficiency small probes can combine ultrasonography with neosonic technology that helps to emulsify a lens very efficiently. These small probes allow for small wounds with tight seals, which contribute to a well-maintained anterior chamber intraoperatively. This improved fluidics system leads to a more controlled surgical environment. Ultrasonic needle sizes vary not only in size but configuration and angulation to help dissolve cataracts of different consistency. Instrumentation used to manipulate, crack, chop, and impale nuclei continues to change to facilitate the lens removal. The newer microincision operation is performed bimanually and is similar to the two-handed technique of cortical removal. The two instruments are separated for irrigation and aspiration allowing for very small incisions. The ultrasonography handpiece used for microincisional operations is ⬍ 1 mm in diameter. These incisions do need to be enlarged for intraocular lens implantation. Also there is a risk of thermal damage from these probes and an ideal incision size may be around 1.5 mm. Perhaps nothing has changed as dramatically in cataract surgery as the IOLs. They have changed dramatically since their early designs. In the early days of lens implantation, anterior chamber lenses were used regularly.2,3 The lenses were being used in Europe with success in the 1970s but the anterior chamber lenses manufactured in the US led to many problems. There was an
Lazzaro
What’s New in Ophthalmic Surgery
97
unacceptable incidence of chronic ocular inflammation leading to uveitis, glaucoma, and hyphema syndrome in some. Corneal decompensation also occurred in some patients. Lens warpage and rough edges led to poor surgical outcomes in many patients. A short time later, in the late 1970s and early 1980s, differently designed haptics, notably tubular in shape, were used on anterior chamber lenses. These also contributed to some poor results. Some doctors continued to leave patients aphakic to avoid the myriad of potential problems with these early phase lenses. Fortunately, there were some anterior chamber IOLs that were well designed and led to few problems. These included the Kelman Tripod and Quadriflex, the Choyce Mark VIII, and the Precision Cosmet lenses. In the 1980s, lenses were moved preferentially to the posterior chamber with great benefits. The preference is for in-the-bag insertion, but ciliary sulcus implantation still leads to excellent results in most patients. When extension of a capsulorrhexis tear occurs intraoperatively, implantation into the sulcus is an excellent option. Current IOLs have different chemical properties and shapes. Rigid polymethyl methacrylate, pliable polymethyl methacrylate (acrysof ), and silicone lenses are routinely used today. The shapes of the lens optics can be different from one lens to another, as design efforts are made to reduce incision size and the incidence of posterior capsule opacification. Unfortunately, even with newer designs of lenses that aim to increase optic-posterior capsule touch, the occurrence of posterior capsule opacification still exists. Although Yag laser capsulotomy is safe in the majority of patients, one must remember that there is a small percentage of patients who will have complications such as glaucoma, retinal detachment, hyphema, inflammation, and IOL pitting. In patients with weak zonules and particularly in cases of pseudoexfoliation syndrome, one can consider use of capsular tension rings to stabilize the bag. The use of these rings; careful surgical technique to lessen the stress on the zonules; and an IOL, possibly with a three-piece design, may reduce risk of IOL dislocation and capsular bag fibrosis in these patients. The US Food and Drug Administration has not yet approved certain rings that are most useful in cases of large zonular dialysis or diffusely weakened zonules. Lenses today can be made with multifocality and with
98
Lazzaro
What’s New in Ophthalmic Surgery
very compliant foldable designs. Foldable lenses are less than 20 years old! An even newer type of lens being used today is an accommodating or pseudoaccommodating lens that allows for some uncorrected reading ability postoperatively. All of these lenses are well suited for the small incision operations prevalent today. Most of the foldable lenses used today can be inserted between 2.0 and 2.5 mm. Injectors for these foldable lenses have also continued to evolve over the past 12 months. The injectors allow for a smaller incision than when one manually folds a lens. Certain lenses today are being manufactured with chromophore pigment in the lens material to filter certain wavelengths of light. These lenses may prove beneficial to the retinal pigment epithelium over the longterm but only time will tell. There is also a new prolate IOL designed for implantation that may improve contrast sensitivity. This lens is steeper centrally and flatter peripherally to offset the induced spherical aberration seen as we age. These lenses differ sharply from the routine spherical IOL used, which can induce spherical aberration even more and hence reduce contrast sensitivity. In the field of pediatric cataract surgery in 2004, the use of acrylic lenses predominates. Results have been very good using this lens.4 The two main problems associated with this operation remain posterior capsule opacification and glaucoma. Use of both anterior and posterior curvilinear capsulorrhexis is recommended by most pediatric surgeons. In the past year, work has continued with laser phacolysis and improvement has been seen. The laser system for lens removal allows for extremely small incisions— smaller than ultrasonography—but lens design has still not caught up with the reduced size of these wounds, necessitating enlargement of the surgical site. Energy delivery to the eye can be decreased with laser phacolysis, which should have a beneficial effect on the eye. This cataract removal system continues to evolve but still lags behind phacoemulsification in its ability to handle most cases. It is currently better suited for softer lenses. Refractive Surgery
Perhaps no field within ophthalmology has changed so dramatically than the still evolving subspecialty of refractive surgery. The roots of refractive surgery can be traced back well over 50 years to Jose Barraquer5 and others. Early work with keratomileusis laid the ground-
J Am Coll Surg
work for present-day laser-assisted in situ keratomileusis (LASIK). The instruments have been markedly improved and are still being modified. I will begin by talking briefly on the salient recent improvements in lasers and keratomes, and then mention on a broader range what is happening in the field in general. The excimer laser is the starting point for much of what is going on in this field. First used in1987, it has undergone great improvements.6 There are numerous manufacturers of these lasers, each with different operational platforms and treatment patterns. There are spot lasers and broader-beam lasers to go along with wavefront-capable machines.7 The wavefront analyzers in use today can be used to determine higher order aberrations that were not possible with older-type videokeratographers. These results can be subsequently translated to wavefront ablations. These custom and now “optimized” custom treatments are being used in an attempt to reduce higher-order aberrations and strive for “super vision.” Wavefront custom corneal ablative lasers likely will be the predominant way to modify the corneal refractive power as LASIK continues to progress. This method to reduce higher-order errors and make the cornea prolate will probably be around for some years to come. The microkeratomes used to generate the cornea flaps in LASIK have improved safety features and offer a fairly reproducible way to expose the stromal bed.8 There are both disposable and reusable microkeratomes used today. Although these are still used by the majority of laser centers, some surgeons are turning to laser creation of the flap with the Intralase system. The Intralase femtosecond laser is felt by some to be more reproducible, accurate, and safer than the present microkeratomes but the latter continue to improve as well. There are studies that favor microkeratomes over the Intralase system so there is no standard of care in this setting. I believe this should be the surgeon’s preference and there is no right or wrong when selecting either the microkeratome or the Intralase. For those patients with marginally thin corneas when ablative correction may lead to iatrogenic corneal ectasia, one must consider surface ablative procedures. Photorefractive keratectomy is being used more now than in recent years past, and laser epithelial keratomileusis is also getting consideration. There are different ways to peel off the epithelial layer in laser epithelial kerato-
Vol. 200, No. 1, January 2005
mileusis, but it this author’s opinion that this procedure has a limited scope in the range of cases that it can be used for. It is the combination of cataract operation and laser vision correction that brings us to the next exciting field within refractive surgery. Phakic IOLs are emerging as a procedure of choice for certain refractive ranges.9 One should consider phakic IOLs not only for certain refractive ranges but also in the settings of thin corneas and dry-eye patients. Currently, phakic IOLs are indicated for moderate and low myopia when the cornea is abnormally thin. They can correct astigmatism to some degree and can also be considered in higher myopes where residual stromal tissue post-LASIK may be a problem. There are anterior chamber, posterior chamber, and iris-fixated lenses used as phakic implants. Anterior implants must be placed with knowledge of the depth of the anterior chamber and one must be sure that there is adequate clearance between the optic and the endothelium. Most people agree that a 1.5-mm space between the optic and endothelium is sufficient. Posterior implants pose potential problems with cataract formation and are used infrequently. There is now a phakic foldable anterior chamber lens being tested in a European multicenter trial. This lens has a silicone haptic with polymethyl methacrylate haptics. The lens is used for myopia between 2 and 12 diopters. In initial studies of 21 eyes, no visual acuity was lost and 77% gained some visual acuity. The lens was very well tolerated but a larger study with followup longer than 6 months is needed. Refractive lens exchange to treat high myopic errors is being used by some surgeons today. There is a postoperative risk of retinal detachment in these high myopes that may or may not be higher than the natural course in high myopia. Also Yag capsulotomy may increase risk of retinal detachment in these postoperative patients as well. Refractive lens exchange comprises a standard meticulous phacoemulsification followed by IOL implantation. Most recently, development of a presbyopic phakic implant has occurred, but more work in this area is required. These lenses would allow patients to view near work without visual aids and would be ideal for the middle-aged patient. Conductive keratoplasty is one of the latest surgical treatments being used to treat presbyopia. This proce-
Lazzaro
What’s New in Ophthalmic Surgery
99
dure entails placement of one to three rings of eight symmetrical spots at the peripheral 6.0-mm, 7.0-mm, or 8.0-mm optical zone. The probe delivers radiofrequency energy through a small needle to shrink corneal collagen. Its aim is to produce a steepening of the cornea to produce a myopic shift and help offset the loss of accommodative potential. Patients best suited for conductive keratoplasty are middle-aged and close to emmetropia for distance. The procedure may not last beyond 5 years because of regression and may require retreatment. This would be in keeping with most other presbyopic surgical procedures used in the past that have also tended to regress over time. One of the problems seen with this treatment is induced astigmatism. The surgeon can test the light reflex and immediate postoperative keratometry values to check for this. An additional spot at the appropriate axis may offset the astigmatism. The currently approved guideline for the ViewPoint CK system is ⬍ 2 diopters of hyperopia and ⬍ 1 diopter of astigmatism. Glaucoma
Glaucoma operation remains an option for resistant glaucoma. With the emergence of the prostaglandin class of drugs and ␣-agonists to lower intraocular pressure, the rate of glaucoma surgical intervention has decreased. There remain cases when maximal medical therapy is not able to achieve a particular target pressure for a given patient and an operation is necessary. Standard laser trabeculoplasty remains an option for lowering pressure but response rates can vary among the different glaucomas and different patient populations. Over the past year, another effective way to decrease pressure by means of laser is selective trabeculoplasty.10 Selective laser trabeculoplasty is a means of more safely lasering the trabecular meshwork.11 This Yag laserbased procedure selectively treats the melanincontaining trabecular meshwork cells. Different studies have concluded the efficacy of this procedure both as a primary treatment and as a replacement therapy after failed medical attempts to control pressure. An attractive feature of this laser surgical procedure is the ability to repeat it because it does not cause thermal damage. A large US multicenter study is currently underway to evaluate its role as a primary therapy in glaucoma. Another advantage of this procedure is the short time it takes to perform—less than 5 minutes.
100
Lazzaro
What’s New in Ophthalmic Surgery
Trabeculectomy remains a very effective procedure for lowering intraocular pressure and can be used either with or without antimetabolites. Success rates of trabeculectomy compare well in some studies with glaucoma implants and a study is currently underway comparing the two modalities. Use of antimetabolites must be looked at from a risk-to-benefit ratio as in any surgical procedure. Their application will have a potentially greater pressure-lowering effect than without their use, but chemical properties of these antiscarring chemicals can also lead to some undesirable side effects.12 Clearly they must be used cautiously and mitomycin, when used, should be irrigated from the ocular surface. Careful application of the antimetabolite with filter paper may help to reduce complications with its use. A recent method developed to surgically reduce intraocular pressure involves placing a miniature glaucoma device under a scleral flap. The device is made of stainless steel and is 2.5 mm in length. The operation can be performed quite rapidly and is being reviewed for different glaucoma entities. A study from South Africa with the miniature glaucoma device looked at 24 eyes of 23 patients who had the device implanted with adjuvant mitomycin-C. The patients had a lowering effect of about 50%, with some complications such as hypotony, device iris touch, flat anterior chamber, and the formation of cystic blebs noted. Many patients did have lasting intraocular pressure lowering at 1 year followup. Another surgical technique being used for glaucoma management is nonpenetrating sclerectomy. In this technique, a scleral flap is created under which a partial sclerectomy is performed. The procedure can be difficult to perform, with inadvertent perforation occurring in some patients. A modification of this procedure using a CO2 laser for the sclerectomy is currently being tested. In an early study, some inflammation caused by the laser was responsible for a few failures. In a modified version of this procedure, mitomycin-C and subconjunctival steroid are used in an effort to reduce the undesirable inflammatory response secondary to the laser. Collagen implants can also be placed in conjunction with deep sclerectomy. In a recently published study of 105 patients, this procedure at 96 months followup showed very good results lowering intraocular pressure.13 There were few immediate postoperative complications noted. Deep sclerectomy with an acrylic implant has also
J Am Coll Surg
been performed recently with success.14 Results from this study compare favorably with viscocanulostomy, which is another effective means of surgically reducing intraocular pressure.15 Retina
Age-related macular degeneration continues to be a leading cause of blindness in our country. The dry form is not amenable to laser or standard surgical intervention. The wet form is currently treated by argon laser therapy, photodynamic therapy, and even subretinal operation. Argon laser therapy has been a mainstay of treatment for years and continues to be used today. The treatment is indicated mostly for lesions outside the fovea. The lesions in the juxtafoveal region can be lasered, with care not to encroach on the foveal avascular zone. Some retinologists recommend treatment of even subfoveal membranes with the argon laser when photodynamic therapy is unavailable. Argon laser therapy is considered better than no treatment at all. One of the main problems with argon laser treatment is recurrence of subretinal neovascularization, which is not uncommon within the first 18 months of treatment. These patients must be followed closely for development of both recurrent and new disease. Careful serial fluorescein and or indocyanin green angiography is important in detecting recurrent disease. Photodynamic therapy (PDT) is being used to treat subfoveal lesions.16,17 An average of three to five PDT treatments may be needed to retard choroidal neovascularization. There is some question about how close to the center of the avascular zone the choroidal neovascularization can be before disregarding the argon laser treatment option. Submacular surgery continues to be explored as a treatment option for some disorders unresponsive to more conventional approaches.18,19 For eyes that have failed PDT after a few attempts and possibly where steroids have not worked, this operation may be attempted. Eyes with better preoperative visual acuity tend to fare better with this intervention, as do eyes that have received fewer PDT treatments. Submacular surgery can be repeated for recurrences with possible success. Also, PDT can be used after a postsurgical recurrence. The vitreoretinal surgeon must be very comfortable with this treatment approach, as
Vol. 200, No. 1, January 2005
surgical complications can readily occur with inexperienced hands. Another interesting surgical procedure being performed today is pneumatic displacement of subretinal clots. Less invasive than the subretinal operation, this procedure tends to give better visual results than the operation and may be more stable longterm. Results are better when the clots are not thick. The pneumatic displacement may be combined with intravitreal tissue plasminogen activator.20 Macular translocation operation is still a relatively new procedure to treat patients with age-related macular degeneration. In a recent review of 39 patients, 33% had improved visual acuity, 46% were within three lines of acuity, and 21% showed a worsening of more than three lines.21 Proliferative vitreoretinopathy and diplopia were two main postoperative complications. In another study of macular translocation, mean near visual acuity was shown to be statistically significantly improved.22 A fascinating operation that holds some promise for retinitis pigmentosa patients is implantation of a silicon microchip in the subretinal space. In a study of six patients where one eye had the implant and the other eye served as the control, visual function was improved in all eyes.23 A larger study with longer followup is necessary to better evaluate the safety and efficacy of the procedure. Miscellaneous Topics Pterygium
Pterygium operations remain a concern with regard to recurrence after surgical removal. Excisional operation can be combined with conjunctival autografting, antimetabolites, and more recently with amniotic membrane transplantation, which has a variety of uses in ocular surface disease.24 It can be used for corneal thinning in the setting of inflammatory disease, for persistent epithelial defects, for conjunctival reconstruction, and for relief of pain in bullous keratopathy. For pterygium operation, the lesion is first removed and the amniotic membrane can be used to replace the resected conjunctiva. This technique can be most useful when there is a nasal and temporal pterygium on the same eye and when a previous operation on the eye has lead to conjunctival scarring. The success rate with this operation is high and the complication rate is low.
Lazzaro
What’s New in Ophthalmic Surgery
101
Oculoplastics
Oculoplastic surgery has had some new technologies available for use. One of the most important chemicals now in regular usage is Botulinum toxin type A for injection. Its main use has been for cosmetic reduction of wrinkles, and the oculoplastic and general plastic surgeon are using it regularly for this. Dermal fillers for cosmetic use are being used in increasing amounts by oculoplastic surgeons. Restylane can be injected in folds and creases and is better tolerated than the previously used bovine-derived products. This procedure will increase as more of the aging population looks to rejuvenating operations. Both hydroxyapatite and high-density porous polyethylene implants are being used in the anophthalmic socket. Both implants are well tolerated and can lead to good motility results. In a recent study comparing the two implants, the fibrovascular ingrowth rate was much more rapid in the hydroxyapatite group.25 Artificial cornea
Corneal transplantation has not changed considerably from a surgical standpoint in recent years. Immunomodulation with various drug regimens can help prevent allograft reactions in high-risk patients. There are some patients that require something different. These patients have multiple graft rejections and a poor prognosis for repeat keratoplasty. They may also be patients unable to tolerate antirejection drugs. A newer type of artificial cornea (keratoprosthesis) named AlphaCor has been used in international trials for 4 years. It has been implanted in the US mostly over the past year. This biocompatible device is inserted into the cornea in a two-stage procedure. The device is best used in patients without dry eye or stem cell deficiency and may give hope to many patients deemed unsuitable for standard corneal transplantation. Pediatric strabismus
Adjustable sutures have been used in strabismus for some years now. Many of today’s performed operations are with this technique. There are some who do not believe that the additional time and potential discomfort are needed in the nonrestrictive cases. In a recent comparative study, 88% of the nonadjustable operations were considered successful versus 81% of the adjustable cases.26 The authors concluded that there was inconclusive evidence to support the increasing trend toward adjustable operation.
102
Lazzaro
What’s New in Ophthalmic Surgery
A modified adjustable technique was described recently for both esotropia and exotropia.27 Sixty-one pediatric patients were treated for their strabismus using a standard adjustable procedure. Four to 6 hours later, an adjustment was made if necessary. Of 22 patients who required an adjustment, 20 were within 10 prism diopters of orthophoria at their final postoperative visit. Restrictive strabismus is an ideal procedure for adjustable suture technique. In a study of 12 patients with restrictive strabismus, a single-stage procedure was used to correct the deviation in this middle-aged group of patients.28 Ten of 12 patients had good alignment postoperatively. The 2 patients with poor alignment had thyroid disease with progressive overcorrection after inferior rectus recession. REFERENCES 1. Kelman CD. Phaco-emulsification and aspiration. Am J Ophthalmol 1967;64:23–35. 2. Jaffe NS. Current status of intraocular lenses. Eye Ear Nose Throat Mon 1972;52:290–296. 3. Binkhorst RD. The optic design of intra-ocular lens implants. Ophthalmic Surg 1975;6(3):17–31. 4. Raina UK, Mehta DK, Monga S, Arora R. Functional outcomes of acrylic intraocular lenses in pediatric cataract surgery. J Cataract Refract Surg 2004;30:1082–1091. 5. Nordan LT. Barraquer lecture. Jose Barraquer: father of modern refractive keratoplasty. J Refract Corneal Surg 1989;5:177–178. 6. Trokel S. Evolution of excimer laser corneal surgery. J Cataract Refract Surg 1989;15:373–383. 7. Reinstein DZ, Neal DR, Vogelsang H, et al. Optimized and wavefront guided corneal refractive surgery using the Carl Zeiss Meditec platform: the WASCA aberrometer, CRS-Master, and MEL80 excimer laser. Ophthalmol Clin North Am 2004;17: 191–210. 8. Barraquer Moner JI, Barraquer Granados JI. Intrastromal keratomileusis: complications associated with the microkeratome. In: Buratto L, Brint S, eds. LASIK principles and techniques. Thoroughfare, NJ: Slack Incorporated; 1998:365–370. 9. Alio JL. Advances in phakic intraocular lenses: indications, efficacy, safety, and new designs. Curr Opin Ophthalmol 2004;15: 350–357. 10. Melamed S, Ben Simon GJ, Levkovitch-Verbin H. Selective laser trabeculoplasty as a primary treatment for open angle glaucoma: a prospective, nonrandomized pilot study. Arch Ophthalmol 2003;121:957–960. 11. Martinez-de-la Casa JM, Garcia-Feijoo J, Castillo A, et al. Selective vs argon laser trabeculoplasty: hypotesive efficacy, anterior chamber inflammation, and postoperative pain. Eye 2004; 18:498–502.
J Am Coll Surg
12. Shu-Wen C. Early corneal edema following topical application of mitomycin-C. J Cataract Refract Surg 2004;30:1742–1750. 13. Shaarawy T, Mansouri K, Schnyder C, et al. Long term results of deep sclerectomy with collagen implant. J Cataract Refract Surg 2004;30:1225–1231. 14. Ates H, Uretman O, Andac K, Azarsiz SS. Deep sclerectomy with a nonabsorbable implant (T-Flux): preliminary results. Can J Ophthalmol 2003;38:482–488. 15. O’Brart DP, Shiew M, Edmunds B. A randomized, prospective study comparing trabeculectomy with viscocanalostomy with adjunctive antimetabolite usage for the management of open angle glaucoma uncontrolled by medical therapy. Br J Ophthalmol 2004;88:1012–1017. 16. Sharma S, Bakal J, Oliver-Fernandez A, Blair J. Photodynamic therapy with verteporfin for subfoveal choroidal neovascularization in age-related macular degeneration: results of an effectiveness study. Arch Ophthlmol 2004;122:853–856. 17. Bressler NM, Vam Study Writing Committee. Verteporfin therapy in age-related macular degeneration (VAM): an open label multicenter photodynamic therapy study of 4,435 patients. Retina 2004;24:512–520. 18. Joseph DP, Uemura A, Thomas MA. Subretinal surgery for juxtafoveal choroidal neovascularization. Retina 2003;23:463– 468. 19. Tennant MT, Borrillo JL, Regillo CD. Management of submacular hemorrhage. Ophthalmol Clin North Am 2002;15: 445–452. 20. Olivier S, Chow DR, Packo KH, et al. Subretinal recombinant tissue plasminogen activator injection and pneumatic displacement of thick submacular hemorrhage in age-related macular degeneration. Ophthalmology 2004;111:1201–1208. 21. Abdel-Meguid A, Lappas A, Hartmann K, et al. One year follow up of macular translocation with 360 degree retinotomy in patients with age related macular degeneration. Br J Ophthalmol 2003;87:615–621. 22. Toth CA, Lapolice DJ, Banks AD, Stinnett SS. Improvement in near visual function after macular translocation surgery with 360-degree peripheral retinotomy. Graefes Arch Clin Exp Ophthalmol 2004;242:541–548. 23. Chow AY, Chow VY, Packo KH, et al. The artificial silicon retina microchip for the treatment of vision loss from retinitis pigmentosa. Arch Ophthalmol 2004;122:460–469. 24. Dua HS, Gomes JA, King AJ, Majarajan VS. The amniotic membrane in ophthalmology. Surv Ophthalmol 2004;49: 51–77. 25. Pan MH, Wu YW, Yen RF, et al. Different fibrovascularization rates between coralline hydroxyapatite and high density porous polyethylene (Medpore) measured by 99mTc-MDP bone scintigraphy 6 months after intraorbital implantation. Nucl Med Commun 2003;24:1237–1241. 26. Bishop F, Doran RM. Adjustable and non-adjustable strabismus surgery: a retrospective case-matched study. Strabismus 2004; 12:3–11. 27. Engel JM, Rousta ST. Adjustable sutures in children using a modified technique. J AAPOS 2004;8:243–248. 28. Sharma P, Reinecke, RD. Single-stage adjustable strabismus surgery for restrictive strabismus. J AAPOS 2003;7:358–362.