Radium and the Eye

Radium and the Eye

512 EDITORIALS RADIUM A N D T H E E Y E The first few years after the intro­ duction of radiotherapy in ophthal­ mology were marked by great caution...

299KB Sizes 0 Downloads 107 Views

512

EDITORIALS

RADIUM A N D T H E E Y E The first few years after the intro­ duction of radiotherapy in ophthal­ mology were marked by great caution in its employment—to such an extent that failures often resulted from in­ adequate dosage. Many radiologists and ophthalmolo­ gists have believed that it was un­ necessary to protect the eye by the use of filters. But others argue that proper filtration makes either roentgen or radium radiation both safer and more effective. Our knowledge of the histologic changes resulting from overdosage was enriched by Lane, who confirmed previous clinical experience of distur­ bances in the cornea, the bloodvessels, and the retina. She further showed that, while dosage had an important influence on the tendency to such changes, heavy filtration was capable of preventing injury even in the pres­ ence of high dosage. That Lane, as well as other labora­ tory investigators, did not encounter cataract as a result of radiation may have been due to the fact that the eyes of experimental animals were enucleated within a few months after exposure to the rays, whereas in hu­ man beings lens opacities have been first noticed at least a year, and usually several years, after radiation. De Vries (Klinische Monatsblatter fur Augenheilkunde, 1929, volume 82, page 145) points out that carcinoma of the eyelid lends itself especially well to the study of radiotherapy, its dosage and results, and also its com­ plications, because this type of tumor is frequent and because its location favors investigation of the influence which filtration may have upon the subsequent integrity of the ocular tissues. A number of the most enthusiastic writers on the subject have remained completely silent as to the problem of injury from the rays. New and Benedict, and also Withers, in this Journal, have recommended a lead prothesis for protection of the eyeball; while Sattler declared that in his

experience such protection was un­ necessary. The material studied by de Vries in the Dutch cancer institute at Am­ sterdam included forty-nine cases in which the diagnosis of lid carcinoma was recorded. The diagnosis was usually clinical, but in three doubtful cases was confirmed by histologic study. Combined treatment with roentgen and radium radiation was formerly employed but has been abandoned since 1920. The method of fractional dosage at rather long intervals has also been avoided as giving poorer results and often leading to tolerance of the cancer cells for radiation, as pointed out by Delbet. The custom­ ary radium dose was 250 milligram hours for each square centimeter. The filters used were 0.5 millimeter of iron, 0.5 millimeter of lead, and one millimeter of India rubber; the appli­ cation being immediately on the eye­ lid. One of the earliest patients was treated at first with a small dose, and failed to obtain a cure. Four other patients had been "inoculated" with radium elsewhere (that is they had had fractional doses, with the pre­ sumable effect of rendering the cancer cells insensitive to radiation); and only one of these four yielded to new radiation. Other thirty-two patients were treated with radium according to the method outlined in the pre­ ceding paragraph. Of these thirty were cured, twenty-two of them re­ maining under observation more than one year, twelve more than three years, and seven for from five to eleven years. Two recurrences were seen. One, five years after the original treatment, yielded to a renewed application to radium, and remained well for five years of further observation. In the second case the relapse occurred six months after the first treatment, but the patient declined further treatment, and this case is included in the two failures. These results are substantially in

EDITORIALS

accord with those obtained by Quig!ey (eighty-nine cures in ninety-six cases) and Regaud (thirty-three cures in forty-one cases), and they emphati­ cally controvert the statement of Dupuy-Dutemps that radium treatment is usually followed by recurrence. The cosmetic result is always ex­ cellent, the site of the tumor being indicated merely by a pale soft scar, a few small teleangiectases, and per­ manent loss of eyelashes in the ex­ posed area, with occasional slight thinning of the lid margin. The lesser disturbances seen after the radium treatment of these tumors included mild chronic irritation and in four cases abnormal dilatation of the conjunctival vessels. In three cases, a few months after the treatment, very fine punctate and linear epithelial lesions were demon­ strable by staining with fluorescein, in the quadrant of the cornea nearest the center of radiation. These le­ sions disappeared later. In two cases there was a localized atrophy of the iris, in a forty-five de­ gree sector corresponding to the cen­ ter of radiation; and in each of these cases there was complete uniform opacity of the lens; so that four and three years respectively after the radi­ ation poor vision developed. In addito these "ripe" cataracts, three pa­ tients showed fine lens opacities be­ neath the posterior capsule, but only in the sector directed toward the center of radiation. These slight opacities had no effect on visual acuity. Their time of onset could not be ascertained, nor could it be discovered whether they were progressive. The radia­ tions had taken place respectively five, eight, and ten years earlier. The lens disturbance in these three cases was strictly unilateral. The fundus was recorded as normal in every case, except in the two cases with mature cataract; and in these two cases light projection was good. Glaucoma was seen once, two years after a very heavy dose of radiation. De Vries is satisfied that the effect of the rays upon the lens is not direct,

S13

but that the basis of radiation cataract is a local injury of the eye. Whether this consists of vascular changes in the ciliary body or whether a general factor plays a part in producing the injury, he is not prepared to say. A joint paper by den Hoed, Stoel, and de Vries (Klinische Monatblatter fur Augenheilkunde, 1929, volume 82, February, page 158) suggests that the mere factor of distance between the vital structures of the eye and the center of radiation is important, and that the most suitable form of pro­ tective screen may be found in a thick layer of some organic substance, like paraffin, introduced into the conjunc­ tival sac. There is serious lack of agreement as to dosage and as to the necessity for filtration, and it may be a long time before the last word is said on either question. In a typical case of basal-cell carcinoma of the lower eye­ lid, about one square centimeter in area, treated by a radiologist in co­ operation with the writer of this com­ ment, a single dose of twenty milli­ gram-hours proved adequate for most satisfactory cure. In this case the treatment was by direct contact of the radium tube (0.4 mm. of Monel metal) with the tumor. Without fil­ tration, the growth is attacked by the rays of long as well as of short wave­ length, greatly lessening the time of exposure required, and therefore dim­ inishing the danger to the deep ocular structures, since the longer wave­ lengths are filtered out by the super­ ficial tissues to a much greater extent than are the short wave-lengths.

W. H. Crisp.

PROFESSIONAL ADVERTISING It has long been a belief held by younger practitioners of medicine that there are certain men in the profession who can "get away with" anything; that is, that without unpleasant con­ sequences to themselves they can do and say things which men of less as­ sured position would not dare to do or say. In Chicago at least this im-