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Albinotic Characteristics in Congenital Nystagmus: Reply
122
AMERICAN JOURNAL OF OPHTHALMOLOGY
nation of the slit lamp narrowed to a small dot and shining directly into an undilated pupil with the axis of illumi nation coinciding with the axis of view ing to obtain a red reflex. Detection of macromelanosomes by skin biopsy is an important test which can confirm the diagnosis of X-linked ocular albinism in both affected individuals and carriers even when the iris transillumination de fects and fundus defects may not be marked. 5 K. G. ROMANCHUK,
Saskatoon,
M.D.
Canada
REFERENCES 1. O'Donnell, F. E., Jr., and Green, W. R.: The eye in albinism. In Duane, T. D., and Jaeger, E. A. (eds.): Clinical Ophthalmology. Hagerstown, Harper and Row, 1983, vol. 4, ch. 38. 2. François, J.: Albinism. Ophthalmologica 178:19, 1979. 3. Donaldson, D. D.: Transillumination of the iris. Trans. Am. Ophthalmol. Soc. 72:89, 1974. 4. Abrams, J. D.: Transillumination of the iris during routine slit lamp examination. Br. J. Ophthal mol. 48:42, 1964. 5. Cortin, P., Tremblay, M., and Lemagne, J. M.: X-linked ocular albinism. Relative value of skin biopsy, iris transillumination and fundoscopy in identifying affected males and carriers. Can. J. Oph thalmol. 16:121, 1981.
Reply EDITOR:
Dr. Romanchuk suggests that some of the patients in our series may have ocu lar albinism. We certainly agree. As we noted, however, this diagnosis can be difficult to make clinically. Other au thors have shared this dilemma. What exactly defines the entity of ocular albi nism? 1 How does one distinguish, for exam ple, an ocular albino with mild skin and hair involvement from an incomplete (tyrosinase-positive) oculocutaneous al bino? Even the results of a skin biopsy may be inconclusive. Abnormal large melanosomes are a characteristic finding in one of the two forms of X-linked ocu
JULY, 1984
lar albinism (Nettleship-Falls type). 2 This finding is absent in the other form of X-linked ocular albinism (ForsiusEricksson syndrome) and in autosomal recessive ocular albinism. 3 This last en tity is particularly difficult to separate from oculocutaneous albinism in that the heredity pattern is the same. At the other end of the spectrum, how does one distinguish an ocular albi no without skin and hair manifestations from a patient with isolated congenital nystagmus? We believe that a specially designed visual-evoked potential proce dure may be helpful in this regard. 4 ' 5 The clinical findings of iris transillumi nation, choroidal depigmentation, and blunting of the macular reflex may be found in varying combinations and in varying degrees in patients with con genital nystagmus. These findings are summarized in Table 2 of our article. Our principal conclusion is that the clinical findings associated with albinism (both ocular and oculocutaneous) are more common in patients with nystag mus than in matched controls. Some of our patients probably do have ocular al binism. In the absence of clear clinical criteria and without benefit of histologie evidence, we do not feel justified in designating which patients these are. J O H N W.
SIMON,
M.D.
GlLLRAY K A N D E L , P H . D .
GREGORY B. K R O H E L , PHILIP NELSEN,
M.D. M.D.
Albany, New York REFERENCES 1. O'Donnell, F. E., King, R. A., Green, W. R., and Witkop, C. J.: Autosomal recessively inherited ocular albinism. Arch. Ophthalmol. 96:1621, 1978. 2. Garner, A., and Jay, B. S.: Macromelanosomes in X-linked ocular albinism. Histopathology 4:243, 1980. 3. Witkop, C. J., Quevedo, W. C , and Fitzpatrick, T. B. : Albinism and other disorders of pigment metabolism. In Stanbury, J. B., Wyngarden, J. B., Frederickson, D. S., Goldstein, J. L., and Brown, M. S. (eds.): The Metabolic Basis of Inherited Dis-
CORRESPONDENCE
VOL. 98, NO. 1
ease, 5th ed. New York, McGraw-Hill, 1983, pp. 301-346. 4. Apkarian, P., Reits, D., Spekreijse, H., and VanDorp, D.: A decisive electrophysiological test for human albinism. Electroencephalogr. Clin. Neurophysiol. 55:513, 1983. 5. Wolf, B. M., Simon, J. W., Krohel, G. B., and Kandel, G. L. : VER correlates of visual pathway anomalies associated with ocular albinism in patients with congenital nystagmus. Invest. Ophthalmol. Vis. Sei. 25(suppl.):1977, 1983.
Inhibitor of Vascular Endothelial Cell Growth in the Lens EDITOR:
The excellent article, "Inhibitor of vascular endothelial cell growth in the lens" (Am. J. Ophthalmol. 97:366, March, 1984), by G. Williams and asso ciates, addresses the question of wheth er leaving a posterior capsule intact at the time of cataract surgery is benefi cial. We do not have the randomized study these researchers desire; how ever, it has been my clinical experience that the diabetic retinopathy was made significantly worse by total removal of the lens. However, by leaving the pos terior capsule intact, the diabetic reti nopathy in approximately 300 patients has not significantly progressed. The surgery did not seem to affect adversely the retinopathy when the posterior cap sule was left intact. This seems to be almost a universal observation. As important as statistical studies are, I would not want to per form cataract surgery on anyone with diabetes without leaving the posterior capsule intact. JAMES P. G I L L S ,
New Port Richey,
M.D.
Florida
Reply EDITOR:
Dr. Gills' clinical impressions con cerning cataract extraction in diabetics are most interesting and raise several questions. Aiello, Wand, and Liang 1
123
have shown that the preoperative status of retinopathy is an important factor in the incidence of postoperative diabetic complications after intracapsular cataract extraction. We need to know, therefore, if Dr. Gills's patients were accurately matched for severity of retinopathy in both his intracapsular and extracapsular groups. In Aiello, Wand, an i Liangs series of 154 eyes following intracapsular cataract extraction, postoperative vitreous hemorrhage occurred twice as often as in unoperated control eyes; however, this was not statistically significant. They, nonetheless, agree with Dr. Gills s observation and state that after intracapsular cataract extraction, patients with diabetic retinopathy undergo acceleration of proliferative diabetic retinopathy. 1 Dr. Gills's impression that preserva tion of the posterior capsule prevents this postoperative exacerbation of reti nopathy is provocative, but in this day of controlled clinical trials cannot yet be considered to be definitive. In addition to the status of retinopathy preoperatively and postoperatively, it would be interesting to know the incidence of iris neovascularization and neovascular glau coma in Dr. Gills's patients. A signifi cant difference from the prospective data of Aiello, Wand, and Liang follow ing intracapsular cataract extraction would support Dr. Gills's contention that preservation of the posterior cap sule is beneficial. An obvious extension of this discussion is whether capsulotomy, either primary or secondary, has any effect on intraocular neovascular events. This requires further study. Our study was prompted by the clini cal observations that in diabetics, lens removal increases the postoperative in cidence of iris neovascularization. While our study is conceptually consistent with putative beneficial effects obtained
AMERICAN JOURNAL OF OPHTHALMOLOGY
nation of the slit lamp narrowed to a small dot and shining directly into an undilated pupil with the axis of illumi nation coinciding with the axis of view ing to obtain a red reflex. Detection of macromelanosomes by skin biopsy is an important test which can confirm the diagnosis of X-linked ocular albinism in both affected individuals and carriers even when the iris transillumination de fects and fundus defects may not be marked. 5 K. G. ROMANCHUK,
Saskatoon,
M.D.
Canada
REFERENCES 1. O'Donnell, F. E., Jr., and Green, W. R.: The eye in albinism. In Duane, T. D., and Jaeger, E. A. (eds.): Clinical Ophthalmology. Hagerstown, Harper and Row, 1983, vol. 4, ch. 38. 2. François, J.: Albinism. Ophthalmologica 178:19, 1979. 3. Donaldson, D. D.: Transillumination of the iris. Trans. Am. Ophthalmol. Soc. 72:89, 1974. 4. Abrams, J. D.: Transillumination of the iris during routine slit lamp examination. Br. J. Ophthal mol. 48:42, 1964. 5. Cortin, P., Tremblay, M., and Lemagne, J. M.: X-linked ocular albinism. Relative value of skin biopsy, iris transillumination and fundoscopy in identifying affected males and carriers. Can. J. Oph thalmol. 16:121, 1981.
Reply EDITOR:
Dr. Romanchuk suggests that some of the patients in our series may have ocu lar albinism. We certainly agree. As we noted, however, this diagnosis can be difficult to make clinically. Other au thors have shared this dilemma. What exactly defines the entity of ocular albi nism? 1 How does one distinguish, for exam ple, an ocular albino with mild skin and hair involvement from an incomplete (tyrosinase-positive) oculocutaneous al bino? Even the results of a skin biopsy may be inconclusive. Abnormal large melanosomes are a characteristic finding in one of the two forms of X-linked ocu
JULY, 1984
lar albinism (Nettleship-Falls type). 2 This finding is absent in the other form of X-linked ocular albinism (ForsiusEricksson syndrome) and in autosomal recessive ocular albinism. 3 This last en tity is particularly difficult to separate from oculocutaneous albinism in that the heredity pattern is the same. At the other end of the spectrum, how does one distinguish an ocular albi no without skin and hair manifestations from a patient with isolated congenital nystagmus? We believe that a specially designed visual-evoked potential proce dure may be helpful in this regard. 4 ' 5 The clinical findings of iris transillumi nation, choroidal depigmentation, and blunting of the macular reflex may be found in varying combinations and in varying degrees in patients with con genital nystagmus. These findings are summarized in Table 2 of our article. Our principal conclusion is that the clinical findings associated with albinism (both ocular and oculocutaneous) are more common in patients with nystag mus than in matched controls. Some of our patients probably do have ocular al binism. In the absence of clear clinical criteria and without benefit of histologie evidence, we do not feel justified in designating which patients these are. J O H N W.
SIMON,
M.D.
GlLLRAY K A N D E L , P H . D .
GREGORY B. K R O H E L , PHILIP NELSEN,
M.D. M.D.
Albany, New York REFERENCES 1. O'Donnell, F. E., King, R. A., Green, W. R., and Witkop, C. J.: Autosomal recessively inherited ocular albinism. Arch. Ophthalmol. 96:1621, 1978. 2. Garner, A., and Jay, B. S.: Macromelanosomes in X-linked ocular albinism. Histopathology 4:243, 1980. 3. Witkop, C. J., Quevedo, W. C , and Fitzpatrick, T. B. : Albinism and other disorders of pigment metabolism. In Stanbury, J. B., Wyngarden, J. B., Frederickson, D. S., Goldstein, J. L., and Brown, M. S. (eds.): The Metabolic Basis of Inherited Dis-
CORRESPONDENCE
VOL. 98, NO. 1
ease, 5th ed. New York, McGraw-Hill, 1983, pp. 301-346. 4. Apkarian, P., Reits, D., Spekreijse, H., and VanDorp, D.: A decisive electrophysiological test for human albinism. Electroencephalogr. Clin. Neurophysiol. 55:513, 1983. 5. Wolf, B. M., Simon, J. W., Krohel, G. B., and Kandel, G. L. : VER correlates of visual pathway anomalies associated with ocular albinism in patients with congenital nystagmus. Invest. Ophthalmol. Vis. Sei. 25(suppl.):1977, 1983.
Inhibitor of Vascular Endothelial Cell Growth in the Lens EDITOR:
The excellent article, "Inhibitor of vascular endothelial cell growth in the lens" (Am. J. Ophthalmol. 97:366, March, 1984), by G. Williams and asso ciates, addresses the question of wheth er leaving a posterior capsule intact at the time of cataract surgery is benefi cial. We do not have the randomized study these researchers desire; how ever, it has been my clinical experience that the diabetic retinopathy was made significantly worse by total removal of the lens. However, by leaving the pos terior capsule intact, the diabetic reti nopathy in approximately 300 patients has not significantly progressed. The surgery did not seem to affect adversely the retinopathy when the posterior cap sule was left intact. This seems to be almost a universal observation. As important as statistical studies are, I would not want to per form cataract surgery on anyone with diabetes without leaving the posterior capsule intact. JAMES P. G I L L S ,
New Port Richey,
M.D.
Florida
Reply EDITOR:
Dr. Gills' clinical impressions con cerning cataract extraction in diabetics are most interesting and raise several questions. Aiello, Wand, and Liang 1
123
have shown that the preoperative status of retinopathy is an important factor in the incidence of postoperative diabetic complications after intracapsular cataract extraction. We need to know, therefore, if Dr. Gills's patients were accurately matched for severity of retinopathy in both his intracapsular and extracapsular groups. In Aiello, Wand, an i Liangs series of 154 eyes following intracapsular cataract extraction, postoperative vitreous hemorrhage occurred twice as often as in unoperated control eyes; however, this was not statistically significant. They, nonetheless, agree with Dr. Gills s observation and state that after intracapsular cataract extraction, patients with diabetic retinopathy undergo acceleration of proliferative diabetic retinopathy. 1 Dr. Gills's impression that preserva tion of the posterior capsule prevents this postoperative exacerbation of reti nopathy is provocative, but in this day of controlled clinical trials cannot yet be considered to be definitive. In addition to the status of retinopathy preoperatively and postoperatively, it would be interesting to know the incidence of iris neovascularization and neovascular glau coma in Dr. Gills's patients. A signifi cant difference from the prospective data of Aiello, Wand, and Liang follow ing intracapsular cataract extraction would support Dr. Gills's contention that preservation of the posterior cap sule is beneficial. An obvious extension of this discussion is whether capsulotomy, either primary or secondary, has any effect on intraocular neovascular events. This requires further study. Our study was prompted by the clini cal observations that in diabetics, lens removal increases the postoperative in cidence of iris neovascularization. While our study is conceptually consistent with putative beneficial effects obtained