Differential diagnosis and treatment of dislocated lenses.

Ectopia lentis continues to be a perplexing diagnostic and therapeutic problem for most ophthalmologists. However, thorough investigation, both systemic and ocular, can in most cases, establish either an environmental etiology or the nature of the heritable disorder. In cases with systemic disease and ectopia lentis, the ophthalmologist should insure that each patient obtains adequate consultation with other specialists in order that proper prophylactic and therapeutic measures are available. The Marfan syndrome, homocystinuria, and the Weill-Marchesani together account for the majority of dislocated lenses. Each of these requires a somewhat different therapeutic approach. Glaucoma should be recognized as a frequent complication in each of these conditions but is most serious in the Weill-Marchesani syndrome in which it often occurs early in life and remains unrecognized until serious damage has occurred. Because of the pupillary-block nature of the glaucoma in this condition, a prophylactic peripheral iridectomy must be seriously considered in every case while lens surgery should be undertaken if the glaucoma cannot be controlled by medical or surgical means. In homocystinuria, because of the potential vascular complications of general anesthesia, the ophthalmologist is often in a dilemma. The lens in this condition seems to be more mobile than in other ectopia lentis disorders and therefore likely to compromise vision earlier in life. However, due to the risk of vascular thrombosis, lens surgery should be delayed whenever possible until the patient is old enough to tolerate local anesthesia. Likewise, patients with the Marfan syndrome should be handled conservatively and, in general, function quite well simple with spectacle correction. Due to the high frequency of immediate surgical complications, it is advisable to avoid an open-sky technique to lens removal, using aspiration or a pars plana approach instead.