Anterior dislocation of the lens in homocystinuria.

Homocystinuria is of particular interest to ophthalmologists, associated as it is with sub-luxated or dislocated lenses in over go per cent. of cases. It was first described by Carson and Neill (I962) and well over I00 cases have since been reported. The subject has recently been reviewed by Cusworth and Dent (I969) and by FranSois (1970). It is our purpose to discuss the management of anterior dislocation of the lens in five patients with biochemically proven homocystinuria. Case reports Case i, a boy born in August, 1957, was referred in February, I968, with bilaterally subluxated lenses and visual acuities of 6/I8 in the right eye and 6,/2 in the left with aphakic corrections. Homocystinuria had been diagnosed before referral. In May, I968, the left lens dislocated into the anterior chamber resulting in acute secondary glaucoma. The lens was extracted under general anaesthesia with anticoagulant cover. There was slight vitreous loss at the time of the operation and in the immediate postoperative period a vitreous haemorrhage was apparent. This took 2 months to clear completely. In July and September, I968, the right lens dislocated into the anterior chamber and on each occasion it was replaced behind the iris by dilating the pupil fully and by pressing on the cornea. On one of these occasions it took an hour to replace the lens. When the patient was last seen in October, 1971, the corrected visual acuity was 6/9 part in each eye. The ocular tensions were normal. There were peripheral pigmentary changes in the right fundus. Ecothiopate iodide 0-125 per cent. was being instilled twice daily into the right eye to prevent a further anterior dislocation of the lens, weaker miotics having proved inadequate. Family This patient has one normal younger brother and one younger sister who is also a known case of homocystinuria. The sister, who was born in I965, has bilaterally subluxated lenses. Case 2, a girl born in June 1954, presented in July, I960, with headache and vomiting. Before referral a lumbar puncture had been performed when a dilated pupil had been noted in conjunction with an equivocal plantar response. Examination revealed an anteriorly dislocated left lens with acute secondary glaucoma. A left cyclodiathermy was performed, but the eye remained hard and painful and enucleation was necessary in August, I960. In I966 homocystinuria was diagnosed when patients with ectopia lentis were screened for this condition.