Ocular complications and a new surgical approach to lens dislocation in homocystinuria due to cystathionine-beta-synthetase deficiency.

The ocular findings in patients with homocystinuria due to cystathionine-beta-synthetase (CBS) deficiency are reviewed and a new approach to lens surgery is presented. Lens surgery in CBS deficiency was reported to be accompanied by a high risk of secondary complications like vitreal prolapse and retinal detachment. So far an operative procedure for these patients that allows a complete preservation of the anterior vitreous cortex, the posterior lens capsule and an implantation of an artificial lens is not established. A minimal invasive method of lens surgery was developed in vitro and applied in the case of a 10-year-old patient with an uncorrectable refractive situation due to progressed lens dislocation. Principle steps of the evolved operative procedure are (1) visco-elastic stabilization of the anterior chamber; (2) small (1.5 mm) peripheral capsulorhexis; (3) manual endocapsular aspiration of lens material and removal of lens epithelium; (4) ab externo introduction of a transcleral fixation suture; (5) positioning of the haptic into the ciliary sulcus in the inferior position; (6) resection of the anterior lens capsule; and (7) positioning of the second haptic into the ciliary sulcus. The first patient treated according to this method presented a stable position of the pseudophakos during the follow up of 1 year. Visual acuity improved from a level of 20/200 (O.D.) and 10/200 (O.S.) to 18/20 in both eyes. The surgical procedure presented in this report seems to be useful for dealing with dislocated lenses due to zonular deficiency in patients with CBS deficiency and hopefully with Marfan disease. It allows a minimal invasive removal of the lens, a complete preservation of the anterior vitreous cortex and at the same time a stable fixation of an artificial intraocular lens.