Mechanical detachment of the anterior hyaloid membrane from the posterior lens capsule

Objective: To investigate the incidence of spontaneous detachment of the an terior hyaloid membrane from the posterior lens capsule and to explore the possibility of surgical separation of the anterior hyaloid membrane. Design: Prospective nonrandomized interventional comparative trial and comp arative human tissue study. Participants: Thirty-eight eyes of 32 patients undergoing primary pars plan a vitrectomy combined with cataract extraction and intraocular lens implant ation and 3 eye bank eyes for histopathologic examination. Methods: The anterior hyaloid membrane and posterior lens capsule were obse rved with a fiberoptic endoscope. Surgical separation of the anterior hyalo id membrane was attempted by either the hydrodissection method before catar act extraction (18 eyes) or the direct suction method after cataract extrac tion (20 eyes). In eye bank eyes, histopathologic examination was performed with (one eye) and without (two eyes) surgical separation of the anterior hyaloid membrane. Main Outcome Measures: Incidence of spontaneous detachment and success rate of surgical detachment of the anterior hyaloid membrane. Results: No eye displayed spontaneous detachment of the anterior hyaloid me mbrane. Using the hydrodissection method, complete detachment of the anteri or hyaloid membrane was achieved in 10 eyes (55.6%), partial detachment was attained in 2 eyes (11.1%), and detachment was not induced at all in 6 eye s (33.3%). With the direct suction method, the anterior hyaloid membrane wa s completely separated from the posterior lens capsule in 10 eyes (50%), pa rtially detached in 10 eyes (50%), and not detached at all in any eye. The direct suction method had a significantly higher success rate than the hydr odissection method (P < 0.001, chi-square test). In eye bank eyes, the surg ical manipulation induced complete separation of the anterior hyaloid membr ane from the lens capsule. Conclusions: Spontaneous detachment of the anterior hyaloid membrane from t he posterior lens capsule is very rare. Under endoscopic observation, surgi cal detachment of the anterior hyaloid membrane was possible in half of the patients. (C) 2001 by the American Academy of Ophthalmology.