BritishJournal ofOphthalmology, 1991,75,501-503 Nd-YAG laser hyaloidotomy for malignant glaucoma following one-piece 7 mm intraocular lens implantation Shlomo Melamed, Isaac Ashkenazi, Michael Blumenthal Abstract Three cases of malignant glaucoma following extracapsular cataract extraction with 7 mm one-piece posterior chamber intraocular lens implantation are presented. Nd-YAG laser hyaloidotomy was successfully performed in all eyes, but was difficult and required several sessions in two eyes. In the third eye, which had a sector iridectomy, laser hyaloidotomy applied over the edge of the lens optic through the iridectomy resulted in brisk deepening of the anterior chamber and reduction of intraocular pressure. We propose that the one-piece 7 mm optic posterior chamber intraocular lens may constitute an obstacle to successful hyaloido- tomy, mainly owing to its large size, as it may block aqueous percolation from the vitreous into the anterior chamber. Eyes prone to develop malignant glaucoma after surgery should have a sector or large peripheral iridectomy to facilitate postoperative Nd- YAG laser hyaloidotomy if required. The application of the Q-switched Nd-YAG laser for aphakic or pseudophakic malignant glaucoma has already been accepted as the surgical treatment of choice in cases where topical treatment with cycloplegic drops has failed. The treatment, as proposed by Epstein et al, 1-3 consists in cutting with the laser through the anterior hyaloid face (hyaloidotomy), with consequent release of aqueous trapped in the vitreous gel. This procedure is very effective in relieving the 'vitreal block', and aqueous diversion is reversed in both aphakic and pseudophakic eyes." In recent years the one piece 7 mm optic posterior chamber intraocular lens (PC-IOL) has become popular. This transition to 7 mm lenses was based on the belief that a larger lens would provide better optical centration, less glare, and fewer optical aberrations. In this study we report on three cases in which malignant pseudophakic glaucoma followed the insertion of 7 mm one-piece IOLs. In two eyes, Nd-YAG laser hyaloidotomy was technically difficult, and the relief of the condition was slow. In the third case hyaloidotomy was easily and successfully done through a pre-prepared sector iridectomy. Possible reasons for such difficulties and some suggestions for minimising them will be discussed. Case reports In the last two years we have detected three eyes that developed malignant glaucoma following extracapsular cataract extraction and insertion of a one-piece 7 mm posterior chamber intraocular lens (IOL). CASE I A 75-year-old woman underwent uneventful extracapsular cataract extraction in the right eye with insertion of a one-piece 7 mm posterior chamber IOL. She was known to have suffered from chronic angle closure glaucoma in both eyes, and five years earlier bilateral laser irido- tomies had been performed. Since then the intraocular pressure (IOP) had been controlled with drops of timolol 0 5% twice a day and pilocarpine 4% four times a day. Prior to surgery the visual acuity of the right eye was counting fingers at 3 feet (1 m), and there was a dense nuclear sclerosis and a moderate diffuse posterior subcapsular cataract. On the first postoperative day the anterior chamber was very shallow, the IOP was raised to 38 mm Hg, and the cornea was diffusely oedematous. Repeated applications of cycloplegic drops were unsuccessful in relieving the condition. Maximal antiglaucoma therapy, which included 0 5% timolol twice a day, 4% pilocarpine, four times a day, acetazolamide tablets 250 mg four times a day, and two doses of hyperosmotic agents (glycerol) were also ineffec- tive. A diagnosis of malignant glaucoma was made, and Nd-YAG laser hyaloidotomy was performed after the cornea had been cleared with the application of glycerin drops. Completely successful hyaloidotomy required four sessions of laser treatment. The laser parameters at each session were: 15-22 pulses of 3-4-2 mJ each delivered through the pupil and the patent laser iridotomy. The aim of the laser treatment was to perforate the hyaloid membrane and allow aqueous, believed to be trapped in the vitreous, to flow into the anterior chamber. After the first three sessions the response was only temporary, with anterior chamber deepening and IOP reduction which lasted no more than 24 hours. Immediately after the fourth laser session the anterior chamber deepened and the IOP dropped to 10 mm Hg and persistently remained in the low teens. After 12 months of follow-up the IOP was 12 mm Hg with timolol 0.5% twice a day only, and best corrected visual acuity was 20/40. CASE 2 A 68-year-old man underwent uneventful extracapsular cataract extraction with implantation of a one-piece 7 mm IOL in the right eye. He was known to be hyperoptic in both eyes, with a visual acuity of 20/200 in the right Goldschleger Eye Institute, Tel-Hashomer, Israel S Melamed I Ashkenazi M Blumenthal Correspondence to: Shlomo Melamed, MD, Goldschleger Eye Institute, Tel-Hashomer, Israel. Accepted for publication 17 January 1991 501 group.bmj.com on June 17, 2017 - Published by http://bjo.bmj.com/ Downloaded from