Changes in AC angle width and depth after IOL implantation in eyes with glaucoma

Abstract

The elegant study by Hayashi et al demonstrated an increase in anterior chamber angle width and depth after intraocular lens implantation in eyes with glaucoma.1Hayashi K. Hayashi H. Nakao F. Hayashi F. Changes in anterior chamber angle width and depth after intraocular lens implantation in eyes with glaucoma.Ophthalmology. 2000; 107: 698-703Abstract Full Text Full Text PDF PubMed Scopus (253) Google Scholar The authors did not, however, state the indentation gonioscopic findings of those 77 eyes with angle-closure glaucoma (ACG) before and after cataract surgery. We believe this is of great relevance, because ACG patients with merely angle narrowing or appositional angle closure behave very differently from ACG patients with extensive or total synechial angle closure. In ACG patients with merely angle narrowing or appositional angle closure, we agree with Hayashi et al that cataract extraction would widen the drainage angle and thus decrease the aqueous outflow resistance, resulting in lower postoperative intraocular pressures (IOPs). In ACG patients with appositional angle closure but no cataract, the mainstay treatment should remain laser peripheral iridotomy and argon laser peripheral iridoplasty.2Ritch R. Argon laser peripheral iridoplasty an overview.J Glaucoma. 1992; 1: 206-213Crossref Scopus (35) Google Scholar In ACG patients with extensive or total synechial angle closure, however, the trabecular meshwork will remain occluded by peripheral anterior synechiae, despite anterior chamber deepening after cataract extraction. The trabecular meshwork will only be exposed if goniosynechialysis3Shingleton B.J. Chang M.A. Bellows A.R. Thomas J.V. Surgical goniosynechialysis for angle-closure glaucoma.Ophthalmology. 1990; 97: 551-556Abstract Full Text PDF PubMed Scopus (46) Google Scholar (GSL) is performed to separate adherent iris from the meshwork. To confirm this, we have performed ultrasound biomicroscopic examination of the anterior segment of an eye with 360° peripheral anterior synechiae and chronic ACG that underwent cataract extraction by phacoemulsification, intraocular lens implantation, and limited GSL over only the inferior 180° of the angle before and after surgery. Before cataract surgery and GSL, the trabecular meshwork was occluded by peripheral anterior synechiae in the whole 360° of the angle. After surgery, the anterior chamber depth and the apparent angle width increased significantly in the whole 360° of the angle as a result of the replacement of the thick cataractous lens by a thin intraocular lens. The trabecular meshwork is, however, only exposed to the aqueous in the inferior 180° of the angle, as a result of the adherent iris having been pulled away from the meshwork by GSL. In the superior 180° of the angle, the trabecular meshwork remained occluded by adherent peripheral iris despite the dramatic deepening of the anterior chamber. The trabecular meshwork had once again become accessible to aqueous in the anterior chamber only in that area where GSL was performed. Hayashi et al also stated in their article that “After cataract surgery, the IOP decreased in all three groups. No statistically significant differences were found in the mean IOPs at 1 and 6 months after surgery between the three groups, … ” Hayashi et al did not, however, report what IOP–lowering medications the glaucoma patients were receiving both before and after cataract surgery. We could not assess the IOP effects of cataract extraction without knowing the preoperative and postoperative glaucoma medications. High-resistance wind instruments and iopOphthalmologyVol. 108Issue 4Preview Full-Text PDF Author’s replyOphthalmologyVol. 108Issue 3Preview Full-Text PDF