Surgical outcome of cats treated for aqueous humor misdirection syndrome: a case series

To evaluate the clinical outcome of cats treated surgically for aqueous humor misdirection syndrome.

A retrospective analysis of cats treated surgically between January 1, 2006, and January 1, 2013, for aqueous humor misdirection syndrome was performed. Signalment, medical therapy, eyes affected, intraocular pressures prior to and after surgery, surgical procedures performed, postoperative complications, and visual status were evaluated.

Seven cats (nine eyes) fit the inclusion criteria. Six of seven cats were female, and five of seven cats were diagnosed with bilateral aqueous humor misdirection syndrome. Three surgical approaches were evaluated as follows: (i) phacoemulsification and posterior capsulotomy, (ii) phacoemulsification, posterior capsulotomy and anterior vitrectomy, and (iii) phacoemulsification, posterior capsulotomy, anterior vitrectomy, and endocyclophotocoagulation. The mean age at diagnosis was 12.9 years. Seven of nine eyes had controlled intraocular pressure (≤25 mmHg) during the first 6 months postoperatively. All cats were visual with controlled intraocular inflammation at 1 year postoperatively; however, one eye had an elevated intraocular pressure. All cats were continued on topical antiglaucoma and anti-inflammatory medications following surgery with the mean number of drops per day decreasing from 3.9 drops/day prior to surgery to 2.2 drops/day postoperatively.

Surgical management for feline aqueous humor misdirection syndrome may be a viable option to maintain a visual and normotensive status in cats that no longer have successful control of intraocular pressure with medical therapy.