Intracameral Injection of Poly(ethyleneglycol)-based Polymers as a Treatment for Post-operative Ocular Hypotony

Abstract

Abstract: : Purpose: To investigate the ability of poly(ethyleneglycol)-based polymers to treat chronic hypotony. Methods: The experiments were performed with rabbits according to ARVO guidelines for the treatment of animals. Preoperative intraocular pressures were recorded with a pneumatonometer. Aqueous fluid was withdrawn from the anterior chamber, and air was injected intracamerally. Either balanced salt solution, 1% sodium hyaluronate (Healon GV) or a photopolymerizable poly(ethyleneglycol)-based polymer precursor was injected into the anterior chamber angle around the edge of the intraocular bubble. In all rabbits, one eye was treated with balanced salt solution, and the other eye was treated with either Healon GV or a poly(ethyleneglycol)-based polymer precursor. In eyes treated with the polymer precursor (and in balanced salt solution controls), the anterior chamber was then exposed to direct illumination with an endoilluminator for 2 minutes in order to polymerize the precursor into a gel. Post-operative intraocular pressures were recorded with a pneumatonometer at approximately 4, 8, and 11 hours, and twice a day thereafter for 5 days. Results: 11 hours after the injections were performed, polymer-treated eyes showed a significant mean pressure increase of 24.5 mmHg compared to control eyes (p=0.008, 2 tailed t-test). At 12 hours Healon GV treated eyes showed a 12 mmHg increase compared to controls; this difference was not significant, however (p=0.126). At 24 hours after the procedure, there was still no significant difference between controls and Healon GV-treated eyes, but the mean IOP in polymer-treated eyes was 11 mmHg higher than in the other two groups. During the next three days, the mean IOP in polymer-treated eyes was 7 mmHg higher than in control eyes and sodium hyaluronate-treated eyes. At six days, the mean IOP in polymer-treated and control eyes was essentially the same. Histopathologic examination showed no evidence of intraocular inflammation or toxicity in polymer-treated eyes. Conclusion: Photopolymerizable poly(ethyleneglycol)-based polymers can cause a sustained increase in intraocular pressure when injected into the anterior chamber of rabbit eyes. This technique may have clinical applications in the treatment of ocular hypotony.

Keywords: 444 intraocular pressure • 317 anterior chamber • 524 proliferative vitreoretinopathy