Intraocular Pressure Elevation in the Contralateral Untreated Eye Following Selective Laser Trabeculoplasty in Rabbit Eyes

Abstract

Our study aimed at evaluating if a single session of unilateral selective laser trabeculoplasty would affect the intraocular pressure of the fellow untreated eye in rabbits. Eleven rabbits were involved. 360° selective laser trabeculoplasty with 532 nm frequency-doubled green Nd:YAG laser was performed over the right eyes. The mean intraocular pressure of both eyes at baseline, 3 hours, 24 hours, 3 days and 7 days after laser were measured. The baseline mean intraocular pressure of the right eye and the left eye were 8.07 ± 1.72 mmHg and 8.27 ± 1.56 mmHg respectively (p=0.78). The mean intraocular pressure of the treated eye was lower than the baseline from 3 hours through 3 days after laser, with a maximum mean decrease of 1.36 mmHg on Day 3. On the contrary, the mean intraocular pressures of the untreated eyes were higher than the baseline throughout the study, particularly at later course (1.91 mmHg on Day 3 and 1.85 mmHg on Day 7). This suggests the change of intraocular pressure in one eye after selective laser trabeculoplasty, leads to a change in the pressure of the fellow eye. It is thought that a neuronal and humoral response is triggered centrally after unilateral intraocular pressure change. The detailed mechanisms would require further studies to evaluate. The rising intraocular pressure trend in the contralateral untreated eye suggests that response may continue to exert its action for some time after the initial laser. This is the first reported study of intraocular pressure elevation of the untreated eye following contralateral selective laser trabeculoplasty.