Abstract
Purpose:
To determine longitudinal changes in angle configuration in eyes of primary angle closure suspects (PACS) treated by laser peripheral iridotomy (LPI) and in untreated fellow eyes.
Methods:
Urban citizens aged 50 to 70 years identified as primary angle closure suspects were enrolled for a randomized controlled clinical trial. Each participant was treated by LPI in one randomly selected eye, with the fellow eye serving as a control. Angle width was assessed in a masked fashion using gonioscopy and anterior segment optical coherence tomography (AS-OCT) before and at 2 weeks, 6 months and 18 months after LPI.
Results:
No significant difference was found in baseline measures of angle configuration between treated and untreated eyes. At 2 weeks after LPI, the drainage angle on gonioscopy widened from a mean of 13.49 degrees at baseline to a mean of 25.72 degrees in treated eyes, which was also confirmed by significant increases in all AS-OCT angle width measures (P<0.001 for all variables). Between 2 weeks and 18 months following LPI, a significant decrease in angle width was observed over time in treated eyes (P<0.001 for all variables), although the change over the first 5.5 months was not statistically significant (P=0.07-1.00). In untreated eyes, angle width consistently decreased across all follow-up visits after LPI, with a more rapid longitudinal decrease compared to treated eyes (P values for all variables ≤ 0.01). The annual rate of change in angle width was equivalent to 1.17 degrees/year (95% CI: 0.75 degrees/year, 1.60 degrees/year) in treated eyes, and 1.64 degrees/year (95% CI: 1.32 degrees/year, 1.95 degrees/year) in untreated eyes (P< 0.001).
Conclusions:
Angle width of treated eyes increased markedly after LPI, remained stable for 6 months, and then decreased significantly by the 18th month following LPI. Untreated eyes experienced a more consistent and rapid decrease in angle width over the same time period.
Keywords: 420 anterior chamber •
550 imaging/image analysis: clinical •
466 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials