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Abstract #58618 Published in IGR 16-3
Longitudinal changes of angle configuration in primary angle-closure suspects: the Zhongshan Angle-Closure Prevention Trial
Jiang Y; Chang DS; Zhu H; Khawaja AP; Aung T; Huang S; Chen Q; Munoz B; Grossi CM; He M; Friedman DS; Foster PJOphthalmology 2014; 121: 1699-1705
See also comment(s) by Noel Chan •
OBJECTIVE: To determine longitudinal changes in angle configuration in the eyes of primary angle-closure suspects (PACS) treated by laser peripheral iridotomy (LPI) and in untreated fellow eyes. DESIGN: Longitudinal cohort study. PARTICIPANTS: Primary angle-closure suspects aged 50 to 70 years were enrolled in a randomized, controlled clinical trial. METHODS: Each participant was treated by LPI in 1 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. MAIN OUTCOME MEASURES: Angle width in degrees was calculated from Shaffer grades assessed under static gonioscopy. Angle configuration was also evaluated using angle opening distance (AOD250, AOD500, AOD750), trabecular-iris space area (TISA500, TISA750), and angle recess area (ARA) measured in AS-OCT images. 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 13.5° at baseline to a mean of 25.7° 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 after 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 for angle width measured under gonioscopy (P = 0.18), AOD250 (P = 0.167) and ARA (P = 0.83). In untreated eyes, angle width consistently decreased across all follow-up visits after LPI, with a more rapid longitudinal decrease compared with treated eyes (P values for all variables ≤0.003). The annual rate of change in angle width was equivalent to 1.2°/year (95% confidence interval [CI], 0.8-1.6) in treated eyes and 1.6°/year (95% CI, 1.3-2.0) 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 18 months after LPI. Untreated eyes experienced a more consistent and rapid decrease in angle width over the same time period.
UCL Institute of Ophthalmology, University College London and Moorfields Eye Hospital, London, United Kingdom; State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
Full articleClassification:
9.3.4 Primary angle closure suspect (Part of: 9 Clinical forms of glaucomas > 9.3 Primary angle closure glaucomas)
2.4 Anterior chamber angle (Part of: 2 Anatomical structures in glaucoma)
6.4 Gonioscopy (Part of: 6 Clinical examination methods)
6.9.2.1 Anterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
