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Ophthalmology. 2014 Sep;121(9):1699-1705. doi: 10.1016/j.ophtha.2014.03.039. Epub 2014 May 15.

Longitudinal changes of angle configuration in primary angle-closure suspects: the Zhongshan Angle-Closure Prevention Trial.

Author information

1
UCL Institute of Ophthalmology, University College London and Moorfields Eye Hospital, London, United Kingdom.
2
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
3
Wilmer Eye Institute, Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland.
4
Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
5
Singapore Eye Research Institute, Singapore National Eye Center, Singapore and National University of Singapore, Singapore.
6
Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
7
NIHR Biomedical Research Centre at Moorfields Eye Hospital, London, United Kingdom.
#
Contributed equally

Abstract

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.

PMID:
24835757
PMCID:
PMC4624262
DOI:
10.1016/j.ophtha.2014.03.039
[Indexed for MEDLINE]
Free PMC Article

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