Residual anterior chamber angle closure in narrow-angle eyes following laser peripheral iridotomy: anterior segment optical coherence tomography quantitative study
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To study quantitative changes in anterior chamber angle (ACA) after laser peripheral iridotomy (LPI) in narrow-angle eyes using anterior segment optical coherence tomography (AS-OCT).
Eighteen subjects with narrow angles were imaged with AS-OCT for determining test–retest variability. Forty-six participants with narrow angles were scanned with AS-OCT before LPI and 4 weeks after LPI. The presence of ACA closure by both AS-OCT imaging and gonioscopy was compared before and after LPI. Three ACA parameters by AS-OCT, angle opening distance at 500 μm (AOD500), trabecular-ris space area at 500 μm (TISA500) and angle recess area at 500 μm (ARA500), at both nasal and temporal quadrants were incorporated for analysis. The increment of ACA parameters defined as exceeding the 95% confidence interval of test–retest variability was assessed after LPI.
All 3 parameters obtained from the 18 eyes showed good measurement reproducibility (intraclass correlation coefficient 0.850–0.979). Persistent angle closure was detected in 23.9% of eyes by gonioscopy, and in 34.8% of eyes by AS-OCT images at temporal quadrant after LPI. When assessed by measurement variability criteria, the percentage of eyes that showed no significant change in ACA parameters ranged from 23.9% to 45.7% after LPI.
Overall, ACA parameters changed significantly after LPI; however, when assessed by AS-OCT, ACA remained unchanged in some narrow-angle eyes despite LPI. Our findings suggest that multiple causes other than pupillary block may contribute to narrow-angle closure following LPI.
KeywordsAnterior segment OCT Anterior chamber angle Laser peripheral iridotomy
Conflict of interest
The authors have no proprietary interest or financial support in the development or marketing of instruments or equipment mentioned in this article, or any competing instruments or pieces of equipment. This study was not supported by any foundation or research grant.
- 2.Foster PJ, Devereux JG, Alsbirk PH, Lee PS, Uranchimeg D, Machin D, et al. Detection of gonioscopically occludable angles and primary angle closure glaucoma by estimation of limbal chamber depth in Asians: modified grading scheme. Br J Ophthalmol. 2000;84:186–92.CrossRefPubMedPubMedCentralGoogle Scholar
- 14.Kim DY, Sung KR, Kang SY, Cho JW, Lee KS, Park SB, et al. Characteristics and reproducibility of anterior chamber angle assessment by anterior segment optical coherence tomography. Acta Ophthalmol. 2009 (doi. 10.1111/j.1755-3768.2009.01714.x).