Appositional Angle Closure in Chinese With Primary Angle Closure and Primary Angle Closure Glaucoma After Laser Peripheral Iridotomy

Abstract

Approximately two-thirds of PAC and PACG eyes of Chinese patients after LPI had AAC. Plateau iris accounted for less than 50% of AAC. Other factors such as a thick peripheral iris and an anteriorly inserted iris also contributed to AAC. DRPT results suggested AAC might have more functional meaning than plateau iris.

Evaluation of circumferential angle closure using iridotrabecular contact index after laser iridotomy by swept‐source optical coherence tomography

“…A recent study by Yan et al. () demonstrated that appositional angle closure was observed in more than one quadrant of the UBM image in 63.4% subjects. The difference in the ITC prevalence between UBM and swept‐source AS OCT is probably attributable to the fact that swept‐source AS OCT provides 32 B‐scan images per quadrant, whereas UBM gives only one B‐scan image per quadrant with the current protocol (Mishima et al.…”

“…Yao et al (2009) used UBM to assess ACA features qualitatively after LI and reported that appositional angle closure was observed in at least one quadrant in 38.2% of the fellow narrow-angle eyes of acute PAC patients after LI. A recent study by Yan et al (2014) demonstrated that appositional angle closure was observed in more than one quadrant of the UBM image in 63.4% subjects. The difference in the ITC prevalence between UBM and sweptsource AS OCT is probably attributable to the fact that swept-source AS OCT provides 32 B-scan images per quadrant, whereas UBM gives only one B-scan image per quadrant with the current protocol (Mishima et al 2013).…”

“…Wang et al (2000) reported that 38.1% of Chinese eyes had PACG caused by a pupil blockage mechanism, whereas 61.9% were caused by a nonpupil blockage mechanism. While plateau iris has been widely investigated among nonpupil blockage mechanisms, a recent study by Yan et al (2014) found that plateau iris accounted for only 44.7% of cases that were attributable to a nonpupil blockage mechanism. They used UBM, and their findings highlight the importance of the position of iris insertion and the thickness of the peripheral iris in the nonpupil blockage mechanism of angle closure.…”

Quantitative assessment of changes in anterior segment morphology after argon laser peripheral iridoplasty: findings from the EARL study group

“…Other mechanisms identified in primary angle-closure eyes include plateau iris syndrome, [14][15][16] thick peripheral iris roll 16,17 and large lens vault (LV). Other mechanisms identified in primary angle-closure eyes include plateau iris syndrome, [14][15][16] thick peripheral iris roll 16,17 and large lens vault (LV).…”

“…The advent of anterior segment imaging has objectively enhanced our understanding as to the reason appositional angle closure persists despite a patent peripheral iridotomy. Other mechanisms identified in primary angle-closure eyes include plateau iris syndrome, [14][15][16] thick peripheral iris roll 16,17 and large lens vault (LV). 17 Approximately 20-30% of PACS and PACG eyes continue to have appositional angle closure in the presence of a patent LPI.…”