A recent study assessing anatomical changes and predictors of angle-widening following laser peripheral iridotomy (LPI) in mainland Chinese people found that the location of the LPI plays a major role in outcomes.

The study included 454 primary angle-closure glaucoma (PACG) suspects between the ages of 50 and 70. Subjects underwent gonioscopy and anterior segment OCT at baseline and at two weeks post-LPI. Of the 454 subjects, 219 received superior LPIs and 235 received temporal or nasal LPIs.

The researchers noted significant changes among many biometric parameters after LPI, including greater mean angle opening distance. They also noted that 26.4% of eyes had residual PACG after LPI.

Overall, LPI location, smaller angle opening distance and greater iris curvature were predictive of greater angle widening. Temporal or nasal LPI and greater baseline angle opening distance were most predictive of poor angle widening, based on anterior segment OCT, and a smaller mean gonioscopy grade was most predictive of poor angle opening.

The researchers concluded that superior LPI location “significantly results in greater angle widening based on anterior segment OCT compared with temporal or nasal locations in a Chinese population with PACG.” They wrote in their paper that superior LPI locations should be considered to optimize any anatomical changes following LPI.

Xu BY, Friedman DS, Foster PJ, et al. Anatomical changes and predictors of angle widening after laser peripheral iridotomy: the Zhongshan Angle Closure Prevention Trial. Ophthalmology. January 23, 2021. [Epub ahead of print].