Prevalence of Plateau Iris in Indian Eyes With Primary Angle Closure Glaucoma (PACG)

Abstract

Purpose: : To determine the prevalence of plateau iris in North Indian PACG patients using ultrasound biomicroscopy (UBM).

Methods: : PACG patients with a patent peripheral laser iridotomy attending the glaucoma clinic were recruited in this observational cross-sectional study. PACG was defined as closed angle (posterior trabecular meshwork was not visible in more than 2 quadrant on indentation gonioscopy with a Sussman gonioscope) with optic nerve head changes typical of a glaucomatous optic neuropathy. UBM was performed using P 40 machine (Paradigm Medical Industries, Salt Lake City, UT) in one randomly selected eye of each patient. Plateau iris was defined in a quadrant by the presence of all of the following features: a steep iris configuration with a closed angle (irido-corneal contact), an anteriorly directed ciliary body and an absent ciliary sulcus. Eyes with the above features in two or more quadrants were classified as plateau iris.

Results: : Fifty one patients with a mean age of 56.4 ± 6.8 years were evaluated. There were 32 females and 19 males. Plateau iris was found in 10 (19.6%) eyes. Superior quadrant was most common quadrant to have plateau iris. None of the eyes had plateau iris in all 4 quadrants, 3 eyes (5.8%) had involvement of 3 quadrants, 7 eyes (13.7%) had only 2 quadrants involved, and 1 quadrant alone was involved in 4 eyes (7.8%).

Conclusions: : One in five eyes with PACG were found to have plateau iris. UBM evaluation should be performed in eyes with PACG post laser iridotomy to evaluate presence of non-pupillary block mechanisms for angle closure.

Keywords: imaging/image analysis: clinical • anterior chamber