Anterior Segment Morphology in Primary Angle Closure Glaucoma using Ultrasound Biomicroscopy.

Tarannum Mansoori,Nagalla Balakrishna

doi:10.5005/jp-journals-10028-1230

Abstract

AimTo evaluate the configuration of the anterior chamber angle quantitatively and study the morphological changes in the eye with ultrasound biomicroscopy (UBM) in primary angle closure glaucoma (PACG) patients after laser peripheral iridotomy (LPI).Materials and methodsA total of 185 eyes of 185 PACG patients post-LPI and 126 eyes of 126 normal subjects were included in this prospective study. All subjects underwent complete ophthalmic evaluation, A-scan biometry, and UBM. The anterior segment and angle parameters were measured quantitatively and compared in both groups using Student’s t-test.ResultsThe PACG patients had shorter axial length, shallower central anterior chamber depth anterior chamber depth (ACD), and anteriorly located lens when compared with normal subjects. Trabecular iris angle (TIA) was significantly narrow (5.73 ± 7.76°) in patients with PACG when compared with normal subjects (23.75 ± 9.38°). The angle opening distance at 500 pm from scleral spur (AOD 500), trabecular-ciliary process distance (TCPD), iris-ciliary process distance (ICPD), and iris-zonule distance (IZD) were significantly shorter in patients with PACG than in normal subjects (p < 0.0001). The iris lens angle (ILA), scleral-iris angle (SIA), and scleral-ciliary process angle (SCPA) were significantly narrower in patients with PACG than in normal subjects (p < 0.0001). The iris-lens contact distance (ILCD) was greater in PACG group than in normal (p = 0.001). Plateau iris was seen in 57/185 (30.8%) of the eyes. Anterior positioned ciliary processes were seen in 130/185 eyes (70.3%) of eyes.ConclusionIn PACG patients, persistent apposition angle closure is common even after LPI, which could be due to anterior rotation of ciliary body and plateau iris and overcrowding of anterior segment due to shorter axial length and relative anterior lens position.How to cite this article: Mansoori T, Balakrishna N. Anterior Segment Morphology in Primary Angle Closure Glaucoma using Ultrasound Biomicroscopy. J Curr Glaucoma Pract 2017;11(3):86-91.

Highlights

The Primary angle closure glaucoma (PACG) patients had shorter axial length, shallower central anterior chamber depth anterior chamber depth (ACD), and anteriorly located lens when compared with normal subjects
Trabecular iris angle (TIA) was significantly narrow (5.73 ± 7.76°) in patients with PACG when compared with normal subjects (23.75 ± 9.38°)
In PACG patients, persistent apposition angle closure is common even after Laser peripheral iridotomy (LPI), which could be due to anterior rotation of ciliary body and plateau iris and overcrowding of anterior segment due to shorter axial length and relative anterior lens position

Summary

Introduction

Primary angle closure glaucoma (PACG) is one of the leading causes of blindness in Asians.[1,2,3] The prevalence of PACG has been reported to be 1.08,1 1.58,2 and 4.32%3 in population-based studies in Asian Indian eyes. Laser peripheral iridotomy (LPI) is a prophylactic treatment for PACG. It eliminates relative pupillary block and equalizes the pressure in the AC and posterior chamber (PC). Post-LPI, angle closure is relatively common in east Asian eyes.[8] In a population-based survey of Chinese persons ≥50 years of age, 20% of PAC suspects remain gonioscopically closed even with a patent iridotomy.[9]

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