Glaucomatous vs. non-glaucomatous anterior segment features in patients with Lowe oculocerebrorenal syndrome using ultrasound biomicroscopy

Abstract

Purpose : All Lowe oculocerebrorenal syndrome (OCRL) patients develop dense bilateral congenital cataracts, but only 50% develop glaucoma. Carriers of OCRL are at risk for early onset cataracts in the 3^rd to 4^th decade, but show no increased risk of glaucoma. The cause of the variable glaucoma phenotype in OCRL is unknown, and contrasts sharply with the highly penetrant cataract phenotype. No studies detail the subclinical structural variations in the anterior segment between glaucomatous and non-glaucomatous pediatric OCRL patients. Quantitating these differences may inform why half of OCRL patients develop glaucoma. Ultrasound biomicroscopy (UBM) is a high-resolution imaging technique for noninvasive in-vivo imaging of these anterior segment structures. This prospective case-series compares structural features in UBM images between a pediatric OCRL patient with glaucoma and an OCRL patient without glaucoma.

Methods : We obtained quantitative UBM images of a 1.2-month boy with OCRL who developed glaucoma (diagnosed at age 2 months) to UBM images of a 0.9-month boy with OCRL who did not develop glaucoma after 5 years of follow up (4 eyes, 2 subjects). Iris, lens, angle, and corneal parameters were extracted from images and compared using box plots.

Results : In the setting of OCRL, increased lens reflectivity, steeper corneal curvature (CRC), increased angle opening distance (AOD), thinner central cornea (CCT), and a deeper anterior chamber (ACD) were noted in two eyes of the subject who later developed glaucoma compared to the subject without glaucoma. Mean differences were CRC= -0.95 mm, AOD=+0.49 mm, CCT=-0.04 mm, ACD=+0.32 mm. Angle to angle distance and lens thickness were similar between the subject with glaucoma compared to the subject without glaucoma.

Conclusions : Anterior segment evaluation using quantitative UBM for individuals with OCRL may identify structural risk factors for glaucoma. Future studies will be needed to determine the sensitivity and specificity of UBM features for prediction of glaucoma.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Figure 1. Pre-lensectomy axial images of anterior segment in eyes with OCRL who did not develop glaucoma and age-matched eyes with OCRL who developed glaucoma.

 

Figure 2. Sample of most significant relationships in non-glaucomatous and glaucomatous eyes: CCT, ACD, CRC, AOD.