Lens thickness in congenital and childhood cataracts: A case control study

Abstract

Purpose : Childhood cataract is defined as a lens opacity resulting in reduced visual acuity observed in the early years of life. As the most common cause of preventable pediatric vision loss worldwide, early diagnosis is key to achieve good visual function. Literature suggests congenital cataract is associated with altered lens structure, but no quantitative baseline has been established for the difference in lens structure in pediatric cataract versus control eyes. We tested the hypothesis that cataract eyes in children 0-5 years old will have significantly thinner lens thickness compared to age-matched healthy/control eyes by performing a prospective observational case control study.

Methods : 63 subjects, 109 eyes (34 subjects, 53 eyes with cataracts and 40 subjects, 56 eyes as controls) were recruited prospectively at 0-5 years old and imaged using ultrasound biomicroscopy (UBM). Lens thickness was measured using ImageJ and UBM software. Inter-observer agreement of lens measurement techniques was determined by calculating intraclass correlation (ICC) and assessing a Bland-Altman plot. Welch’s two-sample two-tailed t-test was used for statistical analysis of lens thickness between groups.

Results : Agreement analysis showed excellent reliability between image measurement tools (ICC = 0.986) and between observers (ICC = 0.989). Cataract eyes had significantly thinner lens (3.17 ± 0.63mm) than control eyes (3.55 ± 0.17mm, p = 0.0008). Stratifying for laterality or prematurity did not yield significant difference in lens thickness within cataract or control groups. Children 0-5 years old with cataracts were 2.9 times more likely to have a lens thickness less than 3.5mm, increasing to 6.6 times if under 7 months of age. Laterality of cataract did not affect odds of having a lens thickness less than 3.5mm. When controlling for age and compensating for correlation between eyes from the same patient, the odds of having cataract decreased by 2.66 for every 1mm increase in lens thickness.

Conclusions : Lens thickness can be measured repeatably and reliably from UBM images in a pediatric population. Cataract eyes in children 0-5 years old have significantly thinner lenses than age-matched control eyes.

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