A Comparative Study of Increase in Central Corneal Thickness Following Congenital Cataract Surgery in Children

Abstract

BACKGROUNDThe incidence rate of paediatric cataracts is high in developing countries like India 1 ; about 7.4 -15.3 % of childhood blindness is due to congenital cataract. Although cataract extraction is performed at early ages in these children to prevent stimulus deprivation amblyopia, other complications such as secondary glaucoma, 2 continue to threaten their long term visual outcome. It was observed that after congenital cataract extraction, the increase in central corneal thickness (CCT) leads to overestimation of Intraocular Pressure (IOP) by Goldman Applanation Tonometry (GAT); and hence overdiagnosis of glaucoma in operated children resulting in unnecessary use of antiglaucoma medications.Aims and Objectives-1) To determine the central corneal thickness in children following surgery for congenital cataract in primary/secondary pseudophakia and aphakia and compare with age-matched normal children. 2) To see the variation in central corneal thickness (CCT) following primary/secondary Posterior Chamber Intraocular Lens (PCIOL) implantation for congenital cataract. MATERIALS AND METHODSThis is a descriptive comparative study conducted among children under 12 years of age who underwent surgery for congenital cataract, who attended the Outpatient Department (OPD) as well as wards of Department of Ophthalmology and/or Institute of Paediatrics at Government Rajaji Hospital, Madurai. The duration of study was 10 months. Subjects, who fulfilled all eligibility criteria, and none of the exclusion criteria, were only recruited in this study after obtaining written informed consent from their parents/guardian. Out of 170 eyes included in this study, 27 were aphakic, 74 were pseudophakic eyes (46 with primary intraocular lens implantation and 28 with secondary intraocular lens implantation) and 69 unoperated eyes in these subjects were taken as controls as preliminary CCT values were unavailable for the aphakic/pseudophakic eyes. A detailed evaluation of the anterior and posterior segment (dilated fundus examination) was done. Visual acuity was recorded in cooperative children. After explaining both the procedures; IOP & CCT measurement; topical anaesthetic drops (0.5% proparacaine) were instilled into the conjunctival sac. Intraocular pressure was recorded with GAT and in uncooperative children with Perkin's handheld Applanation tonometer. After 5 minutes, child is reassured and asked to fix at a distant target. CCT was measured using ultrasonic pachymeter by placing the tip of the probe gently on the centre of cornea. An average of 5 readings is taken. Uncooperative children were examined under oral sedatives. After IOP and CCT measurement, these were compared to the IOP and CCT readings of their corresponding age-matched healthy children. RESULTSThe age distribution of cases and controls varied from 4 -12 years. There was no significant difference in age between the study group and control group. Among the 85 children (170 eyes) studied, 52 were male and 33 were female. In the study group, total number of...