Abstract
Abstract: :
Purpose: We wished to determine whether we could predict intra-ocular lens (IOL) power in infants and young children with cataracts by predicting ALG prior to surgery and be able to adjust IOL power to be in synchrony with ALG. We also wished to compare ALG in these children with ALG in normal children. Such relationships have not been previously documented and are essential if we are to obtain improved results by IOL implantation adjusted for ALG. Our study set out to compare real-time ALG versus predicted ALG in these children and compare these measures with ALG in normal children. Methods: We pooled published cross-sectional data on normal ALG for the first three years of life and derived ALG curves (mean, 5% and 95% curves) using a ‘best-fit' exponential function. This model allowed us to predict Ocular Growth Rate as OGR=df(t)/dt). 27 eyes of 18 children (age 3 months to 3 years) with cataracts underwent sequential axial length measurements for a minimum follow up of 2 years. Axial length was measured at presentation and ALG predicted for age one, two and three years by our OGR function and masked during further measurements. Longitudinal axial length measures (real-time) were obtained at intervals of 3 to 6 months. Surgery was carried out when appropriate followed by optical rehabilitation (IOL n=15; or Contact Lenses (CL) n=10; or Spectacles n=2). Clinical and operative details; K readings; intra-ocular pressure and refraction were recorded. Results: There was no significant difference (p>0.05; ttest) in real-time versus predicted OGR either at one, two or three years of age. 14/15 (93%) with IOL and 7/10 (70%) with CL remained within +/-10% of mean normal ALG. 4 of the five eyes that exceeded >10% mean normal ALG developed secondary/associated glaucoma. Conclusions: Our results indicate that the OGR predictive model accurately predicts ALG in children with cataracts thus providing an algorithm for IOL power calculation; initial results show ALG undisturbed by IOL implantation and ALG measures appear to be a sensitive predictor of development of glaucoma in children with cataracts.
Keywords: cataract • clinical (human) or epidemiologic studies: tre • visual development: infancy and childhood