Thickness of the Retinal Nerve Fibre Layer Estimated With the Scanning Laser Polarimeter in Healthy Children

Abstract

The scanning laser polarimeter [GDx variable corneal compensation (VCC)] measures the thickness of the retinal nerve fibre layer (RNFL) and has, therefore, a possible potential for the diagnosis and follow-up of glaucoma in children. The aim of the present study is to establish reference values of the RNFL thickness in children. The RNFL thickness was measured with a GDx VCC in 72 children aged 4 to 15 years without ocular diseases. The difference in the temporal-superior-nasal-inferior-temporal (TSNIT) average (TA), superior average (SA), and inferior average (IA) between the boys and the girls was estimated with a t test. A 95% confidence interval (CI) of the TA, SA, and IA was calculated for the whole group and compared with those of 4 previous studies. The reproducibility of the examination was estimated in 10 consecutive children and was expressed as 95% CI of the differences between the repeated measurements. There were no statistically significant differences in the TA, SA, and IA between the boys and girls. The 95% CI for the TA, SA, and IA was 61.1+/-1.5, 73.5+/-2.3, and 73.5+/-2.0 microm, respectively. These values did not overlap with those reported previously in the adult groups, confirming a statistically significant age-related thinning of the RNFL. The 95% CI of the differences between the repeated measurements was -0.4+/-1.4 microm for TA, -1.5+/-3.6 microm for SA, and 1.6+/-3.9 microm for IA, suggesting that the examination was reproducible. The GDx VCC examination is reproducible in children. The present RNFL results should represent useful reference values in the evaluation of pediatric glaucoma.