Retinal Nerve Fiber Layer Thickness in Children <18 Years by Spectral-domain Optical Coherence Tomography

Objectives: To establish a normative database for retinal nerve fiber layer (RNFL) thickness in children<18 years by spectral-domain optical coherence tomography (SD-OCT). Methods: Children <18 years, who were consecutively enrolled from July-August 2011 in this cross-sectional hospital study, underwent Cirrus SD-OCT. Recorded demographics and clinical characteristics included age, sex, axial length, spherical equivalent, intraocular pressure (by Perkins tonometry) and cup disc ratio. The RNFL thickness full circle (RNFL-FC), superior, (RNFL-S), inferior (RNFL-I), temporal (RNFL-T), and nasal (RNFL-N) and the influence of clinical and demographic factors on the RNFL thickness were assessed using linear regression analysis. Results: 148 eyes of 74 children were analyzed (females: males = 37: 37) with a mean age of 10 +/- 3.4years (range 4-17 years) and a mean spherical equivalent of -0.6 +/- 1.2 dioptres. The mean RNFL-FC was 94 +/- 10.9 and 93 +/- 10.6 mu m in the right and left eyes, respectively, with maximum thickness found in the superior quadrant. The RNFL-FC and RNFL-S decreased by 1.9 mu m for every 1 dioptre increase in myopic shift, p < 0.001, and by 1.9 mu m for every mm increase in axial length, p < 0.001. There was no effect of age on RNFL thickness in females or males. Conclusions: The RNFL thickness in children was influenced most by axial length and refractive error while it was independent of age. The normative data from this study could serve as reference for further studies on pediatric glaucoma using newer imaging devices.