Pediatric normative Retinal nerve fiber layer thickness in south Indian population

Abstract

To study the retinal nerve fiber layer (RNFL) thickness in pediatric age group and its correlation with age, gender, refractive error and axial length Prospective observational study of 200 eyes of 100 children aged between 5-18 years presenting to the ophthalmic department. All children underwent detailed ophthalmic evaluation and SD OCT examination for RNFL thickness, Standard RNFL assessment protocol was used. Mean RNFL thickness in micrometers along the whole circle circumference, four quadrants, 12’o clock hours were obtained. RNFL measurements included average/full circle thickness — RNFL-FC (360ºmeasure), temporal quadrant thickness, RNFL-T, superior quadrant thickness, RNFL-S, nasal quadrant thickness, RNFL-N, inferior quadrant thickness, RNFL-I. Mean age was 13.3 ± 2.4 years. The refractive error in spherical equivalent was -0.28 ± 0.91 dioptre (SE). The mean axial length was 23.1 ± 0.7mm. The mean global RNFL thickness (RNFL-FC) was 97.0 ± 8.8mm (range 79.4 -114.6). RNFL thickness was maximum in the inferior quadrant (RNFL-I) 126 ± 13.7mm followed in order by superior (RNFL-S) 126 ± 16.3mm, nasal (RNFL-N) 70.5 ± 12.3mm and temporal (RNFL-T) 63.4 ± 9.2mm, in both the sexes. For every increase in one diopter of spherical equivalent of refractive error the mean RNFL increased by 3.77 microns and there was a reduction in mean RNFL thickness by 4.86 micron for every 1mm increase in axial length. RNFL varied minimally with gender. Positive correlation was seen with refractive error while inverse or negative correlation was seen with axial length and age. RNFL measurements could serve as reference for further studies on pediatric glaucoma or other optic nerve head pathologies.