Relationship between Optic Nerve Head Morphology, Retinal Nerve Fiber Layer Thickness and Refractive Errors in a Saudi Pediatric Population: A Cross-Sectional Study
Author(s): Khalid M Alabdulwahhab*
Abstract
Background: Many biographical, ocular parameters and ocular pathologies like Glaucoma and Diabetic Retinopathy (DR) are known to affect the optic disc or macula, causing changes in the morphology of the Optic nerve head and variations in the retinal nerve fiber layer. Objective: To compare the Optic Nerve Head (ONH) morphology and Retinal Nerve Fiber Layer (RNFL) thicknesses of eyes with different types of refractive error among Saudi children from Al Hasa region, Saudi Arabia. Methods: This cross-sectional study was conducted among 117 Saudi children between 5 to 18 years of age visiting the Al-Moosa specialist hospital in Hofuf city. Children who presented with refractive errors were selected using Consecutive sampling method. An optometrist assessed the refractive status of each eye. A pediatric ophthalmologist examined anterior segment, measured intraocular ocular pressure, and assessed the posterior segment of the eye. The neuro-retinal rim area was 1.87 mm2 (± 0.93 mm2) and RNFL thickness was 130 µ (± 15.7 µ) in hypermetropic eyes. The neuroretinal rim area at disc and RNFL thickness were 1.74 mm2 (± 0.61 µ) and 90.71 µ (± 14.88 µ) in astigmatic (≥ 2D) eyes. Results: We examined 234 eyes of 117 children, myopia 66 (28.21%), emmetropia 121 (51.71%), hypermetropia 21 (8.97%) and 26 (11.11%) astigmatism. Horizontal integrated rim area (mm2) was significantly higher in emmetropic eyes than in eyes with myopia (p=0.019). Other morphological parameters did not vary significantly among myopic and emmetropic eyes (p>0.05) respectively. The average RNFL thickness at optic disc was significantly higher in emmetropic eyes than in the myopic eyes (p<0.001). RNFL at inferior quadrants (p=0.090), superior quadrants (p=0.072), nasal quadrants (p=0.129) and temporal quadrants (p=0.460) does not differ significantly among myopic and emmetropic eyes. Similarly, high myopic had significantly higher RNFL thickness as compared to moderate myopia (p<0.001). Conclusion: This study showed that refractive errors have a significant influence on the optic nerve and retinal parameters of Saudi children and therefore while interpreting the ONH parameters and RNFL thicknesses in children, status of refractive error must be considered.