Macular and Peripapillary Retinal Nerve Fiber Thickness in Unilateral Amblyopic Eye

Chunu Shrestha,Manish Poudel,Reeta Rajbhandari

doi:10.3126/nmcj.v23i2.38522

Abstract

Amblyopia is the most common cause of monocular visual impairment in both children, and young to middle-aged adults, affecting 2%–5% of the general population. The objective of this study was to compare the peripapillary nerve fiber thickness and macular thickness in amblyopic eyes, fellow eyes and normal control eyes using spectral domain optical coherence tomography. This was a cross-sectional observational study conducted at R M Kedia Eye Hospital, Birgunj, Nepal from February 2020 to July 2020. Pediatric patients with unilateral amblyopia (anisometropic amblyopia, strabismic amblyopia or both) among the age group of 6-18 years attending pediatric department of RM Kedia Eye Hospital were enrolled for the study. All patients underwent a full ophthalmological assessment, including visual-acuity testing, anterior segment evaluation with Topcon slit lamp and fundus examination with Volk +90D lenses. All statistical analysis was done in SPSS V. 20. The average peripapillary retinal nerve fiber layer thickness was 120.6 μm (SD=14.6 μm) in the amblyopic eye, 118.1 μm (SD=15.6 μm) in the fellow eye and 113.2 μm (SD=9.4 μm) in the normal eye (p=0.104) respectively. The average macular thickness was 298.6 μm (SD=19.1 μm) in the amblyopic eye, 296.9 μm (SD=11.2 μm) in the fellow eye and 303 μm (SD=12.4 μm) in the normal eye (p=0.260) respectively. In conclusion, our study did not find any significant difference in the peripapillary retinal nerve fiber thickness or macular thickness when compared between amblyopic eyes, fellow eyes, gender and age matched normal eyes.

Highlights

Amblyopia is a deficiency of form sense resulting in the reduction in visual acuity of greater than two lines between the eyes or an absolute reduction in acuity below 6/9 in either eye, associated with decrements in visual processing, accommodation, motility, spatial perception or spatial projection.[2]
Yen et al[4] has hypothesized that there is a measurable increase in retinal nerve fiber layer thickness in amblyopic eyes as amblyopia may affect the postnatal maturation of the retina, including the postnatal reduction of ganglion cells
Fellow eyes and normal eyes were taken for comparison with affected eyes

Summary

Introduction

Amblyopia is a deficiency of form sense resulting in the reduction in visual acuity of greater than two lines between the eyes or an absolute reduction in acuity below 6/9 in either eye, associated with decrements in visual processing, accommodation, motility, spatial perception or spatial projection.[2] It is the most common cause of monocular visual impairment in both children, and young to middle-aged adults, affecting 2–5% of the general population.[1]. The types of amblyopia in frequency is strabismus (about 50%), usually esotropia in infancy or early childhood. 17%), followed by a combination of strabismus and anisometropia (about 30%), and the least frequent cause is visual deprivation (≤3%) this one may result in severe amblyopia.[3]. Most of the deficit is believed to be the result of impairment of cortical development, changes have been seen in the lateral geniculate nucleus of nonhuman primates and humans after visual deprivation amblyopia during the neonatal period.[5,6]

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