Optical Coherence Tomography Measurement of Peripapillary Retinal Nerve Fiber Layer Thickness in Patients with Unilateral Amblyopic Eyes

Abstract

Background: Amblyopia is unilateral or less commonly bilateral reduction of best corrected visual acuity that cannot be attributed directly to the effect of any structural abnormality of the eye or posterior visual pathway. Amblyopia caused by abnormal visual experience early in life resulting from one of the following: Strabismus, anisometropia or high bilateral refractive error or stimulus deprivation.it is responsible for more unilateral reduced vision of childhood onset than all other causes combined. It affects 2-6% of general population.
Aim of Study: To compare RNFL thickness between normal and amblyopic eyes by OCT technique to define any structural abnormality in amblyopic eye.
Materials and Method: A case control hospital-based study was performed at Al-Sadder Medical city, Al-Najaf city. A total of 30 patients (14 female with 16 male) in (11-40) years old, range 29 years, who were diagnosed with unilateral amblyopia, 10 of them with strabismic amblyopia and the others 20 patient with anisometropic amblyopia were included in this study for a period started on January, till September 2014.
Full ophthalmologic examination was performed for both eyes for all patients,as the fellow eye taken as a control group, examination include: visual acuity and best corrected visual acuity (measured with snellen chart adjusted at 6 m), refraction ; slit lamp bio microscopy, intraocular pressure measurement using Air-buff tonometer (Topcon®), extraocular movement, dilated fundoscopic nation and oct examination for peripapillary retinal nerve fiber layer thickness.
Results: The study included 30 patient with unilateral amblyopic eyes (14 female and 16 male) 20 of them with anisometropic amblyopia and 10 with strabismic amblyopia. Mean age for patients with anisometropia was (24.8 years ± 9.7) with range of 29 years, Maximum 40 years and Minimum 11 years.
Mean age for patients with squint was (19.1 years ± 8.9) with range of 29 years, Maximum 39 years and Minimum 10 years. In our study we found that the superior and inferior peripapillary RNFL thickness in anisometropic amblyopic eyes are significantly thinner than the other normal eyes. While in strabismic amblyopia the inferior peripapillary RNFL thickness is significantly thinner than the other normal eyes.
Conclusion: Our results suggest that amblyopia seems to have a significant effect on the peripapillary RNFL thickness, in strabismic and anisometropic amblyopia.