Evalution of retinal nerve fiber layer thickness with optical coherence tomography in various amblyopia types

Amblyopia is the lack of vision which occurs due to abnormal visual development without any organic pathology in one or both eyes. Although visual cortex is the primer location in amblyopia, it should be discussed concomitantly that retina and retinal nerve fiber layer (RNFL) thickness have changed. In this study, it was aimed to compare unilateral anisometropic and strabismic amblyopia patients with retinal nerve fiber layer thickness of the control group. A total of 111 patients, 35 strabismic and 36 anisometropic amblyopia patients and 40 control group, were included. Patients in the control group had similar age and gender distribution. The average and four quadrants (superior, inferior, nasal, temporal) RNFL thickness measurements of amblyopic eyes of patients with amblyopia and the right eyes of the control group were compared with spektralis optical coherence tomography (OCT). The difference between average RNFL thicknesses of the two groups was not significant (p>0.05). Significant thinning in the inferior quadrant in the strabismic group was viewed (p=0.007). When refraction and RNFL thicknesses of anisometropic amblyopic patients were compared, it was observed that the average RNFL thickness increased with increasing hyperopic refraction and the average RNFL thickness decreased with increasing myopic refraction. However, this change was thought to be due to myopia and hyperopia, rather than amblyopia. As a result, significant change was not observed in average RNFL thickness in amblyopia cases. In patients with amblyopia, the higher visual pathways like lateral geniculate nucleus (LGN) and visual cortex might be considered as damaged rather than structural damage of the retina. Key Words: Amblyopia, RNFL, OCT, Anisometropia, Strabismus.