Evalution of macular and retinal nerve fiber layer thickness using optical coherence tomography in cases with unilateral amblyopia

Purpose: To investigate the effects of amblyopia on the macular thickness and retinal nerve fiber layer by measuring the macular thickness and retinal nerve fiber layer thickness in unilateral strabismic amblyopia patients and unilateral anisometropic amblyopia patients using optical coherence tomography. Material and Method: 84 eyes of 42 unilateral strabismic amblyopia patients, 100 eyes of 50 anisometropic amblyopia patients and 100 eyes of 50 healthy control subjects between the ages of 5-62 included to the study. We evaluated retinal nerve fiber layer and macular thickness using optical coherence tomography. We excluded patients having ocular pathology except mild refractive error, amblyopia and strabismus. All the measurements taken using optical coherence tomography (Spectralis®) and the measurements were taken without pupil dilatation by same examiner. Statistical data were given as a mean value ± standart deviation. The "student's t test for independent samples" was used for statistical assesment. Results: The mean age of the strabismic, anisometropic and control groups were 21.79±11.51, 24.68±14.41 and 25.96±15.01, respectively. There was no statistically significant difference in macular thickness between the groups (p>0.05). The global retinal nerve fiber layer thickness of strabismic amblyopia and control groups were 98.07±10.92 µm, 101.50±9.56 µm, respectively and there was no statistically significant difference (p>0.05). The superotemporal, temporal and inferotemporal segments of retinal nerve fiber layer in the strabismic group was significantly thinner than the control group (p<0.05). However, the nasal segment of retinal nerve fiber layer in the strabismic group was thicker than the control group (p<0.05). The global retinal nerve fiber layer thickness of anisometropic amblyopia group and control group was 108.26±10.86 µm and 101.50±9.56 µm, respectively. In the anisometropic amblyopia group the global retinal nerve fiber layer was significantly thicker than the control group (p<0.001). Conclusion: It was found that patients with anisometropic amblyopia have thicker retinal nerve fiber layer thickness comparing to strabismic amblyopia patients and healthy control subjects. Hyperopia and shorter axial length will be contributing factors for the difference between groups. Key Words: Amblyopia, macular thickness, optical coherence tomography, retinal nerve fiber layer.