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Bulgarian Review of Ophthalmology

Evaluation of peripapillary and macular retinal nerve fiber layer thickness in anisometropic amblyopic children with spectral-domain optical coherence tomography

B. Mihaylova, G. Dimitrova



Introduction: Anatomical and functional changes in visual cortex and lateral geniculate nucleus are well established in amblyopia process, but the part of retina is still controversial. It is supposed that retinal ganglion cells, nerve fiber layer (RNFL) and optic nerve are also involved.

Purpose: To evaluate the peripapillary and macular RNFL thickness (pRNFL, mRNFL) in anisometropic amblyopic children with spectral-domain optical coherence tomography (SD-OCT). The RNFL thickness was compared between the amblyopic, the nonamblyopic sound eye and control group of eyes.

Material and methods: This was a prospective observational study of 90 children (180 eyes) aged 4-18 years (mean 8.55±2.65) divided into two groups - controls (56 children) and anisometropic amblyopic group (34 children) with two subgroups- anisohyperopic amblyopia- 23 and anisomyopic amblyopia- 11. A Total of 9 RNFL parameters were measured using Topcon 3D OCT 2000+, protocols Circle and Glaucoma AnalysisMacula. The obtained data was statistically analyzed.

Results: Mean total values of pRNFL and mRNFL thickness were respectively 111.72±6.72 μm and 37.18±3.88 μm in control group of eyes, 119.96±11.39 μm and 35.09±4.22 μm in anisohyperopic amblyopic eyes, 102.18±9.64 μm and 36.73±4.05 μm in anisomyopic amblyopic eyes. In comparison with control group, statistically significant greater pRNFL thickness was found in anisohyperopic amblyopic eyes, and significantly smaller pRNFL thickness in anisomyopic amblyopic eyes. There was no significant difference in Mrnfl thickness among the three investigated groups. No significant difference in pRNFL and mRNFL thickness was observed between amblyopic and nonamblyopic sound eye in the two subgroups.

Conclusion: Our pRNFL thickness results in anisometropic amblyopia show similar changes to that of refraction errors without amblyopia. The well studied relationship between pRNFL thickness and the axial length (AL) prevents the precise interpretation of pRNFL thickness results in amblyopia, because it is not possible to determine whether the pRNFL thickness changes are due to anisometropic amblyopia or refraction error alone. In our previous investigations we did not find a correlation between mRNFL and AL. Therefore mRNFL seems to be a more accurate and reliable parameter than pRNFL for exploring retinal changes due to anisometropic amblyopia. Based on mRNFL results, we did not observe structural retinal changes in anisometropic amblyopia. Further study of mRNFL in strabismic and microstrabismic amblyopia is needed to confirm the statement that no structural changes take place in the retina as a result of amblyopia.


anisometropic amblyopia, retinal nerve fiber layer, optical coherence tomography

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About The Authors

B. Mihaylova
Medical University - Sofa, Faculty of Medicine, Department of Ophthalmology, University Hospital `Alexandrovska`, Sofia

G. Dimitrova
Medical University - Sofa, Faculty of Medicine, Department of Ophthalmology, University Hospital `Alexandrovska`, Sofia