Structure versus function in high myopia using optical coherence tomography and automated perimetry.

BACKGROUND: To examine the structure-function relationship between retinal thickness using spectral-domain optical coherence tomography and standard automated perimetry in high myopia.

METHODS: The study population comprised 58 highly myopic individuals with no posterior abnormalities (mean spherical equivalent refraction ≤ -6.00 D and axial length ≥ 26.0 mm). All eyes underwent optical coherence tomography with the Spectralis spectral domain optical coherence tomograph and visual field evaluation with the Humphrey Field Analyzer II-i. Average macular layer thicknesses in each quadrant were calculated in a 6 × 6 mm area centred on the fovea. The visual field was assessed from 17 central locations (10°), approximately the equivalent of the area tested by optical coherence tomography in the macular scan. Linear correlations were made between different macular layer thicknesses and peripapillary retinal nerve layer thickness with their matched visual field sensitivities.

RESULTS: Participant ages were 28.2 ± 6.4 years, mean spherical equivalent refractions were -8.20 ± 1.40 D and axial lengths were 26.7 ± 0.7 mm. There were significant positive correlations between layer thickness and corresponding visual field sensitivities as follows: ganglion cell layer in all quadrants, temporal quadrant of the nerve fibre layer with nasal quadrant of the visual field, inferior quadrant of the outer nuclear layer with superior visual field, and temporal-superior peripapillary nerve fibre layer with nasal-inferior visual field.

CONCLUSION: The correlation between retinal layer thicknesses and visual field sensitivity could be explained by myopia-related losses due to lateral retinal stretching, with further research required to investigate this.