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The effect of high myopia on retinal nerve fiber layer (RNFL) thickness has been a subject of numerous studies. It has been speculated that the retinal stretch in elongated eyes is causing RNFL thinning that might confound the RNFL thinning measured to indicate glaucoma. Schweitzer et al. (1103) evaluated the relationship between RNFL thickness and axial length in age matched healthy subjects with emmetropia and high myopia (spherical equivalent ≥-10 D OU). Ten participants from each group had comprehensive ophthalmic examination, axial length measurements and Stratus optical coherence tomography (OCT; Carl Zeiss Meditec, Dublin, CA) scanning of the peripapillary region. The authors reported a negative and statistically significant relationship, or a decrease in overall mean RNFL thickness with increase in the axial length.
The actual effect of high myopia on RNFL thickness is yet to be determined
However, several limitations of the study should be considered when evaluating this finding. The authors did not examine the visual field and therefore inadvertently might enroll subjects with glaucoma, did not consider the scan quality which can be challenging in subjects with high myopia, did not rule-out the presence of peripapillary atrophy along the scanning pathway, which is a common feature in such eyes that might affect the thickness measurements, and did not account for the correlation between both eyes of each participants in the analysis. The actual effect of high myopia on RNFL thickness is yet to be determined.