Retinal nerve fiber layer thickness in dominant optic atrophy: Measurements by optical coherence tomography and correlation with age

Purpose: To measure the retinal nerve fiber layer (RNFL) thickness by means of optical coherence tomography (OCT) in patients with dominant optic atrophy (DOA). Design: Cross-sectional study. Participants: Thirty-three patients from 15 pedigrees with DOA harboring heterozygous mutations in the OPA1 gene and 43 healthy subjects were enrolled. Methods: The RNFLs of DOA patients were studied by OCT and compared with those of 43 healthy subjects matched for age and optic nerve head (ONH) size. Main Outcome Measures: Retinal nerve fiber layer thickness. Results: Dominant optic atrophy patients revealed a significant RNFL thickness reduction in all quadrants, with a preferential involvement of the temporal and inferior sectors. The progressive decline of RNFL thickness with age was similar to that observed in healthy subjects and was more evident in the 2 quadrants with higher residual amounts of fibers, that is, the superior and the inferior. The temporal quadrant was profoundly depleted of fiber so that the further rate of loss of microns per year is close to zero, whereas the nasal quadrant was spared the most by neurodegeneration. Conclusions: The present findings, taken in conjunction with the authors' previous description of small ONH size in DOA, strongly suggest that patients with this disease are born with fewer optic nerve axons and support the hypothesis that subsequent visual loss depends on further age-related loss of fibers, which also occurs in controls. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.