Quantitative assessment of retinal microvasculature using optical coherence tomography angiography and correlation with visual acuity in leber's hereditary optic neuropathy.

Purpose: To analyze macular microvascular networks and investigate correlations between visual acuity and quantitative parameters in patients with Leber's hereditary optic neuropathy (LHON) using optical coherence tomography angiography (OCTA).

Methods: An observational, cross-sectional study was conducted, including 25 eyes from 25 genetically confirmed chronic LHON patients and 25 eyes from 25 age-matched healthy controls. Images were obtained using a spectral domain OCTA system. Student's t-test for independent variables was employed to compare continuous variables between the LHON and control groups. Pearson correlation coefficients were calculated to analyze the correlation between best-corrected visual acuity (BCVA) and OCTA parameters, which included vessel area density (VAD), vessel skeleton density (VSD), vessel diameter index (VDI), vessel complexity index (VCI), flux, foveal avascular zone (FAZ) parameters, and the thickness of the general ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) in LHON patients.

Results: LHON eyes exhibited significant reductions in VAD, VSD, and flux across all sectors in the foveal region. VAD, VSD, VCI, and flux decreased in all sectors, while VDI increased in all sectors except the temporal sector in the parafovea, based on the traditional four sectors. In the six sectors matched with the GCC, VAD, VSD, and flux decreased in all sectors; VDI increased in the superonasal, inferior, and inferotemporal sector, while VCI decreased except in the inferotemporal sector. The circularity of FAZ decreased. BCVA was correlated with VAD in the inferotemporal, inferior, and inferonasal sector, VSD in all sectors, and GCC thickness only in the inferonasal sector.

Conclusion: LHON is characterized by diffuse impairment of the retinal microvasculature, predominantly affecting the macular region and corresponding to the papillomacular bundle. Furthermore, BCVA demonstrated significant correlations with retinal blood flow and structural parameters.