Comparison of macular and peripapillary vascular density measured by optical coherens tomography angiography in different types of amblyopia

SUMMARY PURPOSE: We aimed to compare the vascular density values in the macular and peripapillary areas in different types of amblyopia (ametropic amblyopia, anisometropic amblyopia, strabismic amblyopia, deprivation amblyopia) with age- and gender-matched healthy control group by optical coherence tomography angiography (OCTA). MATERIAL AND METHODS: Patients aged 8-18 years who applied to the Afyon Kocatepe pediatric ophthalmology clinic between May 2020 and February 2021 were included in this prospective, cross-sectional study. 32 eyes of 16 patients with hyperopic ametropic amblyopia, 21 eyes of 21 patients with hyperopic anisometropic amblyopia, 15 eyes of 15 patients with strabismic amblyopia due to esotropia, 12 eyes of 12 patients with deprivation amblyopia and 30 eyes of 30 individuals with emmetropia (as the control group) were included. The patients' refraction errors and best corrected visual acuity (BCVA) were recorded as logMAR with the Snellen chart. In all cases, superficial vascular plexus, deep vascular plexus whole image vessel density, foveal vessel density, parafoveal vessel density, perifoveal vessel density values and foveal avascular zone area (FAZ) values were measured and recorded to evaluate macular region vascular density with OCTA. Whole image, intra-disc and peripapillary vessel density were measured to evaluate the retinal nerve fiber layer (RNFL) and peripapillary region vascular density. Kruskal Wallis test was used for statistical analysis and post hoc test was used for intergroup comparison. RESULTS: There was no statistically significant difference between the groups in terms of age and gender. The best corrected visual acuity was found to be statistically significantly lower in the group with anisometropic amblyopia (0.44 ±0.16) , strabismic amblyopia (0.40 ± 0.13) and deprivation amblyopia (0.98 ± 0.23) (unilateral amblyopa) compared to ametropic amblyopia (0.26 ±0.10) (bilateral amblyopia) and healthy groups (0) (p<0.001). In anisometropic amblyopia, strabismic amblyopia, and deprivation amblyopia, parafoveal vessel density, foveal vessel density, and overall image of the superficial and deep vascular plexus were found to be statistically significantly lower than in ametropic amblyopia and healthy volunteers (p < 0.001). FD-300 vessel densities and optic disc whole image vessel densities were found to be statistically significantly lower in unilateral amblyopia compared to ametropic amblyopia and healthy subjects (p < 0.001). There was no statistically significant difference between the five groups in terms of FAZ and PERIM measurements, RNFL values, and optic disc intra-disc and peripapillary vessel densities. In the correlation analysis, a negative correlation was found between best corrected visual acuity in LogMAR and superficial vascular plexus foveal vessel density (p < 0.001, r= - 0.622), superficial vascular plexus parafoveal vessel density (p < 0.001, r= -0.556), deep vascular plexus foveal vessel density (p <0.001, r = -0.636) and deep vascular plexus parafoveal vessel density (p < 0.001 r=-0.596). CONCLUSION: In anisometropic amblyopia, strabismic amblyopia and deprivation amblyopia, the vascular densities of the macular region superficial and deep vascular plexus are affected, and OCTA is a useful tool to detect these changes.