Association between outer retinal alterations and microvascular changes in intermediate stage age-related macular degeneration: an optical coherence tomography angiography study

AIMS: To investigate associations between changes in retinal vessels and alterations detected by spectral domain optical coherence tomography (SD-OCT) scans in intermediate stage age-related macular degeneration (AMD). METHODS: Thirty eyes of 30 patients with intermediate dry AMD were enrolled in the study. Of the cohort study, 15 eyes (changes-AMD group) showed OCT changes preceding the development of drusen-associated atrophy. A control group of healthy subjects was selected for statistical comparisons. All patients underwent an ophthalmologic evaluation, including OCT angiography (OCTA) and SD-OCT scans. Main outcome measures were superficial vessel density, deep vessel density, macular thickness. RESULTS: Foveal macular thickness was 215.2±32.9 μm in changes-AMD patients and was significantly thinner than no changes-AMD patients (248.3±23.3 μm, p=0.002) and healthy subjects (268.1±19.2 μm, p<0.0001). Furthermore, in the parafoveal area, the thicknesses of both the inner retina and the outer retina were reduced in the changes-AMD group, after comparison with the two other groups. Parafoveal superficial vascular plexus flow density was 43.3±2.7% in changes-AMD patients and was decreased compared with the no changes-AMD group (48.7±3.3%, p=0.003) and healthy controls (50.4±6.1%, p=0.001). A direct correlation of the superficial plexus flow density with the inner retina parafoveal macular thickness (R2=0.761, p=0.028) was found. CONCLUSIONS: We demonstrated an association between SD-OCT signs and retinal blood supply in patients with intermediate AMD and we showed that patients with signs predicting development of geographic atrophy have a reduced flow in superficial vascular plexus and damage of the inner and the outer retina.