PHOTORECEPTOR DAMAGE IN DIABETIC CHOROIDOPATHY

PURPOSE: To investigate the relationship between choriocapillaris (CC) hypoperfusion and photoreceptor alterations in eyes with nonproliferative diabetic retinopathy (NPDR). METHODS: In this prospective, observational, case-control study, 30 eyes (30 patients) with NPDR and 30 healthy eyes from 30 controls were enrolled at the University G. d'Annunzio, Chieti-Pescara, Italy. This study cohort underwent an ophthalmologic examination, including optical coherence tomography and optical coherence tomography angiography. The main outcome measures were as follows: 1) "normalized" reflectivity of en face image segmented at the ellipsoid zone level, which was calculated to quantify the photoreceptor damage, and 2) CC perfusion density. Secondary outcome measures were as follows: 1) superficial retinal capillary plexus (SCP), intermediate retinal capillary plexus (ICP), and deep retinal capillary plexus (DCP) perfusion density (based on the area of vessels); 2) SCP, ICP, and DCP vessel length density (based on a map with vessels of 1-pixel width); and 3) SCP, ICP, and DCP vessel diameter. RESULTS: Mean ± SD age was 58.9 ± 11.1 years (range 38-79 years) in the NPDR group and 61.7 ± 11.3 years (range 39-87 years) in the control group (P > 0.05 for all the comparisons). Compared with controls, NPDR eyes displayed a lower "normalized" reflectivity (0.96 ± 0.25 in controls and 0.73 ± 0.19 in the NPDR group, P < 0.0001). Moreover, the NPDR group was characterized by an impaired perfusion in both the retinal and choroidal vasculature. In multiple regression analysis, ellipsoid zone "normalized" reflectivity displayed a significant direct association with CC perfusion density in patients with NPDR (P = 0.025 and P = 0.476, in NPDR and controls, respectively). CONCLUSION: Eyes with NPDR are affected by macular hypoperfusion and photoreceptor damage, the latter investigated as ellipsoid zone "normalized" reflectivity. The diabetic choroidopathy seems to be strongly associated with photoreceptor damage.