Diabetic retinopathy (DR) is one of the most severe diabetes-related complications, and macular edema stands as the primary contributor to the loss of central vision in individuals diagnosed with diabetes mellitus. The purpose of this study was to investigate the anatomical and functional effects of the oral administration of bromelain and curcugreen in patients controlled by therapy with non-proliferative DR presenting focal edema. Patients were enrolled and divided into two groups: group A (n = 18) received two tablets a day of bromelain and curcugreen (Retinil Forte®) orally, and group B (n = 15) underwent observation. The protocol included four visits: the screening visit (T0) and follow-up checks every 3 months up to 12 months (T3-T6-T9-T12). Best-corrected visual acuity (BCVA), central macular thickness (CMT) measured by optical coherence tomography (OCT) and vascular perfusion (VP) in superficial capillary plexus (SCP) and the deep capillary plexus (DCP) measured by optical coherence tomography angiography (OCTA) were analyzed. A mixed-design ANOVA was calculated to determine whether the change in BCVA, CMT, VP in SCP and DCP over time differed according to the consumption of Retinil Forte®. The results indicated that the interaction between time and treatment on the CMT and VP in DCP were significant, with F (4, 124) = 6.866 (p < 0.0001) and F (4, 124) = 3.263 (p = 0.0140), respectively. Conversely, the interaction between time and treatment was not significant on BCVA and VP in SCP with F (4, 124) = 1.121 (p = 0.3496) and F (4, 124) = 1.473 (p = 0.2146), respectively. In conclusion, our results suggest a protective role of the oral administration of bromelain and curcugreen in patients with DR and focal edema, in terms of the improvement of baseline CMT and VP in DCP over time.
Keywords: bromelain; curcumin; diabetic retinopathy; macula edema; nutraceuticals; optical coherence tomography.