Foveal avascular zone area and parafoveal vessel density measurements in different stages of diabetic retinopathy by optical coherence tomography angiography

AIM：To investigate foveal avascular zone（FAZ）and parafoveal vessel densities（PRVD）by means of optical coherence tomography angiography（OCTA）in diabetic patients with or without diabetic retinopathy（DR）and to assess the reproducibility of FAZ and PRVD measurements.METHODS：Sixty diabetic patients（60 eyes）with different stage of DR（graded according to the International Clinical Severity Scale for DR）and 20 healthy subjects underwent FAZ area and PRVD measurements using OCTA by two experienced examiners.FAZ area in all patients was also assessed using fluorescein angiography（FA）.RESULTS：In subject with proliferative DR and with moderate-severe non proliferative DR,FAZ area was significantly increased compared to healthy controls（P=0.025 and P=0.050 respectively measured with OCTA and P=0.025 and P=0.048 respectively measured with FA）.OCTA showed significantly less inter-observer variability compared to FA.Concordance correlation coefficient（CCC）for FAZ area measurements was 0.829（95%CI：0.736-0.891）P〈0.001 with FA and 1.000（95%CI：0.999-1.000）P〈0.001with OCTA.CCC was 0.834（95%CI：0.746-0.893）P〈0.001and 0.890（95%CI：0.828-0.930）P〈0.001 for parafoveal superficial and deep vessel density measurements,respectively.CONCLUSION：OCTA shows progressive increase of FAZ area and reduction of PRVD in both superficial and deep plexus at increasing DR severity.FAZ area and PRVD measurements using OCTA are highly reproducible.

Anatomical and functional changes after dexamethasone implant and ranibizumab in diabetic macular edema: a retrospective cohort study

AIM: To investigate the efficacy and safety of ranibizumab(RZB group) and dexamethasone implant(DEX group) intravitreal treatments in patients with treatment-na?ve center involved diabetic macular edema(DME) by means of functional and morphological assessments.METHODS: This retrospective cohort study included 50 eyes of 50 patients with DME treated either with RBZ or DEX. Best-corrected visual acuity(BCVA) and microperimetry were evaluated at baseline and during a 6-month follow-up. In addition, central macular thickness(CMT) by means of structural optical coherence tomography(OCT) and retinal capillary plexus density and choriocapillary density by means of OCT angiography were assessed in all cases.RESULTS: Functional and morphological parameters significantly improved during the study period in both groups. BCVA improved significantly in both groups witha greater increase in the DEX group compared to the RBZ group(P=0.030). Microperimetry significantly differed during follow-up between the two treatments(P=0.031). In both groups CMT significantly decreased(P<0.001) without statistically significant differences between the two groups. A statistically significant increase of deep capillary plexus density was detected in both groups at 30 d after therapy. The retreatment rate was 0.70±0.10 and 0.65±0.10 in the RBZ group and 0.65±0.10 and 0.50±0.11 in DEX group at 120 and 180 d respectively. Two out of 25 patients in DEX group showed intraocular pressure increase requiring hypotonic eye drops.CONCLUSION: Both treatments are very effective for DME treatment during 6 mo of follow-up with a lower retreatment rate in DEX group.