Optic nerve head perfusion changes in eyes with proliferative diabetic retinopathy treated with intravitreal ranibizumab or photocoagulation: a randomized controlled trial

Background: Proliferative diabetic retinopathy (PDR) is a serious sight-threatening disease, and half of the patients with high-risk PDR can develop legal blindness within 5 years, if left untreated. This study was aimed at comparing panretinal photocoagulation (PRP) and intravitreal ranibizumab injections in terms of radial peripapillary capillary (RPC) density on optical coherence tomography angiography (OCTA) in patients with treatment-naive PDR.  Methods: This open-label, prospective, randomized clinical trial included 50 patients with treatment-naive PDR with optic disc neovascularization and randomized them into two groups: group 1, with patients undergoing two sessions of PRP 2 weeks apart, and group 2, with patients received three intravitreal ranibizumab injections (0.5 mg) 1 month apart for 3 consecutive months. Patients underwent a full ophthalmological examination, including best-corrected distance visual acuity (BCDVA) measurement in the logarithm of minimal angle of resolution (logMAR) notation and OCTA before intervention and monthly after the last laser session or the first intravitreal ranibizumab injection for 3 months of follow-up. Visual field (VF) was tested at the beginning and end of 3 months.   Results: Forty-two (84%) eyes completed the 3-month follow-up, including 22 eyes in the PRP group (88%) and 20 (80%) eyes in the ranibizumab group. The two groups were comparable in terms of demographic characteristics, diabetes duration, baseline BCDVA, glycated hemoglobin level, OCTA parameters, VF indices, and intraocular pressure (all P > 0.05). The RPC density change from baseline to the 3-month follow-up was significantly lower in the PRP group than in the ranibizumab group (mean difference in RPC density change: - 3.61%; 95% confidence interval: - 5.57% to - 1.60%; P = 0.001). The median (interquartile range) logMAR change from baseline to the 3-month follow-up (0.0 [0.2]) was significantly higher in the PRP group than in the ranibizumab group (- 0.15 [0.3]; P < 0.05). The median changes in central foveal thickness from baseline to the 3-month follow-up differed significantly between the two groups (P = 0.001). Conclusions: In eyes with PDR and neovascularization of the disc RPC density on OCTA increased in the ranibizumab group and decreased in the PRP group. Visual acuity gain was higher in the ranibizumab group than in the PRP group. Future multicenter trials addressing our limitations are required to verify the findings of this study

Safety and efficacy of photodynamic therapy using BCECF-AM compared to mitomycin C in controlling post-operative fibrosis in a rabbit model of subscleral trabeculectomy

AIM: To evaluate the safety and efficacy of cellular photoablation using BCECF-AM [2’, 7’-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester mixed isomers] as a method to control postoperative fibrosis in subscleral trabeculectomy (SST) compared to mitomycin C (MMC) in a rabbit model. METHODS: A comparative prospective case-control animal study was conducted. Fourteen rabbits were subjected to SST with intraoperative use of wound modulating agents (MMC or BCECF-AM) of the right eye (study groups I and II respectively) and SST without use of intraoperative wound modulating agents for the left eye (control group II). Two rabbits 4 eyes were considered as control group I with no surgical intervention. BCECF-AM was injected subconjunctivally 30min before surgery followed by intraoperative illumination with diffuse blue light for 10min. Antifibrotic efficacy was established by clinical response and histological examination. Clinical response was assessed by measuring intraocular pressure (IOP) at day 1, 3, 5, 7, 14, 21 postoperatively. Success was defined by ＞20.0% reduction in IOP from the preoperative values without anti-glaucoma medications. RESULTS: The mean percentage of reduction was 35.0% in the study group I with only one eye (14.3%) had 12.5% reduction. The mean percentage of reduction was 28.0 % in the study group II with two eyes (28.6%) in study group II had 14.2% reduction each. Regarding the control group II, the mean percentage of reduction was 14.3 % with 64.3% eyes had ＜20.0% reduction. There was a highly statistically significant difference between each of the study groups (right eyes) and the corresponding control group II (left eyes) as regards the mean postoperative IOP values started from day 5 in both study groups and this highly significant difference remained so till the end of the follow up period. Histologically, MMC treated blebs showed thinning of conjunctival epithelium with marked reduction of the goblet cells relative to control. Marked sub-epithelial edema was seen along with variable collagen dispersion. Mild cellularity was noted in sub-epithelial tissue. BCECF-AM treated blebs showed normal conjunctival epithelial thickness with abundant goblet cells. Mild sub-epithelial edema was noted along with moderate collagen dispersion. No histological abnormality was noted in the ciliary body or the cornea in any of the studied groups. CONCLUSION: Cellular photoablation using BCECF-AM is a safe and effective wound modulating agent to control postoperative fibrosis in trabeculectomy. However MMC considered as a more potent adjuvant to trabeculectomy than BCECF-AM in promoting IOP reduction