Author: Colin Tan (Singapore)
Co-authors: Wei Kiong Ngo
To investigate the effect of treatment in eyes having center-involving diabetic macular edema (ciDME) with intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy on macular perfusion measured using optical coherence tomography angiography (OCT-A).
Tertiary Ophthalmology referral center
In a prospective interventional cohort study, 22 patients with at least 1 eye having ciDME referred to the Medical Retina service were recruited. All patients enrolled received 3 consecutive monthly loading doses of intravitreal anti-VEGF injections starting at baseline. All patients had OCT-A and spectral-domain optical coherence tomography (SD-OCT) scans performed at baseline and subsequently at month 3, after the completion of the anti-VEGF therapy. The 3x3 mm macular scans on OCT-A were used in this analysis. Using the in-built manufacturer software, average vessel density and size of the fovea avascular zone (FAZ) measurements in the superficial capillary plexus were generated. Central retinal thickness (CRT) in the central 1-mm Early Treatment Diabetic Retinopathy Study (ETDRS) standard subfield measured on SD-OCT were also recorded. These imaging parameters were correlated with baseline patient demographics and disease parameters such as the severity of background diabetic retinopathy to investigate their relationships.
Twenty-two patients (11 males and 11 females) were enrolled into the study. The mean age was 62.1 years old (range 50-81 years). Of the 44 eyes, 32 eyes had ciDME and received anti-VEGF injections while 12 eyes did not have ciDME. Four (9.1%) eyes had background mild non-proliferative diabetic retinopathy (NPDR), 19 (43.2%) eyes had moderate NPDR, 10 (22.7%) eyes had severe NPDR, 5 (11.4%) eyes had proliferative diabetic retinopathy (PDR) and 6 (13.6%) eyes were status post panretinal photocoagulation (PRP). At baseline, average vessel density was significantly higher in the group with mild-moderate NPDR compared to the group with severe NPDR-PDR and status post PRP (44.0% vs. 40.5%, p=0.007). However, there is no difference in size of the FAZ when the two groups based on background retinopathy were compared (0.380 mm2 vs. 0.387 mm2, p=0.865). CRT in eyes with ciDME at baseline (mean CRT 441.7um) decreased significantly after anti-VEGF therapy at month 3 (mean CRT 377.3um, p=0.001). Despite a significant decrease in CRT after anti-VEGF injections, there was no significant difference between average vessel density (42.2% vs. 43.2%, p=0.145) and size of the FAZ (0.404 mm2 vs. 0.419 mm2, p=0.504) at baseline and month 3 after treatment.
At baseline, there is an association between the average vessel density at the macula with the severity of background retinopathy. Following treatment of ciDME with 3 consecutive monthly loading doses of intravitreal anti-VEGF injections, there is significant decrease in CRT and edema. Despite this, the average vessel density at the macula and size of the FAZ remained statistically unchanged in the short-term after injections.
Novartis - conference support Bayer - conference support