Abstract
Purpose :
To evaluate the changes of relevant optical coherence tomography (OCT) and OCT angiography (OCT-A) parameters before and after treatment with intravitreal dexamethasone implant in eyes with diabetic macular edema (DME).
Methods :
type 2 diabetic patients with untreated center involving DME were enrolled. The main exclusion criteria were: high refractive error (> 6 diopters), significant media opacity, severe non-proliferative and proliferative diabetic retinopathy (DR), recent intraocular surgery (6 months), poor glycemic control. All eyes underwent full ophthalmologic evaluation including: best-corrected visual acuity (BCVA); intraocular pressure measurement, DR-grading and wide-field angiography. Central retinal thickness (CRT), retinal volume (RV) and number of hyperreflective spots (HRS), counted with two different modalities, were measured on Spectral Domain OCT (SD-OCT). Measurement of foveal avascular zone (FAZ) area of the superficial and deep capillary plexuses (SCP, DCP) on OCT-A was performed. All parameters were analyzed at baseline and at follow-up. After baseline visit, patients were injected with dexamethasone implant.
Results :
Eleven patients were enrolled. Mean age was 72.2 ± 10.9, mean HbA1c was 7.46 % ± 1.01%. Compared to baseline, at 1-month post injection, mean number of letters significantly increased (75.6 ± 9.0 vs 69.9 ± 11.2, p<0.05) while mean CRT and RV significantly reduced (337.7±80.8 μm vs 473.4±133.6 μm and 9.8±1.3 μm2 vs 11.1±1.8 μm2, respectively, p<0.05 for all). The number of HRS significantly reduced both at 1 and 3 months post injection (49.2±11.7 and 39.0±15.5 respectively vs 63.2±20.9, p value<0.05 for both). The FAZ area of SCP at baseline showed a reduction trend at 1 month and remained stable (0.46±0.20 mm2 and 0.46±0.15 mm2 vs 0.63 ±0.24 mm2), while measurement of FAZ area of DCP resulted unreliable for statistical analyses. No adverse events were registered.
Conclusions :
Untreated DME eyes showed a marked improvement of BCVA and reduction of CRT, RV and FAZ area of SCP after treatment with dexamethasone implants. The number of HRS, representing a sign of retinal inflammation, showed a significant reduction after treatment. The reduction of HRS seems to mirror the anti-inflammatory effect of intravitreal steroid. HRS number and FAZ area of SCP may represent new valuable OCT and OCT-A parameters to monitor retinal response to treatment in DME eyes
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.