First Author: A.Kuzmin RUSSIA
Co Author(s): V. Surguch D. Lipatov E. Bessmertnaya
Back to previous
To determine the factors impacting visual acuity and central macular thickness (CMT) after pars plana vitrectomy for the diabetic macular edema (DME).
Cross-sectional study with following prospective observation.
A consecutive series of 16 eyes in 16 patients with DME who underwent pars plana vitrectomy were recruited into the study. 2 of them suffered from diabetes mellitus type 1 (mean age was 37 years, diabetes duration was 20.5 years), 14 suffered from diabetes mellitus type 2 (mean age was 65±5.6 years, diabetes duration 15.9±6.5 years). All patients underwent 23Ga pars plana vitrectomy by one surgeon. The indication for the vitrectomy were DME with tractions or diffuse DME resisted to the therapy by VEGF inhibitors. There was one technique of the vitrectomy with membrane staining by Membrane Blue Dual, inner limiting membrane peeling and air tamponade in all cases. Spectral-domain optical coherence tomography and visual acuity were obtained preoperatively, 3 and 6 months after surgery. The observation period was 2 years or up to macular edema relapse. 6 patients had proliferative diabetic retinopathy (DR), 7 patients had nonproliferative DR, 9 patients were treated by laser photocoagulation preoperatively. The best corrected visual acuity (BCVA) before operation was 0.38±0.12, mean CMT was 484.4±122.4 µm, mean DME duration was 15.5±8.8 months, 10 eyes were treated by VEGF inhibitors injections, from 1 till 4 injections were performed before surgery.
There were mean BCVA 0.43±0.2 and mean CMT 311.8±58.2 µm 6 months after vitrectomy. Mean change of CMT was 172.3±130.4 µm. Outcomes of the vitrectomy were significantly better in the group of patients without previous VEGF inhibitors injections than in patients treated by VEGF inhibitors: CMT 6 months after operation was 287.3±57.3 µm and 326.5±56.4 µm accordingly, BCVA was 0.53±0.25 and 0.36±0.2 accordingly, p<0.05. There were similar CMT 6 months after surgery in groups of patients with previous retinal laser photocoagulation and without: 304.6±73.7 µm and 321.1±32.4 µm accordingly, however BCVA was better in group of patients without laser photocoagulation of the retina – 0.54±0.18 against 0.33±0.23 in patients treated by laser (p<0.05). Delta CMT was significantly correlated with DME duration (negative association). 5 patients (31%) demonstrated DME relapse in time from 6 till 17 months after surgery. All of them were treated by laser photocoagulation before surgery, 2 of them had proliferative DR, 3 of them were treated by intravitreous injections of the VEGF inhibitors.
Outcomes of the pars plana vitrectomy were better in patients with neither previous retina lasercoagulation nor intravitreous VEGF inhibitors injections. This can be explained by a shorter time before operation and retinal changes associated with laser treatment and VEGF inhibitors. Risk of the DME relapse was associated with higher DME duration.