Abstract
Purpose:
The purpose of this study was to evaluate a single session of PRP using the PASCAL laser compared to a single session of PRP plus immediate intravitreal bevacizumab in the treatment of high risk proliferative diabetic retinopathy (PDR) with center involving diabetic macular edema (DME).
Methods:
This was a retrospective comparison of type 2 diabetics with high risk PDR by ETDRS criteria and no history of prior laser therapy who received a single session of PRP with the PASCAL laser (PRP-only) or PRP plus immediate injection of intravitreal bevacizumab (PRP-plus) for the treatment of high risk PDR with center involving DME. Main outcome measures included changes in best corrected visual acuity (BCVA) and central submacular thickness (CST) measured with the Spectralis instrument after 24 weeks. Exclusion criteria included a history of focal laser, vitreoretinal surgery or tractional retinal detachment in the study eye. Mean values were compared with unpaired t-test. Statistical significance was accepted at p < 0.05.
Results:
Twenty patients (PRP-only, n = 10; PRP-plus, n = 10 eyes) were matched for baseline characteristics including age (PRP-only, 63 ± 9 vs. PRP-plus, 54 ± 13 years, p = 0.10), BCVA (20/87 vs. 20/135; LogMAR 0.64 ± 0.27 vs. 0.83 ± 0.60, p = 0.39), intraocular pressure (15.6 ± 2.1 vs. 18.2 ± 6.6 mmHg, p = 0.24), CST (402 ± 129 vs. 414 ± 138 μm, p = 0.87), number of PASCAL spots (2033 ± 675 vs. 2173 ± 817, p = 0.68) and follow up visits (3.4 ± 2.0 vs. 4.3 ± 2.3, p = 0.36). After 24 weeks, BCVA was similar between the two groups (20/110 vs. 20/105; LogMAR 0.74 ± 0.48 vs. 0.72 ± 0.59, p = 0.62), however there was a significant decrease in CST in the PRP-plus group (414 to 323 μm, p < 0.05), but not in the PRP-only group (402 to 403 μm, p = 0.99). During the follow up period, the PRP-only group received a total of 19 additional treatments (11 anti-VEGF injections, 3 PRP with anti-VEGF, 3 PRP and 2 vitrectomies) versus 13 in the PRP-plus group (9 anti-VEGF and 4 PRP). The mean interval before the first retreatment was similar for both groups (11.5 vs. 13.4 weeks, p = 0.61).
Conclusions:
PRP using the PASCAL laser combined with intravitreal bevacizumab is associated with a greater reduction in CST compared to PRP alone and may be a useful therapy for patients with high risk PDR and center involving DME.