Aims: To evaluate the efficacy of a single posterior sub-Tenon′s capsule injection of triamcinolone acetonide (PSTA) before panretinal photocoagulation (PRP).
Methods: In this 6-month study, we randomized 82 eyes of 41 patients with bilateral severe nonproliferative diabetic retinopathy or proliferative diabetic retinopathy to a single PSTA 20 mg or to no injection before PRP. Main Outcome Measures: The primary end-point was change in best-corrected visual acuity (BCVA) at 6 months compared to that at baseline using logarithm of the minimum angle of resolution (logMAR). Secondary end-points were changes in retinal thickness, and intraocular pressure (IOP).
Results: The mean changes in logMAR BCVA at 6 months compared to that at baseline was a worsening of 0.010 ± 0.029 in the control group (no injection) and an improvement of 0.072 ± 0.028 in the PSTA group; this constituted a significant difference (P = .04). The mean change in foveal thickness at 6 months compared to baseline measurements was an increase of 32.8 ± 82.8 µm in the control group and a lessening of 9.7 ± 85.6 µm in the PSTA group, which was also significant different (P = .03). There were no significant differences between the two groups in IOP at any follow-up point.
Conclusions: PSTA before PRP appears to be beneficial in preventing PRP-induced visual loss in eyes with severe nonproliferative or proliferative diabetic retinopathy by reducing the chance of macular thickening.