Randomised controlled trial of posterior sub-Tenon triamcinolone as adjunct to panretinal photocoagulation for treatment of diabetic retinopathy

Abstract

Aims: To evaluate the efficacy of a single posterior sub-Tenon capsule injection of triamcinolone acetonide (PSTA) before panretinal photocoagulation (PRP). Methods: This 6-month study involved the randomisation of 82 eyes of 41 patients, with bilateral severe non-proliferative diabetic retinopathy or proliferative diabetic retinopathy to a single PSTA 20 mg or to no injection before PRP. The primary end-point was change in best-corrected visual acuity (BCVA) at 6 months compared with that at baseline using the logarithm of the minimum angle of resolution (logMAR). Secondary end-points were changes in retinal thickness and intraocular pressure. Results: The mean changes in logMAR BCVA at 6 months compared with that at baseline were a worsening of 0.010 (SD 0.029) in the control group (no injection) and an improvement of 0.072 (0.028) in the PSTA group (p=0.04). The mean changes in foveal thickness at 6 months compared with baseline measurements were an increase of 32.8 (82.8) mm in the control group and a lessening of 9.7 (85.6) mm in the PSTA group (p=0.03). Conclusions: PSTA before PRP appears to be beneficial in preventing PRP-induced visual loss in eyes with diabetic retinopathy by reducing the chance of macular thickening.