Posterior sub-Tenon's capsule injection of triamcinolone acetonide prevents panretinal photocoagulation-induced visual dysfunction in patients with severe diabetic retinopathy and good vision.

PURPOSE

To evaluate prospectively the efficacy of a single sub-Tenon's capsule injection of triamcinolone acetonide (TA) against panretinal photocoagulation (PRP)-induced macular thickening and visual disturbance in patients with severe diabetic retinopathy and good vision.

DESIGN

Prospective, comparative, interventional case series.

PARTICIPANTS

Twenty eyes of 10 patients with severe nonproliferative diabetic retinopathy or non-high-risk proliferative diabetic retinopathy whose visual acuity was 20/40 or better (<0.3 in logarithm of the minimum angle of resolution [logMAR] acuity) before the PRP, whose retinopathy was bilateral and symmetrical. The averaged parafoveal retinal thickness was more than 300 microm, leading to a worse visual prognosis after PRP.

INTERVENTION

Sub-Tenon's capsule injection of 20 mg TA.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA) with logMAR chart and averaged foveal thickness (FT) using the retinal mapping program of optical coherence tomography.

METHODS

In all patients, PRP was performed every other week for 4 sessions on both eyes, and 1 week before PRP; 1 eye received the TA injection, and the other eye served as a control. The clinical course of BCVA and FT was monitored for up to 24 weeks after beginning PRP.

RESULTS

Before TA injection, BCVA and FT were 0.055+/-0.072 and 235.5+/-37.5 microm in the TA-injected eye and 0.065+/-0.071 and 233.7+/-39.8 microm in the control eye, respectively; there was no significant difference between eyes. After the TA injection, FT in the TA-injected eyes was significantly decreased. During and after the PRP, FT in the control eye increased dramatically and reached 312.0+/-68.2 microm at 24 weeks, which was significantly different from that in the TA-injected eyes (235.3+/-38.6 microm at 24 weeks). Best-corrected visual acuity in the control eye decreased with time to 0.24+/-0.13; in contrast, and BCVA in the TA-injected eye was good (to 0.085+/-0.11) .

CONCLUSIONS

As a pretreatment for PRP, a single sub-Tenon's capsule injection of TA has beneficial effects for preventing PRP-induced foveal thickening and visual dysfunction in patients with severe diabetic retinopathy and good vision.