Posterior Hyaloid Changes Following Intravitreal Triamcinolone and Macular Laser for Diffuse Diabetic Macular Edema

In Brief Purpose: To compare the effects of intravitreal triamcinolone and macular grid laser photocoagulation on the vitreomacular relationship in diffuse diabetic macular edema. Methods: Review of optical coherence tomography images gathered in a prospective, interventional randomized clinical trial. Setting: Institutional Practice. Procedures: Seventy-seven optical coherence tomography images of 88 consecutive patients entered into a randomized clinical trial of the treatment of persistent diffuse diabetic macular edema were reviewed by two independent observers. All patients in the trial had diabetic macular edema following at least two macular grid laser treatments and were randomized to intravitreal injections of 4 mg triamcinolone or to further macular grid laser. Optical coherence tomography images were recorded at baseline, 4, 8, and 12 months and the patterns of vitreomacular relationship were classified into six categories. Main outcome measures: The patterns of vitreomacular relationship in the two groups were compared and correlated with the response to treatment. Outcome measures were defined as changes in best-corrected visual acuity Early Treatment Diabetic Retinopathy Study letters and central macular thickness on optical coherence tomography. Results: Six eyes had peri-foveal vitreous detachment with or without traction in each group at baseline. At 12 months, the prevalence of peri-foveal vitreous detachment was significantly higher after intravitreal triamcinolone (n = 11) than macular grid laser (n = 8). These patients had poorer visual outcome (P = 0.01) and increased central macular thickness (P = 0.002). The development of complete posterior vitreous detachment was associated with significantly decreased central macular thickness (P = 0.001) but not better visual outcome (P = 0.72). Conclusion: These results suggest that posterior hyaloid changes may play a more influential role in the response to intravitreal triamcinolone than laser treatment for diffuse diabetic macular edema. Analysis of serial OCT in a randomized controlled trial that compared intravitreal triamcinolone versus macular argon laser for diffuse diabetic macular edema show that at 12 months, the prevalence of peri-foveal vitreous detachment is significantly higher after IVTA than macular grid laser and this influenced both the central macular thickness and visual acuity. Posterior hyaloid changes may play a more influential role in the response to IVTA than laser treatment for diffuse DME.