Changes in Ganglion Cell Layer Thickness after Treatment with the 0.2 μg/day Fluocinolone Acetonide Implant in Vitrectomized and Nonvitrectomized Eyes with Diabetic Macular Edema

Abstract

Introduction: The objective of this study is to compare changes in ganglion cell layer (GCL) between vitrectomized and nonvitrectomized eyes with diabetic macular edema (DME) over a 2-year period following treatment with 0.2 μg/day fluocinolone acetonide (FAc) implant. Methods: Eighteen vitrectomized (group 1) and 8 nonvitrectomized (group 2) eyes were included in this cohort study. Changes in central macula GCL thickness were measured using the Spectralis spectral domain-optical coherence tomography at baseline and 6, 12, and 24 months of follow-up. Other parameters analyzed included best-corrected visual acuity (BCVA), central foveal thickness (CFT), and intraocular pressure (IOP). Results: Treatment with the FAc implant led to small reductions in mean global GCL thickness versus baseline and contrasts with the control group that was stable or slightly increased versus baseline. FAc therapy also led to improvements in mean BCVA and CFT that were observed at Month 6 and maintained to Month 24. For vitrectomized and nonvitrectomized eyes, no differences were observed between mean global GCL, BCVA, and CFT values during follow-up. Linear correlations revealed that in all groups mean BCVA at Month 24 positively correlated with mean GCL thickness at baseline and at Month 24. IOP remained stable throughout the 24 months. Conclusion: There was no evident retinal neurodegeneration in the 2-year period following treatment with FAc in both groups. GCL thickness may be a useful biomarker for assessing safety and effectiveness in patients with DME.