Title: Evaluation of retinal ganglionar cell using optical coherence tomography in patients with DME treated with the 0.19 mg fluocinolone acetonide implant

Abstract

Purpose : Diabetic retinopathy is a microvascular neurodegenerative pathology and, therefore, this study aimed to determine retinal neurodegeneration through changes in ganglionar cell layer (GCL) in patients following treatment with the fluocinolone acetonide (FAc; ILUVIEN) implant.

Methods : A retrospective study in thirty eyes with DME that had been treated with a single FAc implant and after injection had a minimum of 24 months of follow-up. GCL changes were measured using the Spectralis (Heidelberg Engineering, Heidelberg, Germany) SD-OCT with automated segmentation software and images of the 3 mm region of the central macula were evaluated at baseline (i.e. 2 months after FAc implant injection to reduce the edematous effect on the GCL analysis), 6, 12 and 24 months. Parameters that were measured included GCL thickness variation (globally and in segmental quadrants), best-corrected visual acuity (BCVA), central foveal thickness (CFT) and intraocular pressure (IOP).

Results : 26 patients aged 67.9±7.2 years were included and 4 patients were excluded due to inconsistent segmentation. There was a statistically significant decrease in GCL thickness (global and segmental) between baseline and month 6 (-4.2 μm, p=0.002), but no change versus the remaining time points (p>0.05). After the FAc implant, BCVA increased by 17.9 ETDRS letters (p=0.001) and CFT decreased by 224.6 μm (p=0.001), and both stabilized by month 6. IOP remained unchanged during the follow-up period (p=0.280). Similar results were obtained in vitrectomized eyes and similar trends, without statistical significance, were observed in non-vitrectomized eyes.

Conclusions : The current findings suggest there was no neurodegeneration in the two-year period following treatment with the FAc implant and that GCL thickness may be a useful biomarker for assessing its safety and effectiveness in patients with DME. Further work is required to support these findings and should include a larger population with longer follow-up (to 3 years).

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.