Retinal thickness fluctuations in patients receiving fluocinolone acetonide implant for diabetic macular edema

Abstract

Objectives

To evaluate central foveal thickness (CFT) variability and accompanying changes in visual acuity (VA) 12 months before and after treatment with the 190 mcg fluocinolone acetonide (FAc) intravitreal implant for diabetic macular edema (DME).

Methods

The Iluvien Clinical Evidence cohort study in the United Kingdom (ICE-UK) investigated the effectiveness of the FAc implant in people treated at 13 hospitals from April 2013 to April 2015. The following parameters were calculated for CFT for each patient: mean, standard deviation (SD), retinal thickness amplitude (RTA, the difference between maximum and minimum values), and coefficient of variation (CV).

Results

In 149 eyes with ≥2 CFT observations both before and after FAc implantation, the median VA was 50 ETDRS letters at implantation. Mean CFT was 487 µm at implantation and 135 µm at 12 months post-implant. Before implantation, the mean CV and mean SD for CFT were 24.6% and 112 µm, respectively; the mean RTA was 254 µm. A statistically significant (p < .001) decrease in all three parameters was observed after implantation (18.3%, 68.2 μm and 146 μm, respectively). There was an association between CFT change between extremes and the corresponding change in VA (Pearson’s correlation coefficient, r = −0.292, p < .001, prior to the implant; r = −0.379, p < .001, post-implant).

Conclusions

After accounting for the reduction in CFT, retinal thickness stabilized following FAc implantation. There might be VA benefits in reducing variability in CFT over time. This merits further exploration but would require more frequent CFT observations in order to properly determine patterns of retinal thickness variability.

Keywords:

• Fluocinolone acetonide
• ICE-UK
• diabetic macular edema
• retinal thickness fluctuations

Transparency

Declaration of funding

This work was supported by Alimera Sciences, the manufacturer of the fluocinolone acetonide 190 mcg intravitreal implant.

Declaration of financial/other relationships

SEH is employed by, and CJC is the director of, Pharmatelligence, a research consultancy that receives funding from the pharmaceutical industry, including Alimera Sciences for the presented work. MSH is the recipient of honoraria and travel expenses from Alimera Sciences. A peer reviewer on this manuscript discloses receiving a salary from and having equity in, Clearside Biomedical. The remaining peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

All authors contributed to the study conception and design. Data analysis was performed by SEH. The first draft of the manuscript was written by SEH and all authors commented on the manuscript. All authors read and approved the final manuscript.

Acknowledgements

The authors thank Chris Wright and Antonio Cutino of Alimera Sciences for their feedback on the study design and manuscript.