Earlier Injections May Reduce Contrast Sensitivity Impairment in DME

Macular edema.
Center involving diabetic macular edema can significantly affect vision.

Patients with center involving diabetic macular edema (CDME) experience significant contrast sensitivity (CS) impairment, according to a study published in Clinical Ophthalmology. Even some patients who have undergone treatment may continue to experience visual defects that could impact their ability to function in everyday life. 

Researchers evaluated 5 aflibercept intravitreal injections for treatment of CDME. The study was performed at Tri Med Laser Eye Center, in Barrie, Ontario, between October 2018 and June 2020. Testing included measurements of central retinal thickness (CRT), best corrected visual acuity (BCVA), Pelli–Robson (PR) CS, and CamBlobs (CB) CS at 20 weeks after baseline.

Investigators reviewed 40 eyes from 40 patients (mean age 62.9±10.6 years, 55% men) with CDME. The CRT at baseline was 365±94.6μm with logMAR BCVA 0.25±0.20. CS PR at baseline was 1.46±0.13 logCS compared with the normal population 1.79±0.10 logCS (P <.01) and CS CB at baseline was 1.55±0.16 logCS compared with 1.92±0.08 logCS in the normal population (P <.01).

At the conclusion of the study, CRT decreased to 289±43.7μm (P <.001), and the logMAR BCVA improved to 0.18±0.02 (P <.05). At the same point, the report notes that CS PR was 1.52±0.16 and CS CB was 1.62±0.16 logCS. At the end of the study, 85% of eyes achieved a BCVA of 0.3 logMAR or better. 

The investigators found a reduction from baseline of 82.5% to 57.5% in the number of patients that had a CS, which was 2 standard deviations below the mean. The greatest recovery in CS was associated with the greatest reduction in CRT. 

The report suggests that clinicians can reduce residual deficit from the treatment with earlier interventions, using reduction in CS as a metric. No adverse events were reported during the study. 

Limitations of the analysis include small sample size, lack of follow-up duration, and limited variety of CD testing conditions and modalities. 

“In this study, we found that CS can be improved with aflibercept therapy, and the amount of improvement was associated with the total reduction in central retinal thickness (CRT) in a naïve population of patients with center involving macular edema and reduced BCVA,” the researchers report. “A significant amount of CS had already been lost at the time of enrolment and although improvement occurred there was still a measurable deficit compared to the normal population.”

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. This research was supported by Bayer and Sentrex. Please see the original reference for a full list of disclosures. 

Reference

Nixon DR, Flinn N, Enderlein C. Contrast sensitivity changes in center involving diabetic macular edema treated with aflibercept. Clin Ophthalmol. Published online November 11, 2021. doi:10.2147/OPTH.S338478