Unraveling the mystery of DME outcomes

Some studies have reported that retinal vascular permeability results in choroidal thickening, while others have reported choroidal thinning or no changes.

There currently is no consensus regarding the impact of changes in the choroidal thickness in patients with diabetic macular edema (DME), a common cause of deteriorated vision in patients with diabetes. Some studies have reported that retinal vascular permeability results in choroidal thickening, while others have reported choroidal thinning or no changes.

However, even with technologic imaging advances such as swept-source optical coherence tomography (SS-OCT) that facilitates deeper penetration of the retinal tissue compared with spectral-domain OCT, no correlations have been identified between the baseline subfoveal choroidal thickness (SFCT) and the visual responses to anti-vascular endothelial growth factor (anti-VEGF) therapy, according to Alaa Dweikat, MD, Department of Medicine, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine.

Because of this, she and her colleagues conducted a retrospective, consecutive case series in which they investigated the changes in the SFCT and the best-corrected visual acuity (BCVA) in response to intravitreal injections of bevacizumab (Avastin, Genentech Inc.) and attempted to identify any correlations between those changes and the OCT findings of changes in the SFCT at 1 month after the third monthly intravitreal bevacizumab injection for treatment-naive patients with DME. Another study goal was to determine if the baseline SFCT might predict the BCVA changes in the 39 patients (59 eyes; mean age, 62.6 years) with treatment-naïve DME.

All patients underwent slit-lamp evaluations and SS-OCT scans; the SFCT and BCVA values from baseline were compared with those from 1 month after the third monthly injection of intravitreal bevacizumab.

SFCT and BCVA evaluations

Dweikat reported that the mean baseline SFCT was 318 ± 82 μm and decreased after 3 months to 300 ± 66 μm (p = 0.021). The mean logarithm of the minimum angle of resolution (logMAR) BCVA improved from 0.7 to 0.5 (p = 0.019).

The investigation did not find an association between the SFCT changes and BCVA changes (p = 0.180). The Wilcoxon signed-rank test showed that a greater BCVA improvement was correlated with a greater baseline SFCT (p < 0.00).

The investigators concluded, “Eyes with a higher baseline SFCT attained greater BCVA improvement than eyes with a lower baseline SFCT. In addition, changes in the SFCT do not appear to be correlated with the BCVA changes. These findings do not support using OCT SFCT changes as a prognostic factor for changes to BCVA after intravitreal bevacizumab treatment in evaluating treatment-naive DME eyes.”

Reference
  • Dweikat A, Jarrar A, Akkawi M, et al. Baseline subfoveal choroidal thickness as a predictor for response to short-term intravitreal bevacizumab injections in diabetic macular edema. Clin Ophthalmol. 2021;15:4175-80; DOI https://doi.org/10.2147/OPTH.S325951