Abstract
Purpose :
Around 25% of patients do not respond to anti-VEGF therapy for diabetic macular edema (DME). Poor response can be determined after 3 months of treatment. Early prediction of poor response might allow the timely choice of alternative treatment strategies. We prospectively recorded and analysed baseline electroretinograms (ERGs) in treatment-naive patients treated with anti-VEGF for DME to examine for baseline predictors of poor response.
Methods :
Patients were prospectively reviewed for the VIDEO trial (ISRCTN59902040). ERGs were performed using a handheld ERG device (RETeval, LKC technologies, MD USA) prior to 1st injection (baseline). Light-adapted flash and flicker stimuli were delivered corresponding to international standard. Waveforms were recorded using skin sensor electrodes affixed beneath the lower eyelid. Patients were classified as poor or good responders after 3 months. Poor response was classified on optical coherence tomography as central 1mm macular subfield thickness greater than 350 microns after 3 injections. Baseline demographics were collected and compared between groups. Only the treated eye was included from each patient.
Results :
23 patients were included for analysis. 14 eyes were classified as responders and 9 as non-responders. Baseline demographics were comparable between groups. Peak times were similar between the two groups. Mean flicker ERG amplitudes and flash a-wave and b-wave amplitudes were greater at baseline in responders, although the differences failed to reach statistical significance. For responders and no-responders respectively, mean flicker ERG amplitudes were 16.1 and 22 microvolts respectively (p=0.13); mean flash a-wave amplitudes were 4.9 and 6.1 microvolts respectively (p=0.34); mean flash a-wave amplitudes were 19.1 and 24.9 microvolts respectively (p=0.18).
Conclusions :
Portable photopic ERG recording was rapid and well-tolerated. Eyes that went on to display poorer responses to 3 antiVEGF injections had smaller average ERG amplitudes at baseline than those that responded to treatment, but the difference did not reach statistical significance. A limitation was the small sample size, and larger studies will be able to test this with greater power.
This is a 2021 ARVO Annual Meeting abstract.