EVALUATION OF CONE FUNCTION IN DIABETIC RETINOPATHY WITH AND WITHOUT MACULAR EDEMA USING THE RABIN CONE CONTRAST TEST

Abstract

Purpose : There are a few studies which evaluate the specific function of macular cones in diabetic retinopathy one of them is the Rabin Cone Contrast Test (RCCT). This is a computer-based cone-specific contrast sensitivity which evaluates red, green and blue cone. There are no studies which evaluate RCCT in different types of diabetic macular edema using the optic coherence tomography (OCT). We evaluated RCCT in diabetic eyes without macular edema and different OCT configurations.

Methods : Retrospective, transversal and observational study using two groups of patients with diabetic retinopathy (DR), one with macular edema and the other without it. We evaluated 20 eyes with macular edema and 20 without it. We classified groups based on OCT configuration (spectralis heilderberg). All patients underwent a comprehensive ophthalmic examination, including best corrected visual acuity. The function of the cone cells was measured with RCCT (Provideo CCT Plus system; Innova Systems, Burr Ridge, IL, USA) in both studies groups. We included patients older than 18 years, patients, with diabetic retinopathy and clear media with and without macular edema. We excluded patients with de BCVA less than 20/60, patients with a diagnosis of glaucoma and atrophy of pigmentation epithelium by means of OCT.

Results : All eyes had different grade of affection in the RCCT. All eyes without macular edema had moderate changes in RCCT even with 20/20 VA. There was a correlation of photoreceptors function and severity of anatomical changes measured by OCT. Eyes with ellipsoid compromise showed a more severe response. Cystic changes were not always associated with a severe RCCT response

Conclusions : RCCT is a useful methodology to evaluate cone function in diabetic retinopathy. There is a correlation between anatomical changes in OCT and functional changes evaluated with RCCT.

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