Abstract
Purpose :
In practice, the best corrected visual acuity (BCVA) of non-diabetics and mild non-proliferative diabetic retinopathy patients do not differ significantly; hence, visual function is incorrectly documented. In this single center, cross sectional study, we tested the hypothesis that the Low Luminance Deficit (LLD) would provide a more holistic view of documenting the visual function of diabetics.
Methods :
32 patients diagnosed with diabetes mellitus and 11 healthy patients were consecutively recruited for vision testing. Subjects had an age range from 20-70 years old. Subjects with >NO3, previous ocular and retinal surgery, previous laser treatments, history of ocular trauma, diabetic macular edema, and tractional retinal detachment were excluded from the study. The best corrected visual acuity (BCVA) in log mar was measured at 4 meters using a standard illuminated ETDRS chart (Lighthouse Distance Visual Acuity testing). Low luminance visual acuity (LLVA) was then measured using a 2- log unit neutral density filter (Kodak Wratten Neutral Density Filter no. 96) with the same testing distance and chart. The LLD was computed (LLVA-BCVA) and collated. 7-Field Fundus photos were captured to document diabetic retinopathy and were read by a masked retina specialist to stage the retinopathy. The primary outcome measure included the LLD compared among different groups. Outcomes were also compared across subgroups based on FBS, HbA1C, creatinine, mean arterial pressure, and duration of diabetes. Results were analyzed using SPSS 24.0. Fisher exact test and one-way ANOVA with Bonferonni correction as post hoc analysis were used to determine the difference among groups.
Results :
LLD was significantly higher in diabetic patients with retinopathy than those without (95% CI, 0.182-0.261) (p<0.05). In addition, LLD was significantly different in patients without diabetes against those with mild diabetic retinopathy (p=0.001) and against those with moderate diabetic retinopathy (p=0.000). In the study, age had the most significant effect on the BCVA and LLVA of patients; however, only the HbA1C and MAP had significant effects on the low luminance deficit (p=0.029, p=0.04)
Conclusions :
LLD was associated with higher log mar values in patients with diabetic retinopathy with an increasing trend according to severity compared to healthy individuals; hence,LLD may be an informative functional biomarker of disease.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.