J Korean Ophthalmol Soc.  2021 May;62(5):638-646. 10.3341/jkos.2021.62.5.638.

Contrast Sensitivity and Inner Retinal Layer Thickness Analysis of Type 2 Diabetic Patients Without Retinopathy

• Lee KY
• Shin SJ
• Moon JS

• KMID: 2515946
• DOI: http://doi.org/10.3341/jkos.2021.62.5.638

Abstract

Purpose
To compare the contrast sensitivities of type 2 diabetic patients without retinopathy and healthy subjects, and to assess the risk factors associated with a change in contrast sensitivity in diabetes.
Methods
A total of 75 (diabetic patients without retinopathy) and 41 (healthy subjects) eyes were reviewed from the medical records. The threshold of contrast sensitivity was measured at 6.3°, 4.0°, 2.5°, 1.6°, 1.0°, and 0.64° under scotopic and photopic states. Optical coherence tomography (OCT) imaging was used to measure the retinal nerve fiber layer (RNFL) thickness and ganglion cell-inner plexiform layer (GC-IPL) thickness in diabetic patients.
Results
Diabetic patients showed a lower threshold of contrast sensitivity at all degree measures than did the controls under both scotopic and photopic states. In subgroup analyses, diabetic patients with abnormal contrast sensitivity showed a longer duration of diabetes, decreased total retinal thickness, and decreased average GC-IPL, superior RNFL, superior GC-IPL, and temporal GC-IPL thicknesses. Multivariate logistic regression analyses showed that the duration of diabetes and total retinal thickness were significant predictive factors of decreased contrast sensitivity (odds ratio = 1.117 and 0.942, respectively).
Conclusions
As the duration of diabetes increased, the contrast sensitivity decreased in type 2 diabetic patients. Neuroretinal degeneration changes both the inner retinal thickness and total retinal thickness and affects contrast sensitivity. Therefore, for longer-term diabetic patients, it is necessary to consider the changes in contrast sensitivity and retinal thickness on OCT evaluation, even if the patient presents with normal fundus findings.

Keyword

Contrast sensitivity, Diabetes, Ganglion cell-inner plexiform layer thickness, Retinal nerve fiber layer thickness, Retinal thickness