Arms
Non-diabetic controls
Aged-matched people without a diagnosis of diabetes. At least one eye must be eligible without retinal pathology.
Subclinical (No diabetic retinopathy on the diabetic retinopathy severity scale)
Eyes of patients with a diagnosis of diabetes, Diabetic Retinopathy Severity Scale = 10, and no diabetic macular edema. Lower limit on duration of disease for Type 1 is 5 years, for Type 2 is 1 year
Minimal to Mild non-proliferative diabetic retinopathy
Eyes of patients with a diagnosis of diabetes, Diabetic Retinopathy Severity Scale = 20-35, and no center-involved diabetic macular edema
Moderate non-proliferative diabetic retinopathy
Eyes of patients with a diagnosis of diabetes, Diabetic Retinopathy Severity Scale = 43-47, and no center-involved diabetic macular edema
Severe non-proliferative diabetic retinopathy
Eyes of patients with a diagnosis of diabetes, Diabetic Retinopathy Severity Scale = 53, and no center-involved diabetic macular edema
Proliferative diabetic retinopathy
Eyes of patients with a diagnosis of diabetes, Diabetic Retinopathy Severity Scale > 60, and no center-involved diabetic macular edema
Interventions
Visual Acuity
Visual Acuity measured with the Electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) visual acuity test on a scale from 100 letters (Snellen equivalent of 20/10) to 0 letters (Snellen equivalent of <20/800). Higher scores indicate better visual acuity, and lower scores indicate worse visual acuity
Reading Speed
The MNREAD (Minnesota Low-Vision Reading) test is a standardized test that measures reading performance in people with normal or impaired vision.
Visual Field testing
The objectiveFIELD Analyzer is a perimetry tool that measures visual fields using electroencephalography-based brain responses to flickering light. Higher sensitivity = better function, Lower sensitivity (more negative deviations from normal) = worse function; Global indices (MD, PSD-like values) indicate overall field loss and pattern of damage.
Contrast sensitivity
A clinical device that utilizes the quick Contrast Sensitivity Function (qCSF) methodology to assess visual function. The qCSF method is a Bayesian adaptive algorithm designed to efficiently estimate a patient's contrast sensitivity across a wide range of spatial frequencies. Higher curve / higher AULCSF = better contrast sensitivity (normal vision). Lower curve / lower Area Under the Log Contrast Sensitivity Function = reduced contrast sensitivity (seen in early AMD, glaucoma, diabetic retinopathy, etc.).
Electroretinography (ERG) and pupillography in light- and dark-adapted states
The RETeval® is a portable, handheld electroretinography (ERG) and visual evoked potential (VEP) device. It enables clinicians to assess the retinal and optic nerve.
Ultrawide field-color photograph
Ultrawide field color photography is a high-resolution, wide-angle retinal imaging technique that captures both central and peripheral retina in natural color. Grading is typically based on the Diabetic Retinopathy Severity Scale or DRSS, which is a standardized grading scale from 10 (no DR) to 85 (severe PDR)
Ultrawide field-Fluorescein angiogram
a high-resolution, wide-angle retinal vascular imaging technique that allows clinicians to see both central and peripheral retina blood flow, detect ischemia, leakage, and neovascularization, and guide diagnosis and treatment
Optical coherence tomography
non-invasive retinal imaging tool that produces detailed cross-sectional images. Disease-specific grading systems (like macular thickness for DME or RNFL thickness for glaucoma) are used to quantify severity and monitor progression
Optical coherence tomography- Angiography
non-invasive, dye-free imaging method that maps retinal and choroidal vasculature, allowing both qualitative and quantitative assessment of microvascular health. Quantitative metrics like vessel density, perfusion, FAZ size, and non-perfusion area serve as functional "scales" for disease severity and progression.