The grading of risk factors for diabetes based on early loss of colour and flicker sensitivity

Abstract

AbstractPurposeThe purpose of this study was to identify and grade risk factors (in clinically normal subjects) that can lead to diabetes based on early changes in chromatic sensitivity and rod‐ and cone‐mediated vision.MethodsA group of ‘high‐risk’ subjects (n = 82) were recruited for this study. All attended a healthcare centre for detailed vision assessment, in addition to other diagnostic and screening tests. The inclusion criteria required subjects to have at least three or more recognised risk factors for diabetes. The factors examined included HbA1C (>5.7), high blood pressure, smoking history, high BMI, family history of diabetes, FPG levels (>100 mg/dl), age (>45 years), unhealthy diet and lack of exercise. In addition, Visual Acuity, Functional Contrast Sensitivity, rod and cone sensitivities and red‐green (RG) and yellow‐blue (YB) colour thresholds were measured in each subject using the Advanced Vision and Optometric Tests (www.avot/city.ac.uk).ResultsEach of the risk factors for diabetes listed above was examined to establish its effects on RG and YB colour thresholds and the loss of rod and cone sensitivity. Subjects with hypertension had higher RG (p = 0.009) and YB (p = 0.003) colour thresholds and increased contrast thresholds for rod‐ (p = 0.04) and cone‐mediated (p = 0.006) vision. In addition, age (>45) (p = 0.02) and the lack of exercise (p = 0.04) caused worsening of YB colour vision. Lack of exercise is also linked to a statistically significant difference (p = 0.02) in cone mediated vision. Neither family history, nor BMI or unhealthy diet had significant effects on colour or rod‐ and cone‐mediated flicker sensitivity.ConclusionsSubjects at risk of developing diabetes can have significant loss of RG and/or YB colour vision and rod and cone‐mediated flicker sensitivity. The most significant risk factors according to this study are high blood pressure, lack of exercise and age. Although these findings are of immediate clinical interest, it remains to be established how these factors are correlated and the neural changes that can be linked directly to the worsening of colour vision and rod and cone‐mediated flicker sensitivity.