The relationship between age and colour content in fundus images

Introduction: The morphological appearance of the ocular fundus is one of the key parameters used in the diagnosis and management of retinal disease. However, optical imperfections in the refractive media result in blurring, low luminance and contrast, and changes in the colour composition of the image which can be seen as an increasing yellowish appearance with age. The introduction of a method for quantifying this age-related change in colour content may help in diagnosing and grading pathological changes in the eye lens which are secondary to ocular and systemic diseases. Methods: A total of 102 digitized fundus images from 102 healthy subjects (mean age = 50.4 years, range 7.0-94.3 years) were used to build a model for estimating the age of the subject from the colour content of the images. Results: Estimation of age from the fundus images could be done within approximately 16 years. This variation could be reduced considerably by analysis of repeated photographs from the same examination. Conclusion:The colour content of fundus images can be used to estimate the ages of healthy subjects. Furthermore, when the colour content of fundus images deviates from that expected according to subject age, this may indicate causes other than age of increased light absorption in the lens, such as cumulative exposure to hyperglycaemia in diabetic patients. This could potentially be used to identify patients with undiagnosed type 2 diabetes in the general population and help to establish their risk of developing late diabetic complications as the cumulative exposure to hyperglycaemia is unknown at the time of diagnosis of the disease.