City Research Online

Colour vision in diabetes

Abdel-hay, A. (2018). Colour vision in diabetes. (Unpublished Doctoral thesis, City, Universtiy of London)


Diabetes Mellitus (DM) has become one of the most important metabolic diseases that reduces one’s quality of life and doubles the risk of early death. Amongst the major complications linked to DM, diabetic retinopathy (DR) leads to gradual loss of vision and blindness. DR is now the second cause of certifiable blindness among the working age adults in the UK. The lifetime costs to the UK government are calculated to be up to £327,000 per person, with almost 50% of these costs being attributed to loss of productivity caused by visual impairment and blindness. The UK is one of the leading countries in the implementation of DR screening programmes. The latter rely heavily on fundus imaging and grading using trained experts and subsequent referral to hospital for further clinical examination and evaluation depending on the grade of retinopathy. It is now known that subtle, structural changes in the retina that are linked to diabetes can precede detectable vascular changes. The former can affect one’s colour vision and this offers the potential of using changes in chromatic sensitivity as an early biomarker of retinal disease.

The first part of this thesis focuses on measuring chromatic sensitivity using the colour assessment and diagnosis (CAD) test in diabetic subjects with varying degrees of retinopathy. The severity of colour vision loss is graded in comparison to other factors that are normally linked to diabetes, such as the type, grade, control methods and duration. The results of this study reveal losses of both red / green and yellow / blue chromatic sensitivity in patients with diabetes, but the correlation with factors, normally associated with high risk of diabetes is low. The results from this study do, however, show that the magnitude of chromatic sensitivity losses correlates with the severity of diabetic retinopathy.

The second, related study examines the effectiveness of intravitreal injection of a dexamethasone implant (Ozurdex) in patients with diabetic macular oedema (DMO) in stabilising and reducing loss of visual function and in particular the reduction in chromatic sensitivity up to 24 weeks. This treatment demonstrated efficacy in the treatment of chronic DMO and DMO which is resistant to anti-VEGF treatment. The results show that intravitreal treatment with Ozurdex causes improvement is visual acuity, central retinal thickness and significant improvement in red / green chromatic sensitivity.

Publication Type: Thesis (Doctoral)
Subjects: R Medicine > RE Ophthalmology
R Medicine > RZ Other systems of medicine
Departments: Doctoral Theses
School of Health & Psychological Sciences > School of Health & Psychological Sciences Doctoral Theses
School of Health & Psychological Sciences > Optometry & Visual Sciences
Text - Accepted Version
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