Retinopathy (disease and damage to the blood vessels of the retina) is a common complication of diabetes mellitus (diabetes). It is the most frequent cause of blindness in the working population.
Importantly blindness from diabetic retinopathy is preventable with regular fundoscopy examinations, which involve an optical inspection of the back of the eye, and treatment with laser photocoagulation.
Less well known is the link between diabetes and developing cataracts.
A cataract is defined as a decrease in the transparency of the crystalline lens of the eye. Symptoms can include faded colours, blurred vision, halos around light, sensitivity in bright lights and trouble seeing at night. In contrast to diabetic retinopathy, it is the primary cause of blindness generally worldwide, but is highly treatable with the surgical extraction of the cataract.
The main risk factors for cataracts in the developed world other than advanced age are smoking, exposure to sunlight and the use of corticosteroids. However, a new study carried out on patients in the United Kingdom by the University of Basel in Switzerland has found that cataracts were nearly twice as common in patients with diabetes than in those without the disorder. Diagnosis of cataracts may be more likely in such patients because of regular fundoscopy examinations. The study, Cataract in patients with diabetes mellitus – incidence rates in the UK and risk factors by Claudia Becker and others, was funded by Alimera Sciences, a company that produces medicines used in the treatment of diseases of the eye.
The imbalance between diabetic and non-diabetic patients becomes more obvious with age, particularly in individuals over 80 years old, and in those suffering with macular oedema, ie the build up of fluid in the centre of the retina. The incidence ratio when compared with non-diabetic patients was however found to be highest in the younger age group (45 – 50 years) and in those with long-standing diabetes. The correlation rate with those with diabetic retinopathy was only slightly higher than those without. The study also revealed that anti-diabetic medication was not associated with the risk of cataracts.
Tim Wright, a senior associate in Penningtons Manches’ clinical negligence team and a member of the specialist ophthalmic group, comments: “This increased risk of cataracts should be well managed as a result of the close monitoring that ought to be provided to a diabetic patient’s eyes. In contrast, a failure to detect this condition in a diabetic patient will amount to a much more serious breach of duty leading to an increased risk of blindness, which otherwise would have been preventable.”