Diabetic eye disease
Diabetic Retinopathy (DR)
This is due to retinal blood vessel damage in the peripheral retina. Initially, small retinal haemorrhages may occur, but can progress to more widespread retinal bleeding and large areas retina becoming starved of oxygen as a result of the damage to blood vessels. If untreated, fragile new blood vessels can grow in the retina and have a tendency to bleed further, causing loss of vision and scar tissue.
To prevent the progression of diabetic retinopathy from mild cases (which only require monitoring) to severe disease, the following management is important:
- Adequate control of blood glucose using dietary and lifestyle measures; oral diabetic therapy and insulin
- Good control of any raised blood pressure of cholesterol level
- Appropriate monitoring of any diabetic retinal changes
- Retinal laser therapy is used to control advanced DR. Laser therapy is known as Panretinal Photocoagulation (PRP) which is applied to areas of affected retina, to reduce the growth of abnormal new blood vessels (see Laser therapy under the Treatments section for more detailed information)
Diabetic Macular Oedema (DMO)
Approximately 10% of patients with diabetic retinopathy will develop DMO, and it is one of the leading causes of visual impairment in the working age. It is caused by damage of fine retinal blood vessels in the macula area, leading to leakage of proteins and fluid (see Images 1 and 2) into the retina, and a reduction in vision. If left untreated, irreversible vision loss can occur due to permanent damage to retinal photoreceptor cells.
Image 1 – Damage to fine retinal blood vessels and leaking of protein into the retina in DMO
Image 2 – Accumulation of fluid in the retina in DMO in this cross-sectional image of the retina
As for DR, the initial management for DMO is to try and prevent the disease by good control of blood glucose levels and any raised blood pressure or cholesterol.
- AntiVEGF injections - if DMO does develop and vision is affected, the standard therapy of choice is with AntiVEGF injections, which have been shown to be the most effective treatment in improving vision. Patients normally require a course of injections with clinical trials providing good evidence on treatment course.
- Laser therapy – inappropriate cases, or in used with in conjunction with AntiVEGF therapy, laser can be effective in reducing the leakage of fluid into the retina and preserve vision.
- Steroid therapy – intravitreal steroid injections (Iluvien) are licensed to treat DMO, however are generally reserved for cases that have persisted despite other therapies.