DIABETIC EYES - RETINOPATHY

What is a Diabetic Retinopathy?

Diabetic Eye Disease or Diabetic Retinopathy is a medical eye condition in which high levels of blood sugar cause damage to and loss of small blood vessels (capillaries) over time within the retina, thereby damaging the retina.

The manifestations of diabetic retinopathy include:

Macular Oedema – swelling at the central part of the retina (macula) due to leakage of damaged capillaries. If the very centre of the macula involved this can result in a reduction incentral vision.
Macular Ischaemia – loss of small vessels (capillaries) at the macula can lead to irreversible central visual deterioration.
Proliferative Diabetic Retinopathy – as capillaries are lost, the retina progressively becomes ischaemic (lacking adequate blood supply). This can lead to the stimulation of new blood vessel growth which unfortunately does not restore the normal blood supply but rather leads to the growth of small fragile blood vessels on the surface of the retina. These new vessels can bleed into the vitreous gel in the centre of the eyeleading to a (usually temporary) loss of vision. The new vessels can also lay down scar tissue which can contract causing tractionalretinal detachment and permanent visual loss if not treated with surgery.

Who is at Risk of Diabetic Retinopathy?

Diabetic Retinopathy is a leading cause of blindness among working-age adults aged 25-74 in Australia.

Patients with both Type 1 and Type 2 diabetes mellitus are at risk of developing diabetic retinopathy. The longer a person has diabetes and the poorer the blood sugar control over this time, the higher their risk of retinopathy. Other risk factors include poor control of blood pressure (hypertension) and blood lipids (cholesterol and trigylcerides).

To reduce the risk of developing diabetic retinopathy a close relationship with your GP or endocrinologist is recommended with the aim of tight glycemic (blood sugar) control as well as good control of blood pressure and blood lipids. Regular exercise is important in all patients and weight loss is particularly beneficial in patients with Type 2 diabetes.

What are the Symptoms of Diabetic Retinopathy?

In the early stages of the disease there are usually no symptoms. For this reason, regular eye examinations are required to detect the development of these changes. As the severity of retinopathy progresses it may become apparent to the patient by way of blurred vision or floaters.

How is Diabetic Retinopathy Diagnosed?

Diabetic Retinopathy is detected by a comprehensive dilated retinal examination in conjunction with Optical Coherence Tomography (OCT) scanning of the macula. Changes over time can be documented by retinal photography. Fluorescein angiography is a dye test used to directly visualize the degree of damage to the retinal blood vessels and is often used in the management of diabetic retinopathy.

How is Diabetic Retinopathy Treated?

Macular Oedema – treatment may be required for cases where swelling of the retina involves the centre of the macula or is threatening the centre of the macula. Milder cases may be observed. Intravitreal anti-VEGF injection therapy with drugs including Lucentis (ranibizumab), Eylea (aflbercept) and off-label Avastin (bevacizumab) is the mainstay of therapy. In some cases steroid injections such as Triescence (triamcinolone) or Ozurdex (dexamethasone)may be also be required.Argon laser therapy may be appropriate in select cases with leakage originating well away from the centre of the macula.

Macular Ischaemia – no treatment is possible.

Proliferative Diabetic Retinopathy – the aim of treatment is to cause shrinkage (regression) of the abnormal new blood vessels. This canreduce the risk of vitreous haemorrhages which are often slow to clear, and prevent the development of severe vision loss that can result from tractional retinal detachment. The main treatment modalities are:

Panretinal Photocoagulation Laser treatment – a destructive treatment that sacrifices peripheral retina that has suffered significant loss of small blood vessels (capillaries).
Intravitreal anti-VEGF injection therapy with drugs including Lucentis (ranibizumab), Eylea (aflbercept) and off-label Avastin (bevacizumab)
Vitrectomy surgery in advanced cases to cleara vitreous hemorrhage or treat a tractional retinal detachment.

Treatment is not a cure as the underlying cause. Diabetes is a lifelong condition. Regular monitoring of the condition of the eye is important and additional treatment may be required.