Visual
impairment
Macular degeneration
Cataract
Glaucoma
[Diabetic retinopathy]
Diabetic Retinopathy
What is Diabetic Retinopathy?
Diabetic retinopathy is currently one of the most preventable causes of
blindness in Australia. Vision loss from long-standing diabetes is often
caused by damage to delicate structures at the centre of vision or 'macula'
(termed 'macular oedema') and from blocked blood vessels in the outer
retina leading to 'proliferative retinopathy', which causes bleeding into
the eye and retinal detachment. Another frequent mechanism is the development
of opacities in the lens of the eye (termed 'cataract').
.
The most important risk factors for development of diabetic retinopathy are the duration of diabetes (which is often present but undiagnosed for a long period in some people) plus the adequacy of blood sugar control with diet, oral medications or insulin.
Everyone with diabetes needs to have regular eye examinations (at least every two years) to screen for signs of early retinopathy. Once detected, retinopathy needs to be followed by an eye specialist at least once per year if mild and more frequently once the signs are moderate.
Any vision-threatening signs (early macular oedema or proliferative retinopathy) need to be assessed for consideration of treatment. Timely laser therapy can prevent loss of vision in almost all people with diabetes.
Once vision worsens, however, it may not be possible to improve vision and some continued deterioration may occur for a period despite laser treatment.
The best chance to maintain vision is to have regular eye screening and treatment of retinopathy at an appropriate early stage.
Risk Factors
Factors shown to increase the development or progression of diabetic retinopathy
include:
- Known duration of diabetes; generally longer duration increases risk
- Blood sugar control; poor control increases risk
- Blood pressure control; hypertension increases risk
- Pregnancy is a short-term higher risk
- Presence of kidney damage accelerates retinopathy
- Cataract surgery can increase risk in the operated eye
Key Points from the NHMRC Guidelines
- The most important modifiable factor preventing the development of retinopathy (in both Type 1 and Type 2 diabetes) is strict blood sugar (glycaemic) control.
- Efforts to achieve strict blood sugar (glycaemic) control should be undertaken by all people with diabetes, while taking care to avoid severe recurrent hypoglycaemia (very low blood sugar episodes).
- The level of blood pressure and blood fats have also been shown to be risk factors for diabetic retinopathy.
- Doctors should aim to adequately manage blood pressure and blood lipid levels in all people with diabetes.
Strong and high quality evidence exists for the benefits of strict blood sugar control in preventing the development or slowing the progression of diabetic retinopathy.
Large, multicentre randomised clinical trials have evaluated the benefits of intensive compared with conventional blood sugar control. This evidence was provided for people with Type 1 diabetes by the Diabetes Control and Complications Trial, and for people with Type 2 diabetes by the United Kingdom Prospective Diabetes Study.
NHMRC Guidelines for
Management of Diabetic Retinopathy
The Australian National Health & Medical Research Council (NHMRC)
has published four books about the evidence-based management of diabetic
retinopathy. Paul Mitchell was a member of the committee that developed
these and both he and Jie Jin Wang were the technical writers for the
principal Guidelines document and the Patient guide (Diabetes and your
eyes).
Management of diabetic retinopathy:
Clinical practice guidelines
http://www.nhmrc.gov.au/publications/synopses/cp53covr.htm
Diabetes and your eyes: A consumer
guide to the management of diabetic retinopathy
http://www.nhmrc.gov.au/publications/synopses/cp54covr.htm
Management of diabetic retinopathy:
A guide for general practitioners
http://www.nhmrc.gov.au/publications/synopses/cp56covr.htm
Preserving vision in diabetes:
A quick reference guide for optometrists, nurses and other health practitioners
http://www.nhmrc.gov.au/publications/synopses/cp55covr.htm
