Optos optomap ultra-widefield image showing proliferative diabetic retinopathy (PDR)
Dr Jeffry D Gerson
Grin Eye Care, Leawood, Kansas USA
Diabetic retinopathy is a leading cause of vision loss in working-age adults in the developed world. According to the Melbourne Vision Project, approximately 29 per cent of Australians with diabetes have some degree of diabetic retinopathy and 4.2 per cent have proliferative diabetic retinopathy.
Another important fact is the sheer magnitude of the number of people with diabetes in Australia and the world. Put these two things together and we have a disease that is becoming more relevant. Optometrists are often on the front line of diagnosing both diabetes and its ocular complications. We need to be looking for not just clinically-significant macular oedema (CSME) but also other signs of diabetic eye diseases that are a window or predictor to ocular and systemic health.
Treatments for diabetic macular oedema, the most common cause of vision loss in diabetes,1 have advanced dramatically in the past decade. Even with studies showing us which anti-VEGF injection is best, if there really is one that is best,1 early identification and referral for treatment remain the most important factors in ultimate success and visual outcome.
Early diagnosis is not confined to early signs of CSME. Detection of early peripheral lesions, which are often the first sign, is significant in determining overall risk of retinopathy progression or progression to proliferative diabetic retinopathy (PDR), even if the peripheral lesions are the primary pathology seen before macular changes.2 These are often seen with a thorough dilated posterior eye examination or with wide-field imaging as a screening procedure.
Although intravitreal injections are the standard of care for CSME, there are treatments for diabetic retinopathy that need to be considered by optometrists and which may prevent progression or retinopathy and less need for rescue laser. For instance, treatment with fenofibrate has been shown to be beneficial in two separate studies, and commonly prescribed in Australia.3,4
It is also imperative to consider the patient beyond their eyes. An important question to ask patients about is their haemoglobin A1c. It is well documented that better control as measured by A1c is more likely to protect against unwanted ocular and systemic side-effects of diabetes.5 Making sure that patients understand this correlation can help prevent poor outcomes.
Besides just asking patients about their blood sugar and medications, lifestyle changes that can be made to improve glycaemic control can also be discussed. Factors such as diet, exercise, smoking status and overall general health have a big impact on our patients. We can take just a few minutes to help educate our patients and help secure our place in their health-care team.
People with diabetes need not only their general practitioner or endocrinologist, but also a dietitian and an eye-care professional, which is where we fit in.
We may be the person that takes care of their eyes and eye health but we should address systemic concerns as well. For people with diabetes, like patients with AMD, loss of vision is of paramount concern. The first step in preventing vision loss is simply to spend time. That time could be in the form of education or just a careful refraction. This gives us an opportunity to use the time we have with each person to make a positive impact.
Our positive impact comes through both better eye care that we provide and better overall health care, which we may be able to help our patients to seek. This integrated approach benefits everyone involved.
1. Wells JA, Glassman AR, Ayala AR et al. Aflibercept, bevacizumab or ranibizumab for diabetic macular edema: two-year results from a comparative effectiveness randomized clinical trial.Ophthalmology in press. Published online February 27, 2016.
2. Silva PS, Cavallerano JD, Haddad NM et al. Peripheral lesions identified on ultrawide field imaging predict increased risk of diabetic retinopathy progression over 4 years. Ophthalmology2015; 122: 5: 949-956.
3. Keech AC, P Mitchell P, Summanen PA et al. Effect of fenofibrate on the need for laser treatment for diabetic retinopathy (FIELD study): a randomised controlled trial. 2007; 370: 9600: 1687–1697.
4. Chew EY, Davis MD, Danis RP et al. The effects of medical management on the progression of diabetic retinopathy in persons with type 2 diabetes: the action to control cardiovascular risk in diabetes (ACCORD) eye study. Ophthalmology 2014; 121: 12: 2443-2451.
5. White NH, Sun W, Cleary PA et al. Prolonged effect of intensive therapy on the risk of retinopathy complications in patients with type 1 diabetes mellitus: 10 years after the Diabetes Control and Complications Trial. Arch Ophthalmol 2008; 126: 12: 1707-1715.