Vision Eye Institute, Melbourne VIC
The Australian Diabetes, Obesity and Lifestyle Study (AUSDIAB 2012) presents sobering statistics regarding the prevalence of diabetes and the clinical characteristics of the Australian population with diabetes.1 Optometrists have a crucial role in the screening and diagnosis of diabetic retinopathy, and this primary care responsibility provides a unique opportunity for optometrists to take the lead in the efforts to reduce the public health impact of diabetic retinopathy.
The AUSDIAB 2012 defines diabetes as those with fasting blood glucose > 7.0 mmol/L and two-hour glucose tolerance > 11.1 mmol/L. The current Australian population prevalence of diabetes is 7.4 per cent, and those with pre-diabetes comprise a further 16.3 per cent. Over the 12 study years 1999-2011, patients with diabetes were more than five times more likely to die than those with normal glucose tolerance.
The NHMRC diabetic retinopathy guidelines (2008) detail Level I evidence for improving glycaemic control (HbA1c < 7.0 per cent) and Level II evidence for blood pressure and serum lipids (systolic BP < 130 mmHg, LDL cholesterol < 2.5 and triglycerides < 2.0 mm/L) indicating that a multi-disciplinary approach will achieve the best results.2 This evidence is provided by the seminal DCCT, EDIC, UKPDS and ACCORD studies among others, which also highlight parallel risk reductions in the other microvascular complications of diabetes, namely peripheral neuropathy and nephropathy.
Taking a thorough history should include asking patients about their diabetic parameters. For the patient, this further reinforces the importance of adherence to targets and shows that their optometrist is a well-informed practitioner who cares about their progress.
The Diabetes MILES Australia study (2011) found that the top two causative areas behind the development of psychological distress in patients with diabetes relate to the concern for the future and worrying about future serious complications, and the feelings of guilt and anxiety when diabetic management goes off track.3 In advising the patient at the conclusion of consulting, the ability of compliance with diabetic targets to reduce the risk of development and/or progression of their retinopathy should be emphasised, but with a considerate and empathetic approach.
The following figures relate to a case history of a female of Somali background and born in 1959, who presented originally in August 2010 with a 10-year history of ‘gestational diabetes’ using only diet and oral hypoglycaemic medication. Visual acuity at first visit was OD 6/12 and OS 6/36 with bilateral visually significant cataract. At presentation, there was severe NPDR, gross CSME with hard exudates and angiographically demonstrated confluent areas of capillary non-perfusion.
At the last visit in April 2014, the VA is R and L 6/6 and there is relatively normal kidney function. In both eyes, treatment has involved pan-retinal photocoagulation (PRP), multiple intravitreal injections of Avastin and periodically triamcinolone, cataract surgery, and focal laser to the macula.
Figure 1 is a retinal colour photograph of the left eye acquired using Optos digital retinal photography from August 2012, where despite good visual acuity there are significant hard exudates and retinal haemorrhages in the retina which has not undergone PRP.
|Figure 1. Retinal colour photograph of the left eye, 2012 (Optos ultra wide field retinal image)
The patient was advised that further pregnancies would be detrimental to her health in general and in particular her vision. About this time, the patient had finally put into practice increased diligence in monitoring her blood sugar, and insulin administration which had commenced in 2011.
|Figure 2. Level of retinal haemorrhages unchanged, 2013
Figure 2 shows the left eye in June 2013. The hard exudates have significantly resolved, although the level of retinal haemorrhages has not changed overall. The patient then began to take the lipid lowering (statin and fenofibrate) and ACE-inhibitor medications regularly. With further effort to reduce the average level of blood sugar, the result was a stable retina that is mostly free of haemorrhages (Figure 3).
Figure 3. Retina mostly free of haemorrhages, 2014
This more advanced case of diabetic retinopathy shows that if this improved outcome is possible in a patient with advanced disease, the impact on retinal physiology for a patient with lesser degrees of diabetic retinopathy is less visible but no less significant. By discussing optimal diabetic parameters and helping to motivate patients to improve compliance with all aspects of their diabetes management plan—using an empathetic approach—optometrists can make a significant contribution to reducing the public health impact of diabetic retinopathy.
- Tanamas SK, Magliano DJ, Lynch B, Sethi P, Willenberg L, Polkinghorne KR, Chadban S, Dunstan D, Shaw JE. AusDiab 2012. The Australian Diabetes, Obesity and Lifestyle Study. Melbourne: Baker IDI Heart and Diabetes Institute 2013.
- Guidelines for the management of Diabetic Retinopathy. National Health and Medical Research Council 2008.
- Speight J, Browne JL, Holmes-Truscott E, Hendrieck C, Pouwer F on behalf of Diabetes MILES - Australia reference group. Diabetes MILES - Australia 2011 Survey Report. Diabetes Australia: Canberra; 2012.