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Pharma Open Access: Ultra-wide field imaging and diabetic retinopathy

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Figure 1. Right eye: extensive pan retinal photocoagulation. Proliferative diabetic retinopathy, VA 6/9.

 

Amira Howari
B.Optom(Hons) MOptom(UNSW)GradCertOcTher CCLSA OA
Therapeutic Medicines Prescriber
Diabetes Australia Ambassador

The growing use of ultra-wide field (UWF) imaging to enhance the early diagnosis and management of diabetic retinopathy has been quite evident for several years.1 Clear correlations between conventional Early Treatment Diabetic Retinopathy Study (ETDRS) seven-standard field colour fundus photographs and UWF images in assessing diabetic retinopathy have been established, where Optomap UWF (Optos) images enable a rapid extended view of the retina and periphery.2

When Price et al.3 compared the diabetic retinopathy severity grading between UWF images and an ETDRS seven-standard field view, it was found that 19 per cent of the images were assigned a higher retinopathy level in the UWF view compared to the ETDRS seven-field view. 

The 200-degree field of view of UWF colour imaging enables detection of more anomalies than standard fields of view, allowing for earlier and more accurate assessment of DR severity that could be otherwise missed.4,5 This was also confirmed by Aiello et al. who stated as much as a third of lesions are found outside the field of view of ETDRS.6 These lesions included peripheral microaneurysms, neovascularisation, vascular nonperfusion and vascular leakages.

A 39-year-old male with type 1 diabetes for 33 years presented to the clinic after noticing a brown-like lesion obscuring his left eye’s vision for over 48 hours. On history taking, it was noted his last HbA1c was 8.2 per cent and has been in this range for the last two years. Prior, his HbA1c had been between 11 and 12 per cent.

Current medications included the insulin pump (Humalog) and self-ceased atorvastatin for cholesterol. The patient also disclosed that he had minimal peripheral retinal photocoagulation some years ago.

On examination, best corrected visual acuity was recorded as OD 6/9, OS 6/9, OU 6/9. On ultra-wide field imaging, the following was noted:

OD (Figure 1)

  • Proliferative diabetic retinopathy
  • Neovascularisation at the disc (NVD)
  • Neovascularisation elsewhere (NVE)
  • Intraretinal microvascular abnormality (IrMA)
  • Spot and blot haemorrhages
  • Extensive long-standing pan retinal photocoagulation (PRP) scars
  • Scattered exudates

OS (Figures 2 and 3)

  • Proliferative diabetic retinopathy
  • Inferior vitreal haemorrhage
  • Inferior and superior scar tissue
  • Extensive NVD
  • Extensive NVE
  • IrMA
  • Spot and blot haemorrhages
  • Long standing PRP scars
  • Scattered exudates

 

Pharma ONLINE UWF DR_Figure -2.jpg

Figure 2. Left eye inferior vitreal haemorrhage, proliferative diabetic retinopathy VA 6/9

 

Pharma ONLINE UWF DR_Figure -3.jpg

Figure 3. Left eye utilising inferior eye steering feature: vitreal haemorrhage, proliferative diabetic retinopathy. VA 6/9

 

The patient was referred immediately to a retinal ophthalmologist whereby he underwent PRP. The patient was advised that a follow-up would be required in three weeks and, pending healing, compliance and progression potential vitrectomy may be considered if necessary.

At two weeks post-treatment, UWF imaging was repeated revealing the dissolving of the vitreal haemorrhage and best corrected vision of 6/7.5-2 both right and left eyes respectively (Figures 4 and 5). The patient is still under continual retinal care and treatment.

 

Pharma ONLINE UWF DR_Figure -4.jpg

Figure 4.  Right eye two weeks post initial UWF, condition unchanged

 

Pharma ONLINE UWF DR_Figure -5.jpg

Figure 5. Left eye two weeks post initial UWF, vitreal haemorrhage almost completely self- resolved VA 6/7.5-2

 

Discussion 

This case demonstrates not only the photo-documentation of diabetic retinopathy, but the extent of retinal treatment history by enabling an extended view into the periphery that otherwise may have been overlooked due to the patient’s recollection and version of history and events. It also enabled—and will continue to enable —long term monitoring of progression which will be crucial in deciding the next steps of his treatment plan.

Diabetes mellitus is a subgroup of metabolic diseases characterised by hyperglycaemia resulting from deficiency in insulin secretion and/or action. Pathogenic processes include autoimmune destruction of the beta cells of the pancreas precipitating an absolute deficiency of insulin secretion in type 1 diabetes, and a combination of resistance to insulin action and an inadequate compensatory insulin secretory response in type 2 diabetes.7

Symptoms of hyperglycaemia typically include polyuria, polydipsia, weight loss, polyphagia and blurred or fluctuating vision. It is well established that several complications may develop due to the chronic and progressive nature of diabetes where the risk increases with the duration of the condition: poor blood glucose control and poor blood pressure. Complications include peripheral vascular disease, nephropathy, cardiovascular disease and neuropathy including peripheral neuropathy that can, in some cases, lead to limb amputations. One of the most common complications encountered with diabetes is diabetic retinopathy.8

Almost all those living with type 1 diabetes and more than 60 per cent with type 2 diabetes will develop some form of diabetic retinopathy within 20 years of diabetes diagnosis.9

The Australian Diabetes, Obesity and Lifestyle study (AusDiab) indicated 19.3 per cent of those with diabetes had non-proliferative diabetic retinopathy, 2.1 per cent had proliferative retinopathy and 3.3 per cent had diabetic macular oedema.10 Locally in Australia, The Melbourne Vision Impairment Project found 29.1 per cent of those living with diabetes over the age of 40 years developed diabetic eye disease, with 4.2 per cent being proliferative and 5.6 per cent clinically significant macular oedema (CSME). This was also confirmed by The Blue Mountains Eye Study which showed 32.4 per cent of those 49 years and older living with diabetes had diabetic eye disease and 4.3 per cent had CSME.11

In contrast, due to limitations in health care and eye care access, Indigenous Australians are four times more likely than non-Indigenous Australians to develop diabetes and hence more likely to develop diabetic eye disease.12

Projections


According to the International Diabetes Federation forecast, there will be 552 million people living with diabetes by 2030. Consequently, unless large scale screening initiatives are implemented, half these cases are predicted to remain undiagnosed.9 

The cost impact of diabetes to the Australian economy by 2033, according to The Australian Diabetes, Obesity and Lifestyle Study (AusDiab) is forecast to be AUD $20 billion.9

Silva et al. showed that eyes with predominantly peripheral diabetic retinopathy lesions have over three times increased risk of diabetic retinopathy progression.6 These eyes also had almost a five times increased risk of progression to proliferative diabetic retinopathy.6

Retinal imaging, and in particular UWF imaging, allows practitioners to gain a ‘blueprint’ of a patient’s ocular status at any given moment that can not only be viewed and assessed by several practitioners and specialists, but can also detect change over time while minimising subjective bias.

In a bid to reduce the statistics around the rate of blindness due to diabetic retinopathy and other retinal related conditions, it is essential that extensive, objective analysis, photo-documentation and continual monitoring of the retina and periphery are conducted.

The integration of UWF imaging techniques into the ocular health examination process has enabled—and continues to enable—eye care practitioners to better detect, diagnose and monitor retinal changes which can ultimately mean earlier and better treatment options and outcomes for patients. UWF imaging is a rapidly growing choice of practising optometrists and can potentially redefine the gold standard of eye examinations in the very near future.    

 

1. Kaines A, Oliver S, Reddy S, et al. Ultrawide angle angiography for the detection and management of diabetic retinopathy. Int Ophthalmol Clin 2009; 49: 53–59.

2. Kernt M, Pinter F, Hadi I et al. [Diabetic retinopathy: comparison of the diagnostic features of ultra-widefield scanning laser ophthalmoscopy Optomap with ETDRS 7-field fundus photography]. Ophthalmologe 2011; 108: 117–123. German.

3. Price LD, Au S, Chong NV. Optomap ultrawide field imaging identifies additional retinal abnormalities in patients with diabetic retinopathy. Clin Ophthalmol 2015; 9: 527–531

4. Patel RD, Messner LV, Teitelbaum B et al. Characterization of ischemic index using ultra-widefield fluorescein angiography in patients with focal and diffuse recalcitrant diabetic macular edema. Am J Ophthalmol 2013; 155: 1038–1044.

5. Wessel MM, Aaker GD, Parlitsis G et al. Ultra-wide-field angiography improves the detection and classification of diabetic retinopathy. Retina 2012; 32: 785–791.

6. Silva PS, Cavallerano JD, Sun JK et al. Peripheral lesions identified by mydriatic ultrawide field imaging: Distribution and potential impact on diabetic retinopathy severity. Ophthalmology 2013; 120: 2587–2595.

7. The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus: Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care 20: 1183–1197, 1997

8. Cheung N, Mitchell P, Wong TY, Diabetic retinopathy. Lancet 2010; 376: 124–136.

9. Klein BE, Overview of epidemiologic studies of diabetic retinopathy. Ophthalmic Epidemiol 2007; 14: 179–183.

10. Mohamed Q, Gillies MC, Wong TY, Management of diabetic retinopathy: a systematic review. JAMA 2007; 298: 902–916.

11. Tapp RJ et al. The prevalence of and factors associated with diabetic retinopathy in the Australian population. Diabetes Care 2003; 26: 1731–1737

12. Xie J et al. Prevalence of self-reported diabetes and diabetic retinopathy in indigenous Australians: the National Indigenous Eye Health Survey. Clin Experiment Ophthalmol 2011; 39: 487–493.




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