Diabetic Retinopathy Management Guidelines

Rahul Chakrabarti; C Alex Harper; Jill Elizabeth Keeffe


Expert Rev Ophthalmol. 2012;7(5):417-439. 

In This Article

Assessment of DR: Standard Classification

The importance of classifying the natural progression of DR is critical for recognition of stages of disease which require treatment. Since the original classification of DR was described in the Airlie House Symposium in 1968, several modified classification systems have developed that have been integrated into the published guidelines.[68–73] The basis of these classification systems has been the understanding of the natural progression of DR gained from the ETDRS. This stratified risk for DR based on observed features of fundus images that were compared with a series of standard stereoscopic slides.[74] The ETDRS levels of retinopathy severity have since been regarded as the 'gold standard' for use in clinical and epidemiologic studies.[68] However, the applicability of the ETDRS scoring system in daily clinical practice was restricted due to its multiple levels of severity that are often unnecessary to patient care, complicated grading rules for the different stages and the need for correlation with standard retinal images.[69]

Alternate classification systems have been developed by the NSC (UK), Scottish Diabetic Retinopathy Grading Scheme and Royal College of Ophthalmologists (RCO; UK). The subtle differences between these and the international classification existed in the description of nonproliferative diabetic retinopathy (NPDR). These were compared in a simple table in the RCO guideline (Appendix C). The simplest grading system was developed by the RCO, which stratified DR into 'none', 'low-risk', 'high-risk' and 'PDR'. However, treatment recommendations by the RCO referred to studies using the ETDRS or international classifications.

The International Clinical Diabetic Retinopathy and Diabetic Macular Oedema Severity Scale, developed in 2001, has since been adopted for guidelines developed in North America, Australia, Asia, Africa and Asia–Pacific region. The new classification incorporated evidence on disease progression from the ETDRS, and stratified DR into five levels of severity based on observed retinal changes.[69] The main distinctions offered in the international severity scale are that the levels of severity are each relevant to the clinical management decisions for the patient. This offered a simpler method to assess risk of progression of DR, and facilitated communication between ophthalmologists and primary healthcare providers. Accordingly, the international classification system has been endorsed by most international authorities including the WHO as a standard system for guiding evidence-based practice. While the international classification system has not replaced the ETDRS, it has been demonstrated as a useful guide for population screening, and facilitating timely treatment.[15,75]