Systematic review of the effectiveness of the single, two and three field digital retinal photography for screening diabetic retinopathy

The objectives of this review are to determine: 1) How sensitive and specific are the single, two, and three field digital retinal photography for screening diabetic retinopathy? 2) Which of the three methods is the most effective? 3) The up-to-date evidence on digital retinal photography screening for informing policy-makers. Inclusion criteria Types of participants The population of interest for this review will consist of adults greater than or equal to 21 years of age with either Type 1 or Type 2 diabetes mellitus who attended an eye screening. Types of intervention(s)/phenomena of interest The intervention of interest includes digital retinal imaging techniques that capture single, two or three visual image fields. Each of these interventions will be analysed separately as a sub-group. The reference standard for screening will include either the seven-field stereoscopic fundus photography or indirect ophthalmoscopy. Types of outcomes Outcomes that are of interest include any diabetic retinopathy including nonproliferative, proliferative and sight threatening diabetic retinopathy. Outcome measures of interest include the following characteristics of the screening instruments - sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratios.