Study designs of evaluations included in the review
No inclusion criteria relating to the study design were specified for diagnostic accuracy studies. Studies of treatment effectiveness were included only if they were randomised controlled trials (RCTs).
Specific interventions included in the review
Screening for diabetic retinopathy.
Diagnostic tests: direct ophthalmoscopy and non-stereoscopic retinal photography. The studies had to provide an adequate description of the test to be included.
Treatment: laser photocoagulation.
Reference standard test against which the new test was compared
Diagnostic accuracy studies had to include a reference standard comprising either retinal examination by an ophthalmologist or stereoscopic retinal photography.
Participants included in the review
Patients with diabetes. The studies had to define the population to be included.
Outcomes assessed in the review
The outcomes assessed were the sensitivity and specificity of the tests and, for treatment studies, visual loss or blindness.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.