Non-stereo photographic screening in long-term follow-up for detection of proliferative diabetic retinopathy.

The efficiency of two non-stereo photographs of the posterior pole as a screening device in long-term follow-up for the detection of proliferative diabetic retinopathy was evaluated in a clinical setting among 1341 diabetic hospital patients. False positive findings occurred in 0.4% (6/1341). Severe irreversible sight-threatening complications from undetected proliferative diabetic retinopathy, such as retinal traction detachment or secondary glaucoma, never occurred. Vitreous haemorrhages due to missed new vessels in the photographic area occurred in only 2 out of 3020 photographic reading sessions over a 5.5 year period. Evaluation of the nature, localization and magnitude of new vessels showed that optic disc new vessels were generally over-diagnosed in younger patients and missed in patients aged 45 years or older. New vessels elsewhere were more frequently misdiagnosed in patients older than 50 years. New vessels were most commonly found on the temporal arcades (48%) of the eyes and nasal to the optic disc (42%) but were significantly rare beyond the posterior pole (13%) (P less than 0.001). Patients younger than 60 years had significantly more lesions (P less than 0.001) and these lesions tended to be bilateral. Two non-stereo photographs of the posterior pole is a safe and efficient alternative method to conventional survey for proliferative diabetic retinopathy. New vessels are significantly most common in the posterior pole and complications from new vessels occurring exclusively outside the posterior pole can be disregarded. Bilateral neovascularization should be anticipated in patients under 60 years.