Purpose:
Diabetic retinopathy affects both the peripheral and central retina, but conventional digital fluorescein angiography only captures 500 of the posterior pole compared to 2000 with a scanning laser ophthalmoscope. Peripheral proliferative diabetic retinopathy may therefore go undiagnosed with the use of conventional imaging, and thwart the opportunity for early intervention. We retrospectively evaluated whether there is a differing degree of peripheral neovascular disease detected in diabetic patients with ultra-widefield (Optos 200TX) fluorescein angiography (FA), versus conventional FA (Zeiss FF 450 plus IR fundus camera) with peripheral mapping techniques.
Methods:
Angiographic features of 15 eyes of 14 diabetic patients were examined by a single retina specialist. All patients had presumed nonproliferative diabetic retinopathy, and were presenting for routine exam. Angiography was conducted on one visit with a single trained technician; first, standard FA (Zeiss FF 450 plus IR fundus camera) with a single dye injection, followed by immediate ultra-widefield (Optos 200TX) angiography. A seven-field montage was created from the standard FA, and compared to one widefield image. Angiograms were individually graded for the amount of neovascularization utilizing a standardized mapping system with a calibrated grid placed on the images. The number of grid sectors with angiographic evidence of retinal neovascularization within each image was recorded. Main outcome measurements were the total number of grid sectors with neovascularization, and the number of patients with neovascular disease found with ultra-widefield alone.
Results:
For ultra-widefield FA with the Optos 200TX, the mean number of grid sectors with retinal neovascular disease was 1.9 ± 1.7, versus 0.73 ± 1.09 grid sectors with the seven-field montage. Peripheral retinal neovascularization was evident on ultra-widefield imaging in 4 of 15 eyes (26.7%) that was not visible with conventional FA.
Conclusions:
Ultra-widefield FA with the Optos 200TX is a superior testing modality for the evaluation of peripheral neovascular disease in diabetic patients compared to conventional seven-field imaging. Greater recognition of peripheral angiographic disease could allow for earlier treatment intervention and consequently prevent blinding complications of diabetic retinopathy.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retinal neovascularization