Abstract
Purpose:
To identify eyes of patients with diabetes type 2 that show progression of retinal disease within a one-year period of follow-up using non-invasive techniques.
Methods:
Three hundred seventy four (374) type-2 diabetic patients with mild nonproliferative diabetic retinopathy (NPDR) (ETDRS levels 20 or 35) were included in a 12-month observational and prospective study to identify retinopathy progression. Patients were included in 19 clinical sites from the European Vision Institute Clinical Research Network (EVICR.net). Four visits were scheduled at months 0, 3, 6 and 12 with the following examinations: color fundus photography (CFP), spectral domain optical coherence tomography (SD-OCT) and blood tests. ETDRS severity level in the first and last visits, and microaneurysm (MA) turnover (formation plus disappearance rates), using the RetmarkerDR, were assessed centrally by the Coimbra Ophthalmology Reading Center (CORC). SD-OCT was used to measure retinal thickness (RT) and ganglion cells layer thickness. One eye per patient was selected as the Study Eye.
Results:
374 patients/eyes with mild NPDR were included (65.0% males and 35.0% females) with ages ranging from 35 to 82 years (18.4% graded as level 20 and 81.6% as level 35, ETDRS severity scale). Mean BCVA was 84.9±6.3 ETDRS letters. Mean HbA1C was 7.8±1.5% and the systolic and diastolic blood pressure was respectively of 137.6±16.6 and 77.4±10.0 mmHg. 328 eyes/patients completed the study (325 completed the 12-month visit and 3 eyes developed CSME between the 6 and 12-month visits). The mean central RT at baseline was 264.9±21.9 µm (Cirrus SD-OCT). At the 6-month visit (336 eyes/patients), 18 eyes (5.4%) showed a central subfield RT decrease of 5% or more, whereas 30 eyes (8.9%) showed a central subfield RT increase higher than 5%. In the period of 12-months of follow-up, a MA turnover equal or higher than 6 was registered in 45.5% of the eyes, whereas 54.5% of the eyes showed MA turnover values of less than 6.
Conclusions:
MA turnover using the RetmarkerDR on field 2 CFP images and central subfield RT changes using SD-OCT over a 12-month period of follow-up in eyes with mild NPDR, identify activity and progression of the retinal disease. Different eyes/patients with diabetes type 2 and mild NPDR show different involvement of the different components of the retinal neurovascular unit.
Keywords: 688 retina •
499 diabetic retinopathy •
550 imaging/image analysis: clinical