Functional and structural change in diabetic eyes. Interim results from an ongoing longitudinal prospective study

To presents results after 18 months of follow-up of a longitudinal study aiming at exploring the correlation between diabetic retinal vascular lesions and functional change.

Patients were consecutively recruited from attendees to the screening program for diabetic retinopathy. Subjects are followed every sixth month for the first 3 years and thereafter annually up to 5 years. Progression of diabetic retinopathy is evaluated using the Early Treatment Diabetic Retinopathy Study (ETDRS) scale and improvement/deterioration in visual fields by predefined significance limits for change.

Of 81 subjects, with no/mild/moderate diabetic retinopathy included, 76 have passed the 18-month visit. At that time, retinal progression by two steps according to the ETDRS scale had occurred in two subjects. Visual acuity was -0.14 logMAR and had decreased with two letters (0.04 logMAR) (p < 0.001) from baseline. The global visual field index mean deviation was almost unchanged with a negligible improvement of 0.03 dB (p = 0.79). In 21 subjects, repeated significant deterioration was seen in ≥10% of all points tested in the field, while almost no improved points were noted. The two subjects with retinal progression were not among those 21 with indication of perimetric progression.

This is, to our knowledge, the first longitudinal study evaluating change of visual fields in a representative diabetic cohort with no or mild/moderate retinopathy. In this interim report, we demonstrate deteriorated perimetric sensitivity in subjects already at 18 months of follow-up. The results will have implications for evaluating change in visual function in future clinical trials.