Retinal thickness as a marker of disease progression in longitudinal observation of patients with Wolfram syndrome

AIMS: Wolfram syndrome (WFS) is a recessively inherited monogenic form of diabetes coexisting with optic atrophy and neurodegenerative disorders with no currently recognized markers of disease progression. The aim of the study was to evaluate retinal parameters by using optical coherence tomography (OCT) in WFS patients after 2 years of follow-up and analysis of the parameters in relation to visual acuity. METHODS: OCT parameters and visual acuity were measured in 12 WFS patients and 31 individuals with type 1 diabetes. RESULTS: Total thickness of the retinal nerve fiber layer (RNFL), average retinal thickness and total retinal volume decreased in comparison with previous OCT examination. Significant decreases were noted for RNFL (average difference −17.92 µm 95% CI −30.74 to −0.10; p = 0.0157), macular average thickness (average difference −5.38 µm 95% CI −10.63 to −2.36; p = 0.0067) and total retinal volume (average difference −0.15 mm(3) 95% CI −0.30 to −0.07; p = 0.0070). Central thickness remained unchanged (average difference 1.5 µm 95% CI −7.61 to 10.61; p = 0.71). Visual acuity of WFS patients showed a strong negative correlation with diabetes duration (R = −0.82; p = 0.0010). After division of WFS patients into two groups (with low-vision and blind patients), all OCT parameters except for the RNFL value were lower in blind WFS patients. CONCLUSIONS: OCT measures structural parameters and can precede visual acuity loss. The OCT study in WFS patients should be performed longitudinally, and serial retinal examinations may be helpful as a potential end point for future clinical trials.