Table 2.

Number of patients tested at entrance examination into the study and retested at annual follow-up intervals after entrance

	Entrance	1-year follow-up	2-year follow-up	3-year follow-up
Visual acuity	23	18	14	11
Retinal nerve fibre layer	20	14	11	10
DT-MRI optic radiation FA	19	13	9	6

DT-MRI, diffusion tensor MRI; FA, fractional anisotropy.