VISUAL DYSFUNCTION IN PATIENTS WITH MITOCHONDRIAL MYOPATHIES .2. CONTRAST SENSITIVITY FUNCTION

Contrast sensitivity function with stationary and temporally modulated (8 Hz) black and white Vertical sinusoidal gratings was investigated in 11 patients with biopsy-confirmed mitochondrial progressive externa l ophthalmoplegia. To evaluate contrast sensitivity function results, the contrast sensitivity versus spatial frequency experimental data fo r each subject were fitted with a second-order polynomial, and the coe fficients of the best-fitting function from normal and patient groups were compared. Patients with progressive external ophthalmoplegia, as a group, showed a decreased sensitivity at the intermediate spatial fr equencies (i.e., around 1.4 c/deg) with stationary gratings and throug h a wider range of spatial frequencies with temporally modulated grati ngs. These findings were confirmed by analyzing contrast sensitivity f unctions from each individual. The study showed that contrast sensitiv ity function detects visual function abnormalities noninvasively in a number of patients with mitochondrial progressive external ophthalmopl egia with unaffected Snellen visual acuity.