Slow saccades in myogenic and peripheral neurogenic ophthalmoplegia Latent ocular myopathy in myotonic dystrophy

Abstract

The difference of slow saccades between ocular myopathy and peripheral neurogenic ophthalmoplegia was studied. Slow saccades in three patient groups were examined. The first group consisted of 16 patients suffering from oculomotor or a bducens paresis. The second group consisted of eight ocular myopathy patients. The mode of decrease in saccade velocity was different between the two groups. The decrease of velocity in large amplitude saccades was more prominent than of small amplitude saccades in the first group. The decrease of velocity in small amplitude saccades was also prominent, like in large amplitude saccades in the second group. The mode of decrease in saccade velocity among the ocular myopathy patients was also found in the third group; seven myotonic dystrophy patients. These results suggested early involvement of extraocular muscles in these myotonic dystrophy patients, although all but one of them showed no apparent eye movement restriction.

Key Words:

• slow saccade
• ophthalmoplegia
• myotonic dystrophy
• ocular motor palsy