Introduction
The predominant ocular findings reported in the familial and heredodegenerative ataxias are nystagmus, optic atrophy, and ocular muscle palsies. Nystagmus is said to be characteristic of the so-called spinal form of familial ataxia (Friedreich's ataxia) and optic atrophy and ocular muscle palsies of the spinocerebellar (Marie's ataxia) and cerebellar forms of heredodegenerative ataxia.1 We are concerned in this paper with some aspects of the ocular findings in the heredodegenerative ataxias which fit broadly within the classification of the spinocerebellar and cerebellar forms of the disease.In the literature we found a group of heredodegenerative ataxias associated with progressive ophthalmoplegia, a group associated with retinal degeneration, and a group associated with both ophthalmoplegia and retinal degeneration.Stephans et al.2 in 1958 reported 4 cases of heredodegenerative ataxia associated with progressive ophthalmoplegia in which the ophthalmoplegia was characterized by an impairment of upward gaze with a preservation of