zonular cataract and nystagmus zonular cataract and nystagmus zonular cataract and nystagmus, also referred as nystagmus with congenital zonular cataract, is a rare congenital disease associated with nystagmus and zonular cataract of the eye. zonular cataract and nystagmusother namesearly-onset non-syndromic cataractspecialtymedical genetics genetics it has been suggested that the disease follows an x-linked pattern of inheritance though studies done on this particular disease are few. diagnosis