1. Familial cases. Since the first reports on familial cases by Schott and by Clausen in 1921, other familial groups have been reported
2. Paramacular coloboma.-A number of macular colobomata reported as such belong to this group. The cases of Beaumont and of Schmidt-Rimpler (1899) are illustrations of a unilateral lesion of this type, both with poor vision. Bilateral paramacular colobomata with full vision in each eye are reported by Lindsay Johnson (case 6) and by Sorsby, whose case showed latent nystagmus. In contrast to these cases in which the paramacular defect was situated temporally, there are the cases of Michaelson and Van Lint, in which a defect in the central area involved the optic nerve; these cases are only doubtfully cases of macular coloboma. A paramacular coloboma in one eye, and in the other eye two colobomata reminiscent of choroidal coloboma and situated above and below the disc respectively, is reported by Forsmark