Necrotic changes of choroidal melanocytes in sympathetic ophthalmia.

There are various theories as to the origin of epithelioid cells in the choroid with sympathetic ophthalmia. Some investigators propose a transformation of choroidal melanocytes as the origin, and others suggest a histiomonocytic derivation. One reason this controversy exists may be the relative lack of investigations into necrotic changes of choroidal melanocytes. The structural alterations in the choroidal melanocytes of an injured eye with sympathetic ophthalmia were studied, and the sequence of events involved in degeneration and necrotic changes were elucidated. The damaged melanocytes developed vacuolation, and the melanin granules were gathered into autophagosomes or had disappeared. The nuclei of the severely damaged melanocytes became pyknotic. Degenerated cell nuclei were phagocytized by macrophages. It is concluded that choroidal melanocytes may not transform into epithelioid cells and that they disappear from the choroid following degeneration.