Episcleral pigment spots were studied clinically in 76 patients and histologically in 15 autopsy eyes. Most commonly, the pigment spots were found in patients with darkly pigmented irides, especially in Negro patients, usually in the superior episclera 3 to 4 mm from the limbus. Inferior, temporal, and nasal episcleral spots occurred in descending frequency. The spots were composed of uveal melanocytes always associated with a perforating anterior ciliary vessel or an intrascleral nerve loop or both. These pigment spots should be differentiated from nevi, cysts, and extensions of adjacent or underlying malignant melanomas.
Yanoff M. Pigment Spots of the Sclera. Arch Ophthalmol. 1969;81(2):151-154. doi:10.1001/archopht.1969.00990010153001