Nanophthalmos is a bilateral condition characterized by a small eye (short axial length) with relatively normal lens volume, leading to severe axial hyperopia, crowding of the anterior chamber angles and a high incidence of angle-closure glaucoma.

The eye often has an excessively thickened sclera interfering with suprachoroidal drainage, resulting in uveal effusion and non-rhegmatogenous retinal detachment.

Folds in the choroid and retina, crowded disks, retinal edema, and yellowish retinal discoloration are common. The foveal reflex is frequently absent.

In microphthalmia all ocular structures are small.