Nanophthalmos is characterized by axial lengths of the ocular globe that are more than 2 SDs smaller than the normal range, or less than 20 mm in adults, with a cornea and lens that are typically of normal size, associated with severe hyperopia (farsightedness) of +7.00 diopters or more. The smaller dimensions of the anterior chamber depth cause the iridocorneal angle to be typically narrow. Abnormal thickening of the scleral connective tissue is often observed (summary by Awadalla et al., 2014). For a discussion of genetic heterogeneity of nanophthalmos, see NNO1 (600165).

Primary closed-angle glaucoma (GLCC) is characterized by age-related variation in the degree of iridocorneal angle closure and its sequelae, with patients in the first 3 decades of life showing a normal eye exam, whereas older patients progressively show more evidence of angle closure and glaucomatous damage, including optic nerve head changes and visual field defects (Suri et al., 2018).