Nanophthalmos is a small eye, typically with an axial length of 18 mm or less and with associated high hyperopia. The cornea is abnormally steep in the recessive form, distinguishing it from ordinary hyperopia. The lens-to-eye ratio is high, with a shallow anterior chamber and risk for angle-closure glaucoma. Another distinguishing feature is a characteristic papillomacular fold. The phenotype can result from biallelic mutations in PRSS56 or MFRP or from heterozygous mutations in TMEM98. When the anterior segment is of grossly normal depth, the phenotype is termed posterior microphthalmos.
Nowilaty SR, Khan AO, Aldahmesh MA, Tabbara KF, Al-Amri A, Alkuraya FS. Biometric and molecular characterization of clinically diagnosed posterior microphthalmos. Am J Ophthalmol. 2013;155(2):361–372.e7.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.