Our study investigated the genetic causes of nanophthalmos, a rare condition where eyes are abnormally small, often leading to severe vision problems. We analyzed the genes of 105 Chinese patients, the largest group of this kind studied so far. Our research found genetic causes in over 70% of patients, primarily in four genes: PRSS56, MFRP, MYRF, and TMEM98. We discovered that the specific gene involved influences the severity of the phenotype. This research expands our knowledge of nanophthalmos, helps doctors better predict patient outcomes based on their genes, and supports using genetic testing to guide treatment for the most severe cases. (By Dr. Qingdan Xu, https://jmg.bmj.com/content/early/2025/09/19/jmg-2025-110905 )