Lamellar cataract A congenital cataract in which opacity is limited to layers of the lens external to the nucleus (i.e., the perinuclear region), i.e., between the nuclear and cortical layers of the lens. HP:0007971 SNOMEDCT_US:21590003 UMLS:C0266537 SNOMEDCT_US:204128001 Zonular cataract