Congenital miosis or congenital microcoria occurs rarely.1,2 This anomaly apparently is due to the partial or complete absence of the dilatator muscle of the iris. Histologic examination of the iris reveals undifferentiated epithelial cells from which the dilatator muscle should have formed.
Four patients with congenital miosis have been observed. Three of these patients were related, and 3 consecutive generations were represented. The first patient (mother of Patient 2, and daughter of Patient 3) also had glaucoma. Congenital miosis associated with a narrow angle of the anterior chamber, with or without increased intraocular pressure, has not been reported previously in the medical literature.
Report of Cases
—A 35-year-old white woman was seen in July, 1958. Intermittent pain, in and around both eyes, was of about 3 weeks' duration. She did not complain of halos or blurred vision. She stated that her right eye was crossed in childhood,
VEIRS ER, BROWN W. Congenital MiosisAssociated with a Narrow Angle of the Anterior Chamber and Abnormally Placed Iris Tissue. Arch Ophthalmol. 1961;65(1):59-60. doi:10.1001/archopht.1961.01840020061011