Peters' anomaly is a congenital disorder characterized by central corneal opacity and iris adhesions that extend to the periphery of the corneal opacity. The depth of the anterior chamber (AC) varies among affected individuals. Even if the AC is shallow, however, the angle usually remains open. As far as we are aware, no cases have been reported in which an AC has not formed. We present a rare case of Peters' anomaly with pupillary block leading to a fl attened AC. Case ReportThe patient was a 2-month-old boy who was delivered spontaneously at 39 weeks of gestation with a birth weight of 2650 g. There was no family history of ophthalmologic problems other than refractive errors. Corneal opacity was present in the patient's right eye at birth. The synechiae extended from the central iris to the periphery of the corneal opacity, and the AC appeared extremely shallow under microscope examination. The corneal diameter was 11.5 mm (horizontal) × 11.0 mm (vertical) OD and 10.5 mm × 10.5 mm OS. The cornea was not bulging forward. No abnormalities of lens, vitreous cavity, or retina were detected by ultrasonography in the B-scan mode. No clinical abnormalities were observed in the left eye. Intraocular pressure was 31 mmHg OD and 10 mmHg OS. We made a diagnosis of unilateral Peters' anomaly. Ultrasound biomicroscopy revealed the absence of an AC in the right eye (Fig. 1). The fi ndings of the lens surface were uncertain. To reduce the intraocular pressure in the right eye, we attempted to perform trabeculotomy under general anesthesia. We fi rst LETTERS