An unusual unilateral benign congenital anomaly of the pupil.

To cite: Rajasekharan C, Thomas VA, Gayathry R, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014204619 DESCRIPTION A 50-year-old male manual labourer attended the outpatient department with history and clinical features of upper respiratory infection. He had studied up to the fifth grade. There was no history of visual symptoms. There was no significant family history of congenital ocular diseases. His vital signs, general and system examinations were normal. However, examination of his left eye showed a small eccentrically placed pupil with reduced papillary diameter (figure 1). The right pupil was of normal size and reaction (figure 2). The comparative images of both eyes are shown in (figure 3A, B, C). The extraocular movements were normal and full bilaterally. His visual acuity and optic fundi were normal. An ophthalmic consultation was done, which demonstrated a normal visual field and acuity. He was diagnosed as having unilateral idiopathic tractional corectopia. Congenital abnormalities of pupil position and shapes are uncommon. The normal pupil sizes in adults vary from 2 to 4 mm in diameter in bright light to 4–8 mm in the dark and are generally equal in size. Pupils are normally situated about 0.5 mm inferonasally from the centre of the iris. Corectopia refers to displacement of the pupil, which is normally situated about 0.5 mm inferonasally from the centre of the iris. Minor deviations of up to 1 mm are usually cosmetically insignificant and should probably not be considered abnormal. In this case, the abnormal position of the pupil is caused by a fibrous structure that tethers the iris pupillary margin to the peripheral cornea. Idiopathic tractional corectopia is an isolated unilateral congenital pupil abnormality with a highly characteristic appearance. Figure 1 Pupil of the left eye is small in size, displaced nasally and inferiorly suggestive of corectopia.