Statistics from Altmetric.com
Editor,—Congenital abnormalities of pupil position and shape are uncommon. Slit lamp examination will usually identify which of the various rare anterior segment developmental anomalies has caused the pupil appearance. Possible associations include iris coloboma, Axenfeld-Reiger anomaly, ectopia lentis et pupillae, persistent pupillary membrane, and hyperplastic pupillary membrane. Surgical intervention for the pupil abnormality is not normally required.
Idiopathic tractional corectopia is an isolated unilateral congenital pupil abnormality with a highly characteristic appearance (Fig 1). The four previously reported cases required no intervention or responded well to simple lysis of the fibrous strand that is characteristic of the condition.1
We report a fifth case, where progression of the tractional process led to failure of initially successful conservative management and a surgical pupilloplasty was required as no benefit was obtained by cutting the fibrous strand.
A healthy male child was referred to the ophthalmology department soon after birth with a unilateral misshapen eccentric pupil. There was no family ocular history. At initial examination he was found to have right corectopia with an oblique oval pupil and a fibrous band extending from the pupil margin to the endothelial surface of the peripheral superonasal cornea. The iris appeared otherwise normal: hypoplasia, polycoria, retroillumination defects, or ectropion uvea were not present. The corneal diameter and intraocular pressure were normal. A pupil opening was present with normal red reflex and limited view of the ocular fundus. The pupil did not dilate with topical mydriatic. Examination of the left eye was unremarkable. Ultrasound of the eyes was normal.
Over the next 5 months the pupil in the right eye became smaller and more eccentric. Occlusion therapy was commenced but the right eye became visually unresponsive. The pupil could be seen to offer no optical pathway by this stage (Fig 1). At surgery the fibrous band was cut with intraocular scissors but there was no effect on pupil morphology. Further attempts to mobilise the pupil threatened to disinsert the iris root superonasally. Therefore a central pupil was created by small multiple iris sphincter incisions. Postoperatively the eye settled well and without complication. At 6 months postoperatively the vision in the right eye had improved to 6/24 with aggressive occlusion therapy.
Early reports of isolated corectopia are not particularly useful owing to inadequate examination techniques and equipment.2Isolated corectopia was considered by Duke-Elder to be a bilateral condition.3
Scott Atkinson et al 1 reported four children with isolated unilateral corectopia, resulting from a white band that extended from the pupil margin to insert in a circumferential condensation of tissue on the endothelial surface of the peripheral cornea that superficially resembled an incomplete posterior embryotoxon. The condition was named “idiopathic tractional corectopia” (ITC). The pupil displacement may progress during the first months of life, possibly by further contraction of the fibrous band. The origin of the band is unknown. Children with ITC need to be monitored closely by monocular vision testing as they are at risk of amblyopia. Prompt laser or surgery may be indicated if vision reduces because of optical pupil occlusion.