Peters’ anomaly – Strabismus and amblyopia: a case report

Peter’s Anomaly, first described by Albert Peter in 1906, consists of a central corneal opacity related to a malformation of the anterior segment of the eye. It’s a disease in a constellation of diseases that causes corneal opacity, iridocorneal adhesions due to dysgenesis of the anterior segment during development. Peters’ Anomaly can cause devastating corneal opacity in an infant leading to severe amblyopia. It frequently occurs with associated strabismus, usually convergent (sensorial type), having also dissociated vertical deviation (DVD). The exact prevalence of Peters’ Anomaly is unknown. This condition is one of a group of disorders known as congenital corneal opacities, which affect three to six individuals per 100,000. Physiopathology: Peter’s Anomaly is a rare dramatic finding at birth, manifests in utero during the first trimester of pregnancy (10-16 weeks of gestation), and can be associated with other systemic malformations. It is classified in two types, which are distinguished by their signs and symptoms. Peters’ Anomaly Type I is characterized by an incomplete separation of the cornea and iris and mild to moderate corneal opacity. Type II is characterized by an incomplete separation of the cornea and lens and severe corneal opacity that may involve the entire cornea. Type II is more associated with systemic alterations and tends to be bilateral. During development of the eyes, the elements of the anterior segment form separate structures. However, in Peters’ Anomaly, development of the anterior segment is abnormal, leading to incomplete separation of the cornea from the iris or the lens. As a result, the cornea is cloudy (opaque), which causes blurred vision. The opaque area (opacity) of the cornea varies in size and intensity from a small, faint streak to a large, white cloudy area that covers the front surface of the eye. Additionally, the location of the opacity varies, the cloudiness may be at the center of the cornea or off-center. Large, centrally located opacities tend to cause poorer vision than smaller, off-center ones. It is important a binocular vision evaluation in order to identify, qualify and quantify the type of ocular deviation, characterize the real and potential binocular single vision and the amblyopia. The motor and sensorial tests must be appropriate to the case in question, in particular, visual acuity and fixation. The treatment involves a corneal transplant which is often complicated due to the young age of the affected. To prevent amblyopia and provide visual rehabilitation a penetrating keratoplasty (PKP) was recommended. Many children with PKP for Peters’ Anomaly Type I can experience good or functional vision in their operated eye. After keratoplasty is very important to improve visual acuity and do amblyopia treatment. Children with glaucoma have a poorer visual prognosis. The treatment of strabismus in cases of Peters’ Anomaly follows the general rules of treatment of concomitant strabismus. The first step should be the best optical correction possible. The surgical proposal must be made after achieving visual acuities between the two eyes. In congenital strabismus, late surgery will only have aesthetic value.