Background
Peters anomaly is a rare congenital form of anterior segment dysgenesis in which abnormal cleavage of the anterior chamber occurs. It is characterized by a central corneal opacity (leukoma) due to defects in the posterior stroma, Descemet membrane, and endothelium. [1, 2, 3, 4, 5]
Peters anomaly is differentiated into 2 types: the milder type 1 Peters anomaly, which typically does not include the lens, and the more severe type 2 Peters anomaly, in which the lens adheres to the cornea (keratolenticular adhesions). [1] Peters anomaly may also be associated with systematic abnormalities. [6, 7]
Genetic mutations within FOXC1, PAX6, PITX2, and CYP1B1 can all result in abnormal neural crest cell migration to the posterior cornea, which can lead to Peters anomaly. [2, 7, 8, 9]
Pathophysiology
Peters anomaly type 1 presents with central or paracentral corneal opacity and iridocorneal adhesions. Keratolenticular adhesions are absent in this type, although the lens may be cataractous.
Peters anomaly type 2 is commonly associated with a denser corneal opacification. It presents with keratolenticular adhesions.
Peters anomaly is bilateral in 60%-80% of cases. [10] It may be associated with other abnormalities of the eye, including congenital glaucoma, myopia, aniridia, iris coloboma, microphthalmos, persistent hyperplasia of primary vitreous (PHPV), and optic disc hypoplasia. [11, 12]
Systemic associations with Peters anomaly include trisomy 13-15, partial deletion of chromosome arm 11q, and Norrie disease. Peters plus syndrome is characterized by cleft lip or palate, short stature, facial dysmorphism, genitourinary abnormalities, syndactyly, brachycephaly, and cardiac, neural, and hearing abnormalities. [6, 13]
Epidemiology
Freqency
United States
The incidence of Peters anomaly in the United States is estimated to be 44-60 cases annually. [14]
International
The incidence of Peters anomaly outside the United States is unknown.
Mortality/Morbidity
In addition to corneal opacity and cataract, glaucoma and deprivation amblyopia may increase morbidity. [13]
The risk of mortality may be increased because of other systemic involvement, especially cardiac and neural abnormalities. [6, 13]
Race
Peters anomaly has no known racial predilection.
Sex
Peters anomaly has no known sexual predilection.
Age
Peters anomaly manifests in utero during the first trimester of pregnancy (10-16 weeks' gestation) and is therefore noted at birth. The anterior segment is formed completely by the 10th week of gestation, and, by the 16th week, most of the Descemet membrane is formed.
Prognosis
The visual prognosis in individuals with Peters anomaly is guarded. The earlier the keratoplasty is performed, the better the chance of preventing deprivation amblyopia. However, keratoplasty is often challenging to perform in infants and young children. The visual acuity in patients after keratoplasty was 20/80 or worse in most series. The likelihood that patients maintain a clear graft was also quite low at 10 years. Patients with glaucoma and cataract had a worse visual prognosis.
Penetrating keratoplasty has a success rate of 22%-83% in patients with Peters anomaly. [2]
Prognosis depends on the severity of the disease. [5]
Peters anomaly type 1 has a significantly higher rate of a clear graft than does type 2.
Patients with glaucoma and cataract have a worse prognosis.
Penetrating keratoplasty should be performed before age 12 months.
Morbidity and mortality depends on concomitant systemic anomalies.
Patient Education
Children with Peters anomaly require special educational needs depending on the visual acuity. A low-vision specialist should evaluate these children. Patients may need special equipment (loupes, binoculars, other low vision aids) depending on the visual potential.
