Peters anomaly is characterized by dysgenesis of the anterior segment of the eye. Several genetic mutations lead to a number of structural deficits, most prominent being corneal opacities and the formation of synechiae between various structures in the eye. In addition to significant visual impairment (that is frequently bilateral), Peters anomaly can present with systemic manifestations such as craniofacial, skeletal, cardiovascular, renal, genital, and central nervous system abnormalities. The diagnosis rests on clinical criteria and genetic studies.
Peters anomaly belongs to a group of diseases known for causing anterior segment dysgenesis (ASD) [1] [2] [3] [4] [5]. ASD is a term describing rare embryological disorders that arise between the 4th and 7th week of embryonal maturation and cause severe anatomical malformations of the iris, the cornea, and the retina [1] [3] [5]. Specifically, the signs and symptoms of Peters anomaly stem from iridocorneal and lenticular-corneal synechiae, corneal opacities, and disruptions of the posterior corneal layers, all occurring due to two events: improper separation of the surface ectoderm and the lens; and abnormal connections between the iris or the lens to the cornea when the anterior chamber is formed [1] [2] [3]. The typical presentation is distinguished by an early onset (infancy) of deficits in the visual field and reduced acuity, either in one or both eyes [1] [6]. Because the trabecular meshwork is not properly developed, glaucoma is a frequent feature in these patients [1] [2] [6] [5] [7]. In addition to ocular findings, numerous systemic manifestations have been documented in the literature [1] [2] [3] [4]. Micrognathia, low-set ears, a cleft palate, underdeveloped teeth and upper lips are notable malformations of the face, whereas skeletal (clinodactyly, brachydactyly, and a rhizomelic stature), cardiovascular (most importantly congenital heart disease), and neuropsychiatric (mental delay, sensory nerve damage, agenesis of the corpus callosum, etc.) are noticed [1] [2] [4] [5]. The term Peters plus syndrome is sometimes used to describe patients with Peters anomaly who suffer from systemic symptoms [2] [4]. Amblyopia is a potential complication of Peters anomaly [5].
Studies have shown that the majority of corneal transplants in infants are indicated for the correction of Peters anomaly [8], thus the condition must be included in the differential diagnosis of corneal opacities causing visual symptoms in this age group. To make the initial diagnosis, a properly conducted physical examination is the crucial step. On the basis of clinical findings during the examination and advanced ocular investigation (slit-lamp evaluation, etc.), two types of Peters anomaly are described: type 1, distinguished by the presence of bilateral avascular corneal opacities distributed centrally or paracentrally; and type 2, where corneal opacities are much denser and accompanied by dislocation of the lens and frequent absence of the iris [5] [7]. A definite diagnosis of an ASD can be made through genetic studies, which are often not performed in patients with Peters anomaly [1]. An array of genetic mutations have been identified in this disorder, thus a molecular genetic analysis of the patient (but also of the parents and close family members, given the autosomal recessive pattern of inheritance) is recommended whenever possible [1] [2] [4].