Possible complications of penetrating keratoplasty surgery are graft failure, infection and steroid-induced glaucoma. Due to all of the factors involved in penetrating keratoplasty, corneal transplants have a variable rate of graft failure of around 20% to 80%.
Over half of individuals with Peters anomaly have secondary glaucoma. This will often require multiple surgeries.
Most patients with PA are left with some level of amblyopia (decreased vision). Infants who have had cataracts removed will need to be fit with a high power, soft contact lens. The resulting amblyopia will need to be treated with occlusion (patching) to achieve their best visual acuity.
It is common for individuals with Peters anomaly to work with a low vision specialist. This is to maximize their vision and visual function throughout all stages of life.
Experts have identified two types of Peters anomaly. In the case of Type I, typically, only one eye is affected. The clouding is limited to the center of the cornea, leaving the peripheral cornea clear. It generally comes with a strong prognosis for vision.
Type II Peters anomaly affects both eyes. The lens of the eye is more likely to be compromised, as well as the cornea, leading to cataracts in addition to corneal clouding. Vision will be more severely compromised in these cases.
Multiple genetic factors, especially the mutation of genes involved in eye development, can cause Peters anomaly.
Children born prematurely have a high risk of developing Peters anomaly. A diagnosis of fetal alcohol syndrome has also been associated with a higher incidence of PA.
Other syndromes associated with Peters anomaly are:
Peters plus syndrome – Peters plus syndrome is an inheritable genetic condition. It is characterized by ocular findings plus dysmorphic facial features, cardiac issues and/or central nervous system malformations.
Axenfeld-Rieger syndrome – Axenfeld-Rieger syndrome has a similar genetic mutation to Peters anomaly. It includes iris and corneal anomalies, cataracts and glaucoma.
Peters anomaly is often detected by a pediatrician shortly after birth. The most characteristic symptom of PA is an opaque area on the cornea. This opaque area is called a leukoma. A leukoma is defined as a dense white scar.
Peters anomaly is responsible for 40% of congenital leukomas detected in infants. The resulting corneal defect often adheres to the iris, causing structural and visual problems.
Leukomas vary in size and transparency from individual to individual. This variance ranges from small, hard-to-see streaks on the cornea to fully opaque leukomas.
Peters anomaly affects both eyes in 80% of cases but is often asymmetric.
Also, Peters anomaly often presents with ocular diagnosis such as:
Glaucoma – a condition in which fluid builds up in the eye increasing intraocular pressure. The elevated pressure within the eye can damage the optic nerve and create significant vision loss. Glaucoma due to Peters anomaly is very difficult to treat and control.
Cataract – when the lens in the eye has an opacity that negatively affects the proper development of vision. In PA the lens may adhere to the back of the cornea.
Amblyopia – reduced visual acuity in one or both eyes commonly known as “lazy eye.” In PA, amblyopia development is secondary to the corneal opacities and cataracts.
Nystagmus – involuntary movement or “dancing” of the eyes. Nystagmus is a manner in which the visual system “ searches” for an area with better visual acuity.
Strabismus – often presents when a deeply amblyopic eye is unable to fixate. Strabismus is also known as “crossed eyes.” The eye often drifts in toward the nose (most common) or out toward the ear causing a misalignment.
Peters anomaly is diagnosed by anterior segment examination, which shows corneal opacification present at birth. B-scan ultrasonography or ultrasound biomicroscopy can be used to examine the anatomic relationship between the lens, iris and cornea. Ultrasound biomicroscopy is useful in detecting central corneal opacity, the absence of Descemet’s membrane, and iridocorneal and keratolenticular adhesions.
If full-thickness corneal transplantation is performed, then histopathologic findings of the cornea are a useful adjunctive tool in the diagnosis of Peters Anomaly as well. Genetic testing of one of the aforementioned genes can help to confirm Peters anomaly, but it is classically diagnosed clinically.
