What are the other Names for this Condition? (Also known as/Synonyms)

• Irido-Corneo-Trabecular Dysgenesis
• Peters Congenital Glaucoma
• Peters’ Anomaly

What is Peters Anomaly? (Definition/Background Information)

• Peters Anomaly is a congenital condition that is characterized by corneal opacity (cloudiness of the cornea) resulting from anterior segment dysgenesis (ASD) during development. This means that the front portion of the eye does not develop normally, during fetal development of the eye (within the mother’s womb)
• The exact cause of Peters Anomaly is believed to be a mutation in any of the FOXC1, PAX6, PITX2, CYP1B1, MAF, or MYOC genes. The risk factors may include having a family history of the disorder, premature birth, deficiency of heparan sulfate (an animal tissue polysaccharide), and fetal alcohol syndrome
• The signs and symptoms of Peters Anomaly are associated with eyes and may include an opaque (cloudy) cornea, decreased vision, amblyopia, and microphthalmia. The complications may include corneal graft failure, infection, steroid-induced glaucoma, and many other conditions
• A diagnosis of Peters Anomaly can be made through physical (eye) examinations and observations, along with genetic testing to establish the involved gene
• Treatment measures for Peters Anomaly include corneal tissue replacement (keratoplasty), surgery with the intent to reduce or eliminate iridotrabecular contact, widening the anterior chamber angle (iridoplasty), or cataract extraction surgery
• The prognosis of Peters Anomaly is generally poor in terms of eyesight as most individuals have a visual acuity of about 20/400 even after a corneal graft surgery

Who gets Peters Anomaly? (Age and Sex Distribution)

• Peters Anomaly is a congenital disorder that is manifested during birth
• Both males and females are affected and no gender preference is observed
• All races and ethnic groups can be affected

What are the Risk Factors for Peters Anomaly? (Predisposing Factors)

The risk factors for Peters Anomaly may include the following:

• It is an autosomal recessive inherited disorder; therefore, having a family history of Peters Anomaly increases the risk for the same
• Premature birth
• Heparin sulfate deficiency: Research on animals have shown that a deficiency of heparan sulfate (a polysaccharide found in animal tissue) can lead to the signs and symptoms of Peters Anomaly
• Fetal alcohol syndrome: A condition causing injury to the child while in the womb, because of alcohol exposure (alcohol consumption during pregnancy)

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others. 

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Peters Anomaly? (Etiology)

The cause of Peters Anomaly may include the following factors:

• Peters Anomaly is more often sporadic (resulting from a novel mutation) than inherited; although, the disorder is known to be inherited as an autosomal recessive pattern too
• Mutations in the FOXC1, PAX6, PITX2, CYP1B1, MAF, or MYOC genes have been identified as being causative
• The FOXC1, PAX6, and PITX2 genes are (each) partly responsible for the development of the anterior segment (front portion) of the eye
• The CYP1B1 is responsible for certain enzyme production in the tissue of the eye, which is responsible for normal growth and functioning

In some cases, no mutations in any of these 4 genes are observed. In such cases, the cause of Peters Anomaly is unknown.

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Peters Anomaly?

The signs and symptoms of Peters Anomaly may include a multivarious set of conditions that affect the eye, which include:

• Opaque (cloudy) cornea which can blur vision
  • The degree of cloudiness of the cornea can vary from one individual to another
  • The location of the cloudiness may vary from one individual to another as well. In some individuals, it can affect the central portion of the cornea; while in others, it can affect the peripheral portion of the cornea
• Decreased vision or complete blindness; in about 25% of cases, there may be a total vision loss right from birth
• Amblyopia (or “lazy eye”)
• Glaucoma (increased eye pressure) due to malformation of angle structures or a shallow anterior chamber of the individual’s eye
• Cataract (blurred lens)
• Microphthalmia (small eyeballs)
• The disorder is commonly bilateral and affects both the eyes (in about 60% of the cases)

The signs and symptoms of Peters Anomaly may also include the following potential complications:

• Sclerocornea: It is a condition in which the cornea merges with the sclera of the eye
• Corectopia: In this condition, the pupil of the eye is displaced from the eye center
• Iris hypoplasia: Poorly-formed iris, which is the colored portion of the eye. This condition can result in light-sensitivity
• ICE syndrome: Iridocorneal endothelial syndrome that leads to fluid accumulation in the cornea (corneal edema), atrophy of iris (colored portion of eye), and secondary angle closure glaucoma (resulting in abnormal pressure within the eye)
• Aniridia, or the absence of iris
• Iris coloboma, which is the presence of an abnormal hole in the iris. This abnormality can cause a second pupil in the eye
• Persistent fetal vasculature: It was previously known as persistent hyperplastic primary vitreous. This condition occurs when the fetal blood vessels do not disappear after birth, resulting in cataracts
• Microcornea or the presence of abnormally small-sized cornea

There are 2 types of Peters Anomaly characterized by slightly differing signs and symptoms:

Type I Peters Anomaly:

• The cornea and iris do not completely separate from each other
• Mild/moderate opacity of the cornea

Type II Peters Anomaly:

• The cornea and lens do not completely separate from each other
• Severe opacity of the cornea, which may cover a large area of the cornea

How is Peters Anomaly Diagnosed?

A diagnosis of Peters Anomaly is made by the following observations and tests:

• A careful physical examination and assessment of medical history
• Observation of certain features during an anterior segment (eye) exam. During the exam, the following may be observed:
  • The iris strands may be attached to the cornea where the blurriness occurs
  • Displaced pupil
  • Lens may be adherent to or close to the cornea in Peters Anomaly Type II
• Genetic testing for the characterization of other potential systemic involvement

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Peters Anomaly?

The possible complications of Peters Anomaly may include the following:

• Infection
• Steroid-induced glaucoma caused during treatment of the condition
• Peters’ Anomaly is often associated with the following conditions:
  • Sclerocornea, where the sclera and cornea of the eye are merged
  • Corectopia, where the eye pupil is placed away from the center
  • Iris hypoplasia: Poorly-formed iris resulting in light-sensitivity
  • Cataract or cloudiness of the eye lens
  • Iridocorneal endothelial (ICE) syndrome causing corneal edema, atrophy of iris, and secondary angle closure glaucoma
  • Aniridia, or the absence of iris
  • Iris coloboma, which is the presence of an abnormal hole in the iris
  • Persistent fetal vasculature: This condition occurs when the fetal blood vessels do not disappear after birth, resulting in cataracts
  • Microcornea or the presence of very small cornea
• Graft failure following surgery
• Potential for reduced quality of life for those with severe eyesight problems
• Total blindness

How is Peters Anomaly Treated?

Currently, there is no cure for Peters Anomaly. The treatment is directed towards addressing the eye-associated signs and symptoms and it may include the following measures:

• Corneal tissue replacement (keratoplasty)
• Surgery with the intent to reduce or eliminate iridotrabecular contact and widening the anterior chamber angle (iridoplasty). This is helpful in treating glaucoma
• Cataract extraction or removal surgery
• Steroids to decrease the inflammation and fluid accumulation
• Treating for glaucoma using medications and surgery
• Surgical treatment measures, such as peripheral optical iridectomy, which is performed to improve one’s peripheral vision
• Placement of eye shunts to decrease eye pressure (for glaucoma)
• Individuals with small iris can be helped by either iridectomy or medication to increase pupil size
• Occupational therapy

How can Peters Anomaly be Prevented?

• Currently, there are no specific methods or guidelines to prevent Peters Anomaly, since it is a genetic condition
• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as Peters Anomaly
• Avoiding drinking alcohol during pregnancy can help lower the risk for this congenital eye condition
• A regular and periodic monitoring of pregnancy can help avoid complications for both the expectant mother and child

What is the Prognosis of Peters Anomaly? (Outcomes/Resolutions)

• The prognosis for Peters Anomaly is generally poor in terms of eyesight, as only about one-fifth of the affected individuals maintain a clear graft after 2 years. This means that a clouding of the graft can occur again
• Only about a third of the individuals have a visual acuity better than 20/400 even after a corneal graft
• The presence of glaucoma can make the visual prognosis even worse
• The prognosis also depends upon the severity of the signs and symptoms and the individual’s response to therapy

Additional and Relevant Useful Information for Peters Anomaly:

Please visit our Eye & Vision Health Center for more physician-approved health information:

http://www.dovemed.com/health-topics/vision-center/