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

• PPCD (Posterior Polymorphous Corneal Dystrophy)
• PPMD (Posterior Polymorphous Corneal Dystrophy)
• Schlichting Dystrophy

What is Posterior Polymorphous Corneal Dystrophy? (Definition/Background Information)

• Posterior Polymorphous Corneal Dystrophy (PPCD or PPMD) is a rare genetic eye condition involving the cornea (specifically causing corneal endothelium and Descemet’s membrane abnormalities). In severe forms of this condition, the cornea is cloudy and shows fluid buildup, resulting in vision impairment from childhood
• Posterior Polymorphous Corneal Dystrophy forms part of a group of disorders named anterior segment developmental anomalies (ASDA). ASDA refers to developmental disorders involving the eye's anterior segment region. These disorders are also termed anterior segment dysgenesis (ASD). The anterior segment anatomical region includes the cornea, lens, iris, and aqueous humor that nourishes the eye
• Posterior Polymorphous Corneal Dystrophy is a lifelong condition, and regular ophthalmic examinations are typically recommended to monitor the health of the cornea and manage associated complications. Genetic counseling may be offered to individuals with PPCD and their families to understand the genetic implications and inheritance patterns
• The treatment of Posterior Polymorphous Corneal Dystrophy may involve monitoring for glaucoma, addressing corneal edema if significant, and considering surgical interventions such as corneal transplantation in severe cases

Who gets Posterior Polymorphous Corneal Dystrophy? (Age and Sex Distribution)

• Posterior Polymorphous Corneal Dystrophy is a rare condition. It is categorized as a subtype of congenital hereditary endothelial dystrophy (conditions that present corneal opacities)
• The presentation of symptoms is noted in early childhood and during adolescence
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Posterior Polymorphous Corneal Dystrophy? (Predisposing Factors)

• A positive family history is a significant risk factor since Posterior Polymorphous Corneal Dystrophy is typically inherited
• Children born to consanguineous partners or spouses are at an even higher risk

It is important to note that having a risk factor does not mean 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 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 Posterior Polymorphous Corneal Dystrophy? (Etiology)

Posterior Polymorphous Corneal Dystrophy (PPCD) is a rare genetic disorder that affects the cornea, specifically the corneal endothelium. The corneal endothelium is a layer of cells on the inner surface of the cornea responsible for maintaining the cornea's transparency by regulating fluid balance.

• PPCD is a genetic disorder inherited in an autosomal dominant manner. The involvement of several genes, such as OVOL2, COL8A2, and ZEB1 genes, on chromosomes 1, 8, 10, and 20 is reported
• PPCD forms part of a group of conditions known as anterior segment developmental anomalies. Abnormalities during embryological development of the cornea result in thickened Descemet’s membrane, leading to corneal clouding and edema

In individuals with anterior segment developmental anomalies (ASDA), frequent disruptions in the aqueous humor production and drainage pathways result in complications, such as increased intraocular pressure, which results in glaucoma.

What are the Signs and Symptoms of Posterior Polymorphous Corneal Dystrophy?

Most Posterior Polymorphous Corneal Dystrophy (PPCD) cases are typically mild, and no significant signs and symptoms are noted. In severe cases, the following may be noted:

• Enlarged or thickened cornea
• Corneal edema (fluid buildup)
• Bilateral corneal opacity (cloudiness)
• Blurred vision
• Increased intraocular pressure leading to glaucoma
• Both eyes are usually involved

The severity and presentation of PPCD can vary among affected individuals, even within the same family.

How is Posterior Polymorphous Corneal Dystrophy Diagnosed?

The following observations and tests may diagnose Posterior Polymorphous Corneal Dystrophy:

• Physical examination and medical history evaluation
• Assessment of signs and symptoms
• General eye exam
• Fundoscopic (ophthalmoscopic) examination by an eye specialist who examines the back part of the eye (or the fundus)
• Visual acuity test using a unique and standardized test chart (Snellen chart)
• Slit-lamp examination
• Gonioscopy, a painless eye exam using special devices
• Visual evoked potential (VEP) test
• Prenatal tests and newborn screening

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 Posterior Polymorphous Corneal Dystrophy?

The complications of Posterior Polymorphous Corneal Dystrophy may include:

• Emotional stress for the parents and caregivers
• Intraocular pressure leading to glaucoma
• Development of amblyopia
• Severe vision loss
• Post-treatment complications

How is Posterior Polymorphous Corneal Dystrophy Treated?

Individuals with asymptomatic Posterior Polymorphous Corneal Dystrophy (PPCD) may not require any treatment. In such cases, the healthcare provider may undertake a wait-and-watch approach with periodic screening exams.

In severe forms of PPCD, the following treatment measures may be considered:

• Symptomatic management
• Control the production of aqueous humor using medications such as beta-blockers, alpha-adrenergic agonists, and carbonic anhydrase inhibitors
• Decrease intraocular pressure through eye drops and medications
• Surgical intervention may be necessary, including corneal transplant (keratoplasty)
• Correction of refractive errors, if any, including the use of eyeglasses or contact lenses
• Close follow-up and periodic visits to the healthcare provider is important

The treatment measures include treating the symptoms and managing any associated condition/disorder.

How can Posterior Polymorphous Corneal Dystrophy be Prevented?

There are no specific methods or guidelines to prevent Posterior Polymorphous Corneal Dystrophy 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 anterior segment developmental anomalies

What is the Prognosis of Posterior Polymorphous Corneal Dystrophy? (Outcomes/Resolutions)

• The prognosis of Posterior Polymorphous Corneal Dystrophy (PPCD) depends on the severity of the condition and one’s response to treatment
• However, most cases are mild, and the outcomes are good since the condition is generally non-progressive. Severe cases of PPCD may be mildly progressive, requiring surgical intervention

Additional and Relevant Useful Information for Posterior Polymorphous Corneal Dystrophy:

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

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