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Persistent Corneal Epithelial Defect (PCED)

An optometrist in an ophthalmic clinic performs an eye examination on a device for measuring diopters, examination of the fundus of the eye, gray and yellow cataracts, examination of the tear ducts. She reads the data from the tablet and from the computer screen.

Persistent Corneal Epithelial Defect (PCED) occurs when the corneal surface fails to heal despite standard treatment and remains open or damaged for more than two weeks which can lead to serious complications including loss of vision.

Affecting fewer than 200,000 people in the U.S., PCED represents a serious rare disease with a high unmet clinical need.(1)

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    Persistent Corneal Epithelial Defect (PCED)

    The cornea is the clear, protective outer layer of the eye. Its surface is made up of specialized cells that constantly renew themselves, to keep the eye healthy and to heal injuries. When this healing process fails and a defect persists for more than two weeks despite standard treatment, it is called a Persistent Corneal Epithelial Defect (PCED). This condition may cause significant pain and blurred vision, and if left untreated, it can lead to serious complications like severe infection, permanent scarring, and partial or complete loss of vision.

Optometry, tablet and optician with man for results, communication and consulting about vision. Healthcare, medical and ophthalmologist talking to a patient about eye care after an exam with tech

Q&A

What causes PCED?

PCED occurs when the eye’s natural healing cycle is interrupted. While many factors can prevent the cornea from repairing itself, common causes include:

  • Injury and Irritation: Physical or chemical trauma, injuries caused by medical procedures (iatrogenic), or long-term contact lens overwear.
  • Infections and Dryness: Severe corneal infections or chronic "dry eye," which deprives the ocular surface of the moisture needed to heal.
  • Underlying Health Conditions: Autoimmune disorders, ocular graft versus host disease (GVHD), or severe allergic reactions like atopic or vernal keratoconjunctivitis.
  • Nerve and Stem Cell Issues: Conditions like Neurotrophic Keratitis (NK), where a lack of corneal sensation stops healing signals, or Limbal Stem Cell Deficiency, where the eye loses its ability to produce new surface cells.

What are symptoms and complications of PCED?

Living with PCED typically begins with noticeable physical symptoms, most commonly persistent ocular pain, general discomfort, and a significant impairment of vision. These early warning signs reflect the eye's inability to maintain its protective surface.

Without proper healing, the cornea becomes highly vulnerable to serious complications, including infections and permanent scarring. In severe cases, thinning corneal tissue may lead to perforation of the eye. Ultimately, these complications can result in a significant decrease in or even a total loss of vision.

How is PCED diagnosed?

Diagnosing PCED begins with a detailed examination of the eye’s surface. Because a healthy cornea typically heals within just a few days, the primary sign of PCED is a persistent delay in that natural recovery process.

To identify the condition, eye care specialists typically use two main tools:

  • Slit-Lamp Examination: A specialized microscope (called a biomicroscope) that allows the doctor to see the structures of the eye in high detail.
  • Fluorescein Staining: The doctor applies a safe, vital dye to the eye. This dye highlights areas where the protective surface cells are missing, making the exact size and shape of the defect visible under a specific light.

Doctors will also assess for underlying triggers such as severe dry eye, physical trauma, and nerve-related issues.

References

  1. Wirostko B, Rafii M, Sullivan DA, Morelli J, Ding J. Novel Therapy to Treat Corneal Epithelial Defects: A Hypothesis with Growth Hormone. Ocul Surf. 2015 Jul;13(3):204-212.e1. doi: 10.1016/j.jtos.2014.12.005. Epub 2015 Mar 28. PMID: 26045234; PMCID: PMC4498999. (Prevalence section pages 2-3)