Persistent Epithelial Defect: Causes, Symptoms, and Treatment
What Is a Persistent Epithelial Defect?
The cornea is the clear, dome-shaped front surface of your eye. Understanding what a PED is and why it forms is the first step toward getting the right care.
The outermost layer of the cornea is called the epithelium. Think of it as a living skin that constantly renews itself. Healthy epithelial cells slide together quickly to seal small cuts and scratches, usually within 24 to 48 hours. This rapid healing keeps the eye clear, comfortable, and protected from infection.
A common corneal abrasion heals fast because the surrounding cells can move freely and seal the wound. A PED is different. The cells near the wound are unable to migrate and bond the way they should, so the surface stays open. This is not simply a slow scratch. It is a breakdown in the healing process itself, and it requires targeted care to address the underlying reason the wound will not close.
Certain people are more likely to develop a PED than others. Your Cornea Specialist will review your full medical and eye health history to identify any contributing factors before creating a care plan.
- Older adults with reduced surface cell activity
- People with severe or long-standing dry eye disease
- Those with a history of herpes eye infections
- Patients with diabetes-related nerve changes in the eye
- Anyone who has had prior corneal surgery or a corneal graft
- People who have experienced a chemical or heat burn to the eye
What Causes a Persistent Epithelial Defect?
A PED is almost always a sign that something is interfering with the normal healing process. Identifying the specific cause shapes every decision about treatment.
The tear film that coats your eye is not just for comfort. It delivers oxygen and growth factors that the epithelium needs to repair itself. When dry eye is severe enough to disrupt this supply, the wound cannot receive what it needs to close. Treating the underlying dry eye is often a critical part of PED care, and your Cornea Specialist may recommend tear duct plugs, advanced lubricating drops, or other dry eye therapies alongside direct wound treatment.
The cornea contains a dense network of nerve fibers that do more than sense pain. They also release chemical signals that trigger epithelial cells to grow and migrate. When these nerves are damaged, the healing signal is lost. This condition is called neurotrophic keratopathy. Because a nerve-damaged cornea has reduced sensation, patients often feel little or no discomfort even as the surface deteriorates, which makes regular monitoring especially important.
- Past herpes simplex or herpes zoster eye infections
- Diabetes causing peripheral nerve changes
- Prior surgery involving the trigeminal nerve
- Long-term use of certain eye drops or contact lenses
Some eye drops used to treat other conditions can slow the healing of the corneal surface over time. Drops containing preservatives, particularly benzalkonium chloride, can be irritating to the epithelium when used frequently. Certain steroid and glaucoma drops may also interfere with cell migration. Your Cornea Specialist may switch you to preservative-free formulas or adjust your drop regimen to reduce this burden on the surface.
Burns from chemicals or heat can destroy the stem cells that live at the edge of the cornea and continuously replenish the surface. Without these stem cells, the epithelium cannot rebuild itself properly. Severe infections, uncontrolled allergic eye disease, and failure of a previous corneal graft can also set the stage for a PED. Each cause has its own treatment pathway, and your care plan will be built around your specific situation.
How Is a Persistent Epithelial Defect Treated?
Treatment for a PED works on two levels: supporting the surface directly and addressing whatever is preventing it from healing on its own. Your Cornea Specialist will choose the approach that fits the severity and cause of your wound.
The first step in most cases is intensive lubrication with preservative-free artificial tears, gels, and overnight ointments. Removing any drop that may be slowing healing is also a priority. A soft bandage contact lens is often placed on the eye to shield the wound from the friction caused by blinking. This lens is worn together with antibiotic drops to reduce the risk of infection while the surface works to repair itself.
When standard lubricants are not enough, your Cornea Specialist may prescribe serum drops, which are drops made from a sample of your own blood. Your blood contains growth factors and proteins that closely mimic the composition of natural tears, and these substances actively promote epithelial healing. Because the drops are made from your own blood, your body recognizes them and there is no risk of rejection. A blood draw is required to prepare them, and your specialist will explain the process in full.
Other specialized drops, including agents that support nerve-signal pathways in the cornea, may also be considered depending on the cause of your PED.
If drops and a bandage lens have not closed the wound, your Cornea Specialist may place a thin patch of amniotic membrane over the surface of the eye. Amniotic membrane is a tissue that releases natural healing factors and acts as a protective barrier for the wound. The patch is secured with a small ring or with a special adhesive and is left in place for several days to a week. Many patients experience wound closure after one or two applications of this treatment.
For wounds that do not respond to the options above, temporarily closing part of the eyelid is sometimes the most effective path forward. This procedure is called a tarsorrhaphy. A small stitch is placed to hold the eyelid partially closed, which removes the mechanical stress of blinking and creates a protected environment for the surface to heal. The eyelid is reopened once the cornea has recovered. While it can feel unusual, a tarsorrhaphy often allows a stubborn PED to close when nothing else has worked.
Warning Signs and When to Seek Care
A PED is an open wound, and an open wound on the eye carries real risks. Knowing when to call for help and when to seek same-day care is an important part of protecting your sight.
If you notice increasing pain, spreading redness, or a drop in your vision, these are warning signs that the wound may be worsening. A white or gray spot on the cornea is particularly concerning because it may signal that the tissue is becoming infected or that a corneal ulcer is forming. Halos around lights and a dull, pressured feeling in the eye can indicate that eye pressure is rising as a result of the prolonged wound. Contact our office promptly if any of these changes appear.
An open corneal surface is vulnerable to bacteria and other organisms that can cause a serious infection called a corneal ulcer. Signs of infection include thick or cloudy discharge, a sudden increase in pain, significant light sensitivity, and a hazy or white appearance to the normally clear cornea. Infections overlying a PED can spread rapidly through the corneal tissue. If you notice these signs, same-day evaluation is essential. A delay of even one or two days can result in permanent scarring.
Seek care the same day you notice a sudden drop in vision, sharp or worsening pain, or any sign of infection described above. If our office is not available, go to an urgent eye care center or a hospital emergency department with on-call ophthalmology services. Fast evaluation and treatment are among the most important factors in preserving sight when a PED takes a sudden turn for the worse.
A PED that remains open for weeks or months can cause the cornea to progressively thin. In serious cases, the cornea may develop a hole, a complication called perforation that requires emergency surgical intervention. Even without perforation, prolonged wounds can leave dense scars that permanently reduce sharp vision. These scars may ultimately require a corneal transplant to restore clarity. Early and consistent treatment gives the surface the best possible chance of healing without lasting consequences.
Frequently Asked Questions
Below are answers to questions we hear often from patients managing a persistent epithelial defect. If your question is not covered here, our team is glad to help at your next visit.
Healing time varies significantly depending on the cause and your overall eye health. Milder cases with an identifiable and treatable cause may close within a few weeks of starting the right drops and protective measures. More complex situations, such as those involving nerve damage or stem cell loss, can take two to three months or longer even with consistent care. Your Cornea Specialist will track the wound at every appointment and adjust the treatment plan based on how the surface is responding.
Yes, recurrence is possible, particularly for patients whose underlying condition has not been fully resolved. Severe dry eye and neurotrophic cornea are the two most common reasons a healed PED reopens. Long-term use of preservative-free lubricating drops, routine follow-up visits, and treating the root cause as aggressively as possible all play a role in reducing the risk of recurrence. Your specialist will outline an ongoing maintenance plan once the wound has healed.
Most persistent epithelial defects do not require a corneal transplant. A transplant becomes a consideration only when the wound has led to deep, vision-limiting scars or when the cornea has thinned to the point that it cannot safely support the surface. Your Cornea Specialist will exhaust all appropriate non-surgical and minimally invasive options before recommending surgery of any kind. If a transplant is eventually needed, our team performs the full range of modern corneal transplant procedures.
Standard daily contact lenses for vision correction are not safe while a PED is present. They can introduce bacteria to an open surface and prevent the wound from receiving adequate oxygen. A soft bandage lens prescribed and monitored by your Cornea Specialist is a different matter. It is specifically designed to protect and support healing when used alongside antibiotic drops. You should wait until your specialist confirms the wound has fully closed before resuming your regular lens wear.
Serum drops are used for more than just persistent epithelial defects. They may also be recommended for severe dry eye, neurotrophic keratopathy, and certain other difficult-to-treat ocular surface conditions. Eligibility depends on your specific diagnosis and overall health. Your Cornea Specialist will determine whether serum drops are an appropriate option for your situation and explain how the preparation and dosing process works before you begin.
Following your drop schedule exactly as prescribed is the single most important thing you can do. Beyond that, wearing wraparound sunglasses outdoors reduces wind, dust, and glare that can irritate the surface. Avoiding smoke and dry environments helps preserve whatever moisture the eye is producing. Resting well and avoiding rubbing the eye are also important. If you notice any sudden change in pain, redness, or vision, contact us right away rather than waiting for your next scheduled appointment.
Expert Cornea Care Close to Home
A wound that will not heal deserves more than a wait-and-see approach. At Rhode Island Eye Institute, our fellowship-trained Cornea Specialists, including Dr. Jane Cook, Dr. Elliot Perlman, and Dr. Christopher Newton, bring deep subspecialty expertise to even the most challenging cases of persistent epithelial defect. Our integrated team of optometrists and cornea surgeons works together under one roof, so your care is coordinated and continuous from the first visit through full recovery. We welcome patients from across Rhode Island and southeastern Massachusetts and encourage you to schedule a consultation if you have a corneal wound that has not healed or if you have concerns about the health of your corneal surface.