The eye surface has an extraordinary capacity to heal. The outermost layer of the cornea serves as a shield against dust, germs, and injury. When the cornea's outer layer is injured, the eye starts a natural healing process that takes about 7 to 14 days. This can be sometimes delayed, leaving the injury left open and is referred to as a Persistent Epithelial Defect (PED).1
Key Takeaways
- A persistent epithelial defect is a non-healing corneal wound that requires proper medical care.
- Multiple factors can delay corneal healing such as diabetes, dry eye disease, neurotrophic keratitis, infections, eye injuries, and previous eye surgeries.
- Treatment should address the underlying cause while supporting corneal epithelial regeneration.
- Management of corneal epithelial defect includes lubricating eye drops, bandage contact lenses, autologous serum eye drops, amniotic membrane transplantation, or surgery in severe cases.
- Advanced interventions are considered when conventional therapies fail.
- OptiCover™, a lyophilized amniotic membrane graft, is designed to support corneal wound management in persistent epithelial defects.
What Is a Persistent Epithelial Defect?
The cornea is the transparent, dome-shaped front surface of the eye that helps to focus light. It also acts as a mechanical barrier to protect the eye. Corneal epithelium forms the protective outermost layer and quickly self-repairs itself after minor injuries.2 But sometimes, if a wound doesn't heal even after 2 weeks of proper treatment, it's called a Persistent Epithelial Defect (PED).
When the healing is delayed, the wound remains open. This paves the way for microbes, which can lead to infections, ulcers, scarring, thinning and in the most severe cases corneal perforation, which can threaten vision.1
Prevalence Of Persistent Epithelial Defect
The exact incidence of persistent epithelial defect (PED) is not well established because it can develop as a complication of underlying eye conditions and surgical procedures. PED can occur at any age but is more associated with pre-existing ocular surface disease, neurotrophic keratopathy, severe dry eye, chronic inflammation, corneal infections, and previous corneal surgery. Available data suggest that fewer than 200,000 cases occur annually in the United States, placing PED within the category of rare diseases.1
What Causes A Persistent Epithelial Defect?
A persistent epithelial defect results from direct corneal injury or disruption of the mechanisms responsible for normal corneal surface repair. Common causes include:
- Corneal surface damage: Trauma, chemical burns, foreign bodies, LASIK, cataract surgery, or corneal transplantation.
- Reduced corneal sensation: Neurotrophic keratitis, diabetes-related nerve damage, or herpes infections.
- Tear film dysfunction: Chronic dry eye, reduced tear production, poor tear quality, or meibomian gland dysfunction.
- Infections and inflammation: Bacterial, viral, or fungal keratitis and chronic ocular inflammation.
- Systemic conditions: Diabetes, autoimmune diseases, vitamin A deficiency, and malnutrition. 1, 3
Symptoms Of Persistent Epithelial Defect
Patients experience symptoms depending on the underlying cause and the extent of corneal involvement. They may include:
- Persistent eye pain
- Redness
- Foreign body sensation
- Burning or stinging sensation
- Blurred vision
- Sensitivity to light
- Difficulty opening the eye
- Not improving with treatment after few days
Risk factors for persistent epithelial defects include older age, diabetes, chronic dry eye, previous eye surgery, contact lens misuse, and corneal infections. Other contributing factors include autoimmune disorders, neurotrophic keratitis, vitamin A deficiency, chemical injuries, and ocular trauma. 1
Evaluation and Management of Persistent Epithelial Defects
An ophthalmologist performs a detailed examination of corneal epithelium of the patient to evaluate the persistent epithelial defect. The choice of treatment is decided based on the underlying cause. Conditions such as infection, dry eye disease, diabetes, or eyelid abnormalities must be treated to achieve healing.
Medical Treatment
Many corneal epithelial defects can improve with conservative, non-surgical treatments, depending on their cause and severity. Common approaches include:
- Preservative-free artificial tears
- Lubricating eye ointments
- Punctual plugs
- Prophylactic antibiotic eye drops when infection risk is present
- Therapeutic bandage contact lenses 4
Advanced Therapies
When conventional treatment fails, advanced therapies are recommended by the opthalmologist. These treatments provide growth factors and biological substances that encourage epithelial regeneration. These include:
- Amniotic membrane grafts
- Autologous serum eye drops
- Platelet-rich plasma (PRP) eye drops
- Recombinant human nerve growth factor
- Punctal plugs to retain natural tears 5
Amniotic Membrane Grafts For Non Healing Persistent Epithelial Defects
Amniotic membrane grafts have become a treatment option, when conservative treatments fail. The amniotic membrane provides a biological scaffold and contains anti-inflammatory and regenerative signals which can support corneal surface repair.6 Clinical study supports the use of amniotic membrane transplantation as an option for selected refractory PEDs, although outcomes vary across patient populations and treatment techniques.7
OptiCoverTM is a lyophilized amniotic membrane graft retaining HC-HA/PTX3, a biologically active complex associated with ocular surface healing. It may be considered in selected cases of persistent corneal epithelial defects and ulcers. OptiCoverTM is also a shelf-stable graft that does not require cold-chain storage. For PED management, this may help clinicians initiate advanced ocular surface treatment without delays, when compared to cryopreserved grafts. 8
Significance of HC-HA/PTX3: HC-HA/PTX3 (heavy chain–hyaluronan/pentraxin 3) is a biologically active matrix component of amniotic membrane that contributes to its anti-inflammatory and anti-scarring properties. It helps create a more favorable ocular surface environment by modulating inflammatory responses and supporting regenerative processes. 9
Surgical Options
In severe or non-healing cases, surgery is necessary. Possible procedures include:
- Temporary or permanent tarsorrhaphy (partial closure of the eyelids)
- Conjunctival flap surgery
- Corneal transplantation 5
Conclusion
A persistent epithelial defect is more than a simple scratch on the eye. When the corneal epithelium remains open, then the eye is at risk for infection, scarring, and vision loss. Cases that fail to respond to conventional management may require transition to advanced therapeutic strategies. In such cases, OptiCover™, a lyophilized, shelf-stable amniotic membrane graft provides a viable option that can be integrated into a clinician-directed treatment. Early recognition and timely ophthalmic evaluation are important for appropriate management and protecting vision.
Frequently Asked Questions
1. What is a persistent epithelial defect?
A persistent epithelial defect is an open wound on the surface of the cornea that fails to heal in two weeks with proper treatment.1
2. What causes a corneal epithelial defect to become persistent?
Impaired tear production, diabetes, neurotrophic keratitis, ocular infections, previous ocular surface surgery, chemical burns and chronic inflammation can all affect healing, resulting in a non-healing corneal epithelial defect.3
3. Can an epithelial defect in the eye heal without surgery?
Yes. This can be treated with preservative free lubricants, bandage contact lenses. Advanced therapies include autologous serum eye drops or amniotic membrane transplantation. Surgery is for more severe cases. 4
4. Is a persistent epithelial defect an emergency?
A persistent epithelial defect requires prompt ophthalmic evaluation. Urgent medical attention may be needed if there are signs of severe infection, corneal thinning, perforation, or sudden deterioration in vision 1
5. When should amniotic membrane grafts be considered over continued conservative management for PED?
Amniotic membrane grafts may be considered when a PED remains refractory despite appropriate conservative measures such as lubrication and surface protection. 1
6. How does a lyophilized graft compare to cryopreserved in clinical use for PED cases?
Lyophilized grafts offer room-temperature storage and avoid cold-chain requirements compared to cryopreserved ones, improving accessibility to advanced treatments. 8
7. What role does HC-HA/PTX3 play in ocular surface healing?
HC-HA/PTX3 is a biologically active matrix complex associated with the anti-inflammatory and anti-scarring properties of amniotic membrane. It can help create a supportive environment for corneal epithelial repair and ocular surface regeneration. 9
8. Is there clinical evidence supporting amniotic membrane grafts for PED?
Yes. Clinical studies have evaluated amniotic membrane transplantation for PEDs, including refractory cases, with evidence of epithelial defect resolution and improvement. 7
