Corneal Scarring
Cloudiness of the clear front surface of the eye
Quick Facts
- Type: Eye (corneal) condition
- Effect: Blurred or reduced vision
- Common causes: Injury, infection, inflammation
- Severe cases: May need a corneal transplant
Overview
The cornea is the clear, dome-shaped front surface of the eye that lets light in and helps focus it onto the retina. Because it must stay transparent for clear vision, any cloudiness or scarring can interfere with sight. Corneal scarring is the formation of opaque or hazy tissue on the cornea, usually after it has been damaged by injury, infection, or inflammation.
A scar in the central part of the cornea, in the line of sight, can cause significant blurring, glare, or vision loss, while scars at the edge may cause few problems. Treatment depends on the size, location, and depth of the scar, and ranges from corrective lenses to surgery, including corneal transplant in severe cases. Many causes of scarring are preventable with eye protection and prompt treatment of infections.
Whether a corneal scar affects vision depends heavily on its position. A small scar near the edge of the cornea may go unnoticed, while even a modest scar directly over the pupil can blur or distort sight. The depth of the scar also matters, since deeper scars are harder to treat and more likely to need surgery to restore clear vision.
Symptoms
Symptoms depend on where the scar is and how dense it is.
- Blurred or hazy vision
- Reduced sharpness of sight
- Glare or halos around lights, especially at night
- Sensitivity to light
- A visible white or gray spot on the cornea in some cases
- Eye discomfort if the scar is associated with surface irregularity
Scars directly in the line of sight cause the most noticeable vision problems, while those off to the side may cause little or no symptoms.
Causes
Corneal scars form when the cornea heals after damage, replacing clear tissue with less transparent scar tissue.
- Infections: Bacterial, viral (such as herpes simplex), fungal, or parasitic keratitis can damage the cornea, sometimes severely.
- Injury: Scratches, cuts, chemical or thermal burns, and foreign objects in the eye.
- Inflammation and dryness: Severe or chronic surface inflammation and severe dry eye.
- Corneal ulcers: Open sores on the cornea that heal with scarring.
- Certain eye diseases and surgeries: Some conditions and procedures can leave scars.
Risk Factors
- Contact lens wear, especially with poor hygiene or overnight wear
- Eye injuries, including work and sports injuries
- A history of corneal infections such as herpes simplex keratitis
- Severe dry eye or chronic eye surface disease
- Exposure to chemicals or welding without eye protection
Diagnosis
An eye doctor diagnoses corneal scarring through a focused eye examination.
- Slit-lamp examination: A microscope with a bright light that lets the doctor see the cornea in detail and assess the scar's depth and location.
- Vision testing: To measure how much the scar affects sight.
- Corneal mapping (topography): To evaluate the shape and surface of the cornea.
- Cultures or staining: If an active infection is present or suspected.
Treatment
Treatment depends on the scar's severity and how much it affects vision.
- Treating the underlying cause: Clearing any active infection or inflammation first.
- Corrective lenses: Glasses or specialized rigid or scleral contact lenses can improve vision when the surface is irregular.
- Medications: Lubricating or anti-inflammatory drops to support the surface.
- Laser treatment: A procedure to smooth or remove superficial scars in selected cases.
- Corneal transplant: Replacing the scarred cornea, partially or fully, when scarring is dense and vision is significantly affected.
Mild, off-center scars may simply be monitored if they do not affect vision.
Prevention
- Wear protective eyewear during sports, yard work, and jobs with eye hazards
- Follow safe contact lens habits: wash hands, do not sleep in lenses unless approved, and replace them as directed
- Seek prompt treatment for eye infections, red eye, or eye injuries
- Use eye protection around chemicals and when welding
- Treat dry eye and chronic eye surface conditions
When to See a Doctor
See an eye doctor promptly for a red, painful eye, sudden blurred vision, light sensitivity, or a visible spot on the cornea, since these can signal an infection or ulcer that may scar if untreated. Seek urgent eye care for a chemical splash to the eye (rinse with water immediately and get help), an eye injury, or rapidly worsening vision. Early treatment of corneal infections and injuries is the best way to prevent permanent scarring.
Frequently Asked Questions
What causes corneal scarring?
Scars form as the cornea heals after damage from infections (such as bacterial, viral, fungal, or parasitic keratitis), injuries, burns, ulcers, or severe inflammation and dry eye. The clear tissue is replaced by less transparent scar tissue.
Does corneal scarring affect vision?
It can. A scar in the center of the cornea, in the line of sight, can cause blurred vision, glare, and reduced sharpness. Scars off to the side may cause few or no symptoms.
Can corneal scarring be treated?
Yes, depending on severity. Options range from corrective glasses or specialized contact lenses to laser treatment for superficial scars and corneal transplant for dense scars that significantly affect vision. Any active infection is treated first.
Can corneal scars heal on their own?
Once a true scar has formed, it generally does not clear on its own, though some haziness can fade over time. The goal is to prevent scarring by treating infections and injuries early and to restore vision afterward.
How can I prevent corneal scarring?
Wear protective eyewear for risky activities, practice good contact lens hygiene, avoid sleeping in lenses unless approved, and seek prompt care for eye infections and injuries. Rinse the eye immediately and get help after any chemical splash.
References
- American Academy of Ophthalmology. Corneal conditions.
- MedlinePlus, U.S. National Library of Medicine. Corneal injury.
- National Eye Institute (NEI). Corneal Conditions.
- Mayo Clinic. Keratitis — Symptoms and causes.