What is a corneal scar/opacity?
The cornea is a truly remarkable part of your body. It is living tissue that does many complex things, yet it remains crystal clear. The cornea is composed largely of collagen (a protein), arranged in a specific pattern which makes it transparent. When the cornea works correctly, like a camera lens, it focuses light onto the eye’s film, the retina.
If the cornea becomes cloudy, so does one’s vision. The cornea can become cloudy several ways including many genetic and metabolic conditions, infection or trauma.
What are the symptoms of a corneal scar/opacity?
Blurry vision is the most common symptom, although patients often complain of glare and halos around lights. Depending on the size and location of the scar, the symptoms may be worse in low light levels as the pupil dilates, or they may be worse at high light levels as the pupil constricts. Scars do not typically cause pain, although they may lead to surface irregularities which can feel like sand or grit in the eye.
How is a corneal scar/opacity diagnosed?
A detailed eye exam performed by your eye doctor can identify the cloudiness or scarring. The cause of the opacity may be readily apparent, or it may be difficult to tell what caused it.
How is a corneal scar/opacity treated?
Prevention is always the easiest and most efficient way to prevent scarring. Conditions that notoriously lead to scarring (corneal infection or ulcer) may be treated with immune suppressing steroid eyedrops after the infection is resolved to minimize or prevent scar formation.
Once a scar or opacity has become a part of the cornea, your doctor may recommend treatment if it affects vision. If the scar makes the surface irregular and distorts the eye’s focusing ability, your doctor may recommend specialty contact lenses. This restores a smooth focusing surface to the cornea. These lenses typically work best for scars not located in the center of your vision.
If scarring involves the center of your vision, your doctor may recommend that it be removed. For central scars, surgical options performed by a skilled corneal surgeon include superficial keratectomy (SK), deep anterior lamellar keratoplasty (DALK), Descemet’s membrane endothelial keratoplasty (DMEK), and penetrating keratoplasty (PK).
- SK is used for opacities in the cornea’s outermost layer, the epithelium. The corneal epithelium replaces itself every week, so after removing such opacities, the cornea will regrow this layer and may look relatively normal within weeks. SK is not a true transplant in that it just removes unhealthy epithelium so that a healthy epithelial layer can regrow. Sometimes, we recommend removing a peripheral superficial opacity if it threatens to grow towards the center of the cornea. With this strategy, a patient can have a problem solved with an SK before it becomes more central or deeper in the cornea which could require a transplant.
- DMEK, DALK and PK are true corneal transplants. Each of these procedures are used to remove and replace opaque tissue in different corneal layers. Generally, your surgeon will want to only replace the layer that is sick and leave any healthy tissue behind. DMEK is far less invasive than DALK or PK. Because of its lower risks, your surgeon will have a lower threshold to offer DMEK and leave DALK and PK as a last resort.