What is it?
Recurrent corneal erosion syndrome (RCES) is a condition in which the epithelial cells fail to adhere to the underling stroma.
The cornea is the clear window at the front of the eye. In simple terms it has three layers – a central ‘cartilaginous’ stroma, epithelial cells on the front surface and endothelial cells on the back.
Causes of RCES
RCES may follow corneal trauma or occur in patients who have abnormailities of the cornea such as Map-Dot-Fingerprint or Lattice Corneal Dystrophy. Glancing injuries from fingernails, paper and vegetation are common causes. Erosions are more common in patients with diabetes.
Corneal erosions that follow trauma may occur a few days or several months after the injury. Erosions are very painful and the affected eye is usually sore, watery and sensitive to light. Erosions heal more slowly than normal abrasions so symptoms may take several days to settle.
Erosions often occur during rapid eye movement sleep or when the eyes are opened in the morning. Changes in the tears during sleep result in greater adhesion between the eyelid and cornea and the two literally stick together. When the eyes move or open the epithelial cells are torn off the underlying stroma.
RCES may resolve spontaneously but most cases require treatment. The prognosis is generally good but approximately 5% of patients continue to have painful erosions despite appropriate management.
The treatment of RCES may involve:
- Pain relief
- Eye movement training
- Bandage contact lenses
- Removal of epithelial cells
- Corneal micropuncture
- Laser resurfacing of the stroma
- Anti-inflammatory drops
- Doxycycline tablets
- Saline ointment
- Serum eye drops
Eye pads, ointments and gels, pupil dilation, bandage contact lenses and pain relieving tablets such as paracetamol and low dose amitryptiline can all be very useful.
Antibiotc ointments may be prescribed for a few days to reduce the risk of infection.
Gels and soft ointments form a soft lubricant barrier between the eyelid and cornea. They are usually instilled before sleep. Lubricants should be used for 3 months after symptoms resolve.
Eye movement training
Many erosions can be avoided by patients learning to wake with their eyes closed and still. The eyes and lids are then slowly moved and opened to avoid any sudden shearing forces.
Bandage contact lenses
Soft contact lenses provide a physical barrier between eyelid and cornea. They need to be used for several months and changed on a regular basis to reduce the risk of infection associated with long term contact lens wear.
Removal of epithelial cells
Epithelial cells that repeatedly detach from the underlying stroma may loose their ability to adhere normally. Removing these cells and allowing new ones to cover the area hastens healing and reduces pain. In some cases it prevents further erosions. Epithelial cells can be removed with cotton buds, corneal scrapers and alcohol solutions.
A needle can be used to create microscopic holes in the anterior corneal stroma. The healing response produces tiny ‘spot welds’ that help allow the overlying epithelial cells to adhere.This treatment is not suitable for erosions close to the centre of the cornea as it can result in decreased vision.
Resurfacing the surface of the stroma
The excimer laser can be used to remove a very thin layer of corneal stroma, a procedure known as Photo Therapeutic Keratectomy or PTK. This removes scar tisse and creates a clean and slightly roughened surface.
Topical steroids such as prednisalone may be used to reduce inflammation and promote healing.
Doxycycline is an antibiotic with anti-inflammatory properties. It promotes epithelial healing and inproves the function of the meibomian glands in the eyelid. These glands secrete oily substances that lubricate the cornea and prevent drying of the surface of the eye.
Saline (salty) ointment may be more effective than other ointments. It reduces corneal epithelial swelling during the night
Serum is the watery component of blood. It can be collected and made into eye drops. Serum contains many substances that promote corneal epithelial healing.