Recurrent erosion syndrome usually occurs following a scratch injury to the surface epithelial layer of the cornea. Probably the commonest causes are a fingernail scratch of the eye (typically a small child accidentally scratches their parent's eye) and gardening injuries where a plant scratches the eye (plant wins!). Some people can have a genetic weakness of the surface epithelium of the eye which may be poorly adherent to its underlying layer. Genetic conditions include map dot fingerprint epithelial dystrophy and microcystic dystrophy.
The epithelium of the cornea is a thin layer of cells that covers the surface of the cornea and forms a barrier to the outside world. There is a dense network of nerves that penetrate the epithelium. When the epithelium is injured there is rapid regeneration of cells from adjacent stem cells and the defect in the epithelium is quickly closed. Recurrent erosion syndrome occurs because the newly healed epithelial layer doesn't stick to the underlying layer very well. It can then be peeled off relatively easily leading to recurrent epithelial breakdown. This usually occurs at night when the eyelid can become dried onto the epithelium. During REM sleep or on waking the epithelium can be peeled off resulting in a painful erosion that usually settles within a day. Patients often notice this as a sudden sharp pain in the middle of the night or on waking followed by stabbing pain, sensitivity to light and streaming of tears. This usually resolves but often reoccurs. In some unlucky patients this cycle can repeat itself many times a week and becomes debilitating as it is difficult to work or function when the eye is very painful.
Treatment of recurrent erosion syndrome
Recurrent erosion syndrome is usually treated conservatively with ocular lubricants. Your doctor will advise you to use regular tear drops in the day and an ointment at night. The purpose of the ointment is to stop the lid sticking to the eye at night. Most patients will settle on this conservative approach. Your doctor may also advise you to treat any blepharitis if present.
Some patients do continue to have problems with recurrent erosion syndrome and further interventions are required. Some of these include bandage contact lens wear, alcohol epithelial debridement, needle epithelial micro-puncture and laser phototherapeutic keratectomy (PTK). The choice of treatment will depend on your doctors access to a laser.
What is laser PTK?
Laser PTK uses the same excimer laser used in laser eye surgery. During PTK the surgeon will rub off the loose layer of epithelium and then use the laser to remove a very small amount of underlying tissue (8-9 microns - a micron is 1/1000 of a millimetre). The treatment takes just a few minutes and is performed with a local anaesthetic drop. The surgeon will then place a bandage contact lens on the eye for comfort and to protect the surface as it heals. This small amount of laser stimulates a wound healing response that tacks down the new epithelial layer more strongly to its underlying surface. A bandage contact lens may be required for 1 month after PTK to encourage good adhesion
Does PTK work in recurrent erosion syndrome?
Current evidence suggests that PTK works in up to 75% of patients with recurrent erosion syndrome. Roughly 25% develop recurrences and PTK can be repeated in these patients if necessary.
What are the risks of PTK?
PTK is a relatively low risk procedure, Risk of infection is the main concern and can occur in a very small number of patients. Scarring is exceptionally rare. A small number of patients may have a change in glasses prescription but this is uncommon with modern lasers such as the Schwind Amaris which maintains pre-operative corneal shape.
Reeves SW, Kang PC, Zlogar DF, Gupta PK, Stinnett S, Afshari NA.
Ophthalmic Surg Lasers Imaging. 2010 Mar 9:1-2.