TREATING RECURRENT CORNEAL EROSION

The treatment algorithm for recurrent corneal erosion syndrome (RCES) begins with conservative measures, including use of topical lubricants, then oral tetracyclines, and application of a bandage contact lens. When those modalities fail or if symptom relief is short-lived, clinicians can intervene with a variety of surgical options.

Speaking at the 5th EuCornea Congress in London, renowned cornea specialist Harminder S Dua MD, PhD, said the list of interventions for recalcitrant RCES includes botulinum toxin injection into the lid margin, mechanical debridement, diamond burr polishing, anterior stromal puncture with a needle or Nd:YAG laser, and phototherapeutic keratectomy (PTK).

Noting that he has experience with several of those techniques and that they all offer success, Dr Dua also highlighted their limitations and discussed why alcohol delamination of the damaged corneal epithelium is his preferred procedure.

“Alcohol delamination is a safe and effective alternative. Unlike anterior stromal puncture, it does not cause corneal haze or scarring.

“In contrast to diamond burr polishing, alcohol delamination provides tissue for histological analysis, and compared with PTK, alcohol delamination is relatively inexpensive and will not induce a hyperopic shift,” said Dr Dua, Professor of Ophthalmology and Visual Sciences, University of Nottingham, UK.

Dr Dua and colleagues described the utility of alcohol delamination as a treatment for recalcitrant RCES in papers published in 2006 and 2007 (Dua HS et al. Alcohol delamination of the corneal epithelium: an alternative in the management of recurrent corneal erosions. Ophthalmology. 2006;113:404-11.Singh RP et al. Alcohol Delamination of the Corneal Epithelium for Recalcitrant Recurrent Corneal Erosion Syndrome. Br J Ophthalmol. 2007;91:908-11).

The findings from those case series showed the treatment resulted in dramatic and persistent relief of symptoms without any deleterious effects during an average follow-up of 24 months.

He told attendees that more recently a follow-up questionnaire was sent to 20 patients whose follow-up duration now extends to 10 years. Fifteen patients responded, of whom 14 reported having no symptoms since undergoing
alcohol delamination.

Dr Dua also noted that his centre’s positive experience with alcohol delamination is corroborated by two studies that reported outcomes for the procedure compared with PTK (Chan E et al. A randomised controlled trial of alcohol delamination and phototherapeutic keratectomy for the treatment of recurrent corneal erosion syndrome. Br J Ophthalmol. 2014;98:166-71).

Alcohol delamination

In his presentation, Dr Dua also described his technique for alcohol delamination and for preparing the removed tissue for histological examination.

Using an optical zone marker, the treatment area is defined and covered with four to five drops of 20 per cent alcohol. After waiting 30 to 40 seconds, the alcohol is removed with a dry swab, and the epithelium peeled off as a sheet. (Figure 1)

Then the eye is covered with a bandage contact lens and treated with topical chloramphenicol.

“Exerting a little downward pressure with the optical zone marker will create a seal and prevent spillage of the alcohol. Therefore, it is possible to get close to the limbus with this technique,” Dr Dua said.

The tissue is prepared for histology by laying it on a piece of paper, covering it with a few drops of water, and gently teasing it flat with two forceps.

To settle the tissue flat on the paper, a dry swab is applied at the periphery of the water bubble to absorb it. Then the fixative is added, and after 10 to 15 minutes the specimen is ready for further handling.

Dr Dua theorised that the efficacy of alcohol delamination for treating RCES lies in its ability to clear away collagenous debris, leaving a smooth surface that enables firm attachment of the new epithelium to the basement membrane.

He explained that microscopic evaluation of debrided sheets of epithelium from eyes treated for RCES show abnormal hemidesmosomes in the basal epithelium along with presence of collagenous debris between the basal epithelium and basement membrane. (Figure 2)

These features prohibit the anchoring filaments from forming firm attachments and therefore enable the epithelium to easily strip away.

The alcohol that is applied percolates down between cells (leaving 30-70 per cent of epithelial cells viable) and below the subepithelial debris.

“Once the epithelium and debris are removed, the smooth clean surface left behind allows for better, stronger adhesion when the new cells grow,” Dr Dua said.

Harminder S Dua:
harminder.dua@nottingham.ac.uk