Article Date: 2/1/2006

treatment plan
Managing Recurrent Corneal Erosions
BY WILLIAM L. MILLER, OD, PHD, FAAO

Many of us have received early morning calls from patients who awoke with pain, photophobia and lacrimation from recurrent corneal erosions (RCEs).  These defects are most commonly associated with corneal trauma, but other causes include epithelial basement membrane dystrophy, diabetes and ocular rosacea. Several targeted treatments can address etiological factors contributing to RCE and minimize its effect on patients' quality of life.

Figure 1. Disruption of hemidesmosomes (HD) and the junctional complexes (A, C) anchoring the corneal epithelium (pink) to the underlying stroma (green) contribute to the formation of recurrent corneal erosions (RCEs). Courtesy of Jan Bergmanson, OD, PhD

Define the Problem

Histopathological examination shows that abnormal basement adhesion complexes or aberrant basement membrane contribute to formation of RCEs. This combination can result in overnight epithelial edema, predisposing the cornea to erosion by the eyelids on wakening. On a molecular level, fatty acids (FA) and matrix metalloproteinases (MMP-2 and MMP-9) disrupt basement membrane formation, resulting in abnormal hemidesmosome formation and junctional complexes, all of which are important for anchoring the corneal epithelium to the underlying stroma (Figure 1).

We can prevent or reduce the incidence of RCEs by targeting these etiological factors with approaches ranging from lubrication to laser procedures.

Smooth the Surface

The standard approach to treating mild RCEs is corneal lubrication. Lacrilube (Allergan) continues to be a favorite among clinicians for overnight lubrication. Hyperosmotic agents, such as Muro 128 (Bausch & Lomb) drops during the day and ointment at night, are preferred over hypo-osmotic agents, which may contribute to anterior epithelial edema. When used overnight, hyperosmotic lubricating agents can eliminate the superficial corneal edema that is thought to interfere with successful epithelial adhesion.

Apply Protective Covering

Bandage contact lenses can reduce pain and protect the ocular surface from forces generated by the eyelid during blinking. When worn overnight, bandage contact lenses may prevent formation of a stagnant tear film during sleep, which causes fragile epithelial cells to adhere to the eyelid. Patients experience pain when the eyelid pulls adherent epithelial cells from the ocular surface upon awakening (Figure 2).

Hyper-Dk lenses, such as silicone hydrogel lenses, can maximize oxygen flow to the cornea during sleep and prevent overnight edema. In addition, improved oxygen flow to the corneal surface can encourage the formation and adherence of new, highly metabolic epithelial cells. With several available options in at least two base curves, these lenses provide a complementary treatment option for more moderate forms of RCE. The higher modulus of silicone hydrogel bandage lenses provides additional protection for the corneal surface.

Two recent papers1,2 discuss the efficacy of Night & Day (CIBA Vision) as bandage contact lenses. Unfortunately, these publications provide only general corneal healing success rates regardless of underlying pathology (bullous keratopathy, entropian and others.) Both papers state that 70% to 83% of patients achieved complete healing and 78% to 91% of patients had complete pain relief.

As with any overnight-wear contact lenses, silicone hydrogel bandage lenses can cause microbial keratitis. Always advise patients of the signs and symptoms of microbial keratitis. If the patient will be using bandage contact lenses long-term, you may need to provide a prophylactic topical solution to prevent such adverse events.

Encourage Epithelial Growth

Figure 2. Recurrent corneal erosion (RCE) showing loose epithelial tissue.

When conservative treatments fail to resolve RCEs, patients may need more invasive therapy, such as anterior stromal puncture or phototherapeutic keratectomy.

Anterior stromal puncture uses a bent tuberculin needle attached to a syringe to create micropunctures in the stroma. Resultant micro-scars encourage the epithelium to adhere to the underlying stroma. Micro-scars also can be created with an Nd:YAG laser or a commercially available device that uses a miniature footplate to puncture the anterior cornea to a defined depth. Laser therapy results are similar to those achieved with a bent tuberculin needle but are more accurate.

Debriding the edges of an RCE or creating a smooth stromal bed also encourages epithelial migration and attachment. One method uses a 5-mm diamond burr to buff the anterior limiting lamina after removal of the corneal epithelium. Phototherapeutic keratectomy also creates a smooth stromal bed and promotes epithelial migration and subsequent attachment, but this method can be painful. For this reason, some practitioners prefer to refer patients for epi-LASIK.

Systemic Therapy

Oral therapeutic options for treating RCE include doxycycline and minocycline, which decrease the amount of FAs, MMP-2 and MMP-9 in the tear film. All these factors decrease epithelial attachment during episodes of RCE. Topical steroids alone or in combination with these antibiotics can interfere with the underlying biochemical factors and assist healing.

Reports suggest topical autologous serum can promote epithelial attachment in eyes with RCEs. This agent's constituents are similar to the natural tear film and provide needed nutrients to the damaged epithelium. At present, little is known about how much or how long this serum needs to be used to be effective. Ongoing studies will assess the essential attributes of topical autologous serum for treating RCE.

Non-traditional Approach

Several practitioners have used more obscure or unique techniques for treating RCEs, with varying degrees of success. For
example, Benitez-del-Castillo and colleagues3 discuss using P-derived peptide and insulin-like growth factor. Their findings indicate that the condition of the neurosensory corneal unit, as well as epithelial cells and adhesion complexes, can contribute to RCE.

Other practitioners have injected botulinum toxin around the eye to eliminate orbicularis movement during REM sleep that may exacerbate RCE episodes.

Tailored Treatment

No single strategy can address every case of RCE. An individualized approach is usually best, treating each patient according to the size of their erosions and the severity of their symptoms. Topical lubrication and bandage contact lenses can help mild to moderate cases, but more severe forms may require additional therapy. Short of a definitive cure, the therapies described here are the best options for decreasing the incidence of RCEs and providing patients with long-term comfort. CLS

Dr. Miller is on the faculty at the University of Houston College of Optometry. He is a member of the American Optometric Association and serves on its Journal Review Board. You can reach him at wmiller@uh.edu.

REFERENCES

1. Montero J, Sparholt J, Mely R. Retrospective case series of therapeutic applications of a lotrafilcon A silicone hydrogel soft contact lens. Eye Contact Lens. 2003;29:S54-S56.

2. Ozkurt Y, Rodop O, Oral Y, Comez A, Kandemir B, Dogan OK. Therapeutic applications of lotrafilcon A silicone hydrogel soft contact lenses. Eye Contact Lens. 2005;31:268-269.

3. Benitez-del-Castillo JM, Rodriguez-Bayo S, Fontan-Rivas E, Martinez-de-la-Casa JM, Garcia-Sanchez J. Treatment of recurrent corneal erosion with substance P-derived peptide and insulin-like growth factor I. Arch Ophthalmol. 2005;123:1445-1446.



Contact Lens Spectrum, Issue: February 2006