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