Corneal resurfacing treats recurrent erosion

Argon laser treatment succeeds where PTK had failed in this case report.

ByGerard M. Nolan, MD

The following case presents an example of the benefits of the corneal resurfacing procedure for patients with recurrent corneal erosion.

This patient, referred by another ophthalmologist for treatment, was typical of patients suffering from recurrent corneal erosion from basement membrane disease. The initial symptom, a sensation of pinching, had begun in the right eye and later spread to the left. By 1 year, there was a daily foreign-body sensation in both eyes, which was treated with hypertonic saline at bedtime and artificial tears during waking hours. In 2 years, recurrent erosions started. These were treated initially with bandage contact lenses and later with bilateral stromal punctures.

The patient described the stromal punctures procedure as “scary” because they were performed at the slit lamp with a needle. For the first 3 postop days, the patient experienced more severe pain than from any previous or subsequent procedure. Nonetheless, recurrences of corneal ulcers continued, requiring treatment with bandage contact lenses.

In 1996, there were two phototherapeutic keratectomy (PTK) treatments performed on the right eye; in 1997, one PTK treatment was performed on the left eye. The lasers were well tolerated, but the patient’s vision deteriorated. Since 1997, the patient has experienced a constant foreign-body sensation and has suffered from frequent recurrent corneal erosions, which required treatment with bandage contact lenses.

The patient was reluctant to have more PTK, because each procedure had blurred her vision. The patient learned about corneal resurfacing from the Internet. She was referred by her ophthalmologist in Massachusetts with a summary of the most recent recurrent erosion in the right eye.

Procedure

My examination revealed a microscopic elevation of a plaqueoid island of corneal epithelium in the right eye (see diagram). There was no fluorescein staining, except for a trace amount at the nasal edge. The corneal resurfacing procedure involved applying a pigment to this nasal area and a light dusting of the pigment to the entire plaqueoid lesion. Using an argon laser, the nasal edge was treated normally: four spots of 50 to 100 µm for 0.2 second each at 250 mW. The body of the lesion was treated with 10 spots at 100 mW.

drawing
Plaqueoid lesion treated at nasal edge with normal corneal resurfacing and to the body with very light applications.

Corneal resurfacing: Pigment applied to edge of defect and treated with argon laser photocoagulation.

By the first postop visit, all symptoms had ceased. Examination revealed no evidence of the lesion. There was a slight fluorescein stain at the nasal edge, in the same position as seen preoperatively. An examination of the left eye, 1 week after the successful treatment of the right, revealed microscopic areas of corneal epithelium irregularity. These were treated successfully and permanently with the corneal resurfacing technique.

For the past 10 years, PTK has been the benchmark for the treatment of recurrent corneal erosions. Certainly, it is more permanent than stromal puncture, corneal scraping or a bandage contact lens. However, large studies have shown a frequent recurrence of both symptoms and erosions, as happened in this patient. This is because PTK is a diffuse treatment for a localized, recurring corneal erosion. Al though basement membrane disease is frequently bilateral and is often diffusely present in the cornea, the erosions recur locally, and their edges are the same at each recurrence.

Focal repair

Corneal resurfacing permits a focal repair, much as surrounding a retinal hole with focal retinal photocoagulation does. In retinal tears, the pigment source is in the retinal pigment epi thelium. In corneal resurfacing, I apply my own pigment to the cornea to achieve the necessary laser re-action.

I believe that corneal resurfacing is successful and permanent because the healing occurs in a physiologically normal manner: The epithelium continues to rest on the basement membrane and Bowman’s membrane, as in the normal cornea.

In contrast, PTK is a photoablation procedure in which the basement membrane and Bowman’s membrane are ablated, and the epithelium rests postoperatively on the corneal stroma, a situation that is not physiologically normal. This may explain why there is a large failure rate with PTK.

I have been treating recurrent corneal erosion for 23 years. It is a terrible disease for a patient, as it can mean a painful daily life with frequent recurrences. What is commonly underestimated by the treating ophthalmologist is that a bacterial corneal ulcer can occur at any time. We need to prophylactically treat these patients with topical antibiotics to prevent blindness.

For the past 4 years, I have treated a large number of patients with corneal resurfacing. There is no blurring of vision as the treatment is focal, there is no removal of tissue, and the topography of the cornea does not change, as it does with PTK. The procedure is essentially painless, and the recovery is fast. Most importantly, patients have continued to be free from symptoms and recurrent erosions since their procedures.

For Your Information:

Gerard M. Nolan, MD, can be reached at 231 Farmington Ave., PO Box 827, Farmington, CT 06034-0827 U.S.A.; +(1) 860-674-9627; fax: +(1) 860-676-8622.

For more information on corneal resurfacing, please visit www.cornealresurfacing.com or Ocular Surgery News, April 15, 2000, p. 50. For patient consultations, or for physicians interested in corneal resurfacing workshops, contact Charlene at +(1) 860-674-9627.