Mitomycin C found effective for haze and regression

Treatment restores most of intended visual correction following PRK.

Issue: October 1, 2000

BOSTON - Mitomycin C is safe and effective for haze and regression following photorefractive keratectomy (PRK), said Francesco Carones, MD, of Milan, Italy.

Serial photos taken over the course of a year show the regression of corneal haze.

Corneal haze is a major complication of PRK, Dr. Carones said. It may induce several side effects, including blurred vision, refractive regression and loss of both uncorrected visual acuity and best corrected visual acuity (BCVA).

"Usually, haze certainly tends to decrease with time," he said. "But in some cases, it doesn't decrease. The question is what to do when we face a severe haze case."

It is possible to wait, but for how long remains in question, he said. Steroids or drugs may or may not be effective. And phototherapeutic keratectomy may change refraction and induce yet more haze.

Regimen defined

---Severe corneal haze causes topographic irregularity.

Another option is to treat those eyes by scraping with a sharp blade and an application of mitomycin C.

"The rationale to this approach is to have a vigorous scraping of the haze after epithelial removal in order to take the newly regenerated material off from the cornea itself," he said. "Then, it is possible to apply mitomycin to inhibit further haze formation."

Dr. Carones spoke about his regimen at the American Society of Cataract and Refractive Surgery meeting.

---Corneal haze will not always regress on its own.

Dr. Carones uses the 0.02% concentration suggested by Parag A. Majmudar, MD, of the Cornea Service at the Rush-Presbyterian-St. Luke's Medical Center in Chicago. Following scraping, he applies with a soaked Merocel corneal shield for 2 minutes, followed by energetic irrigation with 20 cc of balanced salt solution.

He tested this method on 27 eyes with grade 3 or 4 haze and myopic regression between 0.75 D and 5.5 D. All eyes lost between one and six lines of BCVA. The eyes all have between 3 and 18 months of follow-up.

Of the 27 eyes, 23 had clear corneas or just haze traces after treatment. Dr. Carones said he saw no recurrence of haze during this period and, more importantly, he saw no toxic effects from the mitomycin.

Positive shift

Before, left, and after, right, mitomycin C treatment for corneal haze.

At 3 months, all eyes were within 1.5 D of intended correction and showed no significant regression afterward.

"There was an incredibly positive shift [in BCVA]," he said. "The situation was dramatically better."

Dr. Carones said the approach was safe and effective, with no side effects.

"The BCVA loss was better than before the treatment, but not completely regained to the same level as before the primary PRK," he said. "This series is still short, the numbers are still few, but I think that this approach is very, very interesting."

For Your Information:

Francesco Carones, MD, can be reached at Carones Ophthalmology Center, Viale Sabotino 19/2, Milan 20135, Italy; (39) 02-5850-5533; fax: (39) 02-5831-8487.