EFFECT OF TOPICAL INTERFERON-ALPHA-2B ON CORNEAL HAZE AFTER EXCIMER-LASER PHOTOREFRACTIVE KERATECTOMY IN RABBITS

BACKGROUND: Anterior corneal stromal keratocytes are activated by exci mer laser photorefractive keratectomy resulting in haze with healing o f the ablated area. In some eyes, this causes a visible haze or scar o n the cornea, and an unpredictable regression of the myopic correction following refractive ablations.METHODS: Following a 6.00-diopter exci mer laser photorefractive keratectomy to both eyes, 16 rabbits were tr eated for 5 weeks with interferon-alpha 2b drops four times a day to o ne eye only. Eight of these rabbits were treated with dexamethasone dr ops four times a day to both eyes. Using a standard grading scale for haze, the corneas were examined and the haze graded weekly. RESULTS: T he observed corneal haze was significantly reduced in the treated eyes by the application of topical interferon-alpha 2b drops (p = .004), a nd topical dexamethasone drops (p < .001). Topical dexamethasone also produced less haze in combination with interferon-alpha 2b than when u sed alone (p = .035). There was continuing resolution of the corneal h aze in those rabbits observed for 7 weeks after the cessation of the d rops. Topical interferon-alpha therapy was not toxic to the rabbit eye and was not associated with delayed reepithelialization after the las er procedure. CONCLUSION: Topical interferon-alpha 2b appears to reduc e the corneal haze produced by excimer laser photorefractive keratecto my in rabbits.