Effect of cytochrome c peroxidase on corneal epithelial healing process after photorefractive keratectomy.

PURPOSE: To evaluate the role of commercially prepared cytochrome c peroxidase eyedrops in corneal epithelial healing after photorefractive keratectomy (PRK). SETTING: Department of Pathophysiological Optics, Faculty of Medicine, University of Bologna, Bologna, Italy. METHODS: Seventy-two eyes of 36 patients affected by low to moderate refractive error (myopia and myopic astigmatism) had uneventful bilateral photorefractive keratectomy (PRK). In each patient, 1 eye (32 eyes) received standard postoperative therapy plus cytochrome c peroxidase eyedrops (3 times a day for 1 week or until corneal reepithelialization was completed, corresponding to 15 000). The fellow eye served as the control and received standard postoperative therapy plus placebo. Patients were monitored daily starting the day after surgery for 7 days to evaluate the corneal reepithelialization rate using a video slitlamp camera with a cobalt blue light. Mean diameter of corneal wounds was measured. Videotaped images were recorded and analyzed by computer planimetry. RESULTS: All the eyes treated with cytochrome c peroxidase eyedrops healed completely before day 5 postsurgery, with a mean reepithelialization time of 91 hours +/- 14 (SD); the mean reepithelialization time was 154 +/- 9 in eyes receiving placebo (P<.05); the mean reepithelialization rate was 0.066 +/- 0.007 mm/hour in the cytochrome c peroxidase group and 0.039 +/- 0.006 mm/hour in the control group (P<.05). There were no statistically significant differences between groups in corneal haze presentation during follow-up (P =.70), perhaps because the time period was too brief (7 days). However, corneal clarity, on slitlamp biomicroscopy in the study group was greater than in the control group. No side effects or toxic effects were documented. CONCLUSIONS: These data suggest that cytochrome c peroxidase significantly accelerates epithelial healing after PRK. Further clinical study should be performed to prove the results obtained in this pilot study and the long-term efficacy of cytochrome c peroxidase to prevent corneal haze.

Argon laser vs. subthreshold infrared (810-nm) diode laser macular grid photocoagulation in nonexudative age-related macular degeneration.

BACKGROUND: A diode laser can be used to create a subthreshold (invisible end point) lesion in patients with age-related macular degeneration (AMD). This has the potential benefit of localizing the treatment effect to the retinal pigment epithelium and sparing more of the overlying sensory retina. We performed a study to compare the safety and efficacy of argon laser and subthreshold infrared (810-nm) diode laser macular grid photocoagulation in reducing the number of drusen in patients with AMD. METHODS: We reviewed the charts of 144 patients with bilateral early-stage nonexudative AMD, characterized by soft drusen. One eye of each patient was treated, and the other eye served as a control. Seventy-eight eyes of 78 patients with a mean age of 67.5 (standard deviation [SD] 8.3) years underwent argon laser macular grid photocoagulation at a university-affiliated hospital in Bologna, Italy, and 66 eyes of 66 patients with a mean age of 66.4 (SD 6.3) years underwent subthreshold infrared (810-nm) diode laser macular grid photocoagulation at a private clinic in Bologna. Each group was classified into three subgroups based on the number of drusen (more than 20, 10 to 20, or less than 10). The patients underwent fluorescein angiography, fundus examination, measurement of far (Snellen chart) and near (Jaeger chart) best corrected visual acuity, and visual field and contrast sensitivity testing. The mean length of follow-up was 18 (SD 0.5) months. RESULTS: At 18 months, far and near best corrected visual acuity were statistically significantly improved in the treatment groups compared with the untreated group (p < 0.001, Mann-Whitney U test). There was no significant difference in visual acuity between the treatment groups. Compared with baseline, the number of drusen was significantly reduced in both treatment groups (p < 0.001). Evolution of the disease was observed in the untreated group. The visual field was slightly but significantly reduced after argon laser treatment (p < 0.001) but not diode laser treatment; the difference in visual field between the two groups was not significant. There was a slight reduction in contrast sensitivity, particularly with night vision, after argon laser treatment but not diode laser treatment. The difference between the two treatment groups was significant (p < 0.01). INTERPRETATION: Subthreshold infrared diode macular grid photocoagulation may be a safe and viable method for preventing progression of nonexudative AMD.