BACKGROUND: Variation in ablation zone diameter may alter visual acuity and/or refractive effect in photorefractive keratectomy. Despite theoretical benefits of using a smaller diameter ablation zone, clinical studies suggest that a larger ablation zone may decrease problems associated with photorefractive keratectomy. METHODS: The results of our initial 34 consecutive eyes treated with a 5-mm diameter ablation zone using a Summit Technology ExciMed UV200LA excimer laser were compared retrospectively to our initial 34 consecutive eyes treated with a 6-mm diameter ablation zone using a Summit OmniMed excimer laser. Eyes had a spherical equivalent refraction between -1.00 and -6.00 diopters (D) and astigmatism less than 1.00 D. Patients were followed for a minimum of 6 months. RESULTS: Eyes treated with a 6-mm ablation zone had less hyperopia and a spherical equivalent refraction closer to emmetropia at 1, 2, and 3 months (P = 0.001). Eyes treated with a 6-mm ablation zone had better uncorrected visual acuity at 1 and 2 months (P = 0.001). Less subepithelial haze was noted at 2 months (P = 0.01) and 3 months (P = 0.002) in the 6-mm group. At 6 months postoperatively, 30 of 32 eyes (94%) treated with a 6-mm ablation zone had a spherical equivalent refraction within 0.50 D of emmetropia, and all 32 eyes (100%) were within 1.00 D of emmetropia; in the 5-mm ablation zone group, 28 of 34 eyes (80%) were within 0.50 D and 29 (85%) were within 1.00 D of emmetropia. Patients treated with a 6-mm ablation zone complained less of night halos and had fewer differences between night and day vision. CONCLUSIONS: In this study of myopia of -1.00 D to -6.00 D, eyes treated with a 6-mm ablation zone achieve a more rapid visual recovery with less variation in refractive outcome and less adverse effects than those treated with a 5-mm ablation zone.
BACKGROUND: Variation in ablation zone diameter may alter visual acuity and/or refractive effect in photorefractive keratectomy. Despite theoretical benefits of using a smaller diameter ablation zone, clinical studies suggest that a larger ablation zone may decrease problems associated with photorefractive keratectomy. METHODS: The results of our initial 34 consecutive eyes treated with a 5-mm diameter ablation zone using a Summit Technology ExciMed UV200LA excimer laser were compared retrospectively to our initial 34 consecutive eyes treated with a 6-mm diameter ablation zone using a Summit OmniMed excimer laser. Eyes had a spherical equivalent refraction between -1.00 and -6.00 diopters (D) and astigmatism less than 1.00 D. Patients were followed for a minimum of 6 months. RESULTS: Eyes treated with a 6-mm ablation zone had less hyperopia and a spherical equivalent refraction closer to emmetropia at 1, 2, and 3 months (P = 0.001). Eyes treated with a 6-mm ablation zone had better uncorrected visual acuity at 1 and 2 months (P = 0.001). Less subepithelial haze was noted at 2 months (P = 0.01) and 3 months (P = 0.002) in the 6-mm group. At 6 months postoperatively, 30 of 32 eyes (94%) treated with a 6-mm ablation zone had a spherical equivalent refraction within 0.50 D of emmetropia, and all 32 eyes (100%) were within 1.00 D of emmetropia; in the 5-mm ablation zone group, 28 of 34 eyes (80%) were within 0.50 D and 29 (85%) were within 1.00 D of emmetropia. Patients treated with a 6-mm ablation zone complained less of night halos and had fewer differences between night and day vision. CONCLUSIONS: In this study of myopia of -1.00 D to -6.00 D, eyes treated with a 6-mm ablation zone achieve a more rapid visual recovery with less variation in refractive outcome and less adverse effects than those treated with a 5-mm ablation zone.
Authors: Marcus Ang; Damien Gatinel; Dan Z Reinstein; Erik Mertens; Jorge L Alió Del Barrio; Jorge L Alió Journal: Eye (Lond) Date: 2020-07-24 Impact factor: 3.775