title: Comparison of corneal centering in photorefractive keratectomy.
abstract: The present study compares three centering methods for excimer laser photorefractive keratectomy (PRK. VISX 20/20) by analyzing the corneal topography. The subjects were grouped according to three different centering methods used in the procedure: an ablation using a light reflex from the patient's cornea pursued by both eyes of the surgeon (Group 1, n = 49); an ablation using a red light reflex from the patient's cornea pursued by the surgeon's left eye only while the right eye remained closed (Group 2, n = 27); an ablation using the patient's center of the pupil pursued by the surgeon's left eye only while the right eye remained closed (Group 3, n = 21). The mean distance from the center of ablation zone to the center of the pupil were; 0.69 +/- 0.45 mm for Group 1, 1.05 +/- 0.48 mm for Group 2 and 0.63 +/- 0.28 mm for Group 3. The degree of deviation in Group 2 was significantly greater than in Group 1 or Group 3. The deviation was greater in the right eyes than the left eyes in Group 2 only. The decentration of the right eye in Group 2 was due to angle Kappa with misalignment of the fixation light and viewing tube containing reticule.
authors.affiliation: Department Ophthalmology, Yonsei University College of Medicine, Seoul, Korea. eungkkim@yumc.yonsei.ac.kr
authors.forename: E K
authors.initials: EK
authors.lastname: Kim
authors.forename: J W
authors.initials: JW
authors.lastname: Jang
authors.forename: J B
authors.initials: JB
authors.lastname: Lee
authors.forename: S B
authors.initials: SB
authors.lastname: Hong
authors.forename: Y G
authors.initials: YG
authors.lastname: Lee
authors.forename: H B
authors.initials: HB
authors.lastname: Kim
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D018903:Photorefractive Keratectomy / Q000379:methods*