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Topography of the excimer laser ablation
Tuesday, Sep 22,1992 Des Iles Borromees
X ICER Abstracts 285
SAFETY AND EXCIMER PRK C.G. Van Mellaert (Beleiumf
Abstract
Twelve myopic eyes (mean -3.18D, range -1.75 to 4.870) underwent excimer laser photorefractive keratectomy (PRK) with the VISX excimer laser system in October of 1990 as part of a Phase IIb FDA study. Preoperative uncorrected visual acuities ranged from 20/200 to count fingers. At 12 months postoperatively the mean spherical equivalent myopia was -0.28D. Eleven of the 12 eyes had an uncorrected VA of 20/30 or better and were corrected to within to.750 of spherical equivalent emmetropia. One eye (which was -4.OOD pre-op) had an uncorrected VA of 20/70 and a spherical equivalent myopia of -2.OOD post operatively. Spectacle corrected acuities were within 1 line of pre-op values in all cases and there were no complications. Forty-six eyes treated in Phase III will be analyzed with a follow-up of 12 months. At 6 months approximately 80% of these eyes are within one diopter of spherical equivalent emmetropia and have uncorrected vision of 20/40 or better. One eye has a best corrected visual acuity of 20/50 secondary to cornea1 irregularity and haze. Haze, irregular astigmatism, induced astigmatism, over and under correction and loss of best corrected spectacle acuity have been encountered in a few patients and will be discussed. Center.
Supported by The Discovery Fund and the National Keratoconus
for Eye Research, Foundation
Ellis
OPTICAL QUALITY AFTER R.J. Auoleeate (USA)
Abstract
Eye
286
5 PRK
Not Available
287
6 TOPOGRAPHY OF TRE EXCIMER LASER ABLATION SD Klvce. MK Smolek SE Wilson. and MB McDonald Louisiana State University Rye Center, New Orleans, Louisiana
288
7
PRELIMINARY RESULTS OF VISX EXCIMER LASER MYOPIC PHOTOREFRACTIVE KERATECTOMY AT CEDARS-SINAI MEDICAL CENTER. Anthonv B. NesburnIt2 Michael BerlinI, John HofbauerIp2 Jonathan I. MacvI,L,3 Ezra MaauenIp2 and James J. SalzIT3 IOphthalmology Research Laboratories and Ellis Eye Center, Cedars-Sinai Medical Center, 2Oept. of Ophthalmology, UCLA, 3Dept. of Ophthalmology, USC, Los Angeles, CA
USA
The 193 nm excimer laser has the potential Par precise stroma tissue removal by photoablation. The corned toJmgraphy of all patlentr ondergoing photorefractive (PRK) keratectomies at LSU has been systematim&y foRowed using computerized topographical analysis (TMS-1). An initial series of 17 eyes of sighted patients treated with PRK for myopia has been followed for over two years. These cameos generally demonstrated a centrally smooth ablation area with a treatment zone of a size consistent with a good visaal result (larger than the average virtual entrance pupil). In 70% d these cases, stability of effect was achieved 3 to 7 months postoperatively. Regression of the intended correction, more common in the higher corrections (> 5 D), may be the result of permanent epithelial hyperplasia or stmmal remodeling beneath the ablated area. Centration oP the ablation WBS measured for each eye at several visits and the results averaged. The average distance of the center of the ablations from the center of the entrance pupil was 0.78 + 0.1 mm with no systematic deviation in any direction. In a second series of 19 corneas, centration was improved through more rlgomus inspection doting surgery, falling to 0.47 It 0.1 mm. No statistkally significant correlation was found between best spectacle corrected visual acuity and mm of decentration, although transient diplopia was reported in one early cage (2.1 mm decentration). These findings andencore the need to devclop surgical aids that can be used to improve centration in comeal surgical procedures. (Supported by NE1 EYO2377 and a Rsearch grant from Computed Anatomy, Jar.)
S.88
Not Available
X ICER Abstracts 285
SAFETY AND EXCIMER PRK C.G. Van Mellaert (Beleiumf
Abstract
Twelve myopic eyes (mean -3.18D, range -1.75 to 4.870) underwent excimer laser photorefractive keratectomy (PRK) with the VISX excimer laser system in October of 1990 as part of a Phase IIb FDA study. Preoperative uncorrected visual acuities ranged from 20/200 to count fingers. At 12 months postoperatively the mean spherical equivalent myopia was -0.28D. Eleven of the 12 eyes had an uncorrected VA of 20/30 or better and were corrected to within to.750 of spherical equivalent emmetropia. One eye (which was -4.OOD pre-op) had an uncorrected VA of 20/70 and a spherical equivalent myopia of -2.OOD post operatively. Spectacle corrected acuities were within 1 line of pre-op values in all cases and there were no complications. Forty-six eyes treated in Phase III will be analyzed with a follow-up of 12 months. At 6 months approximately 80% of these eyes are within one diopter of spherical equivalent emmetropia and have uncorrected vision of 20/40 or better. One eye has a best corrected visual acuity of 20/50 secondary to cornea1 irregularity and haze. Haze, irregular astigmatism, induced astigmatism, over and under correction and loss of best corrected spectacle acuity have been encountered in a few patients and will be discussed. Center.
Supported by The Discovery Fund and the National Keratoconus
for Eye Research, Foundation
Ellis
OPTICAL QUALITY AFTER R.J. Auoleeate (USA)
Abstract
Eye
286
5 PRK
Not Available
287
6 TOPOGRAPHY OF TRE EXCIMER LASER ABLATION SD Klvce. MK Smolek SE Wilson. and MB McDonald Louisiana State University Rye Center, New Orleans, Louisiana
288
7
PRELIMINARY RESULTS OF VISX EXCIMER LASER MYOPIC PHOTOREFRACTIVE KERATECTOMY AT CEDARS-SINAI MEDICAL CENTER. Anthonv B. NesburnIt2 Michael BerlinI, John HofbauerIp2 Jonathan I. MacvI,L,3 Ezra MaauenIp2 and James J. SalzIT3 IOphthalmology Research Laboratories and Ellis Eye Center, Cedars-Sinai Medical Center, 2Oept. of Ophthalmology, UCLA, 3Dept. of Ophthalmology, USC, Los Angeles, CA
USA
The 193 nm excimer laser has the potential Par precise stroma tissue removal by photoablation. The corned toJmgraphy of all patlentr ondergoing photorefractive (PRK) keratectomies at LSU has been systematim&y foRowed using computerized topographical analysis (TMS-1). An initial series of 17 eyes of sighted patients treated with PRK for myopia has been followed for over two years. These cameos generally demonstrated a centrally smooth ablation area with a treatment zone of a size consistent with a good visaal result (larger than the average virtual entrance pupil). In 70% d these cases, stability of effect was achieved 3 to 7 months postoperatively. Regression of the intended correction, more common in the higher corrections (> 5 D), may be the result of permanent epithelial hyperplasia or stmmal remodeling beneath the ablated area. Centration oP the ablation WBS measured for each eye at several visits and the results averaged. The average distance of the center of the ablations from the center of the entrance pupil was 0.78 + 0.1 mm with no systematic deviation in any direction. In a second series of 19 corneas, centration was improved through more rlgomus inspection doting surgery, falling to 0.47 It 0.1 mm. No statistkally significant correlation was found between best spectacle corrected visual acuity and mm of decentration, although transient diplopia was reported in one early cage (2.1 mm decentration). These findings andencore the need to devclop surgical aids that can be used to improve centration in comeal surgical procedures. (Supported by NE1 EYO2377 and a Rsearch grant from Computed Anatomy, Jar.)
S.88
Not Available