VISX Star S2 Excimer Laser System: FDA Test Results
Device Trade Name: VISX Star S2 Excimer Laser System
Applicant: CRS Clinical Research, Inc., Scottsdale, Arizona, USA.
Approved By The FDA: July 22, 1999
This device was originally approved on March 27, 1996 for use in myopic (nearsighted) patients who were 21 years of age or older. This new study was performed to include FDA approval for patients aged 18-21, and to provide laser surgery to patients with hyperopia (farsightedness). As of the date of this report, VISX has over 500 Excimer Systems located in approximately 50 countries. The VISX Excimer System has not been withdrawn from any country or market for reasons of safety or effectiveness.
The VISX Star S2 Excimer Laser System is intended for use in LASIK/PRK procedures:
*In patients 18 years of age or older in treatments for the reduction or elimination of myopia (nearsightedness) from 0 to -14.0 diopters with or without -0.50 to -5.0 diopters of astigmatism; or for the reduction or elimination of hyperopia of between +1.0 and +6.0 diopters with no more than 1.0 diopters of refractive astigmatism; and
*In patients with documented evidence of a change in manifest refraction of less than or equal to 0.50 diopters for at least one year prior to the date of the pre-operative examination.
Summary Of Clinical Studies:
This study of the LASIK procedure using the VISX Star S2 Laser System and managed by CRS was a large, multi-center project involving 24 surgeons at 21 centers. From this population, a group of 1276 treated at 19 centers is the subject of this study.
A. Study Objective
The CRS LASIK study reported here evaluated the safety and efficacy of the VISX Excimer Laser to treat 0 to -14.0 diopter of myopia with and without astigmatism of 0.25 to 6.0 diopters.
B. Study Design
This was a prospective, non-randomized, unmasked, multi-center clinical study where the primary control was the preoperative state of the treated eye (ie comparison of pretreatment and post-treatment visual parameters in the same eye).
Damage To Epithelium |
0.5% |
Epithelial Defect |
0.6% |
Free Cap
|
4.2% |
Oval Keratectomy
|
0.7% |
Small Flap
|
0.2% |
Small Flap With Thin Flap
|
0.1% |
Surgery Aborted-Inadequate Flap
|
0.2% |
Thin Flap
|
0.3% |
With regard to post-operative adverse events, a corneal epithelial defect occurred in 1.2% of eyes at 3 months and in 2.6% at 6 months. The following adverse events and compications occurred at a rate of less than 1% at 6 months: interface epithelium (0.9%); stromal edema (0.3%); and wrinkling of the cap (0.3%). Flap edema did not occur after the 1 month examination. The following adverse events and complications did not occur in this study: corneal infiltrate or ulcer; melting of the flap; retinal detachment; and retinal vascular accidents.
Patient Satisfaction:
Listed at right are the responses to questions about patient subjective complaints. They were obtained from a patient questionnaire that was administered pre-operatively and at 3 months post-operatively.
All Eyes |
Pre-Operative: |
3 Months: |
|
Marked/ Severe |
Marked/ Severe |
Glare
|
37% |
27%
|
Halo
|
27%
|
25%
|
Visual Fluctuations
|
12%
|
13%
|
Conclusions Drawn From The Clinical Study:
The data in this application provides reasonable assurance that the device is safe and effective when used in accordance with the directions for use. The FDA issued its approval of expanded use of the VISX Star S2 Excimer Laser System on July 22, 1999.
Demographics:
The distribution of male and female subjects in the study was approximately even (43.2% male, 56.8% female). Racial distribution of the enrolled patients was predominantly caucasian. 67.0% of participants were White, 0.3% Black, 2.4% Asian, 5.1% Other, and 25.2% Not Reported. Ages ranged from 18 to 84, with a mean age of 42.0 years.
Results Of The Study:
Adverse intra-operative (occurring during the surgery) complications that occurred in the clinical study are shown below:
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