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Photorefractive keratectomy. A 6-year follow-up study
C G Stephenson1, D S Gartry, D P O'Brart
1Department of Ophthalmology, St. Thomas' Hospital, London, England.
Ophthalmology
|February 28, 1998
Summary
Excimer laser photorefractive keratectomy showed stable refractive outcomes up to 6 years, with no significant regression after one year. However, higher corrections resulted in undercorrection, and a small 4mm ablation zone caused night halos in some patients.
Area of Science:
- Ophthalmology
- Refractive Surgery
- Corneal Surgery
Background:
- Excimer laser photorefractive keratectomy (PRK) is a surgical procedure to correct refractive errors.
- Long-term stability and efficacy data are crucial for understanding the full impact of PRK.
Purpose of the Study:
- To evaluate the long-term (6-year) stability and efficacy of excimer laser photorefractive keratectomy.
- To assess refractive outcomes, corneal haze, glare, halo, and late-phase complications following PRK.
Main Methods:
- A 6-year follow-up was conducted on 83 patients from the first UK PRK clinical trial.
- Patients received spherical corrections ranging from -2 to -7 diopters using a 4mm ablation zone excimer laser.
- Refractive change, corneal haze, glare, halo, and complications were analyzed.
Main Results:
- Refractive undercorrection was observed, increasing with attempted correction magnitude.
- Refraction stabilized by 6-12 months and remained stable for 6 years.
- Visual acuity within +/- 1 D of intended refraction varied from 91% (-2D) to 19% (-7D).
- 7% showed residual corneal haze (3% visually significant); 12% reported significant night halos due to the 4mm ablation zone.
Conclusions:
- Excimer laser PRK demonstrated long-term refractive stability with no regression or diurnal fluctuation after 1 year.
- Corneal haze diminished over time with no noted intraocular or retinal side effects.
- Significant night halos remain a concern for patients treated with the 4mm ablation zone.