The minimum age of people undergoing LASIK and other types of laser vision correction can safely be lowered in certain cases, according to a new large-scale study.
Researchers in Jordan recently conducted a study of the stability of refractive errors to determine which types of patients are most likely to have stable vision correction after refractive surgery and which are at greatest risk for refractive change.
Stability of refractive errors: Study design and methods
The researchers conducted a retrospective study of the refractive errors of 46,384 consecutive patients who were seen at an outpatient clinic in Amman, Jordan.
Patients were distributed into four groups, based on refractive error:
- Emmetropia – Those with no nearsightedness, farsightedness or astigmatism.
- Low to moderate myopia –Those with up to -6.00 diopters (D) of nearsightedness.
- High myopia – Those with greater than -6.00 D of nearsightedness.
- Hyperopia – Those with any degree of farsightedness.
The age of the patients in the study ranged from 3 to 82 years.
Stability of refractive errors: Study results
Analysis of the study data revealed:
- Refractive errors were found in 45.1 percent of the patients, and ranged from +8.00 D of hyperopia to -22.00 D of myopia.
- The prevalence of myopia was 23.8 percent.
- The prevalence of high myopia was 3.8 percent.
- The prevalence of hyperopia was 17.5 percent
Regarding the stability of refractive errors:
- Patients with less than -1.00 D of myopia at age 10 and less than -3.00 D of myopia at the time of LASIK surgery had a stable refraction at age 18.
- In patients with high myopia, 7.4 percent demonstrated corneal changes that did not stabilize until age 30.
- Patients with hyperopia tended to experience a progression of their refractive error from age 30 to age 50.
Stability of refractive errors: Conclusions
Based on the results of the study, the researchers concluded that the minimum age of patients undergoing LASIK for the correction of less than -3.00 D of myopia can be safely lowered from 20 years to 18 years with little risk of progression of myopia after surgery.
All patients seeking laser vision correction should be educated prior to surgery regarding the risk of progression of refractive error and other LASIK risks, the researchers said.
SOURCE: Age and refraction in 46,000 patients as a potential predictor of refractive stability after refractive surgery. Journal of Refractive Surgery. August 2009.