In recent years, fewer refractive surgeons prefer PRK and LASIK for the correction of myopia greater than –10 diopters (D). This change is due in part to concerns about a higher risk of ectasia and other PRK and LASIK complications when significant reductions in corneal thickness are required.
Also, many refractive surgeons now prefer intraocular refractive procedures such as phakic IOL implantation and refractive lens exchange (RLE) for the correction of high myopia, which may provide better visual outcomes and greater refractive stability after surgery.
Among the results of the 2009 International Society of Refractive Surgery (ISRS) survey of refractive surgeons, when asked their procedure of choice for a 30-year-old patient with –10 D of myopia, 43 percent of surgeons identified phakic IOL implantation as their preferred procedure, compared with 40 percent who said they prefer laser vision correction.
Recently, researchers in Spain conducted a retrospective study of 192 highly myopic eyes that underwent PRK (51 eyes) or LASIK (141 eyes) for vision correction. The degree of pre-operative myopia in all eyes in the study ranged from –10.00 to –18.00 D.
All PRK and LASIK procedures were performed between 1992 and 1995 at Instituto Oftalmologico de Alicante (Alicante, Spain). PRK patients had a mean age of 33.96 years, and LASIK patients had a mean age of 32.44 years.
Ten years after surgery, 31.2 percent of eyes in the PRK group and 45.5 percent of eyes in the LASIK group achieved uncorrected visual acuity (UCVA) of 20/40 or better.
Among eyes treated with PRK, 41 percent were within +/–1.00 D of the desired refractive endpoint 10 years after surgery. Among LASIK-treated eyes, this figure was 42.5 percent.
A total of six eyes (14 percent) in the PRK group and seven eyes (6 percent) in the LASIK group lost two or more lines of best spectacle-corrected visual acuity 10 years after the laser eye surgery.
Eyes in both treatment groups showed statistically similar mean regression of myopia over the 10-year study period: –1.28 D in the PRK group and –1.49 D in the LASIK group.
Corneal haze was a significant long-term problem for PRK-treated eyes in the study, according to the researchers.
The study authors said that, based on the results of this and other studies, the use of LASIK for the correction of myopia equal to or greater than –10 D is no longer “routinely advocated,” and that they no longer recommend PRK for the correction of high myopia.
SOURCE: Comparison of LASIK and photorefractive keratectomy for myopia from –10.00 to –18.00 diopters 10 years after surgery. Journal of Refractive Surgery. March 2010.
Tags: myopia