Laser Refractive Surgery is able to most high contrast acuity levels of myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. Corrective lenses are the traditional method of treating refractive errors. Myopia is treated with concave lenses with minus or divergent power to focus light rays on the retina. Convex lenses with plus or convergent power help correct vision in the hyperopic eye, and cylindrical lenses are used to reduce the effect astigmatism.
A loss of 1-2 Snellen line of visual acuity occurred in 13% of cases at one year, and 3% of eyes at the 10 year follow up. A common complication is a diurnal fluctuation in refractive error and hence visual acuity due to the structurally weakened cornea. The PERK researches encountered an increase in myopia greater than 0. 50D in 30% of eyes. A study of a group of firefighter applicants who had undergone radial keratotomy, found a myopia shift occurring between morning and afternoon of -0. 41 +/-0. 33D compared to +0. 06 +/- 0. 42D in the control group.
Reference:
Laser Refractive Surgery, http://www. college-optometrists. org/index. aspx/pcms/site. Public_Related_Links. Laser_Eye_Surgery. Laser_Eye_Surgery_home/, 07 Dec 2008 A Patients’ Guide to Excimer Laser Refractive Surgery, The royal college ophthalmologist, 2006, www. rcophth. ac. uk/docs/publications/patient-info-booklets/ExcimerLaserPatientGuideMarch2006. pdf , 07 Dec 2008
Dr Catharine Chisholm MCOptom, July 2002, Report on the current status of refractive surgery, , http://www. bsrs2000. fsnet. co. uk/refracrive. htm, 07 Dec 2008 MD. J. Bradley Randleman, LASIK Eye Surgery, http://www. medicinenet. com/lasik_eye_surgery/article. htm, 07 Dec 2008 Michael A. Lawless, November 2006, Fulfilling the Promise of Laser Refractive Surgery Journal of Refractive Surgery Vol. 22 No. 9, Alcon Sponsored Section, 07 Dec 2008