The refractive changes and long-term (3 years) results of radial keratotomy performed at high altitude

Purpose: To evaluate the development of regression or progression following radial keratotomy (RK) performed at high altitude (1,720 meters) at long-t erm follow-up (3 years). Methods: Thirty-nine eves of 21 myopia patients (between -3.25 D and -11.00 D) whose ages were 19-32 years were included in the study. The RK procedur es were performed in standard Russian style. Results: The average spherical equivalent cycloplegic refractions were -5.4 9 D +/- 2.08 (SD) preoperatively, -1.64 +/- 1.59 D in the short-term(3.41 /- 1.46 months) and -1.40 +/- 1.71 D in the long-term (30.72 +/- 4.36 month s) follow-up period. There was no statistically significant difference betw een these values at the short- and long-term follow-up measurements (t = -1 .57. P = .12). Conclusions: The refractive changes following RK performed at high altitude occur through a combination of both the direct effect of reduced barometri c pressure and the edematous corneal expansion because of hypoxia. An ophth almologist performing RE; surgery at high altitude must consider the long-l asting therapeutic effects of high altitude surgery compared to surgery at sea level. (C) 2001 Japanese Ophthalmological Society.