The etiology of refractive changes at high altitude after radial keratotomy. Hypoxia versus hypobaria

Ophthalmology. 1998 Feb;105(2):282-6. doi: 10.1016/s0161-6420(98)93094-9.


Objective: Refractive changes at high altitude that occur after radial keratotomy (RK) may be caused by hypoxia or hypobaria.

Design: A prospective study was performed to evaluate the effects of hypoxia on RK and non-RK corneas.

Participants: There were 20 RK and 20 control eyes.

Intervention: These eyes were subjected to ocular surface hypoxia using an air-tight goggle system at sea level for 2 hours.

Main outcome measures: Keratometry, cycloplegic refraction, and pachymetry were evaluated using repeated measures analysis of variance.

Results: A significant hyperopic shift (P < 0.0001) and corneal flattening (P < 0.0013) occurred in all subjects with RK compared with those of control subjects. Corneal thickening occurred symmetrically in both groups.

Conclusions: These results suggest that refractive changes in subjects with RK occur at high altitude as a direct result of corneal hypoxia.

MeSH terms

  • Adult
  • Altitude*
  • Atmospheric Pressure*
  • Cornea / surgery
  • Female
  • Humans
  • Hyperopia / etiology*
  • Hypoxia / complications*
  • Keratotomy, Radial*
  • Male
  • Middle Aged
  • Myopia / surgery
  • Postoperative Complications*
  • Prospective Studies