What Researchers Did
Researchers conducted a prospective longitudinal study of 29 patients undergoing 40 HBOT sessions, measuring visual acuity, refraction, and lens changes at baseline, during treatment, and 12 weeks after completing HBOT.
What They Found
77.6% of eyes developed a myopic shift of at least 0.5 diopters during treatment, with a median change of -0.75 diopters. Lens nuclear color and opalescence increased significantly. At 12-week follow-up, the myopic shift largely reversed, but a small residual change toward myopia persisted.
What This Means for Canadian Patients
Temporary nearsightedness is a predictable and common side effect of HBOT that resolves after treatment ends. Canadian patients beginning HBOT should be warned in advance that their glasses prescription may change temporarily during a course of treatment, and that they should not update their glasses until several weeks after completing therapy.
Canadian Relevance
No direct Canadian connection identified.
Study Limitations
The study had 29 patients and only 12-week follow-up; long-term lens transparency changes and the clinical significance of the residual myopic shift beyond 12 weeks are not addressed.