[The rate of development of myopia during hyperbaric oxygen therapy]

Hyperbaric oxygenation (HBO) is a common treatment both for emergency medicine as well as for chronic treatments. One of the most common indications for treatment is a non-healing wound due to diabetes. It is known that prolonged HBO treatments cause a myopic change in refraction. From the literature we know that the myopic shift is usually temporary, reversing back to basic refraction within a few weeks of cessation of the HBO course. There is controversy in the literature regarding the cause of refraction change, but research with animals reinforces the view that the source is the lens nucleus.

To measure the refractive change following 30 HBO treatments, and to quantify the rate of change.

A prospective study that included 44 eyes of diabetic patients treated with HBO in Rambam and Elisha Hyperbaric Center. Follow-up examinations were carried out every 10 treatments for spherical equivalents, sphere components, cylinder powers and axes (SPHER, SE, CYLINDER and AXIS respectively). The measurement device was an autorefractometer. A single examiner performed all the measurements; the examiner was blinded to the previous results. For each parameter, a regression equation was calculated after plotting the myopic change over time.

A positive correlation was found between HBO treatments and a myopic shift in the refraction. The correlation was statistically significant for: SPHER, SE. (0.58D, 0.61D) respectively. The change accrued from the first examination and remained throughout the follow-ups at a steady rate. Both eyes behaved similarly. The authors did not find a correlation between the myopic shift and gender, age or basic refraction. This information is vital both to clinicians, to understand the physiologic changes occurring during chronic HBO treatments, and especially to our patients, who are about to receive HBO treatments.