Phakic and pseudophakic eyes in patients during hyperbaric oxygen therapy

To examine the optical components of phakic and pseudophakic eyes during hyperbaric oxygen (HBO) therapy, and to quantify their relative impact on ocular refractive changes.

HBO therapy was given to 16 phakic and six pseudophakic patients for 90 min daily at a pressure of 240 kPa, 5 d a week for 20 days. An eye examination was performed on the first day of HBO therapy and repeated when the patients had completed 19 days of the treatment. Refractive error, best-corrected visual acuity, corneal power, radius, thickness and volume, anterior chamber depth, axial length, lens opacity, and intraocular pressure were measured in all patients. Serum glucose, glycosylated hemoglobin, serum electrolytes, and protein were measured in the phakic patients.

In the phakic group, a significant myopic shift (≥ -0.50 D) occurred in 26 (81%) single eyes during the treatment. The median myopic shift was -0.63 D (min -0.25 D/max -1.88 D) in the OD, and -0.69 D (min -0.38 D/max -2.25 D) in the OS. No myopic shift appeared in the pseudophakic patients; the median refractive changes were +0.06 D (min -0.13 D/max +0.25 D) in the OD and +0.13 D (min 0.00 D/max +0.25 D) in the OS. Intraocular pressure, serum electrolytes, glucose, and glycosylated hemoglobin remained unchanged.

Myopic shifts occurred in phakic but not in pseudophakic eyes during HBO therapy. The myopic shifts must be attributed to changes in the crystalline lens.