Abstract
Purpose: :
To examine the optical components of the eye during hyperbaric oxygen (HBO) therapy, and to quantify their relative impact on ocular refractive changes.
Methods: :
HBO therapy was given to 16 phakic and 6 pseudophakic patients (with in-the-bag implants) for 90 min daily at a pressure of 240 kPa, five days 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 curvature, thickness and volume, anterior chamber depth and volume, lens opacity, axial length of the eye, and intra ocular pressure was measured in all patients. Osmolarity of the plasma, blood glucose and glycosylated haemoglobin (HbA1c) was measured in the phakic patients.
Results: :
In the phakic individuals, a significant myopic shift (≥ -0.50D) occurred in 26 (81%) single eyes during the treatment. The mean refractive changes were -0.77D ± 0.44D (range -0.25D to -1.87D) in the right eye (p=0.000), and -0.81D ± 0.47D (range-0.37D to -2.25D) in the left eye (p=0.000). Lens opacity remained unchanged. No myopic shift appeared in the group of pseudophakic patients. The mean refractive changes were +0.06D ± 0.16D (range +0.25D to -0.12D) in the right eye and +0.12D ± 0.11D (range +0.25D to 0.00D) in the left eye (p=0.041).
Conclusions: :
Ocular biometry showed myopic shifts in phakic but not in pseudophakic eyes during hyperbaric oxygen therapy. Hence, the myopic shift must be attributed to changes in the crystalline lens.
Clinical Trial: :
REK 3.2007.1422
Keywords: myopia • oxygen