The myopia reverses slowly over a course of many weeks. Cataracts have been reported to occur among patients undergoing a prolonged course of daily hyperbaric oxygen treatment which may not be reversible following cessation of treatment, particularly among adults of advanced age. K.K. Jain indicates cataracts may occur among patients undergoing hyperbaric oxygen treatment but that these were seldom observed when less than 200 treatments were administered. K.K. Jain reports that the most useful role of hyperbaric oxygen in eye care is the relief of blood vessel constriction in central retinal artery occlusion with a success rate as high as 60 percent. Hyperbaric oxygen does not appear to have a useful role in the treatment of diabetic retinopathy.
Hyperbaric oxygen appears to be a safe treatment from the ocular point of view.
Confirming its safety, hyperbaric oxygen treatment has been applied in cases of multiple sclerosis with optic neuritis without loss of vision or narrowing of the visual field. Most of the studies reporting adverse effects from hyperbaric oxygen therapy administered oxygen at greater pressure than is clinically used in everyday practice. Non-ocular side effects of hyperbaric oxygen treatment include oxygen convulsions, sinus blockage, confinement anxiety and inability to equalize middle ear pressure, though these side effects are uncommon. How to prepare for hyperbaric oxygen treatment K.K. Jain, author of the Textbook of Hyperbaric Medicine, suggests the use of oral antioxidants during therapy to counter possible side effects such as cataracts in elderly subjects or transient myopia. High doses of vitamin C may be counter-productive, particularly when consumed without other antioxidants.