RETINITIS PIGMENTOSA
Retina is exposed to an environment high in polyunsaturated fatty acids, with a large oxygen flux and high exposure to light. This is an ideal environment for oxidative damage. While retinal cells respond to chronic hyperoxic environments with increased production to enzymes, such as glutathione peroxidase, the effects of transient changes in oxygen which are encountered during hyperbaric therapy have not yet been identified.
Investigative Conditions Certain life and/or limb threatening conditions or unusually difficult conditions for which evidence is strong that adjunctive HBO therapy could be of value are equally recognized by the committee. Carbon Tetrachloride Poisoning (Acute) Cerebrovascular Accident (Acute - Thrombotic or Embolic) Head Injury (Cerebral Edema) Fracture Healing and Bone Grafting Hydrogen Sulfide Poisoning Pyoderma Gangrenosum Retinal (Central) Artery Insufficiency - Acute Selected Refractory Mycoses: Mucormycosis, Canibolus Coronato, Invasive Aspergillosis Sickle Cell Anemia Crisis Spinal Cord Injury (Acute) Contraindications Contraindications of HBO therapy include: Absolute Untreated Pneumothorax, Doxorubicin, Cis- Platinum Relative Upper Respiratory Infections Chronic Sinusitis Ear Surgery Seizure Disorders Emphysema (CO2 Retention) History of Spontaneous Pneumothorax History of Thoracic Surgery Viral Infections High Fever Congenital Spherocytosis Optic Neuritis Cataracts Refractory Osteomyelitis Osteomyelitis is essentially a surgical disease.
Appropriate antibiotics and debridement are effective in the majority of cases. Where bone infections persist, adjunctive hyperbaric oxygen has been demonstrated to help the healing process in a high ge of otherwise refractory cases, through a number of direct and indirect mechanisms. SPECIAL REPORT..... HYPERBARIC OXYGEN TREATMENT AS A RESCUE REMEDY FOR RETINITIS PIGMENTOSA By Bill Sardi, reporter at large for FOCUS For the first time eye researchers are reporting a breakthrough treatment for retinitis pigmentosa with the use of hyperbaric oxygen therapy. Researchers in Italy employed daily hyperbaric oxygen at 2.2 atmospheres of pressure among 24 RP patients for two years. The electroretinogram readings of RP patients undergoing hyperbaric oxygen treatment improved from 4.86 at the beginning of the study to 14.4 at the end of the study. RP patients who did not undergo oxygen therapy experienced diminished electroretinograms, beginning with an average of 4.92 decreasing to 2.97. Hyperbaric oxygen therapy may rescue retinal photoreceptors (Investigative Ophthalmology 38; 5713 Abstract #3296, 1997).
This report provides encouraging news to RP patients since there is no proven treatment for RP save for vitamin A therapy which only slows down progressive loss of vision as measured by an electroretinogram and does not improve the ERG. K.K. Jain, author of The Textbook of Hyperbaric Medicine, indicates the retina has the highest rate of oxygen consumption of any organ in the body. That hyperbaric oxygen treatment is helpful in cases of RP is an anomaly because it has been shown to cause severe constriction (narrowing) of retinal blood vessels. The hallmark of RP is poor retinal circulation. The constriction of the retinal blood vessels however is offset by the greatly increased oxygen-carrying capacity of the blood during treatment (oxygen saturation increases by 23 percent). What is hyperbaric oxygen therapy? Hyperbaric oxygen chambers are located in hundreds of locations in the United States and other sites throughout the world. These chambers are often used to treat deep sea divers who have experienced rapid reduction of air pressure from rising to the water surface too quickly and who subsequently experience decompression sickness (also called "the bends").
Hyperbaric oxygen applies this essential gas at pressures many times greater than normal atmospheric pressure at sea level. It is also a useful treatment for gas gangrene, radiation damage, osteomyelitis, carbon monoxide poisoning, anaerobic infections and for immune suppressed individuals. Humans breathe air that is 21 percent oxygen. Hyperbaric oxygen involves 100 percent oxygen administered at pressures two or three times normal. This increases the amount of oxygen the blood caries to body tissues which in turn enhances tissue repair. Hyperbaric oxygen treatment costs $100+ for each treatment. RP patients would need to check with their health insurance plan to determine coverage for treatment.
Eye physicians are likely to be unfamiliar with this type of therapy though some retinal specialists may have experience with hyperbaric oxygen. Hyperbaric oxygen treatment improves contrast sensitivity (ability to see shades of grey) when administered to healthy volunteers. Even though patients with non- retinal eye disorders have experienced constriction of retinal blood vessels following hyperbaric oxygen treatment, when there is a lack of oxygen supply to the retina narrowing of retinal blood vessels does not occur. (Undersea & Hyperbaric Medicine 21; 387-90, 1994) History of hyperbaric oxygen treatment and retinitis pigmentosa The medical literature reveals that hyperbaric oxygen treatment has been tried on cases of retinitis pigmentosa as early as 1965. (New England Journal of Medicine 281; 25-30, 1969) A 1987 report in the Journal of French Ophthalmology indicates hyperbaric oxygen treatment improved the visual acuity of a patient with retinitis pigmentosa and macular edema. (Journal French Ophthalmology 10: 381-86, 1987) Hyperbaric oxygen therapy and the optic nerve Hyperbaric oxygen treatment has been used as a rescue remedy for optic nerve damage caused by radiation treatment for brain tumors. (Ophthalmology 93; 1083- 88, 1986; Journal Clinical Neuro-ophthalmology 113; 98-101, 1993) Hyperbaric oxygen improved vision among individuals who experienced a sudden loss of vision due to diminished blood supply to the optic nerve.
Oxygen therapy must be administered early following onset of the event before shrinkage of the optic nerve occurs. (Arh Hig Rada Tokaikol 45; 19-24, 1994) Multiple sclerosis patients undergoing 20 hyperbaric oxygen treatments experienced temporary improvement of their symptoms including visual symptoms. (New England Journal Medicine 308; 181-86, 1983) Recently 100 percent oxygen delivered at 2 times atmospheric pressure did not produce a significant improvement in visual acuity or peripheral vision among patients suffering from a condition known as non-arterial anterior ischemic optic neuropathy. (American Journal Ophthalmology 122; 535-41, 1996) Hyperbaric oxygen therapy and glaucoma Among glaucoma patients, hyperbaric oxygen has been shown to expand peripheral vision, an effect which lasted for 3 months. (Acta Ophthalmologica 71; 315-19, 1993) The fluid pressure in the eye of humans and animals decreases as atmospheric pressure is raised in a hyperbaric chamber. (Investigative Ophthalmology 19; 43-48, 1980) K.K. Jain, author of Textbook of Hyperbaric Medicine, reports that hyperbaric oxygen has been used to successfully treat cases of glaucoma. Twenty or more 90-minute treatments at 2 atmospheres of pressure expanded the visual field among all glaucoma subjects tested. There was no change in eye fluid pressure.
Hyperbaric oxygen therapy and retinal artery and vein occlusion Hyperbaric oxygen treatment combined with a blood-vessel widening drug (vasodilator) has been shown to improve visual function among individuals experiencing retinal artery occlusion. (European Journal Ophthalmology 3; 89-94, 1993) Hyperbaric oxygen treatment has been successfully used to improve vision among patients with retinal swelling (macular edema) and retinal vein occlusion. (Survey of Ophthalmology 39; 347-66, 1995) Hyperbaric oxygen treatment has been administered successfully to patients with central retinal swelling (macular edema) resulting from retinal vein occlusion. Among 12 patients who were treated, 10 experienced visual improvement, with median visual acuity improving from 20/100 to 20/25. The hyperbaric oxygen treatment is believed to constrict retinal capillaries and thus decrease leakage of fluid that causes edema.
(Ophthalmologica 210; 168-170, 1996) Possible ocular side effects of hyperbaric oxygen therapy It has been known that healthy persons can breathe oxygen at 3 times normal atmospheric pressure for 3 hours without any ocular side effects, but during the fourth hour some begin to experience a narrowing of their visual field. One reported side effect of hyperbaric oxygen treatment is the development of myopia (nearsightedness). (Journal Hyperbaric Medicine 1; 69-73, 1987) Myopia was first reported in 1978 among 18 of 26 patients undergoing hyperbaric oxygen treatment at 4 atmospheres of pressure. (Transactions American Ophthalmology Society 76; 118-24, 1976) Note: Italian doctors only used 2.2 atmospheres of pressure in their successful treatment of RP with hyperbaric oxygen.
Dogs exposed to 3 atmospheres of pressure at 100 percent oxygen developed retinal problems and a reduction in their electro-retinograms. Narrowing of the visual field and impairment of central vision has been recorded among humans undergoing hyperbaric oxygen treatment at 3 atmospheres of pressure for more than 4 hours. (Science 151; 466-68, 1966) Captain Frank K. Butler, Jr. of the U.S. Navy reviewed the ocular effects of hyperbaric oxygen treatment in a recent issue of Review of Ophthalmology. Hyperbaric oxygen may induce myopia (nearsightedness) at the rate of one quarter diopter change in eyeglass prescription per week among patients receiving daily hyperbaric oxygen treatment. 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. (Survey of Ophthalmology 39; 347-66, 1995) 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. K.K. Jain states "With the pressure and duration of exposures used in clinical practice, ocular complications are not a problem...
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. An extensive discussion on the use of hyperbaric oxygen for eye conditions is included in K.K. Jain's Textbook of Hyperbaric Medicine, 2nd edition, 1996 Hogrefe & Huber Publishers, Seattle. 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. Jain suggests the use of magnesium (250-400 mg.) and vitamin E (400 units) daily starting two days prior to hyperbaric oxygen treatment to prevent undesirable side effects. High doses of vitamin C may be counter-productive, particularly when consumed without other antioxidants. Other useful oral antioxidants which may be consumed prior to and during hyperbaric oxygen treatment are alpha lipoic acid, vitamin B12, lutein, beta carotene, lycopene, selenium, bioflavonoids (bilberry) and coenzyme Q10. Iron should be avoided. Ultraviolet blue-violet blocking sun lenses should be worn outdoors following oxygen therapy. Hyperbaric oxygen treatment has been shown to adversely affect the electroretinograms (ERGs) of rodents fed a diet deficient in vitamin E and selenium. But rodents fed vitamin E alone or vitamin E plus selenium showed no decreases in their ERGs after 15 weeks of hyperbaric oxygen treatment.
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