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Eye problems

Hyperbaric oxygen in ophthalmology

Hyperbaric oxygen therapy has been recognized as an effective treatment method for various eye complications associated with diabetes, infections, intoxications, injuries, degenerative diseases or radiation therapy.

Indications for HBO Therapy in Ocular Diseases:

  • A. Recommended as primary treatment
    • 1. Occlusive vasculopathies (central retinal artery occlusion, branch retinal artery occlusion)
    • 2. Cystoid macular edema of vascular origin (central retinal vein occlusion, branch retinal vein occlusion, retinitis pigmentosa)
    • 3. Scleral necrosis of avascular origin (scleral thinning after pterygium surgery)
    • 4. Orbital infections of mycotic and anaerobic origin (rhino-orbito-cerebral mucormycosis)
    • 5. Nonhealing corneal edema
    • 6. Anterior segment ischemia


Preventive care for our eyes:

  • Maintaining blood glucose level under control may prevent damage to the small blood vessel supplying the eyes.
  • Regularly check your blood pressure and try to keep it within the normal values.
  • Avoid activities that can raise the blood pressure. Also, birth control pills can increase the blood pressure.
  • If eye problems develop then early intervention such as laser treatment for retinopathy can decrease the risk of blindness by 90%.

Yearly visits to ophthalmologist can confirm some of the following early signs of diabetic retinopathy:

  • Trouble reading books or traffic signs
  • Problems distinguishing familiar objects
  • Other visual problems such as spots, “floaters” or cobwebs in your field of vision, blurring or distortion, detection of blind spots, eye pain or persistent redness
  • Increased pressure inside the eye may be awarning sign of glaucoma
  • Sudden blindness or partial blindness (one eye) can be caused by the rupture of the vessels supplying the retina

Uses of Hyperbaric Oxygen Therapy (HBO) in eye complications:

  • Hyperbaric oxygen improves visual sharpness (acuity) and reduces the incidence of blindness caused by lack of oxygen.
  • Hyperbaric oxygen improves retinal blood flow and circulation. It is also effective in reducing swelling and thereby the risk of developing glaucoma and cataract.
  • Hyperbaric oxygen reduces scar formation after surgery.
  • Hyperbaric oxygen speeds up the healing after surgery and reduces complications.
  • Hyperbaric oxygen suppresses infection either directly by destroying bacteria or assisting white blood cells in phagocytosis.
  • Hyperbaric oxygen improves the immune system response.
  • Hyperbaric oxygen enhances the effect of some antibiotics.

Macular degeneration

Macular degeneration is a damage of the retina causing in severe cases the loss of vision in the central visual field. It is usually occurring in older population and is called age-related macular degeneration (AMD) and is a significant cause of visual loss in North America. As the population ages, the prevalence rate of advanced age-related macular degeneration is expected to double by 2030.

“A one-hour session of hyperbaric oxygen therapy was used to treat a group of 14 patients with advanced age-related macular degeneration. Eight patients were treated at 1.75 ATA, and six patients were treated at 1.5 ATA for one hour. Significant improvements in visual acuity and/or visual field, with improvements in the activities of daily living were observed.”

Weiss (2010)

Retinal vein occlusion, diabetic macular edema and cystoid macular edema

Macular edema is defined as swelling of the retina due to protein and fluid deposits under the macula of the eye. It could be the result of cataract removal surgery, ischemic retinal vein occlusion and is common complication in diabetics. Hyperbaric oxygen therapy reduces swelling in the eye, decreases intraocular pressure, has anti-inflammatory effect, restores normal oxygen levels and micro-circulation, restores vision and improves visual acuity and has stable long term results. (Please see references below) Three-week treatment schedule by Pfoff and Thom (1987) on five patients with cystoid macular edema showed improvement in vision in all patients within first two weeks. More related references are listed below but in some individuals, mostly with chronic condition such as diabetes, the vision tends to regress with time.

Increased intraocular pressure

Reduced intraocular pressure by hyperbaric oxygen was reported in largest study by Ensali in 2006. In his compression to 2.5 ATA on 56 patients who have all improved with therapy. This was consistent with previous and later results listed below.

Effects of Hyperbaric oxygen therapy in the disorders of the eye:

  • oxygenation and neo-vascularization
  • instant increase of oxygen partial pressure in the eye stops further retinal damage
  • reduced retinal swelling caused directly by oxygen induced vasoconstriction
  • reduced bleeding by vasoconstriction and elimination of hemorrhagic damage by improved blood flow
  • reduced inflammation and improved oxygen transport
  • restored micro-circulation and blood flow to retina
  • preservation and regeneration of the optic nerve
  • decreased intraocular pressure
  • reduced infection. Oxygen has bactericidal and bacteriostatic effects. Oxygen reduces infection by enhancing white blood cells phagocytosis and strengthening the effect of some antibiotics while protecting the body from the side effects
  • improved visual acuity by preservation of retinal receptors and restored vision by all of the above
  • reduced toxic effect by increased partial oxygen pressure and retinal oxygenation
  • reduced scar formation following surgery

Infections involving the eye and the orbit

Eye infections can be result of injury, or compromised immune system in diabetics and post-surgery, such as: cataract extraction and intraocular lens implantation. Hyperbaric oxygen has multiple effects on bacteria: Hyperbaric oxygen is bactericidal and bacteriostatic, enhances white blood cells phagocytosis, strengthens the effect of some antibiotics while protecting the body of the side effects.

Radiation-induced optic neuropathy, Diabetic retinopathy and Glaucoma

Optic neuropathy and glaucoma are both results of damage of the optic nerve due to various reasons: increased intraocular pressure, radiation due to cancer, poor blood supply, inflammation of the nerve itself (optic neuritis) or supplying blood vessels, trauma or injury to the eye or intoxication (mostly methanol). Optic neuropathy and glaucoma which can result in sudden or gradual loss of vision can be treated with hyperbaric oxygen therapy. Hyperbaric oxygen canprevent further optical nerve damage and start nerve regeneration, reduce retinal swelling, reestablish normal blood supply and decrease intraocular pressure.

Retinitis Pigmentosa

Retinitis Pigmentosa is a progressive degenerative genetic eye disorder caused by loss or abnormality of eye photo receptors. Retinitis pigmentosa can lead to night blindness, tunnel vision or ultimately blindness. Hyperbaric oxygen therapy can save retinal receptors from deterioration and improve visual acuity.

Corneal disorders

Corneal disorders such as: keratitis, traumatic injuries and ulceration can benefit from antibacterial effect of hyperbaric oxygen and neovascularization. Hyperbaric oxygen therapy counteracts hypoxia, reduces corneal edema, and prevents scar formation after surgery.

Central retinal artery occlusion (CRAO)

Central retinal artery occlusion is a sudden painless and profound vision loss due to blockage of the arterial blood supply to the eye. Retinal occlusive arterial disease is condition which is quite rare and has very poor prognosis may be result of thrombosis, vasospasm (collapse of the blood vessel), arteritis (inflammation of the walls of the supplying arteries) or embolus causing rapid death of retinal cells in people with giant cell arteritis, atherosclerosis or thromboembolic disease (deep venous thrombosis, pulmonary thromboembolism). Poor eye circulation is categorized with ocular ischemic syndrome such as in central retinal vein occlusion or diabetic retinopathy (retinal hemorrhage or retinal bleeding in people with diabetes). Retina has the highest rate of oxygen consumption (13ml/100gr/min) compared to any other organ in the body, even brain and heart and is extremely sensitive to reduced blood supply (ischemia) or lack of oxygen (hypoxia). Therefore, early application of hyperbaric oxygen therapy before the irreversible retinal damage occurs can be eye- and vision- saving. Various studies (listed below) quote promising results depending on the severity of the condition. Anywhere from three days to two weeks of the therapy after diagnosis may be needed for complete vision restoration. Hyperbaric oxygen treatment must continue until inner layers of the retina are re-oxygenated by retinal arteries and micro-circulation restored.

Effects of hyperbaric oxygen therapy in Central Retinal Artery Occlusion (CRAO):

  • instant increase of oxygen partial pressure in the eye to stop further retinal damage
  • improved or restored vision
  • improved visual acquity
  • reduced edema (swelling) caused directly by oxygen induced vasoconstricion
  • reduced inflammation by down-regulation of inflammatory cytokinesis
  • restored micro-circulation and blood flow to retina

Best results are achieved in acute stages of CRAO, however the clinical evidence shows the success even when hyperbaric oxygen therapy (HBOT) is given at the later stage (see  Gokce et al 2014). Hyperbaric oxygen therapy is clinicaly shown to slow the further retinal damage, slowing the degenerative process and have a long lasting effect on the eye. In five decades from early scientific clinical studies by Saltzman in 1960-ies on ocular disorders and effect of oxygen to comprehensive reviews by Butler in 2008 the list of authors recommended indication for hyperbaric oxygen includes(as referenced):

decompression sickness or arterial gas embolism with visual signs or symptoms, central retinal artery occlusion, ocular and periocular gas gangrene, cerebro-rhino-orbital mucormycosis, periocular necrotizing fasciitis, carbon monoxide poisoning with visual sequelae, radiation optic neuropathy, radiation or mitomycin C-induced scleral necrosis, and periorbital reconstructive surgery. Other ocular disorders that may benefit from hyperbaric oxygen therapy include selected cases of ischemic optic neuropathy, ischemic central retinal vein occlusion (CRVO), branch retinal artery occlusion with central vision loss, ischemic branch retinal vein occlusion (BRVO), cystoid macular edema associated with retinal venous occlusion, post-surgical inflammation, or intrinsic inflammatory disorders, periocular brown recluse spider envenomation, ocular quinine toxicity, Purtscher’s retinopathy, radiation retinopathy, anterior segment ischemia, retinal detachment in sickle cell disease, refractory actinomycotic lacrimal canaliculitis, pyoderma gangrenosum of the orbit and refractory pseudomonas keratitis”.

Of all of the above in 2009, the Undersea and Hyperbaric Medical Society (UHMS) added the Central Retinal Artery Occlusion (CRAO) to their list of approved indications for hyperbaric oxygen (HBO) therapy medical reimbursement.

Further reading:
  1. Weiss JN: Hyperbaric oxygen therapy and age-related macular degeneration: Undersea Hyperb Med; Mar-Apr;37(2):101-5, 2010.
  2. Miyamoto H, Ogura Y, Wakano Y, Honda Y: The long term results of hyperbaric oxygen treatment for macular edema with retinal vein occlusion; Nippon Ganka Gakkai Zasshi; Sep;97(9):1065-9 1993.
  3. Pfoff DS, Thom SR:Preliminary report on the effect of hyperbaric oxygen on cystoid macular edema; J Cataract Refract Surg;Mar;13(2):136-40, 1987.
  4. Jansen EC, Nielsen NV: Promising visual improvement of cystoid macular oedema by hyperbaric oxygen therapy; Acta Ophthalmol Scand, Aug;82(4):485-6, 2004.
  5. Flach, A: The incidence, pathogenesis and treatment of cystoid macular edema following cataract surgery; Tr Am Ophth Soc vol XCVI, 1998
  6. Letters to the Editor: Long term effect of repeated hyperbaric oxygen therapy on visual acuity in inflammatory cystoid macular oedema; British J of Ophthalmology 1997;81:329–332
  7. Miyamoto H, Ogura Y, Honda Y: Hyperbaric oxygen treatment for macular edema after retinal vein occlusion–fluorescein angiographic findings and visual prognosis; Nippon Ganka Gakkai Zasshi, Feb;99(2):220-5, 1995.
  8. Miyamoto H, Ogura Y, Wakano Y, Honda Y: The long term results of hyperbaric oxygen treatment for macular edema with retinal vein occlusion; Nippon Ganka Gakkai Zasshi; Sep;97(9):1065-9, 1993.
  9. Xu YN, Huang JG: Hyperbaric oxygen treatment for cystoid macular edema secondary to retinal vein occlusion; Zhonghua Yan Ke Za Zhi; Jul;27(4):216-8, 1991.
  10. Miyake Y, Awaya S, Takahashi H, Tomita N, Hirano K: Hyperbaric oxygen and acetazolamide improve visual acuity in patients with cystoid macular edema by different mechanisms; Arch Ophthalmol; Dec;111(12):1605-6,1993.
  11. Ogura Y, Kiryu J, Takahashi K, Honda Y: Visual improvement in diabetic macular edema by hyperbaric oxygen treatment; Nippon Ganka Gakkai Zassh; Sep;92(9):1456-60,1988.
  12. Ogura Y, Takahashi M, Ueno S, Honda Y: Hyperbaric oxygen treatment for chronic cystoid macular edema after branch retinal vein occlusion; Am J Ophthalmol; Sep 15;104(3):301-2,1987.
  13. Suttorp-Schulten MS, Riemslag FC, Rothova A, van der Kley AJ, Riemslag FC: Long-term effect of repeated hyperbaric oxygen therapy on visual acuity in inflammatory cystoid macular oedema; Br J Ophthalmol; Apr;81(4):329,1997.
  14. Krott R, Heller R, Heimann K: Adjuvant hyperbaric oxygen therapy (HBO) in cystoid macular edema–preliminary results; Klin Monbl Augenheilkd, Aug;215(2):144,1999.
  15. Kiryu J, Ogura Y: Hyperbaric oxygen treatment for macular edema in retinal vein occlusion: relation to severity of retinal leakage; Ophthalmologica; 210(3):168-70,1996.
  16. Johnson GP: Cases from the aerospace medicine residents’ teaching file. Case #38. A navigator with nonischemic central retinal vein occlusion progressing to ischemic central retinal vein occlusion; Aviat Space Environ Med; Oct;61(10):962-5,1990.
  17. Roy M, Bartow W, Ambrus J, Fauci A, Collier B, Titus J: Retinal leakage in retinal vein occlusion: reduction after hyperbaric oxygen; Ophthalmologica; 198(2):78-83,1989.
  18. Ogura Y, Takahashi M, Ueno S, Honda Y: Hyperbaric oxygen treatment for chronic cystoid macular edema after branch retinal vein occlusion; Am J Ophthalmol, Sep 15;104(3):301-2,1987.
  19. Gismondi A, Colonna S, Micalella F, Metrangolo C: Hyperbaric oxygen therapy in thrombotic occlusion of the central retinal vein; Minerva Med; May 31;72(22):1413-5,1981.
  20. Bojić L, Kovacević H, Andrić D, Romanović D, Petri NM.Hyperbaric oxygen dose of choice in the treatment of glaucoma; Arh Hig Rada Toksikol, Sep; 44(3):239-47,1993.
  21. Bojić L, Racic G, Gosović S, Kovacević H:The effect of hyperbaric oxygen breathing on the visual field in glaucoma; Acta Ophthalmol (Copenh); Jun, 71(3):315-9,1993
  22. The Undersea and Hyperbaric Medical Society (UHMS), Hyperbaric Oxygen Therapy Committee. Guidelines: Indications for Hyperbaric Oxygen. Durham, NC: UHMS; 2009.
  23. Gokce G, Metin S, Erdem U, Sobaci G, Durukan AH, Cagatay HH, Ekinci M.: Late hyperbaric oxygen treatment of cilioretinal artery occlusion with nonischemic central retinal vein occlusion secondary to high altitude.   High Alt Med Biol. 2014 Apr;15(1):84-8.
  24. Cope A, Eggert JV, O’Brien E. Retinal artery occlusion: visual outcome after treatment with hyperbaric oxygen. Diving Hyperb Med. 2011 Sep;41(3):135-8.
  25. Weiss JN. Hyperbaric oxygen treatment of retinal artery occlusion. Undersea Hyperb Med. 2010 May-Jun;37(3):167-72.
  26. Oguz H, Sobaci G. The use of hyperbaric oxygen therapy in ophthalmology. Surv Ophthalmol. 2008 Mar-Apr;53(2):112-20. doi: 10.1016/j.survophthal.2007.12.002. Review.
  27. Vingolo EM, Rocco M, Grenga P, Salvatore S, Pelaia P.Slowing the degenerative process, long lasting effect of hyperbaric oxygen therapy in retinitis pigmentosa.Graefes Arch Clin Exp Ophthalmol. 2008 Jan;246(1):93-8. Epub 2007 Aug 3.
  28. Cope A, Eggert JV, O’Brien E. Retinal artery occlusion: visual outcome after treatment with hyperbaric oxygen. Diving Hyperb Med. 2011 Sep;41(3):135-8.
  29. Krott R, Heller R, Aisenbrey S, Bartz-Schmidt KU. Adjunctive hyperbaric oxygenation in macular edema of vascular origin. Undersea Hyperb Med. 2000 Winter;27(4):195-204.
  30. Chang YH, Chen PL, Tai MC, Chen CH, Lu DW, Chen JT. Hyperbaric oxygen therapy ameliorates the blood-retinal barrier breakdown in diabetic retinopathy.  Animal Study, Clin Experiment Ophthalmol. 2006 Aug;34(6):584-9.
  31. Butler FK, Hagan C, Murphy-Lavoie H: Hyperbaric oxygen therapy and the eye: Journal of the Undersea and Hyperbaric Medical Society, Isep – Oct; 35(5): 333–87, Review, 2008
  32. Oguz H, Sobaci G: The use of hyperbaric oxygen therapy in ophthalmology. Surv Ophthalmol; Mar-Apr;53(2):112-20, Review, 2008.
  33. Weiss JN: Hyperbaric oxygen treatment of retinal artery occlusion; Undersea Hyperb Med; May-Jun;37(3):167-72, 2010.
  34. Wright JK, Franklin B, Zant E: Clinical case report: treatment of a central retinal vein occlusion with hyperbaric oxygen; Undersea and Hyperbaric Medicine; 34(5): 315–9, 2007.
  35. Butler Jr, FK: Hyperbaric oxygen for central retinal artery occlusion; Wound Care & Hyperbaric Medicine 1 (3): 25, 2010
  36. Haddad HMLeopold IH: Effect of hyperbaric oxygenation on microcirculation: use in therapy of retinal vascular disorders; Invest Ophthalmol; Dec;4(6):1141-51, 1965
  37. Beiran I, Goldenberg I, Adir Y, Tamir A, Shupak A, Miller B: Early hyperbaric oxygen therapy for retinal artery occlusion.Eur J Ophthalmol; Oct-Dec; 11(4):345-50, 2001
  38. Weiss JN: Hyperbaric oxygen treatment of nonacute central retinal artery occlusion; Undersea Hyperb Med. Nov-Dec;36(6):401-5, 2009.
  39. Matsuo T: Multiple occlusive retinal arteritis in both eyes of a patient with rheumatoid arthritis; Jpn J Ophthalmol, Nov-Dec;45(6):662-4, 2001.
  40. Li HK, Dejean BJ, Tang RA: Reversal of visual loss with hyperbaric oxygen treatment in a patient with Susac syndrome; Ophthalmology; Dec;103(12):2091-8,1996.
  41. Saltzman HA, Hart L, Sieker HO, Duffy EJ: Retinal vascular response to hyperbaric oxygenation. JAMA. 1965 Jan 25;191(4):290-2.
  42. Waddell WB, Saltman HA, Fuson RL, Harris J: Purpura gangrenosa treated with hyperbaric oxygenation: JAMA; Mar 22;191:971-4, 1965.

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