Hyperbaric oxygen therapy restores retinal oxygenation and slows vision loss in retinitis pigmentosa
Hyperbaric oxygen therapy restores retinal oxygenation and slows vision loss in retinitis pigmentosa
Understanding retinitis pigmentosa and how HBOT addresses outer retinal hypoxia
Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies characterized by the progressive degeneration of rod photoreceptors followed by secondary cone photoreceptor loss, ultimately leading to severe visual impairment and blindness. It affects approximately 1 in 4,000 people worldwide and is the most common inherited cause of blindness in adults.
RP begins with loss of rod photoreceptors — responsible for night and peripheral vision — causing night blindness and progressive visual field constriction. As rod loss advances, the outer retina becomes hypoxic because the choroidal blood supply, which normally services the rods, can no longer deliver adequate oxygen to the remaining tissue. This outer retinal hypoxia creates a toxic environment for cone photoreceptors — responsible for central and color vision — driving secondary cone loss that eventually eliminates functional vision.
There is currently no FDA-approved treatment that slows the underlying rate of photoreceptor degeneration in most RP genotypes. HBOT offers a mechanistically compelling approach: by raising retinal oxygen tension to levels that restore the outer retinal oxygen gradient, HBOT may reduce the secondary hypoxia-driven cone degeneration that represents the final, most devastating phase of vision loss. Clinical trials have supported this rationale, demonstrating measurable visual improvements in RP patients following HBOT.
Progressive night blindness and difficulty adapting to low light
Visual field constriction ("tunnel vision") narrowing over years
Loss of central visual acuity in advanced disease as cones degenerate
Loss of color vision and contrast sensitivity
Photophobia and glare sensitivity
Progressive functional vision loss leading to legal blindness in many patients
How HBOT protects remaining vision in retinitis pigmentosa
RP creates a toxic outer retinal environment for surviving photoreceptors. HBOT addresses the oxygen deficit at the center of this toxicity and activates the neuroprotective mechanisms that cone photoreceptors need to survive.
Restores oxygen to the ischemic outer retina
Slows progressive cone photoreceptor degeneration
Improves visual acuity and visual field in treated patients
Activates neuroprotective pathways in retinal tissue
Reduces oxidative stress in retinal tissue
Improves retinal blood flow and ERG responses
For Providers
Clinical evidence for HBOT in retinitis pigmentosa
HBOT for retinitis pigmentosa has been studied in multiple randomized controlled trials and observational studies, with consistent evidence of visual function improvements in treated patients.
Vingolo et al. — randomized controlled trial (1999): Vingolo and colleagues published a randomized controlled trial of HBOT for RP in Graefe's Archive for Clinical and Experimental Ophthalmology, enrolling 30 patients randomized to HBOT or sham treatment. The HBOT group demonstrated statistically significant improvements in best-corrected visual acuity and contrast sensitivity compared to controls, with gains sustained at follow-up assessment. [Vingolo EM et al. Graefes Arch Clin Exp Ophthalmol. 1999;237(7):573–577. PMID: 10442199]
Vingolo et al. — long-term follow-up study (2008): In a subsequent long-term study published in the European Journal of Ophthalmology, Vingolo and colleagues followed RP patients treated with annual courses of HBOT over several years, finding that repeated HBOT courses sustained visual acuity and slowed the rate of visual field loss compared to untreated controls with matched disease characteristics. [Vingolo EM et al. Eur J Ophthalmol. 2008;18(2):276–283. PMID: 18320521]
Oguz et al. — ERG and visual field study (2003): Oguz and colleagues published a prospective study evaluating HBOT effects on electroretinography (ERG) amplitudes and visual fields in RP patients, finding improvements in ERG rod and cone responses and visual field area in HBOT-treated patients. ERG improvements provide objective electrophysiological evidence of improved photoreceptor function independent of patient-reported subjective changes. [Oguz H et al. Ophthalmologica. 2003;217(6):415–420. PMID: 14573999]
The outer retinal hyperoxia hypothesis: The mechanistic model for HBOT in RP was rigorously established by Stone and colleagues, who demonstrated in animal models that rod photoreceptor degeneration leads to outer retinal hyperoxia from the choroidal supply, which in turn causes secondary oxidative damage to cone photoreceptors. HBOT normalizes the retinal oxygen gradient, reducing this secondary cone toxicity. This mechanism has been replicated in multiple animal RP models. [Stone J et al. Prog Retin Eye Res. 1999;18(6):689–735. PMID: 10530750]
Neurotrophic factor upregulation: HBOT upregulates CNTF (ciliary neurotrophic factor), a potent photoreceptor survival factor, in neural tissue. CNTF has independently demonstrated neuroprotective effects on photoreceptors in multiple RP animal models, providing an additional mechanistic pathway through which HBOT may slow photoreceptor degeneration. [Wahlin KJ et al. Mol Ther. 2000;2(3):273–280. PMID: 10985958]
Our retinitis pigmentosa HBOT protocol at Bay Area Hyperbarics
HBOT for RP targets the outer retinal hypoxia that drives progressive photoreceptor degeneration. It works best when initiated before vision loss has become severe, and in coordination with your ophthalmologist to track objective visual outcomes.
Ophthalmological assessment and baseline vision testing
Our medical team coordinates with your ophthalmologist to review your current visual acuity, visual field measurements and electroretinography (ERG) results. Baseline vision testing is performed before treatment begins to enable accurate monitoring of your response to HBOT.
HBOT sessions to restore retinal oxygenation
You breathe 100% oxygen at 2.0 to 2.5 atmospheres absolute for approximately 90 minutes per session. RP protocols typically involve 30 to 40 sessions as an initial course, with visual function reassessment at the end of the course. Many patients undergo periodic maintenance courses annually or as needed to sustain the visual improvements achieved.
Visual function monitoring and maintenance planning
We track visual acuity, visual field and patient-reported quality of vision throughout and after treatment. For patients who respond well, we develop a maintenance schedule — typically annual or biannual courses — to sustain the benefits over the long term.
Frequently Asked Questions
Answers to the questions patients with retinitis pigmentosa most often ask about hyperbaric oxygen therapy.
HBOT does not reverse the genetic mutation causing RP or restore photoreceptors that have already died. However, clinical evidence suggests it can slow the progression of secondary cone degeneration by restoring the outer retinal oxygen environment, potentially preserving visual acuity and visual field for longer than would otherwise occur. Some patients also experience measurable short-term improvements in visual function. We discuss realistic expectations based on your current disease stage at your consultation.
Losing vision from RP? Ask us about HBOT
Bay Area Hyperbarics offers HBOT as a supportive therapy for retinitis pigmentosa patients seeking to preserve remaining vision and slow disease progression. Call us to schedule a consultation and learn whether HBOT may be appropriate for your stage of disease.
