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Hyperbaric Oxygen Therapy and Visual Acuity

Hyperbaric Oxygen Therapy and Visual Acuity

Hyperbaric Oxygen Therapy and Visual Acuity



Vision changes as a side effect of hyperbaric oxygen therapy (HBO) therapy have been observed in patients undergoing prolonged periods of daily HBOT.[1] 

Myopia is a defect of vision consisting of an error of refraction in which rays of light entering the eye parallel to the optic axis are brought to a focus in front of the retina, so that vision for near objects is better than for far. This results from the eyeball being too long from front to back. (also called nearsightedness). The mechanism of progressive myopia remains vague. It is apparently lenticular in origin and usually reverses completely within a few days to several weeks after completion of the last treatment.[1]

Providers should consider ordering a baseline visual ophthalmology exam in patients with risk factors, and if possible weekly prior/after their HBO therapy. Information about the vision change should be a part of the informed consent for each HBO patient. Patients who develop vision change during HBO therapy should avoid the expense of obtaining new glasses (or use a less expensive alternative in the interim) until enough time has elapsed for the changes to reverse. In those patients with persistent change, consider ophthalmology referral to assess for other causes.[2]

This topic provides documentation templates for weekly Patient Eye Exams and Notification of Instructions in case change in visual acuity is detected.

Of note, visual acuity alone is not an adequate measure of visual function to monitor the efficacy of HBOT in ocular dysfunctions in which HBOT is a primary or adjunctive therapy (e.g., 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). In these cases, ocular examinations should also include automated perimetry to evaluate the central 30 degrees of visual field at appropriate intervals.  [3]


Patient Eye Exam

 Patients who wear corrective lenses will do the eye exam while wearing them. 

1) Have the patient stand 20ft from the eye chart. 

2) Have the patient cover their left eye and read the lowest letter line possible. 

3) Then cover their right eye and read the lowest letter line possible. 

4) Finally, they will read the lowest letter line possible with both eyes.

Patients who wear hard contact lenses; these lenses will need to be removed prior to beginning treatment, as discussed in their patient education 

Date Right EyeLeft EyeBoth Eyes

Exam Score > 20/70 Letter given:                                  Date/Initials  


Notification of Instructions Due to Change in Visual Acuity

As discussed during your hyperbaric patient education, vision changes are possible after receiving several (>20) hyperbaric treatments.  This is usually a temporary change that will resolve within 3 to 4 months after your last hyperbaric treatment.

You are receiving this notification because during your last eye exam in the Hyperbaric Clinic your visual acuity score was above 20/70 on the Snellen Eye Chart. According to many state vision screening standards, it is illegal for you to drive without some form of corrective lenses. Refer to: State Vision Screening and Standards for License to Drive

Your initial eye exam: R_________ L_________ B_________
Your eye exam today: R_________ L_________ B_________

You now require a new prescription if you are driving.  It is illegal for you to operate a vehicle.  Your treatments will be placed on hold until adequate corrective lenses can be obtained.  You may continue treatments if you have another means of transportation.

I have read and understand the above information.  My plan is as follows:




Patient Signature:                                                         Date/Time:                              


Physician Signature:                                                      Date/Time:                               

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Topic 1180 Version 1.0