History and Physical
Sample history for Central Retinal Artery Occlusion is shown below:
"Mr. Roberts is a 76 y/o man who awakened this morning with total blindness of the right eye. He went to bed at 10PM last night with good vision bilaterally. He states that he arose once in the middle of the night to urinate. He cannot remember his visual status at the time, but he was not concerned and turned on no lights. This morning at 7AM, he arose and noted no vision in the right eye.
He came to the emergency room for evaluation. The emergency room doctor confirmed that there was no vision in the right eye, and he also confirmed that the retina was pale. The ophthalmologist evaluated Mr. Roberts, performed an injection in the right eye and called us to evaluate the patient for Central Retinal Artery Occlusion.
We noted that the retina has been without blood flow for at least 9 hours from the middle of the night, and at most 12 hours from bedtime the night before. In this situation, time from onset of occlusion is vitally important. This patient is a good candidate for hyperbaric oxygen therapy in hopes to provide oxygen to the damaged retina for the next 36 - 48 hours while the retinal artery recanalyzes. This is an emergent indication for hyperbaric therapy. Failing to act will ensure total, irreversible blindness in the eye. We are happy to assist."
Physical Exam
- Sudden, painless visual loss, generally unilateral
- Findings upon fundoscopic exam with dilation:
- Pale yellow/ white-appearing retina due to ischemia or necrosis
- A cherry red spot in the macula (this is finding may not always be present) (Figure 1)
- Other physical exam findings may include an afferent pupillary defect (Marcus Gunn pupil) and segmentation of blood in retinal arterioles (boxcarring)
Figure 1. Central retinal artery occlusion with cherry-red spot, retinal edema and narrowing of the vessels.
Impression
- Central Retinal Artery Occlusion Refer to ICD-10 Crosswalk
Plan
There are several treatment options described in the medical literature. Hyperbaric oxygen can be delivered at 2.4 atmospheres absolute with 90 minutes of oxygen breathing during a 120 minute treatment. This will be repeated twice daily until maximum visual acuity is obtained. A second option for treatment involves treating at 2.4 atmospheres absolute for 30 minutes. If there is no improvement in visual acuity, the treatment pressure is increased to 2.8 atmospheres absolute, following a US Navy Treatment Table 6 protocol. Further treatments at 2.4 or 2.8 atmospheres absolute are administered on a twice daily regimen until visual acuity no longer improves.
Risk and Benefit of Hyperbaric Oxygen Therapy
- Please refer to topic "Documentation HBO: Risks and Benefits"
Indication for Hyperbaric Oxygen Therapy (HBOT)
Central retinal artery occlusion (CRAO) is a rare eye disorder that typically produces severe and irreversible vision loss in the affected eye. There is some anatomic variation to the arterial blood supply to the retina. However, these patients usually present to the ophthalmologist with sudden visual loss, generally unilateral, and painless. Once the arterial supply to the retina is occluded, variable degrees of tissue loss occur within 90 to 120 minutes. This may be irreversible without intervention.
A number of different treatment regimens have been used with variable degrees of success. Frequently, there has been no improvement in visual acuity once blood supply to the retina has been lost. There have been a number of different pathophysiologic etiologies described with a common denominator of interrupted arterial supply to the retinal tissue. Here have been several studies showing that addition of HBOT as soon as possible has resulted in increased visual acuity by 2 to 3 lines on a Snellen eye chart. This may make the difference between light perception only to finger counting or television vision.
Hyperbaric Plan
There are several treatment options described in the medical literature. Hyperbaric oxygen can be delivered at 2.4 atmospheres absolute with 90 minutes of oxygen breathing during a 120 minute treatment. This will be repeated twice daily until maximum visual acuity is obtained. A second option for treatment involves treating at 2.4 atmospheres absolute for 30 minutes. If there is no improvement in visual acuity, the treatment pressure is increased to 2.8 atmospheres absolute, following a US Navy Treatment Table 6 protocol. Further treatments at 2.4 or 2.8 atmospheres absolute are administered on a twice daily regimen until visual acuity no longer improves. There is currently AHA Level IIb evidence suggesting that hyperbaric oxygen is helpful.
Sample Order
- See sample physician order
CATEGORY A CONTINUING EDUCATION CREDIT
This topic has been reviewed and approved by the National Board of Diving and Hyperbaric Medical Technology (NBDHMT) for one (1) Category A Credit.
To claim the credit:
- Read the topic
- Answer the examination and course critique questions. See "Central Retinal Artery Occlusion - Examination and Course Critique Questions"
- Receive the certificate by e-mail. A passing score of 70% is required (please allow up to 8 business days for processing)
For more information on Category A continuing education credits see blog post " Hyperbaric Certification and Continuing Education for Technicians & Nurses".
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