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PubMed This is a summary of 22 peer-reviewed journal articles Updated
Ophthalmology

Identifying the Problem: Symptoms and Diagnosis of CRAO

At a Glance

Central Retinal Artery Occlusion (CRAO) is an 'eye stroke' that causes sudden, painless vision loss in one eye. It is a medical emergency diagnosed by finding retinal swelling and a 'cherry-red spot' during an eye exam. Patients require immediate testing for underlying brain stroke risks.

Recognizing the symptoms of Central Retinal Artery Occlusion (CRAO) is the first step toward receiving life-altering care. Because this condition is an “eye stroke,” the diagnostic process is designed to move quickly to identify the cause and protect as much vision as possible [1][2].

Primary Symptoms and The “Cherry-Red Spot”

The hallmark of a CRAO is the sudden, painless loss of vision in one eye [3]. Most patients describe it as if a light was suddenly switched off. When a doctor looks into your eye during the acute phase, they often see two classic signs:

  • Retinal Whitening: As the retina is starved of oxygen, it swells and turns a pale, milky white color [3][4].
  • Cherry-Red Spot: Because the central part of the retina (the fovea) is much thinner, the red blood vessels of the layer underneath (the choroid) show through the pale, swollen tissue, creating a distinctive red dot [4][5].

The Role of the Cilioretinal Artery

About 15% to 30% of the population has a biological “backup” called a cilioretinal artery [6]. If you are among this group, this small extra artery provides a separate blood supply to the very center of your vision.

  • Vision Sparing: If the main retinal artery is blocked but the cilioretinal artery remains open (patent), you may still be able to see relatively well in the very center of your visual field, even if your side (peripheral) vision is gone [7][8].
  • Prognosis: Finding a patent cilioretinal artery is a positive sign, as it often leads to a better long-term visual outcome compared to a total blockage [9][8].

Modern Diagnostic Tools

To confirm the diagnosis and find the source of the blockage, your medical team will use several specialized tests:

  • Optical Coherence Tomography (OCT): This non-invasive “ultrasound with light” creates high-resolution maps of your retina. It allows doctors to see the exact thickness of the retinal layers and the degree of swelling [10][5].
  • Retrobulbar Spot Sign (RBSS): Using a bedside ultrasound, doctors look for a bright white spot (hyperechoic density) inside the optic nerve. This “spot sign” is highly suggestive of an embolus—a piece of calcium or cholesterol that has traveled from the heart or neck and lodged in the artery [11][3][12].
  • Fluorescein Angiography: A special dye is injected into your arm, and a camera takes pictures as the dye travels through the blood vessels in your eye. This reveals exactly where the blood flow has stopped [13][14].

Critical Pitfalls: What Else Could It Be?

CRAO is sometimes confused with other conditions, but getting the diagnosis right is essential for treatment.

  • Optic Neuritis: Unlike CRAO, this is an inflammatory condition that usually causes painful vision loss and is often seen in younger patients or those with multiple sclerosis [15][14].
  • Ophthalmic Artery Occlusion (OAO): This is a more severe blockage that happens further back in the eye’s blood supply. In OAO, even the “cherry-red spot” is usually missing because the blood supply to the layer under the retina is also blocked [16][17].
  • Giant Cell Arteritis (GCA): This is a medical emergency involving inflammation of the arteries. Doctors must rule this out immediately—especially in patients over 50—because it requires high-dose steroids to prevent permanent blindness in both eyes [14][18].

Diagnostic Completeness Checklist

To ensure a thorough evaluation, you should generally have the following:

  • [ ] Dilated Eye Exam: To look for retinal whitening and the cherry-red spot [4].
  • [ ] OCT Imaging: To measure retinal swelling and damage [10].
  • [ ] Blood Tests (ESR and CRP): To rule out life-threatening inflammation like GCA [14].
  • [ ] Carotid Ultrasound: To check for blockages in the neck arteries [19].
  • [ ] Heart Monitoring (EKG/Echocardiogram): To check for clots or irregular rhythms like atrial fibrillation [20][21].
  • [ ] Brain Imaging (MRI/CT): Because an eye stroke often means you are at high risk for a brain stroke [19][22].

Common questions in this guide

What does a cherry-red spot mean on my eye exam?
A cherry-red spot is a classic sign of an eye stroke. It appears when the surrounding retina becomes swollen and turns pale from a lack of oxygen, which makes the normal red center of your vision stand out sharply.
What is a cilioretinal artery and how does it affect my vision?
A cilioretinal artery is a biological backup blood vessel present in up to 30% of people. If you have an eye stroke, this extra artery can provide a separate blood supply to the center of your eye, which may help preserve some of your central vision.
Why do I need heart and brain tests for an eye problem?
Because an eye stroke is caused by a blood clot or plaque that has traveled to your eye, it is a major warning sign that you are at high risk for a brain stroke. Doctors run heart and neck tests to find where the blockage came from and prevent future strokes.
How is Central Retinal Artery Occlusion (CRAO) diagnosed?
Doctors use a dilated eye exam to look for signs of oxygen loss in the retina. They also use specialized imaging like Optical Coherence Tomography (OCT) to measure retinal swelling and bedside ultrasounds to locate the exact blockage in your eye's blood vessels.
Could my sudden vision loss be something other than CRAO?
Yes, sudden vision loss can be caused by optic neuritis, a deeper blockage known as ophthalmic artery occlusion, or a dangerous inflammatory condition called Giant Cell Arteritis (GCA). Doctors perform specific tests to quickly rule out these conditions and determine the right course of action.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Did my imaging show a 'cilioretinal artery,' and how does that affect my long-term vision?
  2. 2.Was a 'retrobulbar spot sign' seen on my ultrasound, and does that mean the cause is an embolus?
  3. 3.How did you rule out Giant Cell Arteritis (GCA) in my case?
  4. 4.Is there evidence of ischemia in the choroid, or is it isolated to the retina?
  5. 5.Based on my OCT scan, how much swelling or 'retinal whitening' is present?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (22)
  1. 1

    Acute Central Retinal Artery Occlusion Seen within 24 Hours at a Tertiary Institution.

    Chan W, Flowers AM, Meyer BI, et al.

    Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association 2021; (30(9)):105988 doi:10.1016/j.jstrokecerebrovasdis.2021.105988.

    PMID: 34271275
  2. 2

    A Randomized Trial of Tenecteplase in Acute Central Retinal Artery Occlusion.

    Ryan SJ, Jørstad ØK, Skjelland M, et al.

    The New England journal of medicine 2026; (394(5)):442-450 doi:10.1056/NEJMoa2508515.

    PMID: 41604638
  3. 3

    Painless loss of vision: rapid diagnosis of a central retinal artery occlusion utilizing point-of-care ultrasound.

    Taylor GM, Evans D, Doggette RP, et al.

    Oxford medical case reports 2021; (2021(6)):omab038 doi:10.1093/omcr/omab038.

    PMID: 34158954
  4. 4

    Clinical Features of Combined Central Retinal Artery and Vein Occlusion.

    Wang H, Chang Y, Zhang F, et al.

    Journal of ophthalmology 2019; (2019()):7202731 doi:10.1155/2019/7202731.

    PMID: 31687201
  5. 5

    Multimodal Imaging of Acute Central Retinal Artery Occlusion.

    Abdellah MM

    Medical hypothesis, discovery & innovation ophthalmology journal 2019; (8(4)):283-290.

    PMID: 31788490
  6. 6

    Evaluation of bilateral central retinal artery occlusions with optical coherence tomography-based microangiography: a case report.

    Lee AY, Zhang Q, Baughman DM, et al.

    Journal of medical case reports 2016; (10(1)):307 doi:10.1186/s13256-016-1095-0.

    PMID: 27802835
  7. 7

    Clinical Manifestations and Visual Prognosis of Cilioretinal Artery Sparing Central Retinal Artery Occlusion.

    Kim YH, Park KH, Woo SJ

    Korean journal of ophthalmology : KJO 2020; (34(1)):27-34 doi:10.3341/kjo.2019.0099.

    PMID: 32037747
  8. 8

    The Association Between Fundus Changes and Visual Prognosis in Central Retinal Artery Occlusion.

    Wang H, Wei H, Dong J, et al.

    Clinical ophthalmology (Auckland, N.Z.) 2025; (19()):4913-4924 doi:10.2147/OPTH.S568753.

    PMID: 41476855
  9. 9

    Abnormal retinal vessel filling in central retinal artery occlusion.

    Venkatesh R, Mangla R, Parmar Y, et al.

    Clinical & experimental optometry 2024; (107(8)):801-805 doi:10.1080/08164622.2023.2298781.

    PMID: 38184849
  10. 10

    Retinal OCT findings in acute central retinal artery occlusion of varying severity at different disease stages - a retrospective, observational study.

    Mangla R, Venkatesh R, Sangoram R, et al.

    International journal of retina and vitreous 2023; (9(1)):37 doi:10.1186/s40942-023-00475-8.

    PMID: 37349781
  11. 11

    Blinded by occlusion: transforming painless vision loss assessment in the ED.

    Vuong N, Richardson E, Silva-Baucage L, et al.

    Journal of ultrasound 2025; doi:10.1007/s40477-025-01034-7.

    PMID: 40560360
  12. 12

    Sonographic Retrobulbar Spot Sign in Diagnosis of Central Retinal Artery Occlusion: A Case Report.

    Usheva E, Williams D, Musgrave H, Zhou S

    Journal of education & teaching in emergency medicine 2023; (8(4)):V5-V8 doi:10.21980/J8735P.

    PMID: 37969157
  13. 13

    Incidence and Clinical Features of Neovascularization of the Iris following Acute Central Retinal Artery Occlusion.

    Jung YH, Ahn SJ, Hong JH, et al.

    Korean journal of ophthalmology : KJO 2016; (30(5)):352-359 doi:10.3341/kjo.2016.30.5.352.

    PMID: 27729755
  14. 14

    Choroidal ischemia as one cardinal sign in giant cell arteritis.

    Casella AMB, Mansour AM, Ec S, et al.

    International journal of retina and vitreous 2022; (8(1)):69 doi:10.1186/s40942-022-00422-z.

    PMID: 36153565
  15. 15

    Polyarteritis nodosa initially presenting as ocular motility impairment and diplopia with subsequent development of bilateral central retinal artery occlusion: A case report.

    Nakagawa S, Akiyama S, Hino S, Ishii K

    American journal of ophthalmology case reports 2025; (37()):102255 doi:10.1016/j.ajoc.2025.102255.

    PMID: 39902399
  16. 16

    A Novel Case of Sudden Monocular Blindness Caused by Undiagnosed Granulomatous Disease Presenting with Acute Ophthalmic Artery Occlusion.

    Gifford-Hollingsworth RC, Yoo MJ, Sletten Z

    Cureus 2019; (11(12)):e6479 doi:10.7759/cureus.6479.

    PMID: 32025403
  17. 17

    Central Retinal Artery Occlusion Due to Intraorbital Ophthalmic Artery Aneurysm.

    Carey AR

    Journal of neuro-ophthalmology : the official journal of the North American Neuro-Ophthalmology Society 2019; (39(1)):125-126 doi:10.1097/WNO.0000000000000698.

    PMID: 30052553
  18. 18

    Diagnosis of giant cell arteritis using clinical, laboratory, and histopathological findings in patients undergoing temporal artery biopsy.

    Muniz Castro HM, Bhattacharjee MB, Chaudhry IA, et al.

    Clinical neurology and neurosurgery 2022; (221()):107377 doi:10.1016/j.clineuro.2022.107377.

    PMID: 35932586
  19. 19

    Stroke Risk Before and After Central Retinal Artery Occlusion in a US Cohort.

    Chodnicki KD, Pulido JS, Hodge DO, et al.

    Mayo Clinic proceedings 2019; (94(2)):236-241 doi:10.1016/j.mayocp.2018.10.018.

    PMID: 30711121
  20. 20

    SUDDEN VISION LOSS FROM CENTRAL RETINAL ARTERY OCCLUSION AS A PRESENTING SYMPTOM OF MITRAL VALVE PAPILLARY FIBROELASTOMA.

    Henao M, Chamchikh J, Chalam KV

    Retinal cases & brief reports 2022; (16(1)):95-98 doi:10.1097/ICB.0000000000000915.

    PMID: 31574007
  21. 21

    Cardiovascular Risk Factors in Central Retinal Artery Occlusion: Results of a Prospective and Standardized Medical Examination.

    Callizo J, Feltgen N, Pantenburg S, et al.

    Ophthalmology 2015; (122(9)):1881-8.

    PMID: 26231133
  22. 22

    Acute Vascular Ischemic Events in Patients With Central Retinal Artery Occlusion in the United States: A Nationwide Study 2003-2014.

    Mir TA, Arham AZ, Fang W, et al.

    American journal of ophthalmology 2019; (200()):179-186 doi:10.1016/j.ajo.2019.01.009.

    PMID: 30689989

This page explains CRAO symptoms and diagnostic procedures for educational purposes. Sudden vision loss is a medical emergency; seek professional medical care immediately.

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