Central Retinal Artery Occlusion (CRAO):

81-year-old white male with sudden, painless vision loss in left eye

Central Retinal Artery Occlusion (CRAO):

81-year-old white male with sudden, painless vision loss in left eye

---

Chief Complaint: 81-year-old white male with sudden, painless vision loss OS.

History of Present Illness: The patient described a sudden black spot in his vision that spread out over his complete visual field OS over a 15-minute time frame. He drove directly to his optometrist. The optometrist documented visual acuities of 20/40 OD and light perception (LP) vision OS. It was noted that the patient had a normal fundus examination. The patient was sent to the University of Iowa for further evaluation on the following day.

PMH/FH/POH: coronary artery disease s/p CABG & balloon angioplasty, right carotid endarterectomy (1980s), left carotid stenting (endovascular) recently with transient right hemiparesis (resolved). No history of ocular surgeries or trauma. MEDS: ASA, Plavix, nitroglycerine PRN and alfalfa pills

ROS: denied headaches, jaw claudication, scalp tenderness, weight loss, and loss of appetite

EXAM

• Best corrected visual acuities: 20/30 OD and HM OS.
• Pupils: greater than 2.5 LU RAPD OS.
• GVF: full OD. Small inferior island of V4e OS.
• EOM: full OU
• Anterior segment: mild nuclear sclerosis cataracts OU
• Fundus: normal OD, see photos OS

Figure 1: DFE OS. This montage fundus photograph of the left eye demonstrates the cherry red spot typical of a central retinal artery occlusion (CRAO). There is also an exudate and hemorrhage superior to the disc and changes in the vasculature that are shown in more detail below.

Figure 2: Details of the dilated examination OS.

Closer view of the optic nerve.	Arteriolar Dropout
There is an exudate and hemorrhage superior to the disc (arrowhead). The vessels also show some attenuation and their normally smooth appearance is irregular, especially in the superior-temporal arcade. Optic nerve is normal in appearance.	There is "box-carring" of the flow through the small vessel nasal to the hemorrhage (arrowhead).
Box-Carring of Vessel	Angiography
There is "box-carring" of the flow through the small vessel nasal to the hemorrhage (arrowhead). This is a magnified view of the photo above.	FFA images at 1:00 minute demonstrating very poor filling. The earliest filling that occurred on the angiogram was not until 21 seconds.

Discussion

The patient’s classic description of painless, sudden loss of vision one day prior to presentation, and the appearance of the "cherry-red spot" on fundus examination made the diagnosis of a central retinal artery occlusion (CRAO). This elderly patient had a history of coronary artery disease s/p bypass surgery as well as carotid vascular disease treated with an endartectomy on the right in the 1980s; and more recently, endovascular stenting of the left carotid, the same side as the CRAO. We believed that the CRAO was likely to have been caused by the carotid disease. Our differential diagnoses included carotid artery dissection, stent thrombosis, carotid artery restenosis, or an arteriole embolism, for example from the carotid or less likely, a cardiac source. Although our patient had a negative review of systems for giant cell arteritis, 5-10% of CRAOs are associated with giant cell arteritis (Walsh and Hoyt). A STAT erythrocyte sedimentation rate and c-reactive protein was performed and both were normal.

We elected to continue the patient’s aspirin and plavix. In the acute presentation of a CRAO, some interventions are recommended to attempt to restore blood flow to the retina. These maneuvers include ocular-digital massage with or without an anterior chamber paracentesis, and with or without oral medications such as acetazolamide to lower the intraocular pressure. The theory behind ocular-digital massage is that the steep increase in pressure followed by a sudden return to normal pressure may act to plunge an embolus farther along the vascular pathway into a distal branch with potentially less catastrophic compromise to the retinal blood supply. The patient should be educated on the use of ocular-digital massage for the contralateral eye if a second CRAO occurs. The anterior chamber paracentesis and oral medications act to lower intraocular pressure and may help to relieve any compression of the vasculature. Some may argue that even in this case of presentation greater than 24 hours after onset, the less invasive procedures should be tried because they could have some benefit. However, Dr. Hayreh has demonstrated that irreversible damage occurs after as little as 100 minutes of occlusion and more recently has demonstrated that greater lengths of time of occlusion (from 97 minutes to 240 minutes) are associated with more damage histopathologically (Hayreh 1980, 2004). Given that the patient presented to us 29 hours after the onset, we did not perform these interventions. However, we did obtain consultation by our neurology Stroke Service. They continued the patient’s aspirin and plavix, admitted the patient to the hospital, and performed an angiogram to evaluate the carotid circulation. This demonstrated a left carotid dissection at the site of the carotid stent. Interventional radiology then placed a telescoping stent over the site of the dissection. The patient will require carotid ultrasound every 6 months to monitor for stenosis or development of new dissection.

Diagnosis: Central Retinal Artery Occlusion (CRAO)

EPIDEMIOLOGY Age > 40 years old. Risk factors may include: hypertension, hypercholesterolemia, diabetes. vascular disease, prior myocardial infarction, cardiac stenting procedures, transient ischemic attacks, and stroke. CRAO may occur in younger patients with systemic disease such as collagen vascular diseases, hypercoagulopathies, or cardiac valvular disease. Rarely it can occur in association with syphilis, sickle cell disease, or because of prolonged ocular compression, as in the case of a patient in a drug induced state in which the patient slumped over face-down and compressed his eye with his own knee for a prolonged period of time (Appen 1975). CRAO is associated with giant cell arteritis in 5-10% of cases.

SIGNS Cherry red spot: The lack of arterial perfusion to the inner layers of the retina results in edema of the retinal nerve fiber layer and ganglion cell layer, which makes it appear opaque. The inner retina is multi-layered throughout the posterior pole except at the fovea; thus, the retinal edema surrounds the fovea. In the fovea, the underlying choroid with intact RPE is visible and appears as a "cherry red spot" when compared to the cloudy, edematous retina adjacent to it. Vascular attenuation and/or "box-carring" of flow in arteries and veins. May see an embolus in vessel on optic nerve.

SYMPTOMS Sudden, painless loss of vision in one eye. May have a history of amaurosis fugax prior to presentation. Vision loss usually in the range of count fingers to hand motions. Unlikely to be no light perception.

TREATMENT Acutely can perform ocular-digital massage +/- anterior chamber paracentesis +/- give oral medications to lower intraocular pressure such as acetazolamide. Carbogen therapy, which is a carbon dioxide and oxygen combination, has been thought to help dilate vasculature and is used by some institutions. Hyperbaric oxygen therapy has also been described as a possible intervention. Even with these treatments, improvement in visual acuity is rare. To evaluate etiology, workup may include: -Neurology evaluation for workup and modification of risk factors. -ESR/CRP and giant cell arteritis review of systems. In the setting of giant cell arteritis, second eye involvement is preventable with high dose steroids. -carotid ultrasound to evaluate stenosis/plaque formation (+/- angiography). -EKG for evaluation of arrhythmias. -cardiac echography to evaluate for embolic source or patent interatrial shunt. -CBC, PT/PTT, consider ANA, syphilis serology if indicated. Modify risk factors with: diet modification, treat hypercholesterolemia, treat hypertension, and treat diabetes. Consider treatment with a daily aspirin.

Differential Diagnoses for Cherry-Red Spot

• Central Retinal Artery Occlusion (CRAO)
• Tay-Sachs disease
• GM1 gangliosidosis
• Niemann-Pick disease
• mucolipidosis