Widefield imaging plays role in diagnosis, management of central retinal artery occlusion
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The central retinal artery is one of the main arterial supplies for the retina. It pierces the eyeball close to the optic nerve and within the dural sheath, and it branches and supplies the inner retinal layers.
Central retinal artery occlusion (CRAO) is not uncommon, and it has various predispositions. The incidence of CRAO is 1 to 10 persons per 100,000. When the blood flow is interrupted for longer than 4 hours, retinal damage is usually massive, and vision loss is usually irreversible. In this column, we describe a patient who developed CRAO following acute migraine and his recovery with prompt treatment.
Source: Shaina Saroya, MS, Dhivya Ashok Kumar, MD, FRCS, FICO, FAICO, and Amar Agarwal, MS, FRCS, FRCOphth
Case summary
A 49-year-old man presented to the outpatient department with sudden painless onset of blurred vision in his right eye for the past 4 hours with an ongoing right-sided migraine attack for the past 4 days. The patient was taking tablet sumatriptan, domperidone, omeprazole and paracetamol, and he was suffering from migraine with aura.
Ocular examination showed visual acuity of counting fingers at 1 m in the right eye and 6/6 in the left eye. On examination of the right eye, the anterior segment was quiet with relative afferent pupillary defect. On fundus examination, the optic disc appeared to be normal with an indistinct developing cherry-red spot surrounded by distinct retinal whitening due to retinal edema at the posterior pole (Figure 1). On examining the peripheral retina (Mirante SLO/OCT, Nidek), distinct areas of retinal whitening, arteriolar attenuation, empty white sclerosed terminal arteries and segmentation of blood (cattle trucking) in a few vessels were noted, leading to the diagnosis of CRAO (Figure 2). Widefield fundus imaging was performed and documented (Figure 1).
The patient was immediately given two tablets of acetazolamide 250 mg followed by 30 minutes of digital ocular massage with enough pressure in the ratio of 15:5 seconds. Optic disc pulsations were checked every 5 minutes, and paracentesis under aseptic precautions was performed. Three hours later, the patient’s vision improved to counting fingers at 5 m, and on the next day’s follow-up visit, the patient could read 6/6 in the right eye with normal pupil reaction. Fundus examination showed reperfusion of the vessels with the disappearance of areas of retinal whitening due to restored blood supply (Figure 3). Systemic evaluation, including HbA1c, blood pressure, C-reactive protein, complete blood count, erythrocyte sedimentation rate, lipid profile, carotid doppler and echocardiography, turned out to be normal.
Central retinal artery occlusion
The ocular equivalent of cerebral stroke is CRAO, which is the obstruction of the central retinal artery, resulting in retinal infarction and visual loss. CRAO is a kind of acute ischemic stroke that is characterized by rapid, severe, acute, painless, unilateral vision loss and is accompanied by considerable functional impairment. Older age, male sex, acute coronary syndrome, valvular disease, carotid artery disease, hyperlipidemia, hypertension, giant cell arteritis, cardiogenic emboli, smoking, diabetes, thromboembolic disease, retinal vasculitis or inflammation, systemic lupus erythematosus and migraine are all significant risk factors.
Migraine and CRAO
Migraine is linked to an increased risk for all forms of retinal artery occlusion, and migraine with aura is linked to an increased risk for retinal artery occlusion as compared with migraine without aura. Prolonged retinal vasospasm associated with migraine can cause retinal arteriolar blockage. Retinal arterioles contain enough muscle fiber to undergo vasoconstriction. It is also known that several powerful vasoconstriction substances, such as serotonin (5-hydroxytryptamine), are produced just before or during migraine attacks. During a migraine attack, retinal vasospasm has been seen, which can lead to ischemia and thus cause ganglion cell death.
Role of widefield imaging
Widefield imaging is highly useful to see the retinal surface for evaluation and follow-up. The clear image of the entire 163° field of view enables detailed evaluation of pathologies from the fovea to the extreme periphery. The Mirante multimodal imaging platform integrates multiple clinically significant imaging technologies into a single platform. With this device, clinicians have access to a wide range of imaging modalities including color fundus retinography (scanning laser ophthalmoscope), contrast angiography (fluorescein and indocyanine green angiography), green and blue fundus autofluorescence, OCT, OCT angiography and Retro mode technique. The Mirante multicolor scanning laser ophthalmoscope easily captures high-quality images of the posterior pole and widefield images even in the presence of media opacity. The field of view on a single wide image is adequate for documenting the findings of retinal vascular diseases.
Management and treatment
Once diagnosed, immediate management of CRAO is needed not only to restore vision but to manage risk factors that may lead to other vascular conditions. For any treatment to be effective, it must be implemented within the appropriate time frame. Glaucoma drugs aim to lower the IOP and increase the gradient across the optic nerve head. Massage with a three-mirror contact lens or digital massage helps in the disintegration of a thrombus or dislodge an occluding embolus into a more peripheral part of the retinal circulation. The combination of acetazolamide and ocular massage can decrease the IOP to as low as 5 mm Hg within a short period of time, helping to increase retinal perfusion. Anterior chamber paracentesis with a 27-gauge needle offers an inexpensive, quick and effective way to lower the IOP, leading to dilatation of the retinal arteries. Other treatment modalities include carbogen (95% oxygen and 5% carbon dioxide) inhalation, rebreathing of expired CO2 in a bag, thrombolysis by giving a thrombolytic agent, sublingual isosorbide dinitrate, hyperbaric oxygen, Nd:YAG laser arteriotomy and embolectomy. Smoking cessation, regular exercise and diet with a low glycemic index would reduce the risk for vascular disease.
Conclusion
CRAO is a serious eye condition that is linked to a number of serious systemic disorders. Systemic evaluation and investigation must be directed to ensure the diagnosis and treatment of these disorders. Prompt treatment can help in the reperfusion of the retina and thus salvage the vision of the patient. Fundus imaging using recent advancements such as scanning laser ophthalmoscope widefield photography can help in diagnosis, management and follow-up of such scenarios.
- References:
- Al-Moujahed A, et al. Am J Ophthalmol. 2021;doi:10.1016/j.ajo.2020.11.004.
- Cugati S, et al. Curr Treat Options Neurol. 2013;doi:10.1007/s11940-012-0202-9.
- Killer HE, et al. Retina. 2003;doi:10.1097/00006982-200304000-00023.
- Olson EA, et al. Mo Med. 2016;113(1):53-57.
- Yi SY, et al. Medicine (Baltimore). 2019;doi:10.1097/MD.0000000000017250.
- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, director of Dr. Agarwal’s Eye Hospital and Eye Research Centre, is the author of several books published by SLACK Books, sister company of Healio publisher Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at aehl19c@gmail.com; website: www.dragarwal.com.
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