RETINAL ARTERY OCCLUSIONS CRAO BRAO CLRAO

Retinal artery occlusion is a blockage in one or more of the arteries that carry blood to the retina.

Central Retinal Artery Occlusion (CRAO) is an ophthalmic emergency which is analogous to a cerebral stroke. It is caused by sudden, painless monocular vision loss.

Branch Retinal Artery Occlusion ( BRAO )
Cilio-retinal Artery Occlusion ( CLRAO )

1. RETINAL ARTERY OCCLUSION BRAO, CRAO, CLRAO PRESENTOR : ASHISH NEUPANE BACHELOR OF OPTOMETRY NEPAL EYE HOSPITAL, NAMS

2. ARTERIAL SUPPLY OF THE RETINA

3. Inner 6 layers - Central retinal artery Outer 4 layers - Posterior ciliary arteries -Anterior to equator - long posterior ciliary arteries -Posterior to equator - short posterior ciliary arteries In some individuals, cilioretinal artery supplies the macular area.

4. RETINAL ARTERY OCCLUSIONS EPIDEMIOLOGY Age : Mid 60’s Gender : M>F Medical conditions : Hypertension and other cardiovascular diseases Laterality : Mostly U/L , 1-2% B/L

5. ETIOLOGY OF RAO Emboli : most common aetiology three types of emboli associated with RAO Cholesterol emboli (Hollenhorst plaque) -arise from atheromas in the carotid artery Calcium emboli - arise from the cardiac valves Platelet fibrin - arise from atheromas in the carotid artery

6. 2 . Atherosclerosis-related thrombosis : 3. Retinal arteritis with obliteration : Giant cell arteritis Periarteritis : associated with polyarteritis nodusa, systemic lupus erythematosus, wegner’s granulomatosis and scleroderma 4. Angiospasm : - Rare - commonly associated with amaurosis

7. 5. Raised IOP : 6. Thrombophilic disorders : 7. Other rare causes : retinal migraine, sickling haemoglobinopathies and hypercoagulation disorders such as oral contraceptives, polycythemia, and antiphospholipid syndrome

8. CLINICAL PRESENTATION CRAO (60%) BRAO (35%) CLRAO (5%)

9. CRAO Ocular Emergency Occurs due to obstruction at the level of lamina cribrosa

10. SYMPTOMS Sudden painless unilateral visual loss: occurs over seconds Amaurosis fugax: in around 10% of patients P ast medical history: atherosclerotic disease or vasculitis Symptoms of temporal/giant cell arteritis: headaches, temporal tenderness

11. SIGNS VA : markedly reduced (<3/60 in 90% cases) except in few cases with cilioretinal artery. 2. Pupillary reflex : RAPD +ve

12. 3. Fundus examination shows : Markedly narrowing of retinal arteries Retina becomes milky white due to ischaemic oedema Cherry red spot is seen in the center of macula Cattle truck appearance

13. video

14. So, findings in ophthalmoscopy reveals : In acute phase In chronic stage Cherry red spots (90%) Post. pole retinal opacity or whitening (58%) Box carring of retinal arteries and veins (20%) Retinal artery attenuation (32%) Optic disc edema (22%) Optic nerve head pallor (39%) Optic atrophy (91%) Retinal arterial attenuation (58%) Cilioretinal collaterals (18%) Macular RPE changes (11%) Cotton wool spots (3%)

15. INVESTIGATIONS : - CRAO is a clinical diagnosis, OCT - edema of inner retina

16. FFA - delayed in arterial filling ( if cilioretinal artery is present , it will fill in early phase ), masking of choroidal vasculature due to retinal opacification.

17. Autofluorescence imaging - reduced autofluorescence ERG - more severe attenuation of b-wave than a-wave Macular VF testing : Central scotoma is most common followed by paracentral scotoma.

18. Laboratory investigations Relevant laboratory investigations include: ESR and CRP: to exclude temporal/giant cell arteritis Full blood count: to check for myeloproliferative disorders or anaemia Coagulation studies : to screen for coagulation disorders

19. Other investigations If an embolic cause is suspected, other investigations to consider may include: Carotid duplex ultrasound (doppler): to look for carotid artery stenosis ECG: to look for atrial fibrillation Echocardiogram: to look for mural thrombus Ambulatory ECG monitoring: to look for paroxysmal atrial fibrillation

20. D/D Cherry red spot Sudden onset U/L painless visual loss Trauma - blunt trauma, concussion Neimann - pick disease Gaucher disease Tay sach disease Sandhoff disease Retinal detachment Vitreous haemorrhage Retinal vein occlusion Acute optic neuritis

21. MANAGEMENT RETINAL ISCHEMIC TIME 90 min - complete recovery can be done 240 min - partial recovery Irreversible after 4 hours

22. Principles of management of CRAO can be divided into : Acute : Restore blood flow Subacute : preventions of secondary complications Secondary prevention : Systemic control and prevention of future vascular ischemic events. T aiwan J Ophthalmol.  2022 Jul-Sep; 12(3): 273–281. Published online 2022 Aug 18. doi:  10.4103/2211-5056.353126

23. Acute management : Non-invasive therapies Invasive therapies Non- invasive therapies: Vasodilation of CRA : sublingual isosorbide dinitrate, inhaling carbogen, hyperbaric oxygen treatment (HBOT) Reducing the intraocular pressure : Ocular massage, IV mannitol, or topical antiglaucoma drops Reducing retinal edema : Taiwan J Ophthalmol.  2022 Jul-Sep; 12(3): 273–281. Published online 2022 Aug 18. doi:  10.4103/2211-5056.353126

24. Invasive therapies : Anterior chamber paracentesis Transluminal ND -YAG laser Pars plana vitrectomy IV and intra-arterial (IA) tissue plasminogen activator (tPA) Intravenous tissue plasminogen activator Taiwan J Ophthalmol.  2022 Jul-Sep; 12(3): 273–281. Published online 2022 Aug 18. doi:  10.4103/2211-5056.353126

25. 2. Sub-acute - preventing secondary ocular complication 3. Secondary prevention - systemic control and prevention of future vascular e vents Taiwan J Ophthalmol.  2022 Jul-Sep; 12(3): 273–281. Published online 2022 Aug 18. doi:  10.4103/2211-5056.353126

26. BRAO Represents 38% of all artery occlusion RE (60%) > LE (40%) Pt presents with monocular vision loss, which may be restricted to one part of VF Presenting VF defect includes : Central scotoma(20%) Central altitudinal (13%) Sector defect (49%)

27. BRAO cont... typically occurs at vessel bifurcation and 98% of time, temporal vessels are affected due to nasal occlusion may be asymptomatic and undetected emboli are visible in 62% of time

28. In chronic stage, sectorial nerve fibre loss and arterial attenuation may be seen, Rarely, iris neovascularization and posterior segment neovascularization particularly in DM patients Artery to artery collaterals are pathognomic of BRAO Risk factor for BRAO is similar to CRAO so similar evaluation is recommended Good visual prognosis so, aggressive therapy is not performed unless foveal involvement is seen

29. D/D of BRAO Artery Obstruction • Cotton–wool spot(s) • Central retinal artery obstruction • Cilioretinal artery obstruction • Retinal astrocytoma • Inflammatory or infectious retinitis

30. CLRAO Accounts for 5% of retinal artery obstruction On FA - they are seen 32 % of time and fill concomitantly with the choroidal circulation When evaluating CLRAO, 3 distinct groups are found : Isolated CLRAO CLRAO associated with CRVO CLRAO in conjunction with anterior ischemic optic neuropathy

31. Isolated CLRAO Usually occur in young patients in setting of collagen vascular disorders. Good visual prognosis CLRAO associated with CRVO Behaves as non-ischemic CRVO with good central vision prognosis Mechanism of association is unclear, But hypothesized that some eyes harbor a primary optic disc vasculitis(papillophlebitis) that affects both arterial and venous circulation

32. CLRAO with ischemic optic neuropathy Grim visual prognosis Strong association with temporal arteritis

33. Optometric Practice Patterns for Acute Central and Branch Retinal Artery Occlusion Abstract Background: Optometrists are often the first providers to evaluate patients with acute vision loss and are often the first to diagnose a central retinal artery occlusion (CRAO). How quickly these patients present to the optometrist, are diagnosed, and referred for evaluation are major factors influencing the possibility of acute therapeutic intervention. Our aim was to survey the U.S. optometric community to determine current optometric practice patterns for management of CRAO. Methods: An anonymous seven-question survey was emailed in 2020 to the 5,101 members of the American Academy of Optometry and the 26,502 members of the American Optometric Association. Mileski, Kelsey M. OD; Biousse, Valérie MD; Newman, Nancy J. MD; Flowers, Alexis M. MD; Chan, Wesley MD; Dattilo, Michael MD, PhD J ournal of Neuro-Ophthalmology ():10.1097/WNO.0000000000001915, September 21, 2023. | DOI: 10.1097/WNO.0000000000001915

34. Results : Of 31,603 optometrists who were sent the survey, 1,926 responded (6.1%). Most respondents (1,392/1,919, 72.5%) worked in an optometry-predominant outpatient clinic and were less than 30 minutes from a certified stroke center (1,481/1,923, 77.0%). Ninety-eight percent (1,884/1,922) of respondents had diagnosed less than 5 CRAOs in the previous year, and 1,000/1,922 (52.0%) had not diagnosed a CRAO in the prior year. Of the optometrists who diagnosed at least one CRAO in the previous year, 661/922 (71.7%) evaluated these patients more than 4 hours after the onset of vision loss. Optometrists who diagnosed a CRAO or branch retinal artery occlusion referred patients to an emergency department (ED) affiliated with a certified stroke center (844/1,917, 44.0%), an outpatient ophthalmology clinic (764/1,917, 39.9%), an ED without a stroke center (250/1,917, 13.0%), an outpatient neurology clinic (20/1,917, 1.0%), or other (39/1,917, 2.0%); most (22/39, 56.4%) who responded "other" would refer to a primary care physician. J Neuroophthalmol. 2023 Sep 21. doi: 10.1097/WNO.0000000000001915 Mileski, Kelsey M. OD; Biousse, Valérie MD; Newman, Nancy J. MD; Flowers, Alexis M. MD; Chan, Wesley MD; Dattilo, Michael MD, PhD

35. Conclusions : Optometrists are likely the first providers to evaluate patients with acute vision loss, including from a retinal artery occlusion. However, only 6.1% of optometrists responded to our survey despite 2 reminder emails, likely reflecting the lack of exposure to acute retinal artery occlusions, and a potential lack of interest of optometrists in participating in research. Of the optometrists who reported evaluating a CRAO in the previous year, less than 29% saw the patient within 4 hours of vision loss. In addition, a large portion of optometrists are referring acute CRAO patients to outpatient ophthalmology clinics, delaying appropriate acute management. Therefore, it is imperative that optometrists and ophthalmologists are educated to view acute retinal arterial ischemia as an acute stroke and urgently refer these patients to an ED affiliated with a stroke center. The delay in patient presentation and these referral patterns make future clinical trials for acute CRAO challenging. J Neuroophthalmol   2023 Sep 21.   doi: 10.1097/WNO.0000000000001915 . Mileski, Kelsey M. OD; Biousse, Valérie MD; Newman, Nancy J. MD; Flowers, Alexis M. MD; Chan, Wesley MD; Dattilo, Michael MD, PhD

36. REFERENCES Clinical ophthalmology - Jack J Kanski Comprehensive ophthalmology - AK Khurana Ophthalmology 5th edition -Myron Yanoff and JAY S. Duker American academy of ophthalmology