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Vision Loss. KHADER M.FARWAN. Objectives. Review of eye anatomy Refine history and examination of the eye Work through emergent causes of sudden monocular vision loss in a case-based format. Spelling Review. Op h th a lmology. Anatomy Review. Function & transperancy. Anatomy Review.

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Vision Loss


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    1. Vision Loss KHADER M.FARWAN

    2. Objectives • Review of eye anatomy • Refine history and examination of the eye • Work through emergent causes of sudden monocular vision loss in a case-based format

    3. Spelling Review Ophthalmology

    4. Anatomy Review Function & transperancy

    5. Anatomy Review

    6. Anatomy Review • Eyelids • Tears • Cornea • Aqueous • Lens • Vitreous

    7. Anatomy Review • Retina • Fovea / “Macula” • Central retinal artery supplied by branch of ophthalmic artery (1st major branch of internal carotid)

    8. Anatomy Review • Optic nerve or retinal lesions do not respect vertical meridian • Defects that clear or start at vertical midline signify lesion at chiasm or beyond http://eyesite.ucsd.edu/viewpoint/images/glaucoma.jpg

    9. Vision Loss • Categorization • Total or Partial • One or Both eyes • Sudden or Gradual • Painful or Painless

    10. History • Question Danger Signs • How long ago? Recent • How sudden? Sudden: ischemia or bleed • Course? Worsening

    11. History • What do they see? • Flashes or floaters • “Curtain” rising or falling • Central patch or distortion • Key symptoms • Pain or headache • Nausea / Vomiting

    12. History • In addition to general Hx/Px: • Usual corrective glasses / contacts? Still in? • Previous transient episodes? • Trauma?

    13. Examination • Visual acuity • Visual field testing • Swinging light test • Direct ophthalmoscopy • Dilating the eye • Tonometry

    14. Examination • Visual acuity • Snellen chart • 20 feet distance • Credit for a line if most letters correctly identified • If acuity poorer than largest letter (eg 20/200), measure distance pt can read it (eg 5/200 at 5 feet)

    15. Examination • Visual acuity • Practically, if that poor, acuity described by • Finger-counting • Hand-motion • Light perception

    16. Examination • Visual acuity To correct refractive error: • Use pin hole • Use ophthalmoscope

    17. Examination • Visual field testing • Confrontation • With the patient looking at your nose, ask if your nose and other facial features are seen clearly • Inability to clearly see your: Nose => central scotoma Eyes or lips => paracentral scotoma Ears => peripheral visual field defect

    18. Examination • Swinging light test • Relative Afferent Pupillary Defect (RAPD) • See http://www.richmondeye.com/apd.htm • “Marcus-Gunn Pupil” • Significant retinal or optic nerve disease, in one eye more than the other • Very helpful for Ophtho to know in consult

    19. Examination • Direct ophthalmoscopy • Close as possible • Remove your glasses • Switch viewing eye • Start at zero correction • Or to correct observer refraction (eg – 4 diopters) • Rotate counter-clockwise for near-sighted pt Better use of the ophthalmoscope. Luff A, Elkington A. Practitioner. 236(1511): 161-5

    20. Examination • Direct ophthalmoscopy • Red Reflex • Compare brightness and color at 1-2 feet • Indicates media free of opacity • Not always easy to do, helpful if (N) • “Eight-ball” Vitreous hemorrhage • Move in along line of red reflex • Aim for opposite mastoid process • Often brings optic disc straight into view

    21. Examination • Direct ophthalmoscopy • Place free hand on forehead • Prevents facial contact • Resting own forehead on thumb stabilises image • Able to lift upper lid if necessary • Comfort • Encourage subject to keep breathing during examination • Sit patient up, avoid hunching

    22. Examination • Direct ophthalmoscopy • Use anti-glare filter • Try red-free filter for better vessel visualization

    23. Examination • Direct ophthalmoscopy • PanOptic Ophthalmoscope • Greater field of view • “5x larger view of fundus” • USD $400 range

    24. Anatomy Review Optic disc • Color: Yellow-orange, central cup whiter • Size: Cup less than half diameter of disc • Margin: Sharp (may be less sharp nasally) imc.gsm.com/integrated/ bcs/heent/page14.html

    25. Anatomy Review Fovea / “Macula” • Color: Slightly darker, devoid of retinal vessels • Size: Same as disc • Location: Temporal and slightly inferior to disc imc.gsm.com/integrated/ bcs/heent/page14.html

    26. Anatomy Review Vessels • Size: 3:2 Vein:Artery • Caliber: look for abnormal tortuosity • 4 main vascular arcades • Superior- & Inferior- • Nasal & Temporal Cilioretinal artery imc.gsm.com/integrated/ bcs/heent/page14.html

    27. Examination • Direct ophthalmoscopy • Four quadrant scan • Follow vessels to periphery (may need to re-focus) • Get pt to look at the light to see macula

    28. Examination • Dilating the eye • Especially important for suspected • Intraocular FB • Central retinal artery occlusion • Retinal detachment • Hesitancy amongst non-ophthalmologists

    29. Examination • Dilating the eye Tropicamide 1% Mydriasis and glaucoma: exploding the myth. A systematic review. Pandit RJ, Taylor R. Diabet Med. 2000 Oct;17(10):693-9 “Risk of inducing acute glaucoma following … tropicamide alone close is to zero, no case being identified” Near fatal anticholinergic intoxication after routine fundoscopy. Brunner GA, et al. Intensive Care Med. 1998 Jul;24(7):730-1.

    30. Examination • Dilating the eye Tropicamide 1% Contraindications: • Acute head injury/coma • Acute or intermittent angle-closure glaucoma (but NOT chronic open-angle glaucoma) • Probably anyone at high risk for above (eg. Older asian lady, severely far-sighted person)

    31. Examination • Dilating the eye Tropicamide 1% • Onset 10-15 mins, duration 4-6 h • Side effects: blurred vision, light sensitvity • Safety: must not drive for 6 h The effect of pupil dilation with tropicamide on vision and driving simulator performance. Potamitis, T., et al. Eye. 2000 Jun;14 (3A):302-6

    32. Examination • Tonometry Tonopen • Contraindicated if suspected ruptured globe • Ttono = 10 – 21 mm Hg (N) • False elevation IOP • Blepharospasm (“squeezers”) • Avoid pressure on the eye by holding eyelids only against bony orbital rim

    33. Case 1 SUDDEN, TOTAL LOSS, ONE EYE • 70 yo F with HTN, DM lost vision in one eye over a few minutes earlier this morning. • No trauma. No eye pain, or N/V • Findings: • (N) External eye and EOM, red reflex • (N) Acuity on left, only hand motion right • RAPD+ • (N) Fundoscopy unaffected eye

    34. Case 1 • Retina pale • “Cherry Red Spot” fovea • Splinter hemorrhage Clinical Eye Atlas

    35. Case 1 • Diagnosis? • Treatment? • Massage eyeball • Timoptic drops • Sticking a needle in the eye Clinical Eye Atlas

    36. Central Retinal Artery Occlusion • Sudden painless monocular loss of vision • May have history of previous transient episodes. “Amaurosis fugax” http://meded.ucsd.edu/isp/1994/im-quiz/images/crao.jpg

    37. Central Retinal Artery Occlusion • Retina infarction => pallor, edema, less transparency • Irreversible damage begins at 90 mins http://meded.ucsd.edu/isp/1994/im-quiz/images/crao.jpg

    38. Central Retinal Artery Occlusion • Macula, thinnest portion, remains visible • Cherry red spot may take 24 h to develop • Visual acuity may be normal if cilioretinal vessel patent http://www.umanitoba.ca/faculties/medicine/units/ophthalmology/tutorial_folders.html/images/Cra.jpg

    39. Central Retinal Artery Occlusion • Causes • Embolic (carotid, cardiac) • Thrombosis • Temporal arteritis • Vasculitis (eg. lupus) • Sickle cell disease • Trauma www.emedicine.com/emerg/ images/521crao1.JPG

    40. Central Retinal Artery Occlusion • Treatment Attempt moving embolus distally: • Digital massage • Firm steady pressure x 15 seconds, release, repeat • IOP lowering drugs • Beta-blockers/CAI/alpha-agonists… • +/- Vasodilation techniques • Rebreathing to increase PaCO2

    41. Central Retinal Artery Occlusion • Treatment • Consult ophthalmology immediately • Paracentesis anterior chamber • ?? HBO, thrombolytics • Locate source • ESR for temporal arteritis • ECG for A. fib • Medicine consult (Carotid doppler, ECHO?…)

    42. How to Tap an Eye Anterior chamber paracentesis • Administer local anesthesia • Use a 30-gauge needle on a tuberculin syringe • Enter the eye at the limbus with bevel up • Ensure that the needle does not damage the lens • Withdraw fluid until the anterior chamber shallows slightly (0.1-0.2 cc) • Administer a topical antibiotic post-procedure http://www.emedicine.com/oph/topic387.htm

    43. Central Retinal Artery Occlusion • Complications • Vision loss • Prognosis poor in most • But up to 10% retain central vision (acuity improves to 20/50 or better in 80% of those) • Recurrent thromboemboli • CVA • Further visual loss to same or contralateral eye • Progression of temporal arteritis

    44. Case 2 PARTIAL LOSS, ONE EYE • A 60 yo M with HTN and DM complains of progressive loss of vision in one eye over the last 2 days. • No other symptoms • Painless uniform dulling of vision. • Findings: • (N) External eye and EOM • Acuity 20/25 OD, 20/200 OS • RAPD+ • (N) Fundoscopy unaffected eye

    45. Case 2 How would you manage this at 2 AM? • Immediate ophtho consult • Thrombolytic therapy • Decrease the intraocular pressure • Globe massage to dissolve clot • None of the above Clinical Eye Atlas

    46. Case 2 Unmistakable fundoscopy: • “Blood and Thunder” or “Ketchup fundus” • Dilated tortuous veins • Flame hemorrhages • Disc edema Clinical Eye Atlas

    47. Central Retinal Vein Occlusion • Key facts • 10 times more common than CRAO • Painless monocular loss of vision over hours to days • Vision may improve through the day • ? CRV impingement by lamina or atherosclerosis of CRA • Ischemic vs. non-ischemic types

    48. Central Retinal Vein Occlusion • Risk Factors • Age > 50 • Diabetes • HTN • Hyperviscosity syndromes • Glaucoma • Recurrent amaurosis fugax http://www.umanitoba.ca/faculties/medicine/units/ophthalmology/tutorial_folders.html/images/CRV_occlusion

    49. Central Retinal Vein Occlusion Non-ischemic • Good vision • RAPD absent • Fewer retinal hemorrhages • Cotton-wool spots • May resolve fully or progress to ischemic type http://webeye.ophth.uiowa.edu/dept/crvo/fig12.htm

    50. Central Retinal Vein Occlusion Ischemic • Severe visual loss • RAPD+ • Extensive retinal hemorrhage and cotton-wool spots http://webeye.ophth.uiowa.edu/dept/crvo/fig12.htm