The_Eye

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					The Eye
     Ocular Pursuit

    “Eye wanna win”
           but
“There is no eye in team”
                   History
• Trauma
    – Consider unrecognized trauma- awoke with
      symptoms
•   Pain? Itch? FB sensation?
•   Visual acuity changes, halos
•   Contact lenses- ? Overwear
•   Sick contacts/Viral symptoms
•   Prior surgery or eye disorders
•   Systemic disease
                    Eye
                     exam
          (the basics.
From a non-ophthalmologist
           who isn’t particularly
                                good
                      at examining eyes.)

    if you can read this last line I’ll eat my shoe right here and now.
                      Eye exam
•   Visual acuity
•   Visual fields
•   Pupil shape and reactivity
•   Lid closure
•   Foreign bodies
•   Ciliary flare
•   Foggy cornea (edema)
•   Corneal infiltrate
•   Fluorescein- corneal defects, Sidel’s sign
•   Anterior chamber cells
•   Intraocular pressure
               Visual Acuity
• Snellen Chart
• Use corrective lenses (or pinhole)
• Examine each eye separately
• If can’t read largest letter, go to finger
  counting
• If can’t count fingers, check motion
  perception
• If no motion perception, go to light
  perception
  Abbreviations which will impress
         your chart reader
• OS – Left eye

• OD – Right eye

• OU – Both eyes

• VA – Visual acuity
   Ocular Pursuit Question #2
• What does the latin abbreviation OS stand
  for?
            More Abbreviations
•   L/L/L – Lids, lashes, lacrimal
•   C/S – Conjunctiva and Sclera
•   K – Cornea
•   AC – Anterior Chamber
•   I – Iris
•   L – Lense
•   AV – Anterior Vitreous
•   CF – Count Fingers
•   HM – Hand motion
•   LP – Light perception
         Match the nerve with the
           extraocular muscle!
• Extraocular Muscle   • Cranial Nerve

•   Superior Oblique   • VI
•   Superior Rectus
•   Lateral Rectus     • III
•   Medial Rectus
•   Inferior rectus    • IV
•   Inferior oblique
         Pupillary Reactions
• Patient looks in the distance

• Hold light in front of eye #1 for 3-5
  seconds, then swing to the other eye

• Should get initial constriction, then dilation
           Anterior – posterior
• Lids, lashes

• Conjunctiva, sclera, cornea

• Evert eyelids

• Anterior chamber

• Retina
Intraocular Pressure Measurement
• Tonopen – need to calibrate first

• Normal measurements 10 – 21 mmHg
       Approach to Ophthalmic
            Emergencies
• Diagnostic Category – trauma, vascular,
  infectious, inflammatory, chemical
  exposure
• Location - extraocular and periorbital,
  conjunctiva, sclera, cornea, anterior
  chamber, lens, posterior chamber, retina,
  vascular
• Symptom
          Symptom approach
•   1. Vision loss
•   Painless
•   Painful
•   2. Eye pain
•   3. Red eye and discharge
•   4. Double vision
          Painless Vision Loss
•   Retinal Detachment
•   Central Retinal Artery Occlusion
•   Central Retinal Vein Occlusion
•   Vitreous hemorrhage
•   Occipital lobe TIA/CVA
•   Toxins (Methanol)
Central Retinal Artery Occlusion
• Anatomy

• Internal Carotid Artery –
        – Ophthalmic Artery
           » Central Retinal Artery
CRAO
                  History
• Sudden, painless, monocular blindness

• Most of the visual field - worse in the
  central visual field
                  Causes
• Emboli – most common

• Vasculitidies (temporal arteritis)

• Trauma
EMERGENCY!!!
         Yes. True. But…
• Loss of vision may be irreversible within
  90 minutes. Needs emergent
  ophthalmology referral.
• Unfortunately… not much evidence for any
  therapeutic interventions. Studies tend to
  be small, not one center, without
  significant change in long term vision.
      Therapies (you can try)
• Hemodilution – bolus 1-2 liters of normal
  saline
• Ocular massage – closed lids – 10 -15
  seconds – sudden release of pressure
• Rebreathing CO2 – paper bag strategy
• Intra-arterial thrombolysis
• Anterior Chamber paracentesis –
  tetracaine – 30 guage needle – aspirate
  0.1 ml.
             Bottom line…
• Call the opthalmologist immediately if you
  suspect this diagnosis.

• Post CRAO immediate window – treat like
  TIA – need to look at risk factors (HTN,
  dyslipidemia, diabetes, smoking), carotid
  doppler U/S, look for Atrial fibrillation.
 Central Retinal Vein Occlusion
• Again, sudden, painless, monocular vision
  loss

• More common than CRAO (CRVO
  prevalence ~ 1%, compared to ~ 1/10000
  for CRAO)

• Ischemic and non-ischemic variants
Central Retinal Vein Occlusion
Branch Retinal Vein Occlusion
 More treatments that may (or may
          not) be helpful
• Aspirin

• Intravitreal t-PA

• Surgical options

• Treat underlying disease
   Which of the following ocular
    problems is most commonly
             associated
with a patient report of “curtain-like”
            vision loss?
•   A. Vitreous hemorrhage
•   B. Retinal detachment
•   C. Optic neuritis
•   D. Central retinal artery occlusion
Retinal Detachment
         Retinal Detachment
• Acute or subacute monocular vision loss

• Floaters

• Peripheral vision loss

• Patients might describe “curtain like” visual
  loss
             Retinal Detachment
•   Occurs in 1/300 over the course of a lifetime
•   Risk factors:
•   Age
•   Previous cataract surgery
•   Focal retinal atrophy
•   Myopia
•   Trauma
•   Diabetic retinopathy,
•   Family history of retinal detachment
•   Uveitis
•   Prematurity
          If you suspect it…
• Immediate ophthalmology consultation

• Surgical options

• Laser treatment of tears –
       Vitreous Hemorrhage
• History – painless, monocular vision loss

• Patients may describe “haze”, “smoke”,
  “streaks”
       Vitreous Hemorrhage
• Causes:

• Diabetic retinopathy
• Posterior vitreous detachment
• Trauma (shaken baby)
        Vitreous Hemorrhage
• Consult ophthalmology:
• Will look for any retinal tears which could
  be mended
• Coag studies
• Avoid exertional activities which could
  increase IOP
                  Doctor…
• My eye hurts!



• And I can’t see out of it!
Optic Neuritis
             Physical exam
• Pain with eye movements

• Afferent pupillary defect

• May see optic disc swelling on fundoscopy
             Optic Neuritis
• Inflammatory demyelination of the optic
  nerve

• Most common in 20-40 year old women

• Association with multiple sclerosis
                 Imaging
• MRI:

• Optic nerve inflammation
• Periventricular white matter lesions
  somewhat predictive of MS
              Treatment
• Generally improves spontaneously over
  days – weeks

• ?Steroids – may decrease progression to
  MS – talk to Neurology
Which of the following is one of the
 diagnostic criteria for temporal
             arteritis?
•   A. Bounding temporal artery pulse
•   B. Erythrocyte sedimentation rate of > 20
•   C. New headache
•   D. Age > 70
          Temporal Arteritis

• Medium/large vessel vasculitis

• Carotid artery branches

• Disease of the elderly
            Physical Exam
• Palpate – firm, tender temporal artery

• Joint pain with movement

• Visual acuity
                  Diagnosis
• Age > 50
• New Headache
• Abnormalities of the temporal artery (tender,
  pulseless)
• ESR > 50
• Positive biopsy

• 3/5 positive findings give sensitivity of 93% and
  specificity of 91%
              Treatment
• Consult Ophtho and/or Rheumatology

• High dose steroids
          Amaurosis Fugax
• Transient monocular vision loss (minutes)

• TIA of the eye

• Neurology consult
  Name the phenomenon
demonstrated in this picture
          Cortical Blindness
• Think about it in the patient with vision loss
  and the absence of eye pathology

• Occipital lobe insults, vertebrobasilar
  infarcts

• Usual stroke treatment
Question – name 3 causes of this
            condition
Lateral Canthotomy/Cantholysis
• Procedure to decompress a compartment
  syndrome of the orbit
Retro-orbital hematoma
        Primary Indications
• Decreased visual acuity

• Intraocular pressure > 40 mmHg

• Proptosis
          Contraindication
• Globe rupture
    The things you’ll need to do your
            very own lateral
        canthotomy/cantholysis
•   1. Lidocaine with epinephrine
•   2. Syringe with 25-gauge needle
•   3. Hemostat or needle driver
•   4. Iris or suture scissors
•   5. Forceps
                   Step 1
• Prep skin

• Anaesthetize – lido with epi into lateral
  canthus
                 Step 2
• Apply needle driver or hemostat from
  lateral canthus to bony orbit to
  devascularize the area for 30 – 90
  seconds.
                 Step 3
• Remove the hemostat and cut the
  demarcated area 1 – 2 cm laterally
                   Step 4
• Use the forceps to pull down the lower
  eyelid until you can see the inferior lateral
  canthal tendon
• Cut through it
                 Step 5
• Reassess IOP
• If still greater than 40 mmHg haven’t
  provided adequate pressure relief:
• Expose the superior lateral canthus and
  cut this too.
Congratulations!
      What is the mechanism of
    action for fomepizole (4-MP) in
             the treatment
      of acute methanol toxicity?
•   A. Active diuresis of methanol through the kidney
•   B. Enhanced hepatic conversion of the toxic methanol molecule
•   through CYP 450 3A
•   C. Competitive elimination with bile
•   D. Competitive inhibition of alcohol dehydrogenase
•   E. Inhibits blood flow through affected organs by the angiotensin
•   pathway
  Examination of a ruptured globe
 with fluorescein may demonstrate
displacement of the fluorescein due
       to aqueous humor flow.
     This has been named the:
•   A. Seidel test.
•   B. Adie’s pupil.
•   C. Gunn’s phenomenon.
•   D. Hoover’s test.
        Intraocular pressures
     associated with acute angle
        glaucoma tend to be:

•   A. > 7 mmHg.
•   B. > 14 mmHg.
•   C. > 21 mmHg.
•   D. > 28 mmHg.
Chemical burns to the eye are true
  ophthalmologic emergencies.
             Generally
speaking, which class of chemicals
 typically causes more damage?
•   A. Acids
•   B. Bases
•   C. No difference
•   D. pH 7.4
    What is the hallmark finding of
     vertebrobasilar syndrome?
•   A. Crossed neurologic deficits
•   B. Unsteady gait
•   C. Afferent pupilary defect
•   D. Bitemporal hemianopsia
•   E. “Cherry red” macula
Name that Finding/Disease!
Epidemic keratoconjunctivitis
Nodular episcleritis
Scleritis
Acute Angle-Closure Glaucoma
  Acute angle closure glaucoma
• Acute angle closure glaucoma has at least 2 of the
  following
• symptoms:
• • ocular pain
• • nausea/vomiting
• • history of intermittent blurring of vision with halos
• And at least 3 of the following signs:
• • IOP > 21 mmHg
• • conjunctival injection
• • corneal epithelial edema
• • mid-dilated nonreactive pupil
• • shallow chamber in the presence of occlusion
                        References
• Basic Ophthalmology – 7th edition. Cynthia Bradford. American
  Academy of Opthalmology.
• Med Clin N Am 90 (2006) 305–328
• Emerg Med Clin N Am
  26 (2008) 233–238
• Ophthal Plast Reconstr Surg. 1994 Jun;10(2):137-41. Efficacy of
  lateral canthotomy and cantholysis in orbital hemorrhage
• CJEM 2002;4(1):49-52
• Cochrane Database Syst Rev. 2009 Jan 21;(1):CD001989.
  Interventions for acute non-arteritic central retinal artery occlusion.
• Emergency Medicine Reports. Volume 29, Number 17. August 4,
  2008.

				
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posted:2/12/2012
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