Ophthalmology Pearls

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Ophthalmology Pearls
2010-10-07 09:28:03
Ophthalmology Pearls

Opththalmology Pearls
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  1. What do you treat elevated IOP with?
    • Elevated IOP is treated with:
    • -topical β-blockers
    • -intravenous mannitol
    • -topical α-adrenergic agonists
    • -oral, topical, or intravenous carbonic anhydrase inhibitors
  2. In a sickle cell patient, what drug do you NOT want to use in the case of a hyphema or any case of increased IOP?
    Carbonic anhydrase inhibitors will lower the aqueous pH in the anterior chamber, causing the red blood cells to sickle and become less flexible. This can clog the outflow through the trabecular meshwork and increase IOP.

    Care should be taken when using Mannitol too, because diuresis can lead to hypovolemia and subsequent changes in the morphology of red blood cells.
  3. You are evaluating a patient in the ED for the onset of an acute, severe headache and you believe the diagnosis is an acute angle closure glaucoma. What is the significance in this scenario of finding a pupil that reacts to light?
    On exam, AACG will usually present with a cornea that appears "steamy" or "hazy".

    The pupil will be mid-dilated and nonreactive. If the pupil reacts, the diagnosis should be reconsidered.

    (EMCNA, Vol. 26, pg. 35).
  4. What is a normal intraocular pressure reading?
    Typically 10 to 21 mm Hg

    (NEJM, Vol. 360, pg. 1113).
  5. What are the classic symptoms that should help suggest a possible Retinal detachment, a time-sensitive emergency encountered in the ED?
    The classic symptoms that should help point to a possible RD are “flashing lights”, ”floater” complaint, “curtain-like or cloudy” painless vision loss, and peripheral shadowing (JEM, 11/09, Pg. 415).
  6. Emergency department evaluation of diplopia is largely based on a comprehensive history and should always include the following questioning with documented findings:
    • 1. Does the diplopia resolve by covering one eye? (Differentiates binocular diplopia (disappears when one eye covered; most common) from monocular diplopia (persists with one eye covered; usually related to a focal, ocular problem).
    • 2. Does the degree of diplopia change with direction of gaze and/or head position? (Determines whether deficit related to cranial nerve innervation, helps localize associated paretic muscle).
    • 3. Is the diplopia horizontal (i.e. two objects side by side) or vertical (i.e. two objects one on top of the other)? (Horizontal diplopia suggests cranial nerve III or VI deficit (i.e. lateral gaze function); vertical diplopia suggests cranial nerve IV deficit (i.e. elevator or depressor gaze function).
    • 4. Is there associated pain? (Suggests possible foreign body or extraocular muscle entrapment).
    • 5. Was there associated trauma? (Blow-out fractures can be associated with diplopia).
    • 6. Is there associated weakness, headache, confusion, or dizziness? (Imaging usually indicated to rule out intracranial processes such as stroke or increased intracranial pressure).