Physical Exam Pearls – 1 (Eye)

This posting begins a few rambling / random tips I find useful for performing physical exam.  A lot of them have been mentioned previously, during symptom work-ups.  Some comments derive from errors I’ve seen various clinicians make (myself included).

We’ll go system by system, head to toe more or less, starting with my favorite — the Eye.  I’d always been scared of this special organ, until I realized how much can be ascertained with basic equipment, & how a competent exam is appreciated by  ophthalmology consultants..

1.  Visual Acuity — Test by Snellen at distance, not near.  If can’t identify the “big E” (20/200), test & chart as follows (order of decreasing acuity):
 
  • Move pt. halfway closer (= 10/200)
  • Finger-Count at 3 feet
  • Hand Motion at 3 feet (“Can you see my hand moving?  Tell me when it stops”)
  • Light Projection — shine penlight from different angles, “Point to the light”
  • Light Perception  —  turn penlight on & off right in front of pt.: “Tell me when you see the light.”
    • “No Light Perception” is what we think of as “totally blind”

2.  What if symptomatic eye has worse visual acuity than the unaffected?  How do you tell if it’s always been like that due to refractive error (glasses would correct it), or the visual deficit is related to current complaint (serious!)?  Click for answer (one of the most important things to understand!).

3.  Visual Fields by Confrontation —  Really part of the Neuro exam, to identify lesions of the optic nerve, chiasma, tract, etc., that cause large hemispheric or quadrant deficits.

  • Does NOT identify subtle field deficits in ocular conditions such as glaucoma, retinitis, or small retinal holes / detachments.
    • This would require formal field testing.
  • Important to include in Neuro exam.
  • Easiest way to perform:
    1. Patient covers one eye, you face them straight on & close your eye that mirrors theirs (pt’s R, your L, etc).
    2. Tell them, “Look right at my eye, not my fingers.  With this hand [touch their free hand ipsilateral to their open eye], point to whichever finger I move.”
    3. Hold your hands apart so you can see your finger at the periphery of your fields.  Wiggle one finger, then the other.
    4. Rotate fingers to include all cardinal fields of gaze.

This is much easier than the technique of inching a finger at a time inward, “Tell me when you see it.”
  • NOTE:  Examiner in above picture should have lowered his head to be more on eye level with patient.

4.  Test color vision as best able in pt. with new visual deficit; may be only clue to eye disease.

5.  Remember to examine the Lids & Lashes.  Some patients’ chronic or recurrent eye complaints are due to skin diseases like Rosacea or Seborrheic Derm — scales tumble into the eye.  Elderly can have ectropion or entropion: lashes turning in (rubbing conjunctiva / cornea) or out (drying the eyes).

6.  Extraocular Muscles — Test EOMs by directing the eyes laterally: horizontal, diagonally up, diagonally down.  Don’t test straight up & down vertically (no single nerve does that).

7.  Pupils  — 
 
  • Don’t chart “PERRLA” unless you test accommodation also. 
  • Always perform a swinging flashlight test for an Afferent Pupillary Defect (APD) (aka Marcus Gunn pupil).  As you swing the light from eye to eye, the affected pupil dilates instead of constricts, indicating an optic nerve (CN-2) disorder.  Click for brief explanation.

8.  Anterior Chamber  —  for patient with “Red Eye” or especially “Eye Pain”

  • “Cross Photophobia” can be a simple & remarkably sensitive & specific test.  In a dark room, shine a pen light in the unaffected eye.  If that causes contralateral pain (in the symptomatic eye), it diagnoses iritis, because the only structure manipulated by consensual pupillary reaction was the iris.  Also useful in eye trauma to assess anterior chamber involvement.  Will be negative if the involved pupil is fixed in spasm.
  • Don’t forget, with patient sitting, to seek a colored layer cells at the bottom of the iris, with meniscus.  If white, it’s a hypopion (pus, in context of iritis).  If red, it’s a hyphema (blood, in context of trauma).

9.  Retinal Exam (fundoscopic)  —  lots of tips here on how to perform:

  • Dark room, but not completely dark (see below).
  • Position patient so you can stand comfortably (no examiner can concentrate or perform well while stretching on tiptoes).
  • Instruct patient to focus on a specific spot straight ahead (thus you need that little light, so patient can see).
  • Hold ophthalmoscope correctly: a) choked-up on handle to easily manipulate focus wheel with index finger); b) Rubber rim firmly against your eyebrow, so your head & scope move as a unit; c) Use your right hand & right eye for patient’s right eye, left & left for left.
  • Know your own vision in each eye — set diopters at “0” if you’re 20/20, negatively (red numbers) if you’re nearsighted, positively (black/green numbers) if farsighted.
  • Approach 15° lateral from midline.
  • Move right up to pupil, as if looking through a keyhole.  Practically rub foreheads with patient.  I never put my free hand on patient’s forehead (as in all the pictures), because that tends to push me away; rather, I place it behind patient’s shoulder, to instinctively draw me in.
  • Realize that your ophthalmoscope’s field is just a tiny bit wider than optic disk diameter.  Most pictures you see in books or Google are actually the entire retina.
  • Start by finding the optic disk.  Then examine vessels and retinal background area by area.  Begin medially (nasally), then laterally (temporally) up, laterally down, & end due lateral.  That’s because the macula & fovea are temporal; if you start there, the pupil will constrict & you won’t be able to complete the exam.
  • Know what you’re looking for before you start — very specific parameters:
    1. Optic Disk
      1. Sharp Margins (r/o Papilledema)
      2. Creamy color (pale = optic atrophy)
      3. Cup-to-Disk Ratio (cup should be <50% diameter of disk)
    2. Vessels
      1. Artery-to-Vein Ratio (width of artery = 4/5 or 2/3 that of vein, not less)
      2. No arteriolar spasms or tortuosity
      3. No A-V Nicking (search for a vessel crossing: vein should abut artery w/o a space or “nick” in the vein
      4. Abnormal positives = severe / long-standing HTN
      5. NOTE: everyone says “artery” & “vein,” but they’re really arterioles & venules
    3. Retinal Background — Seek out:
      1. Hemorrhages (red)
      2. Exudates (white)
      3. Scars (black)
      4. Can also seek tufts of tiny vessels = Neovascularization (bad diabetic “proliferative” retinopathy), but I never bother, because 1) they’re real hard to find; and 2) the direct ophthalmoscope can only see 10% of retina, so all diabetics need annual dilated exams by eye doctors with indirect ophthalmoscopes, anyway!

Moving on down the body next posting, to HENT.

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3 responses to “Physical Exam Pearls – 1 (Eye)

  1. Really helpful. Lookin forward to more PE tips!

  2. Thank you! Illustrations of these would be nice, especially the optic disc and retina points.

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