cranial nerves examination

Eye: History, Examination

1. History
2. Inspection
3. Visual acuity
4. Visual fields
5. Ophthalmoscopic (fundi)
6. Pupils
7. Corneal reflections
8. Eye movements
9. Corneal reflex

History 

• Presenting complaint:
  • Onset: gradual vs. sudden vs. asymptomatic.
  • Duration: brief vs. continuous.
  • Location: focal vs. diffuse, unilateral vs. bilateral.
• Eye Hx: squint, amblyopia, glasses, glaucoma.
• Family Hx: squint, lazy eye, glasses, glaucoma, cataract (young person).
• Past medical Hx: especially vascular (diabetes, hypertension).
• Medications: current meds, Hx of drugs affecting eye.
  • Is pt on or been on eye drops.
• Social Hx: relevant post-op (to put eye drops in).

Inspection
In all, looking for asymmetry, deformities, discoloration, redness, discharge, lesions.

• Diagnostic facies.
• Orbit, rim: palpate for lumps.
• Brow: lost sweating (Horner's).
• Eyelids: xanthelasma, ectropian, entropian.
• Eyelids: pus on lids (blepharitis).
• Ptosis.
• Exophthalmos.
• Iris: colour, defects.
• Cornea: transparent vs. opaque, corneal arcus, band keratopthy, Kayser-Fleischer rings, lesion, scars.
• Ask the patient to look up and pull down both lower eyelids to inspect the conjuntiva and sclera.
  • Conjunctiva: clear/infected. If conjuntivitis, wash hands immediately: viral form contagious.
  • Sclera: jaundice, pallor, injection.
• Spread each eye open with Dr's thumb, index finger. Ask pt to look to each side and downward to expose entire bulbar surface.
  • Eyeball tenderness.

Visual acuity
If  eye pain, injury, visual loss, check visual acuity before rest of the exam or inserting medications into eyes [so don't get sued].

• Let pt to use glasses, contacts if available.
• Put pt 20 feet from Snellen eye chart, or hold Rosenbaum pocket card 14 inches away.
• Pt. covers an eye at a time with a card, reading smaller letters till stop.
• Record smallest line read, eg 20/40.

Visual fields

• Stand 2 feet in front of pt, who looks in Dr's eyes at eye-level.
• Dr's hands to side half way between Dr and pt, wiggle fingers, ask which they see move.
• Repeat 2-3 to test both temporal fields.
• If suspect abnormality, test 4 quadrants of each eye while card covers other.

Ophthalmoscopic (fundi)

• Darken room, adjust scope so light is no brighter than necessary.
• Adjust aperture to a plain white circle.
• Set diopter dial to zero, unless have a preferred setting.
• Dr. uses left hand and left eye to examine the patient's left eye.
• Dr's free hand onto the pt's shoulder or forehead for control.
• Tell pt to stare at wall.
• Look through scope, shine light into pt's eye from 2 feet away at a 45º angle.
• See the retina as a "red reflex.". Reflex: clear vs. opaque (cataract). Follow red color to move within a few inches from pt's eye.
• Adjust diopter dial to bring the retina into focus. Find a blood vessel and follow it to the optic disk, use this as a point of reference.
• Inspect optic disk:
  • Colour of disc: pink vs. pale.
  • Margins clear.
  • State of cup.
• Inspect vessels: all 4 quadrants, veins are darker than arteries:
  • Bleeding, exudate.
  • Pigmentation, occlusion.
• Inspect macula, by moving the scope nasally:
  • Foveal light reflex
  • Bleeding, exudate.
  • Edema, drusen.

Pupils

• Shape, relative size.
• Light reaction: dim lights if needed.
  • Pt looks in distance, shine light in from side to gauge pupil's light reaction. Record size, irregularity.
  • Assess both direct (same eye) and consensual (other eye) responses.
• Assess afferent pupillary defect by moving light in arc from pupil to pupil, and if L eye light makes R eye dilate, not constrict (Marcus Gunne). Optionally: as do arc test, have pt place a flat hand extending vertically from his face, between his eyes, to act as a blinder so light can only go into one eye at a time. 
• Accommodation: pt alternates between looking into distance, and a hat pin 30cm from nose.

Corneal reflections

• Shine a light from directly in front of the pt.
• Corneal reflections should be centered over pupils.
• Assess asymmetry (extraocular muscle pathology).

Eye movements

• "Follow finger with eyes without moving head": test the 6 cardinal points in an H pattern. Assess:
  • Failure of movement.
  • Nystagmus [pause to check it during upward, lateral gaze]).
• Convergence by moving finger towards bridge of pt's nose.
• Gaze palsies (supranuclear lesions).
• Fatiguability (myasthenia).

Corneal reflex

• Corneal reflex: patient looks up and away.
• Touch cotton wool to other side.
• Look for blink in both eyes, ask if can sense it.
• Repeat other side. [Tests V sensory, VII motor].