Immersion: Eye

Structures of the eye

Visible structures of the external eye
Cross section of the eye

Note that the anterior chamber lies between the transparent cornea and the pupil and iris.  As you examine the central part of the eye you are seeing all of these structures.

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Exam steps

Step 1. Measure visual acuity in each eye

Hold a pocket vision screener or smartphone app the indicated distance away from your patient.  Ask them to cover one eye and read the lowest line they can with the other, then switch eyes and repeat.

Normal visual acuity is 20/20, meaning your patient can read print at 20 feet that someone with normal vision can read at 20 feet. As visual acuity decreases, the lower number goes up

Step 2. Inspect the external eye

Carefully observe eyelids, lashes, bulbar & palpebral conjunctiva, sclera, cornea, anterior chamber, and iris. Note any differences in symmetry, redness or swelling of the eyes and surrounding tissues.

Step 3. Observe the corneal light reflex

Hold your penlight directly in front of your patient, about 12 inches away. The light should appear in the same spot in both eyes, indicating that they are normally aligned. An asymmetric corneal light reflex indicates that your patient has strabismus, which can cause long term vision problems in children. 

Step 4. Assess pupil symmetry & reactivity

Observe the size of the pupils, which are typically equal in size.  Anisocoria of < 0.5 mm is common and is considered normal if the pupils react to light. 

Next, assess the reactivity of the pupils by observing pupillary constriction with direct and consensual light. In people with dark brown irises, pupils may be easier to see if the light is shone from below.

Step 5. Perform fundoscopy

The ophthalmoscope allows you to view the interior structures of the eye: the retina, retinal vessels, macula and optic disc, also called the fundus. In Immersion, you will only be expected to be able to demonstrate the red reflex (steps 1-3). We will return to examine the retina later in the year.

  1. Position your patient so that your eyes are at the same level.
  2. Have the patient gaze at a distant object in a darkened room.
  3. Starting with a 0 lens, focus on the lashes from 124 inches away, and look for the red reflex. The red reflex should be symmetric and without spots, indicating that light is reflecting equally off of each retina.
  4. Hold the ophthalmoscope in the R hand and use your R eye to examine the patient’s R eye. Switch hands/eyes to examine the patient’s L eye.
  5. Moving in at an angle of 15 degrees lateral to the patient’s line of vision, focus on the retina by rotating the lenses until the retinal vessels are clearly visible.  Follow the vessels until you see the optic disk.  Carefully examine as much of the retina as you can.

Sample documentation

Eyes: Vision 20/20 in each eye with corrective lenses. Conjunctivae without injection. No scleral icterus. Lids without lesions. Corneal light reflection symmetric. Pupils equal, round, and reactive to light directly and consensually. Red reflex present bilaterally.

Video of the eye exam

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License

The Foundations of Clinical Medicine Copyright © by Karen McDonough. All Rights Reserved.