icon Mneme

Assessment of the Eye and Vision

4 min read

Ocular History

Questioning elicits necessary information for the diagnosis of an ophthalmic condition. Pertinent questions to ask when taking an ocular history include:

  • What does the patient perceive to be the problem?
  • Is visual acuity diminished?
  • Is the patient experiencing blurred, double, or distorted vision?
  • Is there pain? Is it sharp or dull? Does blinking make it worse?
  • Is the discomfort an itching sensation or more of a foreign-body sensation?
  • Are both eyes affected?
  • Is there a history of discharge? If so, inquire about the color, consistency, and odor.
  • What is the duration of the problem?
  • Is this a recurrence of a previous condition?
  • How has the patient self-treated?
  • What makes the symptoms improve or worsen?
  • Are there any systemic diseases? What medications are used in this treatment?
  • What other eye conditions does the patient have?
  • Is there a history of eye surgery?
  • Have other family members had the same symptoms or condition? Genetics may play a role in the causation and progression of eye and vision disorders.

Visual Acuity

Following health history, a patient’s visual acuity is assessed. This is a measure against which all therapeutic outcomes are based. It is tested for near (14 inches via a Rosenbaum pocket screener) and distance (20 feet via a Snellen chart) vision, performed separately for both eyes. Tumbling/Illiterate E Tests, Number Tests, or Picture Charts are used for illiterate patients or those who use other writing systems.

  1. Snellen Chart: a series of progressively smaller rows of letters. The patient is asked to read the lowest (smallest) line possible. Each line has its standardized score, with the smallest line being 20/20. The standard of vision (20/20) reflects normal vision, and indicates “able to see 20 feet away what a normal person can see 20 feet away”. As such, a reading of 20/100 would indicate that the patient is able to see only 20 feet away what a normal person can see 100 feet away.
  2. Counting Fingers (CF) Test: if the largest letter is unreadable, the nurse stands five feet from the person and holds up a random number of fingers, which the patient should state. If they are unable to, move one foot closer to the patient until they are able to. The result is recorded as CF/5, which indicates “can count fingers 5 feet away”.
  3. Hand Motion Test: if the patient is unable to count fingers, hand motions are used; moving the examiner’s hand up, down, or side-to-side, then asking the patient what direction the hand is moving in. This level of vision is known as hand motion.
  4. Light Perception: patients may only be able to see light, described as “having light perception”. If they are unable to perceive light, they have no light perception.

External Eye Examination

The nurse uses a systematic approach to perform an external eye examination. Assess for symmetry and placement of eyelids, pupils, and muscles. CNs III, IV, and VI (oculomotor, trochlear, abducens) control movement and pupil size.

  1. The eyelids should rest just above and below the corneal limbus without exposure of the sclera.
  2. Check for ptosis (drooping of the eyelid), ectropion (turning out of the lower eyelid), or entropion (turning in of the lower eyelid). Entropion may involve trichiasis (turning in of the eyelashes).
  3. Eyelids and lashes should be free of drainage and scaling.
  4. The room should be darkened so that the pupils can be examined. The pupillary response is checked with a penlight to determine if the pupils are equally reactive and regular. Pupils are normally black. Pupils may become abnormal due to trauma, previous surgery, or a disease process.
  5. Eyes are observed in primary or direct gaze, and any head tilt is noted. A head tilt may indicate CN palsy.
  6. Have the patient stare at a target; each eye is covered and uncovered quickly while the examiner looks for any shift in gaze.
  7. Nystagmus is noted when present.
  8. Extraocular movements are tested by having the patient follow the examiner’s finger, pencil, or a hand light through the six cardinal directions of gaze: up, down, right, left, and both diagonals.

Graph View