The nurse asked the client to read the Snellen chart. Which of the following is tested?

Appeared in: UPUMS Nsg.Officer-2024

Explanation

The Snellen chart is the standard clinical tool for assessing distance visual acuity.
Visual acuity is the primary sensory function of the Optic nerve (Cranial Nerve II).
This nerve is responsible for transmitting sensory information for vision from the retina to the brain for interpretation.
Therefore, asking a client to read a Snellen chart is a direct test of the Optic nerve's integrity.

Option A: The Trochlear nerve (CN IV) is a motor nerve that controls the superior oblique muscle, which moves the eye downward and inward. It does not relate to visual acuity.
Option B: The Olfactory nerve (CN I) is a sensory nerve responsible for the sense of smell. It has no role in vision.
Option D: The Oculomotor nerve (CN III) is primarily a motor nerve that controls most of the eye's movements, pupillary constriction, and eyelid elevation. While it moves the eye to focus on the chart, it does not process the visual information itself.

Clinical Relevance

Nursing practice connection: Use the key finding related to Cranial nerve assessment (CN II, Optic Nerve) using a Snellen chart to guide bedside assessment, documentation, and the next nursing action.
Assessing visual acuity with a Snellen chart is a fundamental component of both routine physicals and detailed neurological examinations.
A deficit detected during this test can be an early indicator of serious underlying conditions such as glaucoma, optic neuritis, cataracts, macular degeneration, or intracranial pressure affecting the optic nerve.
What if? If the patient could read the chart but complained of seeing double (diplopia) during the test, the nurse's focus would shift to assessing the motor nerves of the eye (Oculomotor, Trochlear, and Abducens) rather than just the Optic nerve.

How to Approach the Question

First, identify the purpose of the clinical test mentioned in the question. The Snellen chart is used to test vision.
Next, recall the primary function of each cranial nerve listed in the options.
Match the function (vision) with the corresponding cranial nerve.
The Optic nerve (CN II) is the sensory nerve for vision.
Eliminate the other options by identifying their distinct functions: Trochlear (CN IV) and Oculomotor (CN III) are for eye movement, and Olfactory (CN I) is for smell.

Concept Tested & Keywords

Concept Tested: Cranial nerve assessment (CN II, Optic Nerve) using a Snellen chart.
Stem keywords: Snellen chart, read
Lead-in keywords: Which of the following is tested

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E6 Medicine Harrison 22e Part 2 p. 1284-1286

E6 Nursing Fundamentals Taylor p. 390-392

Practise the full UPUMS Nsg.Officer-2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.