Ishihara chart is used for the assessment of?

Appeared in: HPSSC Staff Nurse - 2021

Explanation

The Ishihara chart is a specific diagnostic tool designed to assess color vision.
It consists of pseudoisochromatic plates with dots of different colors that form numbers or patterns.
Its primary function is to screen for red-green color vision deficiencies, the most common type of color blindness.
Individuals with normal color vision can easily see the numbers, while those with a deficiency cannot.

Option A: Night blindness (nyctalopia) is the inability to see in dim light. This condition is related to the function of rod cells in the retina, not the cone cells responsible for color vision.
Option C: This option is incorrect because the Ishihara chart is specific to color vision and has no role in assessing night blindness.
Option D: This is incorrect because the Ishihara chart has a well-established and specific purpose, which is the assessment of color vision.

Clinical Relevance

Nursing practice connection: Use the key finding related to Purpose of the Ishihara chart in vision assessment to guide bedside assessment, documentation, and the next nursing action.
Nurses may be involved in preliminary vision screenings in schools, clinics, or occupational health settings, where a basic understanding of tools like the Ishihara chart is essential.
Identifying color vision deficiency is crucial for patient safety and career counseling, as certain professions (e.g., pilots, electricians, designers) require normal color perception.
A sudden change in color vision can be a symptom of an underlying medical condition (e.g., optic neuritis, medication toxicity), and a nurse should recognize this as a sign that needs further investigation.

How to Approach the Question

First, identify the key term in the question: 'Ishihara chart'. This is a specific piece of medical equipment.
Recall or deduce the function of this equipment. This is a factual recall question.
Evaluate each option based on your knowledge of the Ishihara chart.
Option A (Night Blindness): Recall that night blindness relates to low-light vision (rods), while color vision relates to cones. The Ishihara test is for color.
Option B (Colour Vision): This matches the known purpose of the Ishihara test.
Option C (Both): Since it does not test for night blindness, this option is incorrect.

Concept Tested & Keywords

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E6 Nursing Brunner Adult Health 3SA Vol 2 Part 1 p. 87-89

E6 Physiology Guyton 4SAE Part 3 p. 158-160

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