Ishihara test helps to identify which condition?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2020

Medical & Surgical Nursing

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2020

Explanation

The Ishihara test is the standard screening tool for detecting color vision deficiencies, particularly red-green color blindness.
It consists of a series of plates, known as pseudoisochromatic plates, which contain circles of colored dots of varying size and brightness.
Within the dot pattern, a number or shape is embedded that is visible to a person with normal color vision but is invisible or appears as a different number to someone with a color vision defect.

Option B: Macular degeneration affects central vision, causing distortion or blind spots. The Ishihara test assesses color perception, not central field integrity.
Option C: Glaucoma is a condition of increased intraocular pressure that damages the optic nerve, primarily affecting peripheral vision first. The Ishihara test does not measure eye pressure or visual fields.
Option D: Refractive errors relate to the eye's ability to focus light to create a clear image, affecting visual acuity. The Ishihara test does not measure how clearly a person can see.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Diagnostic procedures for common eye conditions, specifically the Ishihara test for color blindness as background academic context rather than a clinical decision trigger.
Nurses in school health, occupational health, and primary care settings may perform vision screenings, making it essential to know the purpose of different tests like the Ishihara chart.
Identifying color blindness is important for patient education and safety, especially for career counseling, as certain professions (e.g., pilots, electricians, designers) require accurate color discrimination.
What if? If a patient reports a sudden 'curtain' or 'shadow' over their vision, the priority is not a color vision test but an urgent referral for suspected retinal detachment, which is a medical emergency.

How to Approach the Question

This is a factual recall question that links a specific diagnostic test to the condition it identifies.
First, identify the key term in the question stem: 'Ishihara test'.
Access your knowledge of common ophthalmic diagnostic tools.
Recall that the Ishihara test uses a series of colored plates (pseudoisochromatic plates) to assess an individual's ability to perceive different colors.
Evaluate the options. 'Colour blindness' is a condition of altered color perception, which directly matches the function of the Ishihara test.
To confirm, mentally eliminate the other options by recalling their primary diagnostic tests: Macular degeneration uses an Amsler grid, Glaucoma uses tonometry, and Refractive errors use a Snellen chart.

Concept Tested & Keywords

Concept Tested: Diagnostic procedures for common eye conditions, specifically the Ishihara test for color blindness.
Stem keywords: Ishihara test, identify condition
Lead-in keywords: helps to identify
Negative lead-in flag: false

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