Color Blindness Test | SLMC

COLOR BLINDNESS TEST INFORMATION SHEET

WHAT IS A COLOR BLINDNESS TEST

A color blindness test checks how well you can recognize and distinguish colors. It is used to detect color vision deficiency, most commonly red-green color deficiency. These tests are widely used for school screening, employment requirements, driver licensing, and medical evaluation.

Two commonly used validated tests are:

1. Ishihara Test Plates

2. Farnsworth D-15 Dichotomous Color Blindness Test

Both are evidence-based screening tools accepted in clinical ophthalmology and occupational screening programs.

PURPOSE OF THE TEST

The test is performed to:

1. Detect inherited or acquired color vision deficiency

2. Classify the type and severity of color vision defect

3. Support medical, school, or employment documentation

4. Guide further eye examination if needed

This is a screening and classification test. It does not treat color blindness.

HOW THE TEST IS PERFORMED

Ishihara Test Plates:

You will be shown a series of printed color dot plates. Hidden within each plate is a number or pattern formed by colored dots. You will be asked to read or trace what you see. Each plate is viewed one at a time under proper lighting.

Farnsworth D-15 Test:

You will be given colored caps or discs and asked to arrange them in color order starting from a fixed reference cap. The pattern of arrangement helps identify the type of color deficiency.

The test is painless, non-invasive, and usually takes 5 to 15 minutes.

PREPARATION AND TEST CONDITIONS

For accurate results:

1. Testing must be done under standardized white lighting

2. Corrective glasses or contact lenses should be worn if prescribed

3. Do not use tinted lenses during testing unless medically required

4. Avoid guessing when unsure; give your best honest answer

LIMITATIONS OF THE TEST

1. Results depend on lighting and test material quality

2. Digital or screen-based versions are less reliable than validated printed sets

3. Screening tests may not detect very mild defects

4. Some eye or nerve diseases can affect color vision and may require further tests

NORMAL AND ABNORMAL RESULTS

A normal result means color discrimination is within standard limits.

An abnormal result suggests color vision deficiency. This may be:

1. Congenital (present since birth)

2. Acquired (due to eye, nerve, or systemic disease, or medication)

Further ophthalmic evaluation may be advised if results are abnormal or inconsistent.

RISKS AND SAFETY

There are no medical risks associated with these tests. They are safe for all ages who can cooperate with instructions.

CONSENT AND USE OF RESULTS

By proceeding with testing, you agree that:

1. The test is a screening and classification tool

2. Results will be recorded in your medical record when applicable

3. Results may be used for medical certification or reports upon request

4. Additional tests may be recommended if clinically indicated

If you have questions about your results, you are encouraged to discuss them with your ophthalmologist.