11/13/24, 6\:58 PM Guide | Colour vision assessment

Colour vision assessment

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Introduction

Wash your hands and don PPE if appropriate.
Introduce yourself to the patient including your name and role.
Con
Brie
Gain consent to proceed with the examination.
Position the patient sitting on a chair.
Ask if the patient has any pain before proceeding.

Colour vision assessment

Colour vision can be assessed using Ishihara plates, each containing a coloured disc of dots. Within the pattern of each disc
are dots which form a number or shape visible to those with normal colour vision. Those with a red-green colour vision defect
may see some plates di
with normal colour vision.
Although the test was originally designed for diagnosing and subtyping individuals with red-green colour blindness, these
plates can be used in the acute setting to identify acute optic neuropathy (such as optic neuritis).
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The Ishihara plates come in the original 36-plate version or the shortened 24-plate version. Only the
plate version and the
individuals who cannot read numbers or determine the extent of red-green blindness.
An easy way to remember this is to stop after the last plate with a number (which reads “73”).

How to use Ishihara plates

If the patient usually wears glasses for reading, ensure these are worn for the assessment.
1. Ask the patient to cover one of their eyes.
2. Then, ask the patient to read the numbers on the Ishihara plates. The
, which does not test
colour vision but assesses contrast sensitivity. If the patient cannot read the test plate, you should document this.
3. If the patient can read the test plate, you should move through the Ishihara plates, asking the patient to identify the number
on each. Stop at the plate that reads “73” (the last plate with a number).
4. Once the test is complete, document the number of plates the patient identi
Also, make a note of the reading speed for each eye.
5. Repeat the assessment on the other eye.
Hold the Ishihara chart at arms length

To complete the examination...

Explain to the patient that the examination is now
Thank the patient for their time.
If mydriatic drops were instilled, remind the patient they cannot drive for the next 3-4 hours until their vision has returned to
normal.
Dispose of PPE appropriately and wash your hands.
Summarise your

Suggest further assessment and investigations

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All of the following further assessments and investigations are dependent on the patient's presenting complaint, and in most
cases, none of them would need to be performed\:
Complete visual assessment\: including visual acuity, visual
Cranial nerve examination\: to further assess for evidence of cranial nerve pathology (e.g oculomotor nerve).
Retinal photography\: to better visualise any abnormalities noted on fundoscopy.
Optical Coherence Tomography (OCT)\: measures the thickness of the retinal nerve
assessment and monitoring of optic nerve head swelling.
Source\: geekymedics.com
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