Name of the Procedure:

Color Vision Examination, Extended (Anomaloscope or Equivalent)

Summary

A color vision examination, extended, is a specialized eye test to assess and diagnose color vision deficiencies. It involves using an anomaloscope or similar device to evaluate how well an individual can distinguish between different colors and shades.

Purpose

This procedure identifies color vision deficiencies, which are often congenital but can also result from certain medical conditions or medications. The goal is to determine the type and extent of the deficiency to guide appropriate measures or adaptations.

Indications

• Reports of difficulty distinguishing colors
• Unexplained visual disturbances
• Screening for occupations requiring accurate color perception (e.g., pilots, electricians)
• Monitoring color vision in patients on medications known to affect eyesight

Preparation

Generally, no specific preparations are required. However, avoiding bright lights and digital screens for a few hours before the test is recommended to avoid eye fatigue. Patients should bring any corrective lenses they normally wear.

Procedure Description

1. Introduction and Explanation: The healthcare provider explains the process and what to expect.
2. Visual Acuity Check: Ensuring the patient’s basic vision is adequate before testing color perception.
3. Anomaloscope Use:
   • The patient looks into the device and is asked to match the color by adjusting knobs that mix red and green lights to match a yellow reference light.
   • Multiple matching tasks may be performed to assess the consistency and accuracy of color perception.

Duration

The examination typically lasts between 30 to 60 minutes.

Setting

This procedure is usually conducted in an optometrist's or ophthalmologist's office, or a specialized vision clinic.

Personnel

• Optometrist or ophthalmologist
• Trained vision technicians or assistants

Risks and Complications

• Generally, there are no risks or complications. It is a non-invasive and safe test.

Benefits

• Accurate diagnosis of color vision deficiencies
• Better understanding of the patient's vision status to guide lifestyle modifications or occupational advice
• Early detection of acquired color vision deficiencies linked to medical conditions

Recovery

No recovery time is needed. Patients can resume normal activities immediately after the test.

Alternatives

• Ishihara Color Test: Uses colored plates with patterns to detect red-green deficiencies.
• Farnsworth-Munsell 100 Hue Test: Involves arranging colored discs in order of hue.
• Pros and Cons: Anomaloscope offers a precise and detailed assessment but may not be as widely available as other tests.

Patient Experience

During the procedure, the patient will sit comfortably and look into the device. They may experience slight eye strain from focusing but generally report no discomfort. There is no need for pain management, as it is a non-invasive procedure.