To diagnose color blindness, your doctor will perform 1 of the following quantitative and qualitative tests.
1. Qualitative color blindness test
Use the Ishihara method. The test is very simple, the patient just needs to look at the table and say the number he sees. Based on the results, the doctor will conclude what the disease is. In children who cannot read numbers or letters, there are special tables that are used to diagnose color blindness.
Some notes for the Ishihara method: the patient's visual acuity must be above 6/60 (1/10). Good light. Examine each eye. The board is held 75cm from the patient and should be perpendicular to the visual axis. Time to look from 3-5 seconds.
Based on Ishihara, the Enchroma method helps determine the degree and type of color blindness of a person. At the same time, the test also has an additional classification for adults and children from 5 years old.
2. Quantitative color blindness test
For detailed analysis, the patient's ability to accurately perceive colors, the doctor uses the Farnsworth-Munsell 100 method. The test consists of 4 trays, which will contain many small plates with different colors. The patient needs to arrange the colored discs in ascending order of color. For accurate results, the test must be performed in a place where the light is closest to natural light.
With this technique, each color disc will be numbered at the bottom for easy checking of the results. If the patient's color arrangement is more similar to the sample, the diagnostic result will be more accurate. The Farnsworth-Munsell 100 technique helps detect color blindness and its severity.
In addition to the above two ways, you can test for color blindness online as a color blind test, a simple test. However, online testing can lead to errors. Therefore, it is still necessary to see an ophthalmologist for early examination, consultation and treatment, early detection of eye diseases.