Regarding color blindness true-a) Mainly congenitalb) Can be tested with Fansworth 100 hue testc) Ishihara chart test red/ green color blindnessd) Jerlin- Merlin cotton wool tests it
**Core Concept**
Color blindness, also known as color vision deficiency, is a condition where a person has difficulty perceiving certain colors. This is usually due to an issue with the genes that code for the light-sensitive cells in the retina, specifically the cone cells responsible for color vision.
**Why the Correct Answer is Right**
The Ishihara chart test is a widely used method for screening for red-green color blindness. This test uses a series of dots of varying sizes and colors to create numbers or shapes that are visible to people with normal color vision but not to those with red-green color blindness. The test relies on the fact that people with red-green color blindness have difficulty distinguishing between red and green colors. This is because the genes that code for the red and green cone cells are located close together on the X chromosome, and mutations in these genes are more likely to affect both red and green cone cells.
**Why Each Wrong Option is Incorrect**
**Option A:** While color blindness can be congenital, it is not the only type. Acquired color blindness can also occur due to various factors such as age-related macular degeneration or head trauma.
**Option B:** The Farnsworth 100 hue test is a more comprehensive test for color vision deficiency, but it is not the most commonly used test for screening red-green color blindness.
**Option D:** The Jerlin-Merlin cotton wool test is not a recognized test for color blindness.
**Clinical Pearl / High-Yield Fact**
The Ishihara chart test is a quick and simple method for screening for red-green color blindness, but it is not a definitive diagnostic test. It is essential to confirm the diagnosis with a more comprehensive test like the Farnsworth 100 hue test.
**Correct Answer: C. Ishihara chart test red/ green color blindness**