Which chart is used to screen for color blindness in a 7 year old boy?

The Ishihara chart is specifically designed to screen for color blindness, making it the correct choice for assessing a 7-year-old boy's color vision. This chart consists of a series of plates with colored dots arranged in patterns that form numbers or shapes visible to those with normal color vision but may not be seen by individuals with color deficiencies. It is effective and widely used for testing color perception, especially in children, as it offers a straightforward way to identify specific types of color blindness, such as red-green color blindness, which is the most common.

In contrast, the Snellen chart is primarily used for testing visual acuity, measuring how well a person can see at a distance. The cover/uncover test is used to assess for strabismus or eye alignment issues rather than color vision. The red reflex test is an ophthalmological assessment to check for abnormalities in the eye, such as cataracts or retinoblastoma, and does not pertain to color vision screening. Thus, the Ishihara chart is the best tool for identifying color blindness in children.