Which statement about the Feinbloom chart is true?

• A. It has a constant number of characters per line.
• B. It is calibrated to a specific test distance.
• C. It uses irregular progression of letter sizes, with most large jumps eliminated.
• D. It is used exclusively for color vision testing.

Answer: (C)

The main idea here is how the Feinbloom chart is designed to measure acuity. It uses an irregular progression of letter sizes, with most large jumps eliminated, so each step in size represents a relatively similar change in difficulty. This makes reading across lines provide a more precise estimate of a person’s visual acuity and reduces chances of guessing based on pattern or memorization. It’s not defined by a fixed number of characters per line, and it isn’t a color vision test, so those statements aren’t the defining trait.