The progression of letter sizes on the Feinbloom chart is described as which?

• A. Regular
• B. Irregular (most large jumps eliminated)
• C. Completely irregular
• D. Irregular (no large jumps)

Answer: (B)

The key idea is that the Feinbloom chart uses an irregular progression of letter sizes rather than equal, uniform steps. This design deliberately avoids large jumps between consecutive sizes, so there are more intermediate steps in the acuity range where a patient is likely to threshold. That makes the test more sensitive and reliable across a wide range of vision, especially for low-vision patients, because small changes in acuity aren’t missed by stepping through only big size differences. If the progression were regular, the sizable gaps could skip over a patient’s true threshold. Saying there are no large jumps would be too strict, since the chart isn’t a perfectly uniform ladder but an irregular sequence with most large steps removed to enhance precision.