Which chart is NOT used to measure contrast sensitivity?

Which chart is NOT used to measure contrast sensitivity?

• A. Pelli-Robson
• B. Vistech Contrast Test System
• C. ETDRS
• D. Bailey-Lovie Chart

Answer: (C)

Contrast sensitivity tests evaluate how well someone can detect differences in light and dark, across different contrasts or spatial frequencies. The Pelli-Robson chart does this by lowering the contrast of letters to map sensitivity. The Vistech system also assesses contrast sensitivity across multiple spatial frequencies. In contrast, high-contrast acuity charts measure the ability to recognize letters at near-full contrast, not sensitivity to contrast. Both the Bailey-Lovie chart and the ETDRS chart fall into this category, as they are designed to quantify acuity with standard, high-contrast letters. Among these, the ETDRS chart is the one primarily used for high-contrast visual acuity testing rather than contrast sensitivity. Therefore, ETDRS is not used to measure contrast sensitivity.

Contrast sensitivity tests evaluate how well someone can detect differences in light and dark, across different contrasts or spatial frequencies. The Pelli-Robson chart does this by lowering the contrast of letters to map sensitivity. The Vistech system also assesses contrast sensitivity across multiple spatial frequencies. In contrast, high-contrast acuity charts measure the ability to recognize letters at near-full contrast, not sensitivity to contrast. Both the Bailey-Lovie chart and the ETDRS chart fall into this category, as they are designed to quantify acuity with standard, high-contrast letters. Among these, the ETDRS chart is the one primarily used for high-contrast visual acuity testing rather than contrast sensitivity. Therefore, ETDRS is not used to measure contrast sensitivity.