Which line on the acuity chart is used in the material to determine legal blindness based on acuity?

Which line on the acuity chart is used in the material to determine legal blindness based on acuity?

• A. 20/20 line
• B. < 20/100 line
• C. 20/200 line
• D. 20/400 line

Answer: (B)

The key idea is how acuity thresholds are used to label someone as legally blind. In the material you’re studying, legal blindness based on acuity is defined by the line worse than 20/100. So if a patient’s visual acuity reads at or beyond that line—less than 20/100—the case meets the material’s criterion for legal blindness. The line representing 20/20 is normal vision, and lines like 20/400 indicate far worse acuity, but the material sets the cutoff at less than 20/100, making the line below that threshold the one used to determine legality based on acuity. (Be aware that the standard clinical definition is typically 20/200 or worse in the better eye, but this question reflects the material’s specific criterion.)

The key idea is how acuity thresholds are used to label someone as legally blind. In the material you’re studying, legal blindness based on acuity is defined by the line worse than 20/100. So if a patient’s visual acuity reads at or beyond that line—less than 20/100—the case meets the material’s criterion for legal blindness. The line representing 20/20 is normal vision, and lines like 20/400 indicate far worse acuity, but the material sets the cutoff at less than 20/100, making the line below that threshold the one used to determine legality based on acuity. (Be aware that the standard clinical definition is typically 20/200 or worse in the better eye, but this question reflects the material’s specific criterion.)