If during projector calibration the 20/20 line is clearly visible at 20 feet, the projector is:

• A. Correctly calibrated
• B. Not calibrated
• C. Too bright
• D. Too dim

Answer: (B)

The key idea is that calibration relies on getting the projected optotype to subtend the correct angle at the viewer at the specified distance. The 20/20 line represents the size that should be just legible for someone with normal acuity at 20 feet. If, at 20 feet, that line is clearly readable, the projected image is larger than intended (or otherwise improperly scaled), meaning the chart is not calibrated to the correct size for that distance.

So, the projector isn’t producing the right angular size at the calibration distance, indicating a calibration issue that needs adjustment of magnification/throw distance or alignment. Brightness would affect visibility, but the decisive factor here is that the line is larger than it should be, pointing to a lack of proper calibration.