Increasing decentration will directly affect which component of MBS?

• A. It does not affect MBS
• B. It increases MBS
• C. It decreases MBS
• D. It makes MBS constant

Answer: (B)

When the optical center is shifted away from the pupil, light rays no longer travel along the eye’s ideal optical axis. This off-axis positioning creates a prism effect and introduces aberrations such as coma and astigmatism, which degrade image quality on the retina. The MBS metric includes a part that specifically reflects image quality loss from blur and aberration. As decentration increases, that aberration/blur portion grows, so the overall MBS increases. The idea that there would be no change, a decrease, or a constant MBS doesn’t fit with how off-axis rays worsen image quality.