Which aberration is of the greatest concern to a spectacle wearer?

Marginal astigmatism is of significant concern to spectacle wearers because it can directly impact the clarity of vision and the overall comfort of wearing glasses. This type of aberration occurs when light rays that hit the lens at different positions do not converge at the same point, leading to a distortion of the image. This can result in blurred vision and visual discomfort, particularly when viewing objects off-axis, which is common in everyday activities.

For spectacle wearers, the importance of correction for marginal astigmatism cannot be overstated. When glasses are improperly fitted or designed, marginal astigmatism can produce inconsistent vision, making it challenging for the wearer to focus clearly on objects. It may even cause eyestrain or headaches due to the extra effort required to see clearly.

While chromatic aberration, spherical aberration, and coma can also impact visual performance, they are typically less concerning for spectacle lenses than marginal astigmatism because they usually cause less distortion in the central field of vision where most visual tasks take place. Spectacle lenses are primarily designed to correct for astigmatism, which makes it a priority for the comfort and satisfaction of the wearer.