American Board of Ophthalmology (ABO) Practice Exam

In optics, what is the effect of an aspheric lens compared to a typical spherical lens?

1. It is less prone to aberrations.

2. It has a uniformly curved surface.

3. It increases light dispersion.

4. It has a higher index of refraction.

The correct answer is: It is less prone to aberrations.

An aspheric lens is designed with a surface profile that is not perfectly spherical; this unique shape helps to minimize optical aberrations, which are flaws in the image produced by lenses. Unlike spherical lenses, which can introduce various types of aberrations such as spherical aberration and coma, aspheric lenses are engineered to provide a more precise focus by allowing for a more complex curvature that effectively compensates for these distortions. By addressing aberrations more effectively, aspheric lenses can produce sharper images across a wider field of view, making them particularly useful in applications like high-performance eyeglasses, camera lenses, and intraocular lenses. This advantage in image quality is a significant reason they are preferred in many advanced optical systems, as it leads to improved visual clarity and accuracy. The other choices don't align with the primary characteristics and advantages of aspheric lenses. While they may have specific benefits, they do not accurately capture the principal reason why aspheric lenses are favored over spherical ones in reducing optical aberrations.