What is an aberration in optical terms?

An aberration in optical terms refers to a defect in a lens or optical system that leads to distortion or deviation from ideal image formation. This occurs when light rays do not converge at a single point, resulting in blurriness or other distortive effects in the image produced. Different types of aberrations can include spherical aberration, chromatic aberration, and astigmatism, all of which impact the clarity and quality of the images that lenses can create. Understanding lens aberrations is crucial for optometrists and opticians, as it affects the design of corrective lenses and optics used in various devices. The other options pertain to different areas of vision and eye health but do not define what optical aberration is.