The working lens used in retinoscopy simulates working at what distance?

In retinoscopy, the working lens is designed to simulate viewing objects at a distance equivalent to infinity. This is because the procedure aims to assess the refractive error of the eye by projecting light into the patient's eye and observing the reflection. When the light source is positioned at infinity, it ensures that the incoming light rays are essentially parallel, which is crucial for evaluating how well the patient's eye focuses that light on the retina.

By simulating this condition, the optometrist can accurately determine the refractive state of the eye by observing the movements and characteristics of the retinal reflex. This method helps to identify whether the patient is hyperopic (farsighted), myopic (nearsighted), or emmetropic (normal vision). As practitioners typically consider object distances at infinity for the assessment during retinoscopy, this principle simplifies finding the appropriate corrective lenses needed to achieve clear vision at standard viewing distances.

The other distances mentioned, such as 10 meters, 20 feet, and 3 meters, do not reflect this simulation effectively, as they involve object distances that would not provide the same information regarding the eye's focusing capabilities as the infinity setting does.