In retinoscopy, which error requires the use of a negative corrective lens?

In retinoscopy, the use of a negative corrective lens is necessary for myopia, which is also known as nearsightedness. Myopia occurs when light entering the eye is focused in front of the retina due to the shape of the eyeball being too long or the cornea having too much curvature.

During a retinoscopy examination, the practitioner observes the reflection of light (the reflex) from the retina in response to the light beam projected into the eye. In a myopic eye, the reflex will appear moving in the same direction as the light. To bring the light focused at the retina, a negative (or concave) lens is introduced, which helps reduce the eye's focusing power, allowing light rays to focus directly on the retina instead of in front of it.

Understanding this process is critical as using a negative lens effectively corrects the visual error caused by myopia, enabling the individual to have clear vision at distance.