A simple retinoscope with a small central plane mirror from the late 19th/early 20th century. It has non folding metal handle and a wide mat black surround and comes in a black leather wallet.
The early retinoscopes were just a perforated mirror on the end of a handle. As optometrists continued to use them into the modern era dating them accurately can be difficult.
Retinoscopy is a technique done at arms length to calculate the refractive error by measuring the reflexion (reflex) of light from the patient’s retina. Whilst moving a spot of light across the pupil, the examiner observes the relative movement of the reflex and can “neutralise” the reflex by placing lenses of varying strength over the eye, hence calculating the refraction. It is an objective test and is useful in prescribing lenses for children or patients communication difficulties which would prevent subjective input.