What type of refractometry is exemplified by retinoscopy?

Retinoscopy is a method used to determine an individual's refractive error and is categorized as an objective form of refractometry. In retinoscopy, the examiner uses a retinoscope to observe the reflection of light off the retina while moving a light source in front of the patient's eye. This allows the practitioner to assess how light rays are being refracted by the eye without relying on the patient's subjective feedback about their vision.

Objective refractometry techniques, such as retinoscopy, provide measurements that do not depend on any responses from the patient regarding what they see, which is a defining characteristic of objective methods. This is particularly useful in cases where the patient may be unable to communicate effectively, such as in young children or individuals with cognitive impairments.

In contrast, subjective methods rely on patient responses, such as using phoropters during refraction tests where individuals indicate which lens makes their vision clearer. Hence, retinoscopy distinctly fits the category of objective refractometry.