Certified Paraoptometric (CPO) Practice Exam

An autorefractor is an instrument designed to provide an estimated prescription for corrective lenses based on objective measurements. It operates by shining light into the eye and measuring how the light is reflected off the retina. This automated process does not require the patient's subjective feedback or responses, making it particularly useful for quickly obtaining an initial assessment of refractive error.

In contrast, while a phoropter is an instrument used in refraction that allows for fine-tuning of the lens prescription based on the patient's responses to various lenses, it relies heavily on patient feedback to reach a final prescription. A slit lamp is primarily used for examining the anterior segment of the eye and does not provide refractive information. A retinoscope, although it measures how light moves through the eye to assess refractive error, ultimately requires manual interpretation often involving the input of the patient's subjective responses.

Thus, the autorefractor stands out in its ability to provide a prescription estimate independently of patient input, making it the correct choice in this context.