Final answer:
Cycloplegic refraction and manifest refraction are two methods used to measure an individual's refractive error. Cycloplegic refraction involves using eye drops to temporarily paralyze the ciliary muscle in the eye, while manifest refraction is performed without the use of eye drops.
Step-by-step explanation:
Cycloplegic refraction and manifest refraction are two methods used to measure an individual's refractive error.
Cycloplegic refraction involves using eye drops to temporarily paralyze the ciliary muscle in the eye. This prevents accommodation, or the ability to focus, allowing for a more accurate measurement of the eye's refractive error. It is commonly used in children or when accurate measurements are difficult to obtain using other methods.
Manifest refraction, on the other hand, is performed without the use of eye drops. The individual is asked to provide subjective feedback on which lens choices provide the clearest vision. This method is commonly used in adults to determine the appropriate prescription for glasses or contact lenses.