What procedure is used to determine the correct prescription for glasses?

The procedure used to determine the correct prescription for glasses is known as a refraction test. This test is essential in optometry, as it evaluates how light rays are focused onto the retina, which is crucial in determining how well a patient can see. During a refraction test, the optometrist uses a series of lenses to measure the patient's refractive error, such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. The test generally involves utilizing a phoropter, where the patient looks at an eye chart through various lenses, and the optometrist adjusts the lenses until the sharpest vision is achieved.

Retinoscopy, while also a valuable procedure, primarily serves as a preliminary method to estimate a patient’s prescription by observing the reflex of light from the retina as a retinoscope is moved in front of the eye. It provides an approximation of the refractive error but does not refine the prescription in the same manner as a refraction test.

Visual field tests assess the range of a person's peripheral vision, which is crucial for identifying conditions like glaucoma but do not involve determining a prescription for glasses.

Tonometry measures intraocular pressure to help detect glaucoma and other eye conditions but is