In ophthalmology, what does the term "refraction" refer to?

Refraction in ophthalmology specifically refers to the bending of light as it passes through different mediums, such as the cornea and lens of the eye. This process is crucial because it determines how light is focused onto the retina, the light-sensitive layer at the back of the eye that transmits visual information to the brain.

When light enters the eye, it first passes through the cornea, which is responsible for most of the eye's total optical power. It then travels through the aqueous humor, the lens, and finally the vitreous humor before reaching the retina. Each of these components has a different refractive index, influencing how light is bent. Accurate refraction is essential for diagnosing vision problems and determining the correct prescriptions for glasses or contact lenses to ensure that images are focused properly for clear vision.

Understanding refraction helps practitioners address various vision issues, such as myopia (nearsightedness) and hyperopia (farsightedness), by calculating the appropriate lens power needed to achieve optimal focus.