How does the eye form an image?

How does the eye form an image?

• A. By refraction in the lens only.
• B. Through sequential refraction: corneal refraction, lens accommodation, and retina image capture.
• C. By a single refraction at the cornea.
• D. Through retinal photoreceptor focusing.

Answer: (B)

Light is bent as it travels through the eye in steps, not all at once. The cornea provides most of the focusing power because of the large air–cornea refractive difference. The lens then adds fine-tuning power and changes shape during accommodation to focus objects at different distances. This sequential refraction brings a sharp image to the retina, where photoreceptors detect the light and convert it into neural signals. The retina holds the image, which is actually inverted, and the brain later interprets it. So, focusing isn’t done by the cornea alone and isn’t performed by photoreceptors; it’s achieved by the combined refraction of the cornea and the lens, with accommodation adjusting the lens for distance.

Light is bent as it travels through the eye in steps, not all at once. The cornea provides most of the focusing power because of the large air–cornea refractive difference. The lens then adds fine-tuning power and changes shape during accommodation to focus objects at different distances. This sequential refraction brings a sharp image to the retina, where photoreceptors detect the light and convert it into neural signals. The retina holds the image, which is actually inverted, and the brain later interprets it. So, focusing isn’t done by the cornea alone and isn’t performed by photoreceptors; it’s achieved by the combined refraction of the cornea and the lens, with accommodation adjusting the lens for distance.