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How the eye works

is the process of changing the shape of the lens to focus on near or distant objects.

To focus on a near object - the lens becomes thicker which allows the light rays to refract (bend) more strongly.

To focus on a distant object - the lens is pulled thin which allows the light rays to refract slightly.

Position of objectCiliary musclesSuspensory ligamentsMuscle tension on lensLens shapeRefraction of light rays
NearContractSlacken / loosenLowFat / thickerLight is refracted strongly
DistantRelaxStretched / tightenHighThinLight is only refracted slightly
Position of objectNear
Ciliary musclesContract
Suspensory ligamentsSlacken / loosen
Muscle tension on lensLow
Lens shapeFat / thicker
Refraction of light raysLight is refracted strongly
Position of objectDistant
Ciliary musclesRelax
Suspensory ligamentsStretched / tighten
Muscle tension on lensHigh
Lens shapeThin
Refraction of light raysLight is only refracted slightly
Diagram showing how an image focuses at the retina
Figure caption,
The lens changes shape to focus on near and distant objects