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Quiz yourself on Nervous SystemGet your flashcardsBuild my revision planTrack my progress⚙️ Accommodation: How the Eye Focuses
Accommodation is the process by which the lens changes shape to focus light from objects at different distances onto the retina. The ciliary muscles and suspensory ligaments work together to control the lens.
| Feature | Focusing on a Near Object | Focusing on a Distant Object |
|---|---|---|
| Ciliary muscles | Contract (get shorter and fatter) | Relax (get longer and thinner) |
| Suspensory ligaments | Loosen (go slack) | Tighten (become taut/pulled tight) |
| Lens shape | Thick and curved (rounds up) | Thin and flat (pulled thin) |
| Refraction | Refracts light more (bends it more sharply) | Refracts light less (bends it gently) |
Common confusion: Many students get the ciliary muscles the wrong way around. Remember: when the ciliary muscles contract, they move inward, which takes the tension off the suspensory ligaments. This lets the elastic lens spring into its natural, rounded shape. Think of it like this: the muscles are pulling on a hat — when they pull tight (contract), the hat rim goes slack.
Memory trick: "Near = Need muscles to Contract" — focusing on near objects requires active effort from the ciliary muscles.
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