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What is Accommodation is brought about by: and explain in detail?
Ans: d (Ciliary body contraction) Ref:Ganong, 22th ed, p. 154Accommodation is brought about by ciliary muscle contractionAccommodationThe process by which the curvature of the lens is increased is called accommodation.Mechanism: At rest the lens is under tension by lens ligaments & lens is pulled into a flattened state.When the gaze is directed towards a nearby object, ciliary muscle contracts. This decreases the distance between the edges of ciliary body & relaxes lens ligaments so that the lens attains a more convex shape. The change is maximum at the anterior surface of the lens (i.e., radius of curvature changes from 10 mm to 6 mm). The curvature of the posterior surface remains almost the same (i.e., 6 mm). This may add as many as 12 D to the refractive power of eye.