IGNOU PHE 9 2016 - b) Discuss the significance of accommodation and convergence of human

Question

b) Discuss the significance of accommodation and convergence of human eye in respect of perception of light.

13 Nov 2017

Answer :

Word Count : 352

Accommodation (Acc) is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies.

Accommodation acts like a reflex, but can also be consciously controlled. Mammals, birds and reptiles vary the optical power by changing the form of the elastic lens using the ciliary body (in humans up to 15 dioptres). Fish and amphibians vary the power by changing the distance between a rigid lens and the retina with muscles.[1]

Image ignouacademy-com--p-discuss-14242

Duane's classical curves showing the amplitude or width of accommodation as changing with age. Mean (B) and approximate lower (A) and upper (C) standard deviations are

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