Most mammals cannot accommodate. In fish and amphibians, focusing is achieved, camera-style, by moving the lens backward and forward in relation to the retina.
A young person's ability to accommodate allows him or her to see clearly far away and up close. At about the age of 40, the lens starts to become less flexible and accommodation is gradually lost, making close-range work increasingly difficult. This condition is known as presbyopia.
Related categories• ANATOMY AND PHYSIOLOGY
• OPTICS AND OPTICAL PHENOMENA
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