Answer: Visual acuity: sharpness of vision.
Myopia: nearsightedness
Refraction: bending of light rays.
Emmetropia: normal vision.
Accommodation: changes the shape of the eye lens to focus light on the retina.
Presbyopia: age-related farsightedness due to loss of elasticity in the lens.
Astigmatism: reduction in visual acuity due to changes in the cornea or lens.
Hyperopia: farsightedness
Myopia and hyperopia are refractive errors of the eye.
Presbyopia occurs in old age people.
Explanation:
Visual acuity: It can be defined as the inability to observe the details of shape of the object. Person loses sharpness in vision.
Myopia: It is a defect in vision in which person is able to observe the near by objects clearly but not able to see the distant objects.
Refraction: It can be defined as the bending of beam of light when it passes through from one substance to another.
Emmetropia: It is a vision without any defect.
Accommodation: It is the ability of the eye to adjust its focal length and adjusting the light on focus.
Presbyopia: It can be defined as the loss of ability of eye to focus on the object. It occurs in old age.
Astigmatism: It is a refractive error in which the eye does not focus light on retina.
Hyperopia: It is also called as farsightedness. Distant objects can be seen clearly but nearby appears blurry.
