Defects of Vision and their Correction
Defects of Vision and their Correction: Overview
This topic explains that when the eye is not able to focus properly, it results in poor vision. The common defects of vision are near-sightedness or myopia, farsightedness and presbyopia. These defects can be corrected by using spherical lenses.
Important Questions on Defects of Vision and their Correction
Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is . What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is .
The far point of a myopic person is in front of the eye. What is the nature and power of the lens required to correct the problem?
A person needs a lens of power diopters for correcting his distant vision. For correcting his near vision, he needs a lens of power diopter. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?
A student has difficulty reading the blackboard while sitting in the last row. What could be the defect which the child is suffering from? How can it be corrected?
A person with a myopic eye cannot see objects beyond distinctly. What should be the type of the corrective lens used to restore proper vision?
What is meant by power of accommodation of the eye?
