Defects of Vision
Physics ⇒ Light and Optics
Defects of Vision starts at 9 and continues till grade 12.
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See sample questions for grade 11
A person can see nearby objects clearly but distant objects appear blurred. Which defect of vision does the person have?
A person’s near point is 50 cm. What is the power of the lens required to correct this defect? (Assume normal near point is 25 cm)
Describe how a concave lens corrects myopia.
Describe how bifocal lenses help people with presbyopia.
Explain the main cause of hypermetropia.
Explain why a convex lens is used to correct hypermetropia.
Explain why a person with hypermetropia cannot see nearby objects clearly.
If a person’s far point is 2 m, what is the focal length of the lens required to correct their myopia?
If the image of a distant object is formed in front of the retina, the eye suffers from which defect?
State one main difference between myopia and hypermetropia.
Which defect of vision is associated with aging and often requires bifocal lenses for correction?
A person with myopia has a far point at 1.5 m. Calculate the power (in diopters) of the lens required to correct this defect so that the person can see distant objects clearly. (Assume the lens is placed very close to the eye.)
A person’s near point is 100 cm. What is the focal length (in cm) of the lens required to correct this defect so that the person can read at 25 cm?
Explain why a person with astigmatism may see vertical lines clearly but horizontal lines appear blurred. Include the role of the cornea or lens in your answer.
Explain, with reference to the structure of the eye, why laser surgery can be used to correct myopia.
State the main optical difference between the correction of myopia and hypermetropia in terms of the type of lens used and the effect on the focal point of the eye.
