Tag: defects of eye
Questions Related to defects of eye
Reduction in elasticity of eye lens with age causes ________.
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Myopia
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Presbyopia
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Cataract
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Hypermetropia
Correct Option: B
Explanation:
A. Myopia occurs when eye ball becomes longer and it results in the formation of image in front of retina. It is corrected using concave lens which diverge the light rays to get focussed on the retina.
B. Presbyopia occurs in the late age (generally after 40 years) due to loss of elasticity of eye lens due to which nearby objects are not correctly visible. It is corrected by using bifocal lengths.
C. Cataract is an eye disease that occurs in older people. The visibility is reduced because the eye lens becomes opaque. It is treated by surgery.
D. Hypermetropia occurs when eye ball becomes shorter and it results in the formation of image behind the retina. It is corrected using convex lens which focus the light rays on the retina.
So, the correct answer is 'Presbyopia'.
The defective condition of eye in which distant objects are seen distinct but near objects are indistinct is called
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Myopia
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Astigmatism
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Presbyopia
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Hypermetropia
Correct Option: D
Explanation:
A. Myopia,, also known as short-sightedness, occurs when eye ball becomes longer and it results in the formation of image in front of retina. The nearby objects are seen clearly but distant objects can't be seen. It is corrected using concave lens which diverge the light rays to get focussed on the retina.
B. In astigmatism, the vision gets blurred due to improper of eye's curvature. It is corrected by using cylindrical lens.
C. Presbyopia occurs in the late age (generally after 40 years) due to loss of elasticity of eye lens due to which nearby objects are not correctly visible. It is corrected by using bifocal lengths
D. Hypermetropia , also known as far-sightedness or long-sightedness, occurs when eye ball becomes shorter and it results in the formation of image behind the retina. The distant objects are visible clearly but nearby objects can't be seen clearly and distinctly. It is corrected using convex lens which focus the light rays on the retina.
So, the correct answer is 'Hypermetropia'.
Convex lenses correct
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Presbyopia
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Myopia
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Hypermetropia
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Glaucoma
Correct Option: C
Explanation:
A. Presbyopia occurs in the late age (generally after 40 years) due to loss of elasticity of eye lens due to which nearby objects are not correctly visible. It is corrected by using bifocal lengths.
B. Myopia occurs when eye ball becomes longer and it results in the formation of image in front of retina. It is corrected using concave lens which diverge the light rays to get focussed on the retina.
C. Hypermetropia occurs when eye ball becomes shorter and it results in the formation of image behind the retina. It is corrected using convex lens which focus the light rays on the retina.
D. Glaucoma is a disorder of eye in which the optic nerve which carries visual information to brain, is damaged and this leads to blindness.
So, the correct answer is 'Hypermetropia'.
Colour blindness is due to defect in
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Cones
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Rods
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Rods and cones
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None of the above
Correct Option: A
Explanation:
The retina of eye has two types of photoreceptor cells:
- Rods: These are the photoreceptor cells that contain rhodopsin pigment and associated with scotopic vision of eye i.e. vision under low light.
- Cones: These are the photoreceptor cells that contain iodopsin, porpyrosin and cyanopsin pigments. These cells are associated with the daylight vision and colour vision of eyes.
Colourblindness is a genetic disorder in which there is malfunctioning or defect in the cones. It is a X-linked recessive disorder in which the allele causing this disorder is being carried on the X chromosome.
So, the correct answer is 'Cones'.
Glaucoma is due to
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Blocking of canal of Schlemm
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Drying up of vitreous humor
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Increased size of eye
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Opacity of lens
Correct Option: A
Explanation:
Glaucoma is a disorder of eye in which the optic nerve is damaged and this leads to blindness. It occurs due to increase in pressure of eye (intraocular pressure) when a fluid is built up in the front part of eye. The fluid builds up when it fails to get drained out due to blockage of canal of Schlemn. Canal of Schlemn is a circular canal that lies at the junction of sclera and cornea, through which excess aqueous humour is drained out from the anterior chamber.
So, the correct answer is 'Blocking of canal of Schlemn'.
Myopia is corrected by
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Cylindrical lens
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Bifocal lens
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Biconvex lens
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Biconcave lens
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Plain glass
Correct Option: D
Explanation:
Myopia is also known as short-sightedness. It occurs when the eyeball becomes longer or the eye lens get more convex due to which light rays get focussed at a point before the retina and as a result, image is formed in front of retina. It is corrected by using concave lens that diverge the light rays to get focussed on the retina and thus, the image is formed on the retina.
So, the correct answer is 'Biconcave lens'.
Glaucoma is caused by increase in
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Intra-arterial pressure
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Intraocular pressure
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Intraventricular pressure
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Intravesicular pressure
Correct Option: B
Explanation:
Glaucoma is an eye disease in which optic nerve is damaged and this leads to damage. It occurs due to build up of a fluid in front part of eye due to which pressure inside the eye called intraocular pressure, is increased. The increased pressure leads to damage of optic nerve. Generally the build up fluid drains out through trabecular meshwork but when the build up fluid fails to get drained out, intraocular pressure increases leading to glaucoma. This occurs in old age people frequently.
So, the correct answer is 'Intraocular pressure'.
Which one is incorrect match?
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Myopia - Biconvex lens
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Olfactory - Smell
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Algesireceptor - Pain
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Organ of Corti - Sensory and supporting cells
Correct Option: A
Explanation:
Myopia is a disorder of eye also known as short-sightedness. In this disorder, the vision of distant objects get blurred. The light rays instead of getting focussed on retina, get focussed in front of retina. This occurs because the eyeball gets longer or lens become more convex. It is corrected using concave lens which increase the focal length and the light rays are focussed on the retina.
So, the correct answer is 'Myopia- Biconvex lens'.
Opacity of eye lens leads to
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Glaucoma
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Cataract
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Presbyopia
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Astigamatism
Correct Option: B
Explanation:
A. Glaucoma is a disorder of eye in which the optic nerve which carries visual information to brain, is damaged and this leads to blindness.
B. Cataract is an eye disease that occurs in older people. The visibility is reduced because the eye lens becomes opaque and cloudy. It is treated by surgery.
C. Presbyopia occurs in the late age (generally after 40 years) due to loss of elasticity of eye lens due to which nearby objects are not correctly visible. It is corrected by using bifocal lengths.
D. Astigmatism is a disorder of eye in which there is improper curvature of eye due to which light rays focus inaccurately on retina. It is corrected by using cylindrical lens.
Hence, opacity of eye lens leads to 'Cataract'.
Which of the following disorder is not hereditary?
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Haemophilia
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Cataract
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Sickle cell anaemia
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Colour blindness
Correct Option: B
Explanation:
A. Haemophilia is a X-linked recessive genetic disorder that occurs due to deficiency of clotting factors in the blood and therefore, there is no formation of clot at the site of wound.
B. Cataract is an eye disease that occurs in older people. The visibility is reduced because the eye lens becomes opaque. It is treated by surgery.
C. Sickle cell anaemia is a autosomal recessive genetic disorder in which red blood cells become sickle shaped and this causes oxygen tension in the body.
D. Colour blindness is a X-linked genetic disorder in which there is inability to distinguish colours due to defect in cones (photoreceptor cells associated with daylight vision and colour vision).
Hence, cataract is not hereditary because it is not a genetic disorder.
So, the correct answer is 'Cataract'.