Human Eye and Its Defects MCQ Quiz - Objective Question with Answer for Human Eye and Its Defects - Download Free PDF

The correct answer is Blind spot.

Key Points

• The blind spot in the human eye is the area on the retina where the optic nerve exits the eye, also known as the optic disc.
• This region lacks photoreceptor cells (rods and cones), making it insensitive to light.
• The blind spot is located slightly nasal to the fovea in the visual field of each eye.
• Despite the presence of a blind spot, the brain compensates for it by using information from the other eye or by filling in the missing details, making it unnoticeable under normal circumstances.
• The phenomenon of the blind spot was first discovered by the French scientist Edme Mariotte in the 17th century.

Additional Information

• Fovea
  • The fovea is a small depression in the retina that contains a high concentration of cones.
  • It is responsible for sharp central vision, enabling activities like reading and driving.
• Photoreceptor Cells
  • There are two types of photoreceptor cells in the retina: rods and cones.
  • Rods are sensitive to low light and help in night vision, while cones are responsible for color vision and work better in bright light.
• Optic Nerve
  • The optic nerve transmits visual information from the retina to the brain.
  • It is composed of over a million nerve fibers and plays a crucial role in the visual system.
• Visual Field
  • The visual field is the total area visible to an eye when it is focused on a central point.
  • Each eye has its own blind spot, and their positioning prevents overlap in binocular vision.

The Correct answer is Presbyopia

Key Points

• Presbyopia is a defect of vision that typically occurs with age, especially after the age of 40.
• This condition is caused by the weakening of the ciliary muscles, which are responsible for changing the shape of the eye's lens to focus on objects at different distances.
• As the ciliary muscles become less flexible with age, the ability to focus on nearby objects diminishes, causing difficulty in reading and performing close-up tasks.
• Presbyopia is often corrected with reading glasses or bifocal lenses, which help improve near vision.
• Unlike other refractive errors, presbyopia is a natural part of the aging process and is not caused by external factors like injury or disease.

 Additional Information

• Astigmatism
  • Astigmatism is a refractive error where the cornea or lens is irregularly shaped, causing blurry vision at all distances.
  • This condition is typically corrected using glasses or contact lenses that compensate for the irregular curvature.
  • Unlike presbyopia, astigmatism can affect individuals at any age, and it is not related to aging.
• Hypermetropia (Farsightedness)
  • Hypermetropia is a condition where distant objects are seen more clearly than nearby objects.
  • This occurs when the eye is too short, or the cornea has too little curvature, causing light to focus behind the retina.
  • Hypermetropia can be corrected with glasses or contact lenses that focus light onto the retina.
• Myopia (Nearsightedness)
  • Myopia is a condition where nearby objects are seen clearly, but distant objects appear blurry.
  • This occurs when the eye is too long, or the cornea has too much curvature, causing light to focus in front of the retina.
  • Myopia is typically corrected with glasses or contact lenses that adjust the focal point to the retina.

The correct answer is Presbyopia.

Key Points

• Presbyopia is a common age-related vision defect caused by the weakening of ciliary muscles and loss of elasticity in the eye's lens.
• It typically occurs after the age of 40 years and progressively worsens with age.
• This condition results in difficulty focusing on nearby objects, often requiring reading glasses or bifocals for correction.
• Presbyopia is a natural part of the aging process and cannot be prevented, but it can be effectively managed with corrective lenses or surgical options.
• Unlike other refractive errors, Presbyopia is not caused by the shape of the cornea or the eyeball, but by age-induced changes in the eye's focusing ability.

Additional Information

• Myopia (Nearsightedness)
  • It is a refractive error where distant objects appear blurry, caused by the elongation of the eyeball or excessive curvature of the cornea.
  • It is corrected using concave lenses or refractive surgeries like LASIK.
• Hypermetropia (Farsightedness)
  • A condition where close objects appear blurry due to the eyeball being too short or the cornea being too flat.
  • It is corrected using convex lenses or surgical options like lens replacement.
• Astigmatism
  • It occurs due to an irregularly shaped cornea or lens, causing blurred or distorted vision.
  • This condition can affect both near and far vision and is corrected using cylindrical lenses.
• Accommodation of the Eye
  • The process by which the eye's lens changes shape to focus on objects at varying distances.
  • Presbyopia occurs when the lens loses this flexibility with age, leading to difficulty in near vision.

The correct answer is Iris.

Key Points

• The iris is a thin, circular structure in the eye responsible for controlling the diameter and size of the pupil.
• It regulates the amount of light entering the eye by adjusting the pupil size, which is essential for optimal vision.
• The iris contains muscles that contract and expand to adjust the pupil size in response to varying light conditions.
• The color of the iris is what gives the eye its color, varying from blue, green, brown, etc.
• The process by which the iris adjusts the pupil size is known as the pupillary light reflex.

Additional Information

• Retina
  • The retina is the light-sensitive layer at the back of the eye that converts light into electrical signals.
  • It contains photoreceptor cells called rods and cones that detect light intensity and color.
  • The retina plays a crucial role in forming visual images and transmitting them to the brain via the optic nerve.
• Cornea
  • The cornea is the transparent, dome-shaped front layer of the eye that covers the iris, pupil, and anterior chamber.
  • It plays a key role in focusing light onto the retina, contributing to the eye's overall refractive power.
  • The cornea is avascular, meaning it has no blood vessels, and receives nutrients from tears and aqueous humor.
• Pupil
  • The pupil is the black circular opening in the center of the iris that allows light to enter the eye.
  • Its size is regulated by the iris muscles, contracting in bright light and dilating in low light to control light intake.
  • The pupil's adjustment is an essential part of the eye's response to different lighting conditions.

The correct answer is Lens type d.

Key Points

• A concave lens (Lens type d) is used to correct myopia (nearsightedness).
• Myopia occurs when the eye is too long or the cornea is too curved, causing light rays to focus in front of the retina.
• A concave lens diverges light rays before they enter the eye, allowing them to focus directly on the retina.
• Concave lenses are thinner at the center and thicker at the edges.
• This type of lens is prescribed based on the degree of myopia, measured in diopters.

Additional Information

• Hyperopia (Farsightedness)
  • Occurs when the eye is too short or the cornea has too little curvature.
  • Light rays focus behind the retina, making nearby objects appear blurry.
  • A convex lens is used to correct hyperopia by converging light rays before they enter the eye.
• Astigmatism
  • Caused by an irregular curvature of the cornea or lens.
  • Leads to distorted or blurred vision at all distances.
  • Cylindrical lenses are used to correct astigmatism, specifically tailored to the irregular curvature.
• Presbyopia
  • Age-related condition where the eye's lens loses elasticity.
  • Difficulty in focusing on close objects, common in people over 40.
  • Corrected with bifocal or progressive lenses.

The correct answer is Iris.

Key Points

• The iris is a thin, circular structure in the eye responsible for controlling the diameter and size of the pupil.
• It regulates the amount of light entering the eye by adjusting the pupil size, which is essential for optimal vision.
• The iris contains muscles that contract and expand to adjust the pupil size in response to varying light conditions.
• The color of the iris is what gives the eye its color, varying from blue, green, brown, etc.
• The process by which the iris adjusts the pupil size is known as the pupillary light reflex.

Additional Information

• Retina
  • The retina is the light-sensitive layer at the back of the eye that converts light into electrical signals.
  • It contains photoreceptor cells called rods and cones that detect light intensity and color.
  • The retina plays a crucial role in forming visual images and transmitting them to the brain via the optic nerve.
• Cornea
  • The cornea is the transparent, dome-shaped front layer of the eye that covers the iris, pupil, and anterior chamber.
  • It plays a key role in focusing light onto the retina, contributing to the eye's overall refractive power.
  • The cornea is avascular, meaning it has no blood vessels, and receives nutrients from tears and aqueous humor.
• Pupil
  • The pupil is the black circular opening in the center of the iris that allows light to enter the eye.
  • Its size is regulated by the iris muscles, contracting in bright light and dilating in low light to control light intake.
  • The pupil's adjustment is an essential part of the eye's response to different lighting conditions.

The Correct answer is Presbyopia

Key Points

• Presbyopia is a defect of vision that typically occurs with age, especially after the age of 40.
• This condition is caused by the weakening of the ciliary muscles, which are responsible for changing the shape of the eye's lens to focus on objects at different distances.
• As the ciliary muscles become less flexible with age, the ability to focus on nearby objects diminishes, causing difficulty in reading and performing close-up tasks.
• Presbyopia is often corrected with reading glasses or bifocal lenses, which help improve near vision.
• Unlike other refractive errors, presbyopia is a natural part of the aging process and is not caused by external factors like injury or disease.

 Additional Information

• Astigmatism
  • Astigmatism is a refractive error where the cornea or lens is irregularly shaped, causing blurry vision at all distances.
  • This condition is typically corrected using glasses or contact lenses that compensate for the irregular curvature.
  • Unlike presbyopia, astigmatism can affect individuals at any age, and it is not related to aging.
• Hypermetropia (Farsightedness)
  • Hypermetropia is a condition where distant objects are seen more clearly than nearby objects.
  • This occurs when the eye is too short, or the cornea has too little curvature, causing light to focus behind the retina.
  • Hypermetropia can be corrected with glasses or contact lenses that focus light onto the retina.
• Myopia (Nearsightedness)
  • Myopia is a condition where nearby objects are seen clearly, but distant objects appear blurry.
  • This occurs when the eye is too long, or the cornea has too much curvature, causing light to focus in front of the retina.
  • Myopia is typically corrected with glasses or contact lenses that adjust the focal point to the retina.

The correct answer is Presbyopia.

Key Points

• Presbyopia is a common age-related vision defect caused by the weakening of ciliary muscles and loss of elasticity in the eye's lens.
• It typically occurs after the age of 40 years and progressively worsens with age.
• This condition results in difficulty focusing on nearby objects, often requiring reading glasses or bifocals for correction.
• Presbyopia is a natural part of the aging process and cannot be prevented, but it can be effectively managed with corrective lenses or surgical options.
• Unlike other refractive errors, Presbyopia is not caused by the shape of the cornea or the eyeball, but by age-induced changes in the eye's focusing ability.

Additional Information

• Myopia (Nearsightedness)
  • It is a refractive error where distant objects appear blurry, caused by the elongation of the eyeball or excessive curvature of the cornea.
  • It is corrected using concave lenses or refractive surgeries like LASIK.
• Hypermetropia (Farsightedness)
  • A condition where close objects appear blurry due to the eyeball being too short or the cornea being too flat.
  • It is corrected using convex lenses or surgical options like lens replacement.
• Astigmatism
  • It occurs due to an irregularly shaped cornea or lens, causing blurred or distorted vision.
  • This condition can affect both near and far vision and is corrected using cylindrical lenses.
• Accommodation of the Eye
  • The process by which the eye's lens changes shape to focus on objects at varying distances.
  • Presbyopia occurs when the lens loses this flexibility with age, leading to difficulty in near vision.

The correct answer is Lens type d.

Key Points

• A concave lens (Lens type d) is used to correct myopia (nearsightedness).
• Myopia occurs when the eye is too long or the cornea is too curved, causing light rays to focus in front of the retina.
• A concave lens diverges light rays before they enter the eye, allowing them to focus directly on the retina.
• Concave lenses are thinner at the center and thicker at the edges.
• This type of lens is prescribed based on the degree of myopia, measured in diopters.

Additional Information

• Hyperopia (Farsightedness)
  • Occurs when the eye is too short or the cornea has too little curvature.
  • Light rays focus behind the retina, making nearby objects appear blurry.
  • A convex lens is used to correct hyperopia by converging light rays before they enter the eye.
• Astigmatism
  • Caused by an irregular curvature of the cornea or lens.
  • Leads to distorted or blurred vision at all distances.
  • Cylindrical lenses are used to correct astigmatism, specifically tailored to the irregular curvature.
• Presbyopia
  • Age-related condition where the eye's lens loses elasticity.
  • Difficulty in focusing on close objects, common in people over 40.
  • Corrected with bifocal or progressive lenses.

The correct answer is Iris.

Key Points

• The iris is a thin, circular structure in the eye responsible for controlling the diameter and size of the pupil.
• It regulates the amount of light entering the eye by adjusting the pupil size, which is essential for optimal vision.
• The iris contains muscles that contract and expand to adjust the pupil size in response to varying light conditions.
• The color of the iris is what gives the eye its color, varying from blue, green, brown, etc.
• The process by which the iris adjusts the pupil size is known as the pupillary light reflex.

Additional Information

• Retina
  • The retina is the light-sensitive layer at the back of the eye that converts light into electrical signals.
  • It contains photoreceptor cells called rods and cones that detect light intensity and color.
  • The retina plays a crucial role in forming visual images and transmitting them to the brain via the optic nerve.
• Cornea
  • The cornea is the transparent, dome-shaped front layer of the eye that covers the iris, pupil, and anterior chamber.
  • It plays a key role in focusing light onto the retina, contributing to the eye's overall refractive power.
  • The cornea is avascular, meaning it has no blood vessels, and receives nutrients from tears and aqueous humor.
• Pupil
  • The pupil is the black circular opening in the center of the iris that allows light to enter the eye.
  • Its size is regulated by the iris muscles, contracting in bright light and dilating in low light to control light intake.
  • The pupil's adjustment is an essential part of the eye's response to different lighting conditions.

The Correct answer is Presbyopia

Key Points

• Presbyopia is a defect of vision that typically occurs with age, especially after the age of 40.
• This condition is caused by the weakening of the ciliary muscles, which are responsible for changing the shape of the eye's lens to focus on objects at different distances.
• As the ciliary muscles become less flexible with age, the ability to focus on nearby objects diminishes, causing difficulty in reading and performing close-up tasks.
• Presbyopia is often corrected with reading glasses or bifocal lenses, which help improve near vision.
• Unlike other refractive errors, presbyopia is a natural part of the aging process and is not caused by external factors like injury or disease.

 Additional Information

• Astigmatism
  • Astigmatism is a refractive error where the cornea or lens is irregularly shaped, causing blurry vision at all distances.
  • This condition is typically corrected using glasses or contact lenses that compensate for the irregular curvature.
  • Unlike presbyopia, astigmatism can affect individuals at any age, and it is not related to aging.
• Hypermetropia (Farsightedness)
  • Hypermetropia is a condition where distant objects are seen more clearly than nearby objects.
  • This occurs when the eye is too short, or the cornea has too little curvature, causing light to focus behind the retina.
  • Hypermetropia can be corrected with glasses or contact lenses that focus light onto the retina.
• Myopia (Nearsightedness)
  • Myopia is a condition where nearby objects are seen clearly, but distant objects appear blurry.
  • This occurs when the eye is too long, or the cornea has too much curvature, causing light to focus in front of the retina.
  • Myopia is typically corrected with glasses or contact lenses that adjust the focal point to the retina.

The correct answer is Presbyopia.

Key Points

• Presbyopia is a common age-related vision defect caused by the weakening of ciliary muscles and loss of elasticity in the eye's lens.
• It typically occurs after the age of 40 years and progressively worsens with age.
• This condition results in difficulty focusing on nearby objects, often requiring reading glasses or bifocals for correction.
• Presbyopia is a natural part of the aging process and cannot be prevented, but it can be effectively managed with corrective lenses or surgical options.
• Unlike other refractive errors, Presbyopia is not caused by the shape of the cornea or the eyeball, but by age-induced changes in the eye's focusing ability.

Additional Information

• Myopia (Nearsightedness)
  • It is a refractive error where distant objects appear blurry, caused by the elongation of the eyeball or excessive curvature of the cornea.
  • It is corrected using concave lenses or refractive surgeries like LASIK.
• Hypermetropia (Farsightedness)
  • A condition where close objects appear blurry due to the eyeball being too short or the cornea being too flat.
  • It is corrected using convex lenses or surgical options like lens replacement.
• Astigmatism
  • It occurs due to an irregularly shaped cornea or lens, causing blurred or distorted vision.
  • This condition can affect both near and far vision and is corrected using cylindrical lenses.
• Accommodation of the Eye
  • The process by which the eye's lens changes shape to focus on objects at varying distances.
  • Presbyopia occurs when the lens loses this flexibility with age, leading to difficulty in near vision.

The correct answer is Blind spot.

Key Points

• The blind spot in the human eye is the area on the retina where the optic nerve exits the eye, also known as the optic disc.
• This region lacks photoreceptor cells (rods and cones), making it insensitive to light.
• The blind spot is located slightly nasal to the fovea in the visual field of each eye.
• Despite the presence of a blind spot, the brain compensates for it by using information from the other eye or by filling in the missing details, making it unnoticeable under normal circumstances.
• The phenomenon of the blind spot was first discovered by the French scientist Edme Mariotte in the 17th century.

Additional Information

• Fovea
  • The fovea is a small depression in the retina that contains a high concentration of cones.
  • It is responsible for sharp central vision, enabling activities like reading and driving.
• Photoreceptor Cells
  • There are two types of photoreceptor cells in the retina: rods and cones.
  • Rods are sensitive to low light and help in night vision, while cones are responsible for color vision and work better in bright light.
• Optic Nerve
  • The optic nerve transmits visual information from the retina to the brain.
  • It is composed of over a million nerve fibers and plays a crucial role in the visual system.
• Visual Field
  • The visual field is the total area visible to an eye when it is focused on a central point.
  • Each eye has its own blind spot, and their positioning prevents overlap in binocular vision.

The correct answer is Option 2.

Key Points

• Neha's mother is suffering from hypermetropia, a condition where the near point of her eye is farther than normal, making it difficult to focus on nearby objects like a newspaper.
• In hypermetropia, the image is formed behind the retina, leading to difficulty in near vision.
• A convex lens is prescribed to correct hypermetropia as it helps converge light rays onto the retina.
• Hypermetropia is primarily caused by either a shortened eyeball or reduced curvature of the lens, making it less effective at focusing light.
• The statements i, ii, and iii are correct, as they describe the condition and the corrective measure accurately.

Additional Information

• Hypermetropia (Farsightedness):
  • It is a refractive defect of vision where distant objects are seen clearly but nearby objects appear blurred.
  • It can be corrected using a convex lens to focus light rays onto the retina.
  • Common causes include genetic factors, aging, or structural abnormalities of the eye.
• Convex Lens:
  • A convex lens is thicker in the middle and converges light rays.
  • It is used to treat hypermetropia by adjusting the focal point onto the retina.
• Retina and Image Formation:
  • The retina is the light-sensitive layer at the back of the eye where images are formed.
  • In hypermetropia, images are formed behind the retina due to improper focusing.
• Other Common Vision Defects:
  • Myopia (nearsightedness): Corrected with concave lenses.
  • Presbyopia: Age-related loss of near vision, often requiring bifocal or progressive lenses.

The correct answer is Lens type d.

Key Points

• A concave lens (Lens type d) is used to correct myopia (nearsightedness).
• Myopia occurs when the eye is too long or the cornea is too curved, causing light rays to focus in front of the retina.
• A concave lens diverges light rays before they enter the eye, allowing them to focus directly on the retina.
• Concave lenses are thinner at the center and thicker at the edges.
• This type of lens is prescribed based on the degree of myopia, measured in diopters.

Additional Information

• Hyperopia (Farsightedness)
  • Occurs when the eye is too short or the cornea has too little curvature.
  • Light rays focus behind the retina, making nearby objects appear blurry.
  • A convex lens is used to correct hyperopia by converging light rays before they enter the eye.
• Astigmatism
  • Caused by an irregular curvature of the cornea or lens.
  • Leads to distorted or blurred vision at all distances.
  • Cylindrical lenses are used to correct astigmatism, specifically tailored to the irregular curvature.
• Presbyopia
  • Age-related condition where the eye's lens loses elasticity.
  • Difficulty in focusing on close objects, common in people over 40.
  • Corrected with bifocal or progressive lenses.