Question 1

Most of the refractive power of the eye is located in which of the following structures?&#10;A)Iris&#10;B)Lens&#10;C)Retina&#10;D)Cornea

Accepted Answer

The cornea provides about 2/3 of the eye's refractive power, while the lens provides the remaining 1/3. The iris is responsible for controlling the amount of light that enters the eye, and the retina is responsible for detecting light and transmitting visual signals to the brain.

Question 2

Hyperopia usually results from which of the following?&#10;A)An unequal curvature of cornea&#10;B)A lens that is too powerful&#10;C)An eyeball that is too short&#10;D)An increase in intraocular pressure

Accepted Answer

Hyperopia, also known as farsightedness, occurs when the eyeball is too short, causing light to focus behind the retina instead of on it. This results in difficulty seeing objects up close. Unequal curvature of the cornea (astigmatism) and a lens that is too powerful (nearsightedness) are other common refractive errors. An increase in intraocular pressure is associated with glaucoma, which can cause vision loss but is not a cause of hyperopia.

Question 3

Which of the following are paired correctly?&#10;A)An increase in resistance to flow through the canal of Schlemm and a decrease in intraocular pressure&#10;B)Myopia and focal point in front of the retina&#10;C)Hyperopia and correction by a concave lens

Accepted Answer

B) Myopia and focal point in front of the retina is correctly paired. Myopia, or nearsightedness, occurs when the eye's focal point falls in front of the retina, causing distant objects to appear blurry.

Question 4

Accommodation will not occur if which of the following nerves is damaged?&#10;A)Facial nerve&#10;B)Vagus nerve&#10;C)Oculomotor nerve&#10;D)Glossopharyngeal nerve

Accepted Answer

Accommodation, the process by which the eye changes optical power to maintain a clear image or focus on an object as its distance varies, involves the ciliary muscles adjusting the lens shape. The oculomotor nerve (Cranial Nerve III) innervates the ciliary muscles responsible for this process. Damage to the oculomotor nerve would impair accommodation.

Question 5

Accommodation for near vision (focusing on an object close at hand) requires which of the following?&#10;A)Constriction of pupil of eye&#10;B)Dilation of pupil of eye&#10;C)Thicker lens&#10;D)Thinner lens

Accepted Answer

Accommodation for near vision requires the lens to become thicker so that it can refract light more strongly and bring the image into focus on the retina. Constriction of the pupil is not directly involved in accommodation and dilation of the pupil is more associated with adaptation to changes in light levels rather than near vision. A thinner lens would actually make it more difficult to focus on objects up close.

Question 6

Which of the following best describes myopia and hyperopia?

Accepted Answer

The answer of Which of the following best describes myopia...

Question 7

What is the leading cause of blindness worldwide?&#10;A)Albinism&#10;B)Cataracts&#10;C)Glaucoma&#10;D)Presbyopia

Accepted Answer

Cataracts are the leading cause of blindness worldwide. They occur when the lens of the eye becomes cloudy, which prevents clear vision.

Question 8

Visual acuity is highest at the fovea centralis partly because each cone cell synapses with multiple ganglion cells in the fovea centralis.&#10;A)Both the statement and the reason are correct and related.&#10;B)Both the statement and the reason are correct but not related.&#10;C)The statement is correct but the reason is not.&#10;D)The statement is not correct, but the reason is correct.&#10;E)Neither the statement nor the reason is correct.

Accepted Answer

The statement that visual acuity is highest at the fovea centralis is correct. However, the reason given that each cone cell synapses with multiple ganglion cells in the fovea centralis is not true. In fact, each cone cell in the fovea centralis synapses with only one bipolar cell, which then synapses with one ganglion cell. This arrangement allows for high resolution and acuity in the center of the visual field.

Question 9

Astigmatism is usually corrected by which of the following?&#10;A)A concave lens&#10;B)A cylindrical lens&#10;C)A convex lens&#10;D)A spherical lens

Accepted Answer

Astigmatism occurs when the cornea or lens of the eye has an irregular shape, resulting in blurred vision. A cylindrical lens is specifically designed to correct astigmatism by counteracting the uneven curvature of the cornea or lens. The other lens types listed (concave, convex, spherical) are used to correct nearsightedness, farsightedness, and general refractive errors, but are not effective in correcting astigmatism.

Question 10

Which of the following is the most important determinant of intraocular pressure?&#10;A)The rate of production of aqueous humor&#10;B)The rate of production of vitreous humor&#10;C)The stiffness of the cornea&#10;D)The resistance to outflow of aqueous humor in the canal of Schlemm

Accepted Answer

The resistance to outflow of aqueous humor in the canal of Schlemm is the most important determinant of intraocular pressure. When there is an increase in resistance to outflow, there is a subsequent increase in intraocular pressure. Therefore, the drainage of aqueous humor through the canal of Schlemm plays a critical role in regulating intraocular pressure. The production of aqueous humor (A), vitreous humor (B), and the stiffness of the cornea (C) also play a role but are not as significant as the resistance to outflow.

Question 11

Astigmatism usually results from which of the following?&#10;A)An unequal curvature of the cornea&#10;B)A lens that is too powerful&#10;C)A lens that is too weak&#10;D)An unequal curvature of the retina

Accepted Answer

The answer of Astigmatism usually results from which of the...

Question 12

Accommodation for far vision (focusing on an object at a distance) requires which of the following?&#10;A)Pupillary constriction&#10;B)Pupillary dilation&#10;C)Thicker lens&#10;D)Thinner lens

Accepted Answer

The answer of Accommodation for far vision (focusing on an...

Question 13

A 70-year-old woman with eye pain has an intraocular pressure of 25 mm Hg. Which of the following most likely explains this value?&#10;A)Decreased hydraulic resistance of trabecular meshwork&#10;B)Decreased production of aqueous humor&#10;C)Increased hydraulic resistance of trabecular meshwork&#10;D)Increased production of aqueous humor

Accepted Answer

The answer of A 70-year-old woman with eye pain has...

Question 14

During accommodation in a 10-year-old child, contraction of the ciliary muscle is most likely to achieve which of the following?&#10;A)Relaxation of suspensory ligament only&#10;B)Thicker lens and relaxation of suspensory ligament&#10;C)Thicker lens only&#10;D)Thinner lens and relaxation of suspensory ligament&#10;E)Thinner lens only

Accepted Answer

The answer of During accommodation in a 10-year-old child, contraction...

Question 15

All the following conditions can be corrected by placing a lens system in front of the eye except:&#10;A)Cataracts&#10;B)Hyperopia&#10;C)Myopia&#10;D)Presbyopia

Accepted Answer

The answer of All the following conditions can be corrected...

Question 16

The condition of hyperopia is usually corrected by which of the following?&#10;A)A concave lens&#10;B)A convex lens&#10;C)A spherical lens&#10;D)A Schmidt-Cassegrain lens

Accepted Answer

The answer of The condition of hyperopia is usually corrected...

Question 17

Which of the following lenses has the greatest refractive power?&#10;A)59 diopter lens&#10;B)25 diopter lens&#10;C)200 diopter lens&#10;D)100 diopter lens

Accepted Answer

The answer of Which of the following lenses has the...

Question 18

Which of the following refractive problems most closely resembles presbyopia?&#10;A)Myopia&#10;B)Astigmatism&#10;C)Hyperopia&#10;D)Cataracts

Accepted Answer

The answer of Which of the following refractive problems most...

Question 19

Which structure of the eye accounts for most of the refractive power of the eye?&#10;A)Anterior surface of the cornea&#10;B)Anterior surface of the lens&#10;C)Posterior surface of the cornea&#10;D)Posterior surface of the lens

Accepted Answer

The answer of Which structure of the eye accounts for...

Question 20

Which of the following is most likely to occur as an object moves closer to the eye of a 10-year-old boy with 20/20 vision?

Accepted Answer

The answer of Which of the following is most likely...

Deck 50: The Eye: I Optics of Vision