Toxic responses of the Ocular and Visual system

Question 1

In which of the following locations would one NOT fine melanin?

a. iris
b. ciliary body
c. retinal pigment epithelium (RPE)
d. uveal tract
e. sclera

Answer 1

e. sclera

Question 2

Systemic exposure to drugs and chemicals is most likely to target which of the following retinal sites?

a. retinal pigment epithelium and ganglion cell layer
b. optic nerve and inner plexiform layer
c. retinal pigment epithelium and photoreceptors
d. photo receptors and ganglion cell layer
e. inner plexiform layer and retinal pigment epithelium

Answer 2

c. RPE and photoreceptors

Question 3

Which of the following structures is NOT part of the ocular fundus?

a. retina
b. lens
c. choroid
d. sclera
e. optic nerve

Answer 3

b. lens

Question 4

Drugs and chemicals in systemic blood have better access to which of the following sites because of the presence of loose endothelial junctions at that location?

a. retinal choroid
b. inner retina
c. optic nerve
d. iris
e. ciliary body

Answer 4

a. retinal choroid

Question 5

All of the following statements regarding irritancy and toxicity are true EXCEPT:

a. The Draize test involves instillation of a potentially toxic liquid or solid into the eye
b. The effect of the irritant in the Draize test is scored on a weighted scale for the cornea, iris, and conjunctiva
c. The Draize test usually uses one eye for testing and the other as control
d. The Draize test has strong predictive value in humans
e. The cornea is evaluated for opacity and area of involvement in the Draize test

Answer 5

d. The Draize test has strong predictive value in humans

Question 6

Which of the following statements regarding color vision deficits is FALSE?

a. Inheritance of a blue-yellow color deficit is common
b. Bilateral deficits in the visual cortex can lead to color blindness
c. Disorders of the outer retina produce blue-yellow deficits
d. Drug and chemical exposure most commonly results in blue-yellow color deficits
e. Disorders of the optic nerve produce red-green deficits

Answer 6

a. Inheritance of a blue-yellow color deficit is common

Question 7

A substance with which of the following pH values would be most damaging to the cornea

a. 1.0
b. 3.0
c. 7.0
d. 10.0
e. 12.0

Answer 7

e. 12.0

Question 8

which of the following statements concerning the lens is FALSE?

a. UV radiation exposure is a common environmental risk factor for developing cataracts
b. Cataracts are opacities of the lens that can occur at any age.
c. The lens continues to grow throughout one’s life
d. Naphthalene and organic solvents both can cause cataracts
e. Topical treatment with corticosteroids can cause cataracts.

Answer 8

d. Naphthalene and organic solvents both can cause cataracts

Question 9

Which of the following is NOT a reason why the retina is highly vulnerable to toxicant-induced damage?

a. presence of numerous neurotransmitter systems
b. Presence of melanin in the retinal pigment epithelium (RPE).
c. high choroidal blood flow rate
d. high rate of oxidative mitochondrial metabolism
e. lack of gap junctions

Answer 9

e. lack of gap junctions

Question 10

A deficiency in which of the following vitamins can result in degeneration of optic nerve fibers?

a. Vitamin A
b. Vitamin B3
c. vitamin C
d. Vitamin B12
e. vitamin E

Answer 10

d. Vitamin B12