Test 57  (Ocular physiology)
1. When light fell on the eye, the pupil:
a. does not constrict if the optic nerve is severed

b. does not respond if the sympathetic system is not 

c. does not respond if the cholinergic system is blocked

d. does not respond if the pretectal nucleus is damaged

e. does not constrict if the ciliary ganglion is damaged

2. Rhodopsin:

a. is a red pigment

b. is least sensitive to red light

c. is regenerated when the eyes are closed

d. is most sensitive to light with a wavelength of 500nm

e. is found in the inner segment of rods


3. The following are true about dark adaptation:
a. only regeneration of rhodopsin is responsible

b. adaptation usually takes about 20 minutes

c. dilatation of pupil plays a part in dark adaptation

d. it is better with the fovea than the peripheral retina

e. wearing dark glasses before entering a dark room 
    decrease the adaptation time

4. True statement about dark adaptation include:

a. the threshold for light intensity falls

b. it is biphasic

c. the initial adaptation is due to rod adaptation

d. the change in the light intensity threshold is usually 
    around 100 folds

e. people who wear red goggle before entering a dark 
    room has a faster dark adaptation

5. Entoptic imagery may be caused by:

a.. opacities of the cornea

b. cells in the tear film

c. cells in the aqueous

d. vitreous cells

e. red blood cells in the retinal vessels

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