Test 191  (Ocular physiology)
1. With regard to nystagmus:
a. caloric nystagmus occurs when iced water is poured 
    into the ear

b. vestibular nystagmus occurs as a consequence 
    of head rotation

c. optokinetic nystagmus occurs as a consequence 
    of the relative motion of the visual field

d. the direction of a jerk nystagmus is characterized by 
    the direction of the slow phase 

e. pendular nystagmus has equal velocity in each direction


2. Visual-evoked response:

a. is used primarily to detect visual loss due to retinal 

b. produces biphasic wavefronts

c. may give falsely delayed latency if the patient is 
    not concentrating

d. produces responses in normal subjects with a latency 
    of 100msec

e. is obtained from the lateral canthi


3. An increase in intra-ocular pressure occurs with:
a. normal blinking

b. coughing

c. hypercarbia

d. pupillary dilatation

e. head down position

. 4. With regard to dark adaptation:
a. is a quicker process than light adaptation

b. the sensitivity of the cones increases more rapidly 
    than the rods

c. it is monophasic in rod monochromatism

d. the first limb of the curve represents rod recovery

e. the peak sensitivity of the retina to light with longer 
    wavelengths increases with dark adaptation

5. True statements about EOG (electro-oculogram) include: 

a. the EOG light-peak to dark-trough ratio is reduced 
    in central retinal vein occlusion

b. the light peak of EOG is abnormal in Best's disease

c. the EOG light rise is produced by depolarization of the 
    basal membrane of the retinal pigment epithelium

d. intact ganglion cells are necessary to generate the 
    light-rise portion of the EOG

e. the amount of melanin within the retinal pigment 
    epithelial cells determines the amplitude of the EOG 
    light rise

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