Entopic Phenomena

Question 1

The entoptic phenomena caused by the shadows of the retinal capillaries are called

a. Haidinger’s brushes
b. Maxwell’s spot
c. Phosphenes
d. Blue arcs of the retina
e. Purkinje Tree

Answer 1

e. Purkinje Tree

Question 2

Maxwell’s spot appears larger as we move back from the viewing screen because

a. retinal image size remains constant but perceived size is proportional to perceived distance
b. perceived size is proportional to retinal image size
c. perceived size is inversely proportional to perceived distance for constant retinal image size
d. retinal image size increases as we move further away
e. retinal image size decreases as we move further away

Answer 2

a. retinal image size remains constant but perceived size is proportional to perceived distance

Question 3

Which of the following is NOT a characteristic of Moore’s lightening streaks?

a. They are vertical.
b. They are in the temporal visual field.
c. They occur during eye movements.
d. They are due to ageing of the vitreous.
e. They are always the sign of a retinal problem that needs treatment

Answer 3

e. They are always the sign of a retinal problem that needs treatment

Question 4

A patient can subjectively see small vitreous opacities, under normal viewing conditions, if they are located near the

a. nodal points of the eye
b. the geometric center of the vitreous
c. the center of rotation of the eye
d. the retina
e. the center of curvature of the cornea

Answer 4

d. the retina

Question 5

The shadows of the central retinal artery and vein cause which entoptic phenomena?

a. Blue arcs of the retina
b. Floaters
c. Purkinje’s tree
d. Haidinger brushes
e. Moore’s lightening streak

Answer 5

c. Purkinje’s tree

Question 6

Which of the following entoptic phenomena is caused by yellow macular pigment?

a. Blue arcs of the retina
b. Phosphenes
c. Purkinje’s tree
d. Haidinger’s brush
e. Moore’s lightening streak

Answer 6

d. Haidinger’s brush

Question 7

Which of the following is NEITHER a cause of floaters nor related to them?

a. corneal mucus
b. hyaloid vascular system
c. erythrocyte chains
d. vitreous degeneration
e. vitreous detachment

Answer 7

a. corneal mucus

Question 8

In Emmert’s law, which of the following factors remains constant?

a. actual target distance
b. perceived target distance
c. perceived target size
d. retinal image size
e. b and c are constants

Answer 8

d. retinal image size

Question 9

. When viewing Haidinger’s brushes, the Polaroid filter must be rotated because

a. electric vector can then be aligned with all the radially arranged macular pigments.
b. otherwise, the brushes would fade from view and could not be seen.
c. the motion makes the brushes more obvious
d. none of the above since a Polaroid filter is not needed to see Haidinger’s brushes.
e. none of the above since the Polaroid filter does not have to be rotated

Answer 9

b. otherwise, the brushes would fade from view and could not be seen.

Question 10

Which of the following entoptic phenomena can be used in the diagnosis of eccentric fixation

a. Maxwell’s Spot
b. Maxwell’s View
c. Blue Field phenomena
d. Floaters
e. Stiles- Crawford effect

Answer 10

a. Maxwell’s Spot

Question 11

A rotating Polaroid lies in front of a blue filter and a light source. You see a small figure whereever you look on the filter. This figure appears somewhat like bundle of wheat and rotates about the point of fixation. This phenomenon is called

a. Blue field entoptic phenomena
b. Maxwell’s Spot
c. Hadinger’s Brushes
d. Blue Arcs of the retina
e. Purkinje’s phenomena.

Answer 11

c. Hadinger’s Brushes