Pupil Size Effects Flashcards
Which of the following statements is not accurate about the pupil of the eye?
a. The entrance and exit pupils of the eye are images of the physiologic pupil.
b. The entrance pupil is 0.5mm closer and 13% larger than the real pupil
c. The exit pupil is .07mm closer to the retina and 3.4% larger than the real pupil.
d. Small pupils reduce chromatic aberration
e. Small pupils block paraxial light ray
e. Small pupils block paraxial light rays
Which of the following is not an accurate description of the Stiles Crawford Effect?
a. It is due to the pipe like structure of the cones
b. It explains why there is a reduced response to oblique light rays
c. It explains why the eye may be less sensitive to spherical aberration than predicted
d. It explains why the fovea is more selective for paraxial rays
e. It explains why blue focuses in front and red focuses behind the retina
e. It explains why blue focuses in front and red focuses behind the retina
Pupil size is important in diffraction. Which of the following correctly characterizes that relationship?
a. Light bends around the edges of a pupil
b. When the pupil is very small none of the light is bent by the edges
c. When the pupil is larger, maximum diffraction occurs
d. A pupil needs to be 6-7mm large before diffraction interferes with acuity
e. Small sized pinholes 1.5mm or less, improve acuity by eliminating diffraction
a. Light bends around the educes of a pupil
For small pupils less than 1mm, the point spread function
a. Is extremely small
b. Is helpful for good quality resolution
c. Is missing
d. Has a widely spread distribution
e. Has multiple tall peaks
d. Has widely spread distribution
What pupil size is ideal for visual acuity and balancing the effects of diffraction with spherical aberration?
a. 0.5-1.5mm
b. 1.0 –2.0mm
c. 2.00- 3.00mm
d. 3.00-4.00mm
e. 5.00-6.00mm
d. 3-4mm
For what pupil diameter pupil will spherical aberration have the greatest effect on VA?
a. 1mm
b. 2mm
c. 3mm
d. 4mm
e. 5mm
7. The size of a retinal blur circle is proportional to
e. 5mm
- The size of a retinal blur circle is proportional to
a. defocus
b. size of the pupil
c. angle of resolution
d. all of the above
d. all of the above
The goal of the pinhole test is to
a. Look for improvement in VA
b. Reduce the pupil size
c. Reduce the blur circle size
d. Differentiate between refractive and non-refractive vision problems
e. All of the above
e. All of the above
. In reference to the depth of field and depth of focus, all the following are true except which one?
a. Linear depth of field equals the dioptric depth of field
b. Depth of field equals the depth of focus dioptrically
c. Depth of field is the variation in object distance which results in an image of acceptable quality
d. Depth of focus is the variation in image distance which results in an image of acceptable quality
e. Depth of field is the greatest distance from the fixation point that an object can be moved without a change in perceived clarity (assuming fixed accommodation).
a. Linear depth of field equals the dioptric depth of field
Which of the following does not provide a larger depth of field
a. The shorter the axial length the larger the depth of field
b. The lower the visual acuity the larger the depth of field
c. The farther away the fixation point linearly the greater the depth of field
d. The larger the pupil size the larger the depth of field
d. The larger the pupil size the larger the depth of field
Which of these factors does NOT contribute to night myopia?
a. Chromatic aberration
b. Alcohol consumption
c. Uncorrected ametropia
d. Accommodation
e. Spherical aberration
b. Alcohol Consumption
What is the linear range of clear vision in an emmetrope with a depth of focus of +/-0.50D focused at their hyperfocal point?
a. 200cm to 100cm
b. 50cm to 200cm
c. infinity to 200cm
d. Infinity to 100cm
e. Infinity to 50cm
d. Infinity to 100 cm
