Accommodation Flashcards
When a patient accommodates which of the following changes occur?
a. the lens gets thinner along it’s optical axis b. the zonules increase their tension c. the cilliary muscle contracts d. the posterior lens surface bulges forward e. the lens rises upward
c. the cilliary muscle contracts
A patient is corrected for infinity with a –12.50D spectacle lens positioned 20mm in front of the eye’s principal plane. The patient has a 5D ocular amplitude of accommodation. What is the closest point in space that the patient can see clearly when he is fully accommodated?
a. 6.7cm in front of the spectacle plane b. 4.7cm in front of the spectacle plane c. 11.2cm in front of the spectacle plane d. 18.0cm in front of the spectacle plane e. 14.6cm in front of the spectacle plane
c. 11.2cm in front of the spectacle plane
A patient is corrected for infinity with a +12.50D spectacle lens positioned 20mm in front of the eye’s principal plane and is fixating a point 20cm in front of the spectacle plane. How much of a reduction in the eye’s total power has to take place for the patient to accommodate from the 20 cm location to a new object positioned 100 cm in front of the spectacle plane?
a. 4.00 D b. 6.11 D c. 7.41 D d. 2.68 D e. 5.88 D
b. 6.11 D
Which of the following individuals would have to exert the greatest amount of ocular accommodation to focus from infinity to a point 20 cm in front of the spectacle plane? Assume that the spectacle plane is 20 mm in front of the eye’s principal plane.
a. a 5D axial hyperope corrected with spectacles b. a 5D axial hyperope corrected with contact lenses c. a 5D refractive hyperope corrected with contact lenses d. an emmetrope e. a 5D axial myope corrected with spectacle lenses.
a. a 5D axial hyperope corrected with spectacles
Which of the following changes does NOT occur when a young eye accommodates from distance to near?
a. the depth of the anterior chamber increases b. the anterior to posterior thickness of the lens increases c. the radius of curvature of the anterior surface decreases more than the posterior surface radius. d. the radius of curvature of the lens core decreases e. the eye’s principal planes move toward the retina.
a. the depth of the anterior chamber increases
A patient is corrected for distance with a –10D spectacle lens positioned 25mm in front of the eye’s principal plane. The patient has a 5D ocular amplitude of accommodation. What is the closest point in space that the patient can see clearly when the patient is fully accommodated?
a. 20 cm in front of the spectacle plane b. 20 cm in front of the eye’s principal plane c. 33.3 cm in front of the eye’s principal plane d. 10.8 cm in front of the spectacle plane e. 16.8 cm in front of the spectacle plane
d. 10.8 cm in front of the spectacle plane
A patient is corrected for distance with a +15D spectacle lens positioned 20 mm in front of the eye’s principal plane. You perform a push-up test and determine that the patient has a spectacle amplitude of accommodation of 5D. What is the patient’s true amplitude of accommodation (i.e., ocular amplitude of accommodation)?
a. 5.0 D b. 8.9 D c. 4.5 D d. 12.5 D e. 7.3 D
b. 8.9 D
Which of the following changes would require the patient to exert more accommodation to focus on a given near point?
a. switching a myopic patient from contact lenses to spectacle lenses b. increasing the vertex distance for the spectacle lenses of a myopic patient from 10 to 20 mm c. increasing the vertex distance for the spectacle lenses of a hyperopic patient from 10 to 20 mm d. switching a hyperopic patient from spectacles to contact lenses e. giving an emmetropic patient a +2.0 D near add
c. increasing the vertex distance for the spectacle lenses of a hyperopic patient from 10 to 20 mm
For a given ametropic eye corrected with spectacles, the difference between spectacle and ocular accommodative demands ______________
a. is independent of the vertex distance of the correcting lens.
b. is independent of fixation distance.
c. gets smaller as fixation distance is increased and the vertex distance is decreased.
c. gets smaller as fixation distance is increased and the vertex distance is decreased.
A refractive ametrope is corrected with a -2.00 -4.00 x 90 contact lens. Assuming that the contact lens is positioned at the eye’s principal plane, how much ocular accommodation is required by the vertical meridian of the eye to focus on an object 40 cm in front of the eye’s principal plane?
a. +1.0 D
b. +2.5 D
c. -1.5 D
d. +0.5 D
b. +2.5 D
. Which of the following does NOT happen during accommodation
a. The anterior surface of the lens moves towards the cornea.
b. The principal planes move towards the cornea.
c. The posterior surface of the lens moves away from the cornea
d. The radius of curvature of anterior surface of the cornea decreases
e. The dioptric power of the lens increases.
b. The principal planes move towards the cornea.
- An uncorrected emmetrope is asked to focus on an object 40cm in front of the plane of the phoropter. The phoropter, is 20mm in front of the eye’s principal plane and there is no lens in the phoropter. How much spectacle accommodation is required to focus on the near object?
a. 2.50D
b. 3.75D
c. 4.00D
d. 5.00D
e. 7.50D
a. 2.50D
- An uncorrected 2D myope has a pushup amplitude ranging from a 50cm starting point, comes in to 20cm. What is this patient’s amplitude of accommodation?
a. 2.50D
b. 3.00D
c. 4.00D
d. 1.00D
e. 1.50D
b. 3.00D
A corrected patient is wearing a +1.50 add. They have clear vision to 20cm. What is the approximate amplitude of accommodation?
a. 2.50D b. 3.00D c. 3.50D d. 4.00D e. 4.50D
c. 3.50D
A 0.50D myopic presbyope wears single vision +1.00 readers, what is the range of clarity if they have 2.00D amplitude?
a. 67-33 cm b. 50-29 cm c. 33.3-10 cm d. 50- 10 cm e. 67- 29cm
e. 67- 29cm
