COT Flashcards : Lensometry 3%
A lens formula of +2.00-3.00x90 degrees has a power at 90 degrees and at 180 degrees?
A. +2.00 and -1.00
B. +2.00 and -3.00
C. +5.00 and +3.00
D. -1.00 and +2.00
A. +2.00 and -1.00
“A patient with a far point of 7.87” (20 cm) in front of the eye requires what spectacle lens power to correct refractive error to emmetropia?”
A. -5.00 D
B. -2.00 D
C. +2.00 D
D. +5.00 D
A. -5.00 D
What type of astigmatism has one focal line on the retina and the other behind the retina?
a. Mixed astigmatism
b. Simple hyperopic astigmatism
c. Compound hyperopic astigmatism
d. Simple myopic astigmatism
b. Simple hyperopic astigmatism
Lensometry of a patient’s spectacles review the single line coming into focus first at -1.50, then the triple lines at zero, with axis at 180 degrees. The lens power is ____
a. -1.50-1.50x180
b. Plano-1.50x90
c. Plano-1.50x180
d. Plano+1.50x90
b. Plano-1.50x90
In lensometry, first the single lines comes into focus at plano and then the triple lines come into focus at -2.00 with the axis at 90 degrees. What is the lens power?
a. -2.00+2.00x180
b. -2.00+2.00x90
c. Plano-2.00x180
d. +2.00-2.00x90
a. -2.00+2.00x180
The results of visual acuity measurements are expressed as a fraction in which the denominator is
a. always twenty feet (six meters)
b. The distance at which a normal eye can see the chart letters.
c. The distance at which the patient can see the chart letters.
d. The distance of the patient from the chart letters
b. The distance at which a normal eye can see the chart letters.
Which of the following statements about vision testing is TRUE?
a. In children, the testing should be done fairly rapidly to rule out amblyopia.
b. In the normal patient, visual acuity is generally the same with both eyes with either eye tested separately
c. Patients with amblyopia will do better if shown individual letters than if shown a whole line.
d. There is a difference in the degree of difficulty between different Snellen letters of the same size.
c. Patients with amblyopia will do better if shown individual letters than if shown a whole line.
The Geneva lens clock measure
a. can be used in lieu of a radiuscope for measuring the base curve of a rigid contact lens.
b. determines the center thickness of a spectacle lens c. is used to verify the axis of astigmatism of a front surface toric soft contact lens.
d. measures the surface curvature of a spectacle lens
d. measures the surface curvature of a spectacle lens
When reading the power of a lens using the plus cylinder technique, what reading is noted when the single lines of triple lines come into focus simultaneously?
a. Prism
b. BIfocal
c. Sphere
d. Cylinder
c. Sphere
