NOCE Contact Lens Fitting and Care Flashcards
6 cards from real NOCE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 NOCE Contact Lens Fitting and Care flashcards as text
Which instrument is used to verify the base curve and power of a rigid gas-permeable (RGP) contact lens?
Answer: Radiuscope
A radiuscope (also called an ophthalmometer or lens clock for RGPs) is used to measure the radius of curvature of the back surface of rigid contact lenses.
When fitting a soft contact lens, which observation indicates an excessively STEEP (tight) fit?
Answer: Reduced or absent lens movement with a push-up test
A steep or tight soft lens fit shows reduced movement on blink and poor mobility on the push-up test because the lens is gripping the cornea too tightly.
Vertex distance compensation in contact lens prescribing is generally required when the spectacle prescription exceeds what power?
Answer: ±4.00 D
Vertex distance correction is clinically significant for prescriptions of ±4.00 D or greater, as the difference in back vertex distance between spectacles and contact lenses changes the effective power.
What does lag (or lens lag) describe in contact lens fitting assessment?
Answer: The movement of the lens in the opposite direction after an eye movement
Lens lag refers to the movement of a contact lens in the opposite direction to that of eye movement, used to assess lens fit by observing how the lens responds when the eye moves laterally.
The push-up test during soft contact lens fitting is used to assess what parameter?
Answer: Lens movement and fit tightness (lens mobility)
The push-up test assesses lens mobility by using a finger to push the lower lid against the lens edge; a properly fitting lens should move smoothly and return to its original position.
In contact lens prescribing, what is the recommended approach when there is a significant amount of residual astigmatism with a spherical soft lens?
Answer: Prescribe a toric soft contact lens to correct the residual cylinder
When residual astigmatism remains uncorrected with a spherical soft lens, a toric soft contact lens should be prescribed to correct both the spherical and cylindrical components of the refractive error.