Quiz 1D
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Questions and Answers

What does a larger base curve result in?

  • More steep lens
  • Increased lens movement
  • No change in lens curvature
  • More flat lens (correct)

    • What does a smaller base curve result in?

  • Decreased lens stability
  • Increased lens movement
  • More steep lens (correct)
  • No change in lens curvature

    • By how much does the flat diameter increase as the flat K goes up by 0.2?

  • 0.5 (correct)
  • Not mentioned in the text
  • 0.2
  • 0.7

    • What is the base curve (BC) value mentioned in the text?

    <p>7.23 mm</p> Signup and view all the answers

    What does no movement in blink or up gaze indicate about the base curve of the lens?

    <p>The base curve is too tight for the cornea</p> Signup and view all the answers

    What is the purpose of the push-up test mentioned in the text?

    <p>To check for lens tightness</p> Signup and view all the answers

    What should be quantified when observing movement of the lens during blinking?

    <p>$1mm dot on nasal edge</p> Signup and view all the answers

    What does it indicate if there is no movement when focusing a 1mm circle on the inferior nasal aspect of the soft lens and half on bulbar conj during blinking?

    <p>Lens is too tight</p> Signup and view all the answers

    What is half a movement of the dotted line during blinking equivalent to?

    <p>$1mm dot on nasal edge</p> Signup and view all the answers

    "+ push-up test" is used to determine what about the lens?

    <p>There is lens tightness</p> Signup and view all the answers

    What does a negative push-up test indicate?

    <p>The lens is tight on the eye and has to come off or with wearing time, it will become tighter</p> Signup and view all the answers

    What does the push up test help determine?

    <p>The interaction between the lid and the lens</p> Signup and view all the answers

    Why might the lens feel sore and cause red eyes?

    <p>Insufficient tear exchange resulting in dryness</p> Signup and view all the answers

    What is the primary purpose of performing a piggy back lens system?

    <p>To address limbal region issues</p> Signup and view all the answers

    How is the base curve related to the fit of the lens?

    <p>A steeper base curve tightens the fit</p> Signup and view all the answers

    What is indicated by excessive lens movement during primary and up gaze?

    <p>Inadequate tear exchange and discomfort</p> Signup and view all the answers

    What does the presence of central air bubbles in the lens indicate?

    <p>Tight fit with no tear exchange</p> Signup and view all the answers

    What is a common method to resolve a loose lens fit?

    <p>Steepening the base curve while keeping diameter constant</p> Signup and view all the answers

    Why might there be hyperemia in the nasal quadrant when using a piggy back lens system?

    <p>Improper fitting of the GP lens</p> Signup and view all the answers

    What does it mean if the lens edge does not move and stays stationary?

    <p>The base curve is too tight or there is little friction</p> Signup and view all the answers

    What is indicated by more than 0.5mm of lag down as the patient looks up or laterally?

    <p>The lens will come more down to bulbar conj affecting correction</p> Signup and view all the answers

    How is the sag depth related to changing the lens fit?

    <p>Enlarging diameter increases sag depth for a tighter fit.</p> Signup and view all the answers

    What is the main difference between Hydrogel and Silicon Hydrogel lenses?

    <p>Silicon Hydrogel lenses have lower water content than Hydrogel lenses.</p> Signup and view all the answers

    What happens if a person with dry eyes is fitted with a contact lens with high water content?

    <p>The lens becomes tighter, causing more water loss.</p> Signup and view all the answers

    What is the purpose of the ultrasoft hydrophilic polymer network on the surface of DAILIES TOTAL1® lenses?

    <p>To reduce friction and minimize interaction with the eye tissues.</p> Signup and view all the answers

    What is the potential consequence of using reusable Silicon Hydrogel lenses?

    <p>Increased risk of corneal ulcers due to trapped debris.</p> Signup and view all the answers

    What should be considered when selecting a replacement lens care appropriate for a patient?

    <p>The power range that suits the patient.</p> Signup and view all the answers

    What should be avoided when fitting soft lenses using keratometry?

    <p>Risking exposure of the limbal region.</p> Signup and view all the answers

    How does oxygen transmission relate to the water content in contact lenses?

    <p>Lower water content results in higher oxygen permeability.</p> Signup and view all the answers

    Why do Silicon Hydrogel lenses have more stiffness compared to Hydrogel lenses?

    <p>Because of the addition of silicone in the lens material.</p> Signup and view all the answers

    What is the potential consequence of insufficient tear exchange under a soft lens?

    <p>Increased risk of red eye and trapped debris.</p> Signup and view all the answers

    Why is fitting a person with dry eyes with a contact lens with high water content not recommended?

    <p>The lens becomes tighter, leading to increased water loss.</p> Signup and view all the answers

    Why is corneal topography not used to fit soft lenses?

    <p>Keratometry is used instead for measuring 3mm of the cornea.</p> Signup and view all the answers

    What is the role of keratometry in fitting soft lenses?

    <p>It measures 3mm of the cornea for better fit and comfort.</p> Signup and view all the answers

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