Toric Lenses Performance Survey
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Questions and Answers

How have advancements in toric soft lens design sought to improve orientation and stability characteristics?

  • By reducing thickness variations
  • By increasing thickness variations (correct)
  • By decreasing oxygen availability
  • By introducing silicone hydrogel materials
  • What was the main issue revealed by a recent wearer survey regarding toric lenses?

  • Lack of advanced designs in the market
  • Inadequate oxygen availability
  • Low durability of toric lenses
  • Poor lens performance in terms of comfort and vision (correct)
  • What percentage of the ametropic population has 0.75D or more of refractive astigmatism?

  • Less than 10%
  • Around 5%
  • Nearly 50%
  • Approximately 30% (correct)
  • What do Rigid Gas Permeable (RGP) lenses correct?

    <p>Corneal astigmatism</p> Signup and view all the answers

    Which type of lenses are now available in silicone hydrogel materials according to the text?

    <p>Custom made toric soft lenses</p> Signup and view all the answers

    What percentage of prescriptions have more than 1.00DC of astigmatism based on the information provided?

    <p>Approximately 16%</p> Signup and view all the answers

    What should be done if the lens rotates to the left?

    <p>Add rotation</p> Signup and view all the answers

    How should the axis be adjusted if the lens rotates clockwise?

    <p>Add axis</p> Signup and view all the answers

    What is the consequence of a toric soft lens being 20 degrees off-axis?

    <p>Over-refraction</p> Signup and view all the answers

    Why is a spherical over-refraction carried out for a toric soft lens?

    <p>To determine cylinder power adjustment</p> Signup and view all the answers

    What indicates that the lens fit is adequate?

    <p>Stability of the end-point</p> Signup and view all the answers

    Why should a new trial lens be inserted after compensating for cylinder axis rotation?

    <p>To allow a meaningful spherical over-refraction</p> Signup and view all the answers

    Why is maintaining the rotational stability of a soft toric lens crucial?

    <p>To allow lateral eye movements without lens displacement</p> Signup and view all the answers

    What is a key difference between a rigid toric lens and a soft toric lens?

    <p>Soft lenses may rotate on the eye due to reduced modulus of elasticity</p> Signup and view all the answers

    What is the purpose of empirical fitting in the context of contact lenses?

    <p>To order a diagnostic lens for the patient</p> Signup and view all the answers

    Why is it important for soft toric lenses to maintain stability during lateral eye movements?

    <p>To ensure consistent optical correction for astigmatic patients</p> Signup and view all the answers

    What feature of a soft toric lens allows it to fit spherical corneas effectively?

    <p>The presence of a toric back surface</p> Signup and view all the answers

    In soft toric fitting, what determines the success of optical correction?

    <p>The surface toricity and alignment with the cornea</p> Signup and view all the answers

    What is one of the reasons for poor vision that can occur due to axis rotation?

    <p>Difference in thickness profiles of lenses</p> Signup and view all the answers

    How can the problem of axis rotation leading to poor vision be avoided?

    <p>Using trial lenses that closely match the patient's ocular prescription</p> Signup and view all the answers

    What does Figure 8 in the text suggest for dealing with poor visual acuity?

    <p>Assessing rotational stability of the lens in the eye</p> Signup and view all the answers

    If a lens is rotationally stable but with a mislocated axis, what action should the practitioner take according to the text?

    <p>Compensate for axis rotation and reorder the lens</p> Signup and view all the answers

    What is recommended if a soft toric lens is rotationally unstable?

    <p>Using a different fit or design of soft toric lens</p> Signup and view all the answers

    What role does a sphere/cyl over-refraction play in determining poor visual acuity causes according to the text?

    <p>Identifying differences between labeled and actual specifications</p> Signup and view all the answers

    What type of lenses were found to be ineffective for correcting low levels of astigmatism?

    <p>Aspheric soft contact lenses</p> Signup and view all the answers

    Which publication discusses a new daily wear silicone hydrogel lens for astigmatism?

    <p>Spectrum, 2007; January. 39-40</p> Signup and view all the answers

    In which study was a clinical evaluation done on factors influencing toric soft contact lens fit?

    <p>Optom Vis Sci, 2002; 79:1, 11-19</p> Signup and view all the answers

    Which publication provides a systematic approach to problem-solving with soft toric contact lenses?

    <p>Optician, 1989; 198:5211, 16-18</p> Signup and view all the answers

    Which study involved a clinical comparison of two soft toric contact lenses?

    <p>Optician, 1996; 211:5549 20-21</p> Signup and view all the answers

    Which publication introduced a new dual-thin zone disposable toric lens?

    <p>Optician, 2000; 219:5736</p> Signup and view all the answers

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