Unit 54: Vision Defects and their Correction
Practice Problems
Note: problem difficulty is ranked using a star system.
(*) One-star problems are fundamental to the unit, and can be done relatively quickly. Use these problems to introduce yourself to the material.
(**) Two-star problems are more difficult, and require an understanding of one or two key concepts. Use these problems to test your understanding of the material.
(***) Three-star problems are the most difficult, and require some creative thinking in addition to a deep familiarity with multiple key concepts. Use these problems to challenge yourself; if you can complete one of these, you’re on your way to mastering the material.
*Q54.1) A person with healthy vision closes one eye and focuses on their pencil with their open eye. As they slowly move the pencil towards their face, at what distance from their face will the pencil begin to appear blurry?
*Q54.2) A person with healthy vision closes one eye and focuses on a distant building. As they back away from the building, at what distance will the building begin to appear blurry?
**Q54.3) A patient has a far point of 2m and a near point of 13cm.
a) Are they myopic or hyperopic?
b) What lens power should be prescribed to correct their vision?
**Q54.4) A patient has a far point of infinity and a near point of 80cm.
a) Are they myopic or hyperopic?
b) What lens power should be prescribed to correct their vision?
**Q54.5) While on a camping trip with your myopic friend, you decide to try to use their glasses to start a campfire. Will you be successful? Why or why not?