UNIT 2

Question 1

Written Rx, Vision Disorders

Answer 1

If there is only Sphere: there is only one power in the lens
Presbyopia; there will be add (ex. +2.00) meaning they will need a distance and near

Question 2

Normal vision:

Answer 2

Through crystalline lens right to the retina

Question 3

Myopia:

Answer 3

Through the crystalline lens, object will focus before the retina (nearsighted) so by the time the object gets to the retina it is blurry
-Minus lens, concave lens (apex to apex)

Question 4

Hyperopia:

Answer 4

Through the crystalline lens, object lands behind the retina (farsightedness)
-Plus lens, convex lens (base to base)

Question 5

Astigmatism

Answer 5

On a certain axis you will need extra power

Question 6

types of astigmatism

Answer 6

Corneal
Lenticular; lens is irregular shape

Question 7

With the rule?

Answer 7

-Steeper axis at 90
-44 x 90 and 43 x 180
-More common in younger patients and myopics eyes

Question 8

seeing through a lens

Answer 8

• Minus lens; Minifies (gets smaller)
  -Thinner in the center
• Plus lens; Magnifies (gets bigger)
  -Thicker in the center
• Cylindrical lens; Elongate it (stretch it out)

Question 9

Using the Lensometer

Answer 9

Mires inside the Lensometer – Spherical
-Black lines (reticle) are the grid you want to see clear
-3 thin lines (sphere)
-3 thick lines (cylinder)

Question 10

Measuring for Vertical Prism

Answer 10

• Strongest Power at 90
• Center on OC and PD
• Measure Rx and any Prism

Question 11

Measuring for Horizontal Prism

Answer 11

• Centre for PD and OC – without moving the table
• Neutralize the Rx
• Determine Prism