Understand a prescription

Question 1

What is the sphere power written in as?

Answer 1

It is written in diopters and will indicate the amount of correction needed.

Question 2

What is another word for no power in Rx?

Answer 2

• Plano (pl)

Question 3

What is another name for a prescription that only has a sphere power?

Answer 3

A diopter sphere (D.S.) or Sphere (sph) will be added to show that the cylinder and axis haven’t been forgotten.

Question 4

Most doctors write their prescriptions in quarter steps but diopters can be broken down to an eighth of a diopter step. What are they?

Answer 4

0.00
0.12
0.25
0.37
0.50
0.62
0.75
0.87

Question 5

What does it mean when the value is listed under the cylinder portion of the prescriptions?

Answer 5

The patient has astigmatism.

Question 6

What is the difference between Optometrists & Ophthalmologiests

Answer 6

• Optometrists are regular eye doctors
• Ophthalmologists is an eye doctor that can do surgery’s

Question 7

What does the axis mean in a prescription?

Answer 7

• The axis is a number from 0 to 180 degrees that provides information for where the lens power is located.

Question 8

What does ADD mean in the prescription?

Answer 8

• Patients who need help with near vision will have a reading add
• The number will be the same for both eyes and will always be a plus number ranging from +0.75D to +3.00D

Question 9

What does “PAL” mean?

Answer 9

• “PAL”= Progressive lens
• PAL is the notation for progressive lenses.

Question 10

What is “FT28”?

Answer 10

• “FT28”= Flat top 28
• Refers to a flat top 28 mm wide bifocal

Question 11

What is TRI?

Answer 11

• “TRI” = Triocal
• Refers to a traditional trifocal design.

Question 12

What is the Trifocal power percentage?

Answer 12

• Traditional Trifocal power is usually 50% of the add
• Intermediate Trifocal power can be noted as a percentage of the added power.

Question 13

How is prism noted?

Answer 13

• Prism is noted in diopters along with direction.
  BO, BI, BU, BD

Question 14

What does “PD”?

Answer 14

• “PD”= Pupillary distance
• Noted in millimeters
• ADD powers requires near PD

Question 15

What is the formula of the lens power?

Answer 15

F1 + F2 +F total
(front curve plus back curve equals total power)

Question 16

Use the lens power to solve the problem
Front curve = +6.00D
Back Curve = -4.00D

Answer 16

+6.00D(+) -4.00D = +2.00D

Question 17

What is cylinder power?

Answer 17

It is the difference between the powers of the two meridians

Question 18

What is Transposition?

Answer 18

Changing the cylinder designations from one form to the other

Question 19

What do you do when the signs of the sphere and cylinder power are the same?

Answer 19

Add them together and keep the same sign

Question 20

What do you do when the signs of sphere and cylinder power are different?

Answer 20

Subtract the smaller number to arrive at the new sphere.

Question 21

Transcribe the Rx
+2.00 -1.00 X 85

Answer 21

+2.00+(-)1.00=+1.00D
new sphere

-1.00 becomes +1.00D
New cylinder

85+90=175
new axis

Plus cylinder form: +1.00 +1.00 x 175

Question 22

Transcribe the Rx
Plano +2.00 x 100

Answer 22

Plano + (+)2.00 = +2.00D
new sphere

+2.00 becomes -2.00D
new Cylinder

100 - 90 = 10
new axis

+2.00 -2.00 x 10

Question 23

Show/explain how the sizing of the lens to the frame.
RX -3.00 -2.00 x 90

Answer 23

-3.00D on vertical meridian
(sphere and axis go together)
-5.00D on the horizontal meridian
(add sphere and cylinder powers)
(This is going to make the lens edge thickest in the horizontal meridian)

Question 24

Use reading Additon
Distance Rx +2.00 -1.00 x 45
Add Rx +2.00

Answer 24

Reading Rx +4.00 -1.00 x 45

Question 25

Use reading Additon Distance Rx -1.50 -0.50 x 175 Add Rx +1.50

Answer 25

Reading Rx Plano -0.50 x 175 recommened trifocals or pregressive lenses

Question 26

Use Trifocal lenses Distance Rx -2.00 -0.50 x 180 Add Rx +2.50 50% +1.25

Answer 26

Trifocal lenses -0.75 -0.50 x 175 You use +1.25 to subtract with -2.00, which gives you -0.75

Question 27

Use Bifocal lenses Distance Rx -2.00 -0.50 x 180 Add Rx +2.50 50% +1.25

Answer 27

Reading Rx +0.50 -0.50 x 180 Use +2.50 and subtract with -2.00, which gives you +0.50

Question 28

Using Reading glasses Distance Rx -2.50 -0.25 x 180 Add Rx +2.00

Answer 28

Reading Rx -0.50 -0.25 x 180 Add the add power to the sphere power to convert a prescription into a reading-only prescription. The cylinder and axis remain the same.

Question 29

Using Intermediate Glasses Distance Rx -2.50 -0.25 x 180 Add Rx +2.00 50% +1.00

Answer 29

Intermediate Rx -1.50 -0.25 x 180 To convert the prescription, add half the added power to the sphere power. Cylinder and axis remain the same. In case 50% of the add is +1.00D, added to the -2.50D sphere power results in eyeglasses with the answer above.

Question 30

The following Rx represents what type of correction? Rx -3.00D sphere

Answer 30

Myopic or nearsighted

Question 31

"Plano" means?

Answer 31

No correction is needed

Question 32

Axis readings may be between 0 and 180 degress

Question 33

If the Rx has the notation "PAL" it means

Answer 33

The patient is presbyopic

Question 34

The common trifocal power is:

Answer 34

50% of the add power

Question 35

Transpose the following Rx: -2.50 +1.25 x 90

Answer 35

-2.50 + (+1.25) = -1.25 new sphere +1.25 becomes -1.25D new Cylinder 90 + 90 = 180 new axis -1.25 -1.25 x 180