Lens Transposition and Spherical Equivalents

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Questions and Answers

Transpose the following prescription: +1.00 +2.00 x 90

+3.00 -2.00 x 180

Transpose the following prescription: +100 +200 × 90

+3.00 -2.00 x 180

Transpose the following prescription: -0.75 +3.00 x 180

+2.25 -3.00 x 090

Transpose the following prescription: +2.25 +1.75 x 085

+4.00 -1.75 x 175 Signup and view all the answers

Transpose the following lens prescriptions: +4.25 +1.50 x 135

+5.75 -1.50 x 045 Signup and view all the answers

Transpose the following lens prescription: -4.00 +3.00 x 45

-1.00 -3.00 x 135 Signup and view all the answers

Transpose the following lens prescription: -3.00 +0.75 x 180

-2.25 -0.75 x 90 Signup and view all the answers

What is spherical equivalent of -1.00 +2.00 x 180?

Plano Signup and view all the answers

What is spherical equivalent of +2.00 +2.50 x 90?

+3.25 Signup and view all the answers

What is spherical equivalent of -0.75 + 1.50 x 180?

Plano Signup and view all the answers

What is spherical equivalent of -2.50 +2.50 x 155?

-1.25 Signup and view all the answers

What is spherical equivalent of +2.25 +0.50 x 150?

+2.50 Signup and view all the answers

The spherical equivalent of +1.00 +2.50 x 90 is?

+2.25 Signup and view all the answers

Transpose the following prescription: -3.00 +2.00 x 30

-1.00 -2.00 x 120 Signup and view all the answers

Transpose the following prescription: -3.00 -2.00 x 30

-5.00 +2.00 x 120 Signup and view all the answers

Transpose the following prescription: +3.00 -2.00 x 30

+1.00 +2.00 x 120 Signup and view all the answers

Transpose the following prescription: +3.00 +2.00 x 30

+5.00 -2.00 x 120 Signup and view all the answers

Convert DVA of 20/20 feet into meters.

6/6 Signup and view all the answers

Convert DVA of 20/30 feet into meters.

6/9 Signup and view all the answers

Convert DVA of 20/40 feet into meters.

6/12 Signup and view all the answers

Convert DVA of 20/50 feet into meters.

6/15 Signup and view all the answers

Convert DVA of 20/60 feet into meters.

6/18 Signup and view all the answers

Convert DVA of 20/70 feet into meters.

6/21 Signup and view all the answers

Convert DVA of 20/80 feet into meters.

6/24 Signup and view all the answers

Convert DVA of 20/100 feet into meters.

6/30 Signup and view all the answers

Study Notes

Lens Transposition

Transposing a prescription involves converting it from its original form to another, maintaining equivalent optical power.
The process adjusts the sphere and cylinder values while changing the axis measurement.

Example Transpositions

From +100 +200 × 90 to: +3.00 -2.00 × 180.
From -0.75 +3.00 × 180 to: +2.25 -3.00 × 090.
From +2.25 +1.75 × 085 to: +4.00 -1.75 × 175.
+4.25 +1.50 × 135 becomes: +5.75 -1.50 × 45.
From -4.00 +3.00 × 45 to: -1.00 -3.00 × 135.
From -3.00 +0.75 × 180 to: -2.25 -0.75 × 90.

Spherical Equivalent Calculations

The spherical equivalent simplifies a lens prescription into a single power.
Example conversions yield:
- For -1.00 +2.00 × 180: Plano.
- For +2.00 +2.50 × 90: +3.25.
- For -0.75 +1.50 × 180: Plano.
- For -2.50 +2.50 × 155: -1.25.
- For +2.25 +0.50 × 150: +2.50.
- For +1.00 +2.50 × 90: +2.25.

Additional Transpositions

Prescription of -3.00 +2.00 × 30 transposes to: -1.00 -2.00 × 120.
-3.00 -2.00 × 30 transposes to: -5.00 +2.00 × 120.
+3.00 -2.00 × 30 turns to: +1.00 +2.00 × 120.
+3.00 +2.00 × 30 results in: +5.00 -2.00 × 120.

Vision Acuity Conversions

Converting Distant Visual Acuity (DVA) measurements from feet to meters involves fractional notation.
DVA of 20/20 feet equates to: 6/6.
DVA of 20/30 feet equates to: 6/9.
DVA of 20/40 feet equates to: 6/12.
DVA of 20/50 feet equates to: 6/15.
DVA of 20/60 feet equates to: 6/18.
DVA of 20/70 feet equates to: 6/21.
DVA of 20/80 feet equates to: 6/24.
DVA of 20/100 feet equates to: 6/30.

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Description

This quiz covers the concepts of lens transposition and spherical equivalent calculations. It includes examples of converting prescriptions while maintaining equivalent optical power. Test your understanding of these essential optical math skills.