Each worksheet is different, because each one was originally written by a different person.  Use the directions at the beginning of each worksheet for that worksheet.

Calculate the dioptric power of the following.  Round diopters to two decimal places.  (Not to 1/8 diopter steps)
 
 

Calculate the radius of curvature for the following.  Round to whole mm.
 
 

1. What is the dioptric power of a crown glass surface if it has a radius of curvature of 135 cm?

 

 

D = ?                                                   D = 0.523/1.35 =  + 0.39D
n = 1.523
r = 135 cm
  =  ? meters = 1.35 m
 

2. What is the dioptric power of a CR39 surface if it has a radius of curvature of 35 mm?

 

 

D = ?                                                    D = 0.498/0.035 =   +14.23D
n = 1.498
r = 35 mm
  =  ? meters = 0.035 m
 

3. What is the radius of curvature in millimeters of a +6.00D crown glass surface?

 

 

D = +6.00                                    6.00 = 0.523/r
n = 1.523                                    r = 0.523/6.00 =   +0.087 m = +87 mm
r = ? meters
  =  ? mm
 

4. What is the radius of curvature in cm of a +2.50D CR39 surface?

 

 

D = +2.50                    r = (n-1)/D = 0.498/2.50 = 0.1992 m =   +20 cm
n = 1.498
r = ? m
  =  ? cm
 

5. What is the radius of curvature in mm of a +6.00D polycarbonate surface?

 

 

D = +6.00                        r = (n-1)/D = 0.586/6 = 0.098 m =   +98 mm
n = 1.586
r =
  =
 

1. Find the nominal power (DN) if:
1. D1 = +10.00 and D2 = -6.00      +4.00
2. D1 = +2.00 and D2 = -4.50      -2.50
3. D1 = +8.00 and D2 = -5.75      +2.25
4. D1 = -1.25 and D2 = -3.75      -5.00
5. D1 = -5.00 and D2 = -6.00      -11.00

 
2. Find the back surface (D2) if:
1. DN = +10.00 and D1 = +6.00      +4.00
2. DN = +2.00 and D1 = +8.50      -6.50
3. DN = +8.00 and D1 = +5.75      +2.25
4. DN = -5.00 and D1 = -1.00      -4.00
5. DN = +6.50 and D1 = +10.00      -3.50
6. DN = -6.50 and D1 = +0.50      -7.00

 
3. Find the front surface (D1) if:
1. DN = +10.00 and D2 = -2.00      +12.00
2. DN = +2.00 and D2 = -8.50      +10.50
3. DN = +8.00 and D2 = -2.75      +10.75
4. DN = -1.25 and D2 = -7.75      +6.50
5. DN = -5.00 and D2 = -3.00      -2.00
6. DN = +6.50 and D2 = -10.00      +16.50

 
4. I need a lens with power +3.50 D.  If I use a lens blank with a front surface power of +8.00 D, what back surface do I need?      -4.50

 
5. I have a lens with a front surface of +9.25 D and a back surface of -2.25 D.  What is the power of the lens?      +7.00

 
6. I want my lens to have a power of -3.00 D.  What back surface do I need if the front surface is +8.00 D?      -11.00

1. A plastic meniscus lens of index 1.50 has a front radius of curvature of 8 cm and a back radius of curvature of 22.22 cm.  What is its dioptric power?  [In this worksheet, meniscus means one surface is + and one is -]

                        n = 1.50
                        r1 = 8 cm = 0.08 m
                        r2 = 22.22 cm = 0.2222 m
                    first surface is 0.50/0.08 = 6.25
                    second surface is 0.50/0.2222 = 2.25
            D1 = +6.25, D2 = -2.25,   DN = +4.00 D
 
2. A barium meniscus lens, n = 1.60, has a front radius of curvature of 12 cm and a back radius of curvature of 7.5 cm.  What is its dioptric power?

                        n = 1.60
                        r1 = 12 cm = 0.12 m
                        r2 = 7.5 cm = 0.075 m
                    first surface is 0.60/0.12 = 5.00
                    second surface is 0.60/0.075 = 8.00
            D1 = +5.00, D2 = -8.00,   DN = -3.00 D
 
3. A flint meniscus lens, n = 1.70. has a front radius of curvature of 11.2 cm and a back radius of curvature of 175 mm.  What is its dioptric power?

                        n = 1.70
                        r1 = 11.2 cm = 0.112 m
                        r2 = 175 mm = 0.175 m
                    first surface is 0.70/0.112 = 6.25
                    second surface is 0.70/0.175 = 4.00
            D1 = +6.25, D2 = -4.00,   DN = +2.25 D
 
4. What is the power of a plano-convex polycarbonate lens with a front surface radius of curvature of 500 mm?  [Plano-convex means one surface is plano, 0 power, and one surface is convex, + power.]

                        n = 1.586
                        r2 = 500 mm = 0.500 m
                    first surface is 0
                    second surface is 0.586/0.500 = 1.172
            D1 = 0, D2 = +1.17,   DN = +1.17
 
5. What is the power of a plano-concave crown glass lens with a back surface radius of curvature of 45 mm? [One surface 0, one surface -.]

                        n = 1.523
                        r2 = 45 mm = 0.045 m
                    first surface is 0
                    second surface is 0.523/0.045 = 11.62
            D1 = 0, D2 = -11.62,   DN = -11.62 D
 
6. What is the power of a biconvex high-lite (n = 1.70) lens with a front surface radius of curvature of 70 cm and a back surface radius of curvature of 1.5 m?  [Both surfaces +.]

                        n = 1.70
                        r1 = 70 cm = 0.70 m
                        r2 = 1.5 m
                    first surface is 0.70/0.70 = 1
                    second surface is 0.70/1.5 = 0.47
            D1 = +1.00, D2 = +0.47,   DN = +1.47
 
7. What is the power of a biconcave CR39 lens with a front surface radius of curvature of 250 mm and a back surface radius of curvature of 37.5 cm? [Both surfaces -.]

                        n = 1.498
                        r1 = 250 mm = 0.250 m
                        r2 = 37.5 cm = 0.375 m
                    first surface is 0.498/0.250 = 1.99
                    second surface is 0.498/0.375 = 1.33
            D1 = -1.99, D2 = -1.33,   DN = -3.32