## Frames for Thick Lenses

Relatively sturdy frames for (consider + numbers same as - numbers):

1. Either Spherical or Cylindrical Lenses

You may consider lens with power more than 4.0 D as thick, whether the power is positive (+) or negative (-).

2. Compound Lenses (Spherical & Cylindrical)

You may consider lens with power more than 4.0 D as thick.

A. If both the Spherical and Cylindrical Powers are either positive (+) or negative (-), add both the numbers after converting - numbers to + numbers.

e.g. If Spherical Power is -3 and Cylindrical Power is -2, the total power is 5, which is more than 4, so you may consider the lenses as somewhat thick.

B. If Spherical and Cylindrical Powers are different, i.e. one is positive and other is negative, take bigger power among Spherical and Cylindrical Powers; + or - doesn't matter.

e.g. If Spherical Power is +2 and Cylindrical Power is -5, the total power is 5, which is more than 4, so you may consider the lenses as somewhat thick.

Acetate frames are good choice for fitting thick lenses.