TruForm Optics

Fitting Support > Extended Karatometer Range

Extended Keratometer Range

A +1.25D or -1.00D diagnostic lens can be held adjacent to the front of the keratometer to extend the dioptric range of the drum readings

Extended Keratometer Range with +1.25D Lens   Extended Keratometer Range with -1.00D Lens
Actual Drum Reading Extended Value   Actual Drum Reading Extended Value
45.00D 52.46D   36.00D 30.87D
45.25D 52.76D   36.25D 31.09D
45.50D 53.05D   36.50D 31.30D
45.75D 53.34D   36.75D 31.51D
46.00D 53.63D   37.00D 31.73D
46.25D 53.92D   37.25D 31.95D
46.50D 54.21D   37.50D 32.16D
46.75D 54.51D   37.75D 32.37D
47.00D 54.80D   38.00D 32.59D
47.25D 55.09D   38.25D 32.80D
47.50D 55.38D   38.50D 33.02D
47.75D 55.67D   38.75D 33.23D
48.00D 55.96D   39.00D 33.45D
48.25D 56.25D   39.25D 33.66D
48.50D 56.55D   39.50D 33.88D
48.75D 56.84D   39.75D 34.09D
49.00D 57.13D   40.00D 34.30D
49.25D 57.42D   40.25D 34.52D
49.50D 57.71D   40.50D 34.73D
49.75D 58.00D   40.75D 34.95D
50.00D 58.30D   41.00D 35.16D
50.25D 58.59D   41.25D 35.38D
50.50D 58.88D   41.50D 35.59D
50.75D 59.17D   41.75D 35.81D
51.00D 59.46D   42.00D 36.02D