A contact lens is built with the following parameters: a (spherical) power (for correcting near- or farsightedness); and, possibly, a cylindrical power and an axis (for correcting astigmatism). For a...

A contact lens is built with the following parameters: a (spherical) power (for correcting near- or farsightedness); and, possibly, a cylindrical power and an axis (for correcting astigmatism). For a particular brand of contacts, the possible parameters for a lens that corrects near- or farsightedness only are

• a power between −6.00 and +6.00 inclusive in 0.25 steps (excluding 0.00); between 6.50 and 8.00 inclusive in 0.50 steps; and between −6.50 and −10.00 inclusive in 0.50 steps, and the parameters for a lens that corrects astigmatism are

• one of the powers listed previously;

• a cylindrical power in {−0.75, −1.25, −1.75, −2.25}; and • an axis between 10◦ and 180◦ in steps of 10◦

A patient needing vision correction in both eyes may get different contact lenses for each eye. A prescription assigns a lens for the left eye and for the right eye. How many contact prescriptions are there?

.