How do I calculate what my regular contact lens prescription would be from my astigmatism lens prescription?

Question

My tonic (astigmatism) contact lens prescription is:
-4.75 -0.75 x010 and
-5.00 -1.25 x170

what would my prescription be for regular contacts?
(I know that I wouldn't be able to see as clear with regular contacts, but I would just like to know)

Answer 1

Add half the amount of astigmatism to the first number, but allowing for the signs. Ignore the third number ( the direction of the astigmatism).

So:
-4.75 -0.75 x010 => -5.00 or -5.25
-5.00 -1.25 x170 => -5.50 or -5.75

If you are younger or do more driving, I'd opt for the higher power, older or do more office work, I'd opt for the lower.

But it's a compromise.
(can be handy for single use throwaway lenses for swimming, for example)

For other people precriptions such as
+4.75 -1.50 x010 => +4.00
-5.00 +1.00 x170 => -4.50

Answer 2

You don't need to worry about how to calculate the conversion, for the optician will do that when you go for your prescription.There is a special kind of contact lens on sale that can auto-focus near and far , meaning for those who are short-sighted and yet cannot see near object clearly, like reading should opt for this kind of contact lenses. Not only glasses has this function, now contact lenses too have it.

Answer 3

You have to have your eye doctor determine this and write you a new prescription.

Answer 4

No, I would NOT ignore it. Have you tried prices lenses at Walmart?