Contact Lens Prescription vs. Spectacle Prescription
This is an article forward from http://biofilcon.com/contact-lens-prescription/#more-800
Contact lens prescription does differ from spectacle prescription, mainly due to the distance between the spectacle and your eyes.
For those with spectacle prescription less than -4.00 D, the difference is insignificant. Patients can choose to wear either the same prescription or slightly lower. Spectacle prescription of -4.00D above, the difference with contact lens prescription will become more significant.
The chart below, is a conversion chart of spectacle prescription to contact lens prescription.
(-) Minus prescription is refer for short sighted or myopia. (+) Plus precription is refer for long sighted or hyperopia.
Besides that, a simple calculation can be done to determine your contact lens prescription (as the diagram below)
_________________from this part, it is my opinion _______________
What if the prescription you are looking for is not available?
1) Try to keep the left-right eye balance
For example, I am shortsighted and have a left eye spectacle prescription of -6.00, which according to the chart, it is -5.62, my right eye is -5.25, according to the chart I need -5.00.
I would like to keep my left - right eye difference ( which is now by a 0.75 difference)
So I choose -5.75 for my left, and -5.00 for my right.
2) Try to choose the power closest to your prescribed power.
So some contact brands does not have -5.75 prescriptions. They only have -5.50 or -6.00.
So I decide to go with -5.50 instead of -6.00, because my real prescription according to chart is -5.62 (closer to -5.50 an further to -6.00)
3) Go with your feeling.
Sometimes you just need to try to know which one is better. Just try and feel it out. Order both prescriptions and try them out for a day.
Hope this helps and Good Luck!
