Changing Conact Lens Brands: How to Convert – SAG to BC?

I am refilling my contact lenses but the optometrist I went to wouldn’t give me my full prescription unless I paid extra to go with their "trial" contacts and buy only from them.

So I’m looking to switch to another brand like Acuvue but the SAG & BC numbers are different, is there a way to convert?

From old box: Prescription= SAG = 3.75, Dia = 14.1
New Prescription = -5.50/-5.75, Cylinder = -0.75

Acuvue asks for either a 8.3 or 8.7 BC. Is there a way to convert?

Edit: Box prescription=-5.00

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  1. It looks like you’re refilling an old prescription that is no longer valid. The law states that you have to have an anually contact lens examination. Usually, the optometrist will give you trial lenses. Once you are fitted, the law also states that the optometrist must give you the prescription. You can then buy it from any source as long as it is the one that you were fitted for and within a year of the prescription.

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