How to know my contact lens power?

Knowing your contact lens power is very important. Bare in mind, contact lens power can sometimes be not the same as your prescription spectacle.

Why is it so?

Your spectacle is worn further from your eye, while contact lens is worn on your eyes. The distance between your eye and spectacle is called ‘vertex distance’. With an average of 12mm distance, your prescription will be different, especially for those with higher prescription; -4.00D and above.

Some simple conversion prescription, ignoring your astigmatism;

  • Power from -0.75D to -3.75D, you can follow back the same prescription as your spectacle
  • Power from -4.00D to -5.00D, your contact lens prescription must be lower 0.25D compare to your spectacle prescription
  • Power from -5.25D to -7.25D, your contact lens prescription must be lower 0.50D compare to your spectacle prescription
  • Power fromĀ  -7.50D to -9.50D, your contact lens prescription must be lower 0.75D compare to your spectacle prescription

For example, if your spectacle prescription is -5,50D, then you should be using -5.00D prescription for your contact lens.

Conversion prescription will varies when there are astigmatism in your eyes. Any inquiry about your prescription conversion, feel free to contact joey@biofilcon.com.

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