Note：The above conversion table is only for reference. If special circumstances such as high power and astigmatism, etc., pls consult physician or optometrist while purchasing.  

Why contact lens power differs from glass power?

The power of contact lenses often differs from that of optical frame glasses due to their positioning relative to the eye. Glasses are worn a certain distance away from the eyes, whereas contact lenses sit directly on the tear layer covering the cornea. Practically eliminating the vertex distance effect. In optical principles, this means that for nearsighted individuals, the power of contact lenses is typically lower than that of glasses. For prescriptions up to -4.00D, this difference is usually negligible and doesn’t require conversion. However, for powers beyond -4.00D, specific adjustments are necessary. Optometrists take these factors into account during eye exams and select the most suitable lens power for each individual’s needs.