What do High Prescription, Single Vision lenses look like?

This photograph shows Single Vision lenses in the higher prescription range. With minus prescriptions, the lens edges are thicker than the centres, with plus corrections, the centres are thicker than the edges. With very high plus corrections, ‘low-volume’ masks are not advised, as the thicker lens centres can come into contact with the eyelashes. Again, the amount of aperture filled by the prescription lens is dependent on any individual’s optical centres ( PD )