Microscratch resistance of ophthalmic coatings on organic lenses

The mechanical properties, the scratch resistance and the surface damage mechanisms of organic lenses and transparent anti-scratch and antireflective coatings, commonly used in ophthalmic industry, have been studied by means of instrumented nanoindentation and microscratch testing. The effect of the tip microscratch velocity on the mechanical response of a polymeric commercial lens has been qualitatively explained in terms of Eyring's formalism. The analysis of the mean residual scratch depth is proposed as a powerful characterization technique to foresee the Bayer abrasion resistance of ophthalmic coatings.