Do you know why high-index and aspheric lenses are suitable for strong presciption? I have a strong prescription (SPH-7.50 for both eyes) and my colleague suggests me to buy 1.67 ASP lenses.

As we know that the stronger prescription we have, the thicker lenses edge there will be. High index and aspheric lenses are thinner than ordinary lenses.
They can give you more attractive appearance.