If the Rx calls for O.U. +14.00D spheres, which lenses would be the best lightweight option?

The best lightweight option for a prescription calling for O.U. +14.00D spheres is high index resin 1.60. High index lenses are designed to bend light more efficiently than standard materials, allowing for thinner lens profiles, especially in higher prescriptions. With a prescription as strong as +14.00D, using high index resin significantly reduces the lens thickness and weight compared to traditional materials.

This is particularly important for maintaining comfort and aesthetic appeal, as thicker lenses can be cumbersome and unflattering. High index lenses also typically offer better cosmetic outcomes by minimizing the "bubble" effect that can occur with stronger prescription lenses made from standard materials.

Crown glass and CR-39, while they have their own properties and benefits, are heavier and would result in thicker, more cumbersome lenses for such a high prescription. Photochromic refers more to the lens's ability to change color with sunlight rather than its weight or thickness, and the material still needs to be lightweight and thin for this prescription.

Thus, high index resin offers the ideal balance of lightweight characteristics and optical performance for high prescriptions.