This technique is well-worth mastering for home cooks, as it's an easy way to cope successfully with thick steak and chop-style cuts of beef, pork and other meats. Step 1 Take the sirloin filets out of the refrigerator 45 to 120 minutes before you plan to cook them; chilled beef doesn't cook evenly.
The refractive index of current eyeglass lens materials ranges from 1.498 (CR-39 plastic) to 1.74 (a specific variety of high-index plastic). So for the same prescription power and lens design, a lens made of CR-39 plastic will be the thickest lens available, and a 1.74 high-index plastic lens will be the thinnest.
With ordinary plastic lenses, a strong prescription can result in a thicker, lens. In contrast, high-index lens material will reduce lens thickness for greater comfort and a better appearance. When it comes to impact resistance, polycarbonate lenses outperform plastic and hi-index, and are typically a good choice for children and teenagers. Essilor and Hi-Index. Despite technological advancements, more than one-third of patients continue to be offered thick, fragile and outdated standard plastic lenses.