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.
Hydrogels absorb significant amounts of water to keep the lenses soft and supple. Because of this water-loving characteristic, the water content of various hydrogel contact lenses can range from approximately 38 to 75 percent (by weight). Generally, hydrogel soft lenses are available in these categories, based on their water content: Low water content (less than 40 percent water)