Flat-top trifocals are the most widely used form. The added segment provides clear vision at arm's length distance, the area that is usually blurred for bifocal wearers. Trifocals are available in all lens materials. This is currently the most popular bifocal. Progressives have the cosmetic advantage of appearing to be single vision lenses so they never reveal that the wearer is using bifocals.
Progressives are available in all lens materials and also made in aspheric form.
Because of their many benefits, they are becoming the lens of choice for bifocal and trifocal wearers. Many occupations impose demanding visual requirements on those who wear bifocals or trifocals. In addition to safety concerns, be sure to discuss the wearer's job tasks so the lenses can be designed for specific requirements. Polycarbonate is the material of choice for active sports. Polarized sun lenses that eliminate reflected glare are especially appropriate for drivers, fishermen, hunters and all types of outdoors activities.