Understanding Free Form Progressive Bifocals

"Free form is to lenses what hand tailoring is to clothing". Meeting the day's call of personalization, many optical shops are utilizing free form progressive (invisible) bifocal lenses. In our own practice it is the only no-line bifocal that we offer for many reasons. The free form lens's greatest benefit is that it requires virtually no adaptation process. So patient's put them on and wear them without the distortions experienced with the traditional no-line bifocal.

Free form is a computerized design and manufacturing process. The free form production process uses a diamond point guided by a computer software program to cut the prescription. Free form processing enables lenses to be produced to 1/100th of a diopter (unit of lens power) accuracy. In the past 12-25/100ths of a diopter were typical. This advance in production enables manufacturers to expand their ablility to correct refractive errors.

When the wearer looks through the peripheral regions of a spectacle lens, aberrations such as oblique astigmatism produce unwanted sphere and cyclinder power errors that degrade vision. Optimal optical performance exists only near the center of the lens. These adverse optical effects of lens aberrations are exacerbated in no-line bifocals. With the free form manufacturing process using sophisticated optimal optimization process, residual lens aberrations are virtually eliminated.

Free form lenses take into acccount measurements such as frame tilt, vertex, wrap angle and panoramic angle(fitting geometry), the patient's prescription and frame information to allow totally customized lenses for individual wearers unlike anything we have had years in the past.

Considering the benefits of these lenses, they offer great value for the money. " The added value of improved vision cannot be overstated. It is one of the senses used all the time! We spend a fortune on High Definition TV's we use for a few hours each day. Don't scrimp on lenses since we use our eyes all our waking hours."

Be sure to ask your eye care professional about free form lenses. They are available for sunglasses, single vision prescriptions and especially for high prescriptions.

1) They provide the best visual acuity at all distances.

2) The intermediate and near zones are wider.

3) There are minimal distortions and aberrations.

4) Field of view increases at all distances.

5) These lenses will fit in many of today's smaller frames sizes.

6) Customized lenses allow millions of prescription combinations which were not possible in the past.