Instead of asking what changes the next 100 years will produce in ophthalmic lenses, it might be more realistic to ask another question: Will lenses still be used to correct eyesight in 100 years?

New advances in refractive surgery techniques continue to dominate medical news stories. For example, a recent ABC network news program explained how lasers were going to produce "better than perfect vision."

Regardless, the current process of correcting sight with lenses and frames will certainly be around for some time to come, even as the number of people undergoing refractive surgery continues to grow. Surgical correction of presbyopia is not in the immediate future, and this gives a certain amount of comfort to lens and frame manufacturers.

With that said, let's look at what will most likely come to pass in ophthalmic lenses during the early years of the 21st century.

Substrates

Without question, we will continue to see additional alternative lens materials. There are serious trade offs to consider as chemists attempt to increase a plastic's refractive index, making the quest for ever thinner lenses difficult. The most recent advancement is a 1.71 plastic index. Raising the index higher will be hard, but it's safe to predict that there will be companies attempting it.

Currently, the major quest is to find an improved material capable of knocking polycarbonate from dominance. Currently, one fourth of all lenses dispensed in the U.S. are polycarbonate, and lens producers don't seem worried about it being replaced.

Coatings

All lenses in the future will have some form of scratch protective coating. Experts believe coatings approaching the durability of glass are possible, and some are already showing up in the marketplace. All high index plastics are softer than CR-39, and so many high index lenses now come with scratch coating on both surfaces. Eventually, all plastic lenses will be coated. And since AR coaters prefer to apply AR on scratch-coated lenses, this is already accelerating the use of scratch coating with AR usage finally up over the 10 percent mark. Many forecasters now see no reason why AR usage here won't finally catch up with that of Europe.

Experts believe it will be possible to produce a coating to make a lens photochromic, lenses that wearers can dial to any light transmission will be possible, probably within 10 to 20 years.

Progressives

Two major design trends point to the future for PALs. The first is progressives designed with atoric back surfaces, and two European manufacturers are currently producing them.

However, laboratories here cannot generate and polish atoric surfaces, so these progressives are fabricated in Europe by the manufacturers and shipped to American labs for edging and mounting. Though it's unlikely that affordable lab equipment for producing atoric back surfaces will be available in the near future, alternative ways of fabricating lenses -- such as the surface-to-coat technology -- may solve the polishing problem.

A second trend in PALs is a design philosophy known by the generic term "as worn." Progressives incorporating this feature are returned to the practitioner with a correction slightly different than what the doctor ordered. The lens packaging identifies what was ordered and indicates how the manufacturer modified the prescription.

In "as-worn" designs, the manufacturer's computer takes into consideration how trial or refractor lenses were positioned in front of the patient during the refraction, how the lenses will be positioned when checked in the lensometer, and the position of the lenses as worn by the patient. Computers calculate and compensate each component of the prescription so that lenses in the wearing position provide the correction determined by the doctor during refraction. The changes can affect the sphere and cylinder power, the axis, and any prism present in the lens. Look for more computer modifications of the written prescription.

Aspherics/Atorics

More and more lenses are being introduced in aspheric form. It's safe to predict that, much as corrected curve lenses replaced toric 6-base lenses, all lenses will eventually be produced in aspheric form. Many believe by 2010, all lenses will be either aspheric or atoric.

Photochromics

We enter the year 2000 with a heating up of this field. Short term, expect to see more variations in photochromic materials and faster reacting lenses that are less temperature dependent.

Longer term, look for electrochromic lenses that will permit wearers to dial up whatever color and density they want for each activity.

Lens Production

The most dramatic changes will be in how lenses are produced.

Casting vs. molding. What are the downsides of the way we make lenses? Traditional methods of casting spectacle lenses are extremely labor intensive. Consider all that goes into producing finished lenses. Assembling two glass molds with a gasket, the manufacturer pours monomer into the cavity (by hand). Half of all lenses are produced in semi-finished form, cast as oversize blanks that are the size of a hockey puck. Seventy-five percent of the material is whittled away by the lab during surfacing, and another 40 percent of the material is lost during edging. In the future, better and less wasteful ways of producing lenses will be introduced.

Nearly all current plastic lenses are made in the casting method described above. The only exception is polycarbonate, an injection molded lens. Injection molding can produce more consistent and reproducible quality, with less labor, and a small labor force.

Casting lenses is labor-intensive, while molding lenses is equipment-intensive, thus requiring a larger capital investment. Experts predict that eventually all lenses will be molded, not cast.

Casting-to-prescription. For now, however, casting remains the dominant way of mass-producing lenses, and it is now being taken to a new level. Two years ago, a company was launched based on the premise of individually casting lenses to each patient's prescription. For progressives and bifocals, the front molds include the reading segment so that, when the gasket is removed, a multifocal lens ready to edge to the frame is produced. The concept was to sell the uncut lenses direct to retailers.

But that's not the entire cast-to-prescription story. There is a growing interest on the part of other lens manufacturers, too, and the market will be seeing more progressives and other lenses cast to prescription. Regardless, it's certainly clear that the market will be seeing many changes and technological advances over the next few years.

Wholesale Labs

These events could forecast a gloomy future for independent laboratories, except for two factors. First, the eyecare professions have grown accustomed to personalized lab service. And second, cast-to-prescription manufacturing lends itself primarily to the most-used range of prescriptions, but anything outside that range must be fabricated in the traditional manner. This leaves a small market that will still need the services of a laboratory. In addition, cast-to-prescription manufacturers may discover they need a strategically located lab to deliver the finished eyewear.

With these potential shifts in technologies, one thing is certain. The optical field is going to be an exciting place to be during the next century. EB