The Soft Lens, 50 Years On Check out articles commemorating the soft lens's anniversary: Material Gains: 50 Years of the Soft Contact Lens Advances in Optics Drive Soft Lens Success Replaceable Lenses, Irreplaceable Progress

In the 50 years since the soft contact lens first arrived on the market, remarkable progress has been made. What began with a child’s building kit and a phonograph motor is now a multi-billion-dollar industry.^1,2

“Since the soft contact lens was first introduced in 1971, the industry has seen significant growth and advancements,” notes Joseph Shovlin, OD, of Scranton, PA. “As innovations in materials grew, so did efforts to enhance manufacturing processes. Different manufacturers developed an assortment of technologies to allow for today’s high production rates of quality lenses.”

Today, an estimated 45 million individuals wear contact lenses, 90% of whom use soft lenses.³ To meet the needs of this market, there was a concerted effort to develop not only revolutionary materials, but also manufacturing processes that could keep up with innovation and allow for the mass production.

The now-ubiquitous blister pack was revolutionary upon its introduction. As a means of packaging and distributing lenses at high volume, the cost per lens was reduced from that of glass vial production lines and more elements of the manufacturing process could be automated—bringing additional cost savings as well as shortening production time. Click image to enlarge.

“The contact lens industry has seen massive improvements, even in the span of my career,” emphasizes Nashville contact lens specialist Jeffrey Sonsino, OD. “The incremental improvements in manufacturing each year have culminated in the ability of manufacturers to cost effectively produce daily disposables, which are the crown jewels of the contact lens industry.”

He goes on, “When Don Korb created the CSI lens, it was arguably the greatest material ever made to that date. Its downfall was protein and lipid deposition after a month’s worth of wear. Manufacturing techniques and yield rates at the time did not allow the lens to be produced in a daily disposable. But now, we can develop similar materials that are highly cost-effective, reproducible and safe for wear.”

The Growth of an Industry

Otto Wichterle, a chemist from Czechoslovakia, produced the first four hydrogel contact lenses using the spin casting process he pioneered.⁴ He created the device with a children’s building kit, a bicycle dynamo belonging to one of his sons and a bell transformer.⁵ HEMA, the polymer created by Wichterle, was heated with a hot plate and added to the mold through a tube while it was spinning.⁶

And this is how Wichterle invented spin casting—a new way of manufacturing lenses that would play a central role in the growth of this industry. He went on to develop another way to produce soft contact lenses in 1963 using lathing machines.⁴ In 1966, sublicensing of Wichterle’s patent was granted to Bausch + Lomb, who received exclusive rights for the spin casting process and non-exclusive rights to hydrogel lens distribution.⁶

In the early days of contact lenses, high manufacturing costs were largely contributed to labor. Trained technicians magnified and inspected early lenses more than 10 times to look for any flaws. Advancing production techniques eventually made this rigorous inspection unnecessary.⁶

Lathe cutting was used to produce PMMA and early hydrogel lenses. This technique has its limitations, including a higher expense since it requires a lathe to cut each lens out of dry material followed by hydration of the final product. This process, which has poor reproducibility, required an evaluation of every lens before it was sent to the consumer. Conversely, spin casting allows for higher production. Additionally, the lens optics can be varied by changing the speed of rotation as well as the mold shape. In 1980, manufacturers started using cast molding for contact lens production. This shift sought to produce low water content polymacon lenses while increasing production capacity without additional labor.⁶

With the introduction of disposable lenses, manufacturing companies had to ramp up production without sacrificing quality. Stabilized soft molding, which is a cast molding process acquired from a Danish engineer, allowed for volume production and led to the United States launch of Acuvue (Johnson & Johnson Vision Care) in 1987.⁷ 

Another significant innovation was Johnson & Johnson’s move away from injection vials to the blister pack that we see today, according to Ross Grant, an optometrist and business consultant to the contact lens industry. They reduced costs by producing molds and packaging into blister packs on the production line. The per-lens cost was lowered with the reduction of labor and an increase in automation.⁶ 

In all of these manufacturing processes, polymerization of monomers using UV light or heat was required, explains Dr. Grant. This resulted in residuals inside the lens, which were toxic. Before sterilizing and packaging the lenses, a lengthy extraction process was required.

In the mid-’90s, Ciba Vision launched a project that aimed to further streamline the manufacturing process, Dr. Grant says. “Through these efforts, they did away with the extraction process,” he recalls. “Instead of starting with monomers and polymerizing them, they polymerized until you had a fairly viscous liquid.” The result was a relatively small molecule that was still polymerized and didn’t have any toxic residue present, which was then put in the mold. 

“It was then exposed to UV light and crosslinked. These small molecules joined together, and you ended up with the gel, which was the contact lens,” Dr. Grant continues. “This process was much faster than previous methods. Ciba Vision then automated the system, allowing for the production of mass quantities of lenses.”

Lens Manufacturing Lingo   Spin Casting: Monomer liquid is injected into a spinning mold. Heat or UV light is used to initiate polymerization. This method uses centrifugal force to form the shape of the base curve while the shape of the front curve is created by the mold. Lathe Cutting: The anhydrous polymer is first cut to small buttons and the surface of the lens is cut by lathe tool to the required curvature. Both sides are then polished to remove any roughness before the lens is soaked in a saline solution to hydrate. Lastly, the lens undergoes a sterilization process.  Molding: This method is used to manufacture some brands of soft contact lenses. Opposing molds are used to cause the materials to become the necessary shape inside the mold. Injection molding and, most recently, computer control, are also used. Stabilized Soft Molding: Developed for high volume production, this method mixes an inert water substitute with lens monomers prior to polymerization; water replaces the substitute at hydration.

The first daily disposable lens launched in 1995 (1-Day Acuvue, J&J). To make daily lenses a cost-effective product, J&J created a second-generation manufacturing process called ‘Maximize.’ This process, which integrated stabilized soft molding manufacturing, optimized polymerization, and included the use of conveyors, robotics and a computerized high-resolution inspection of lenses among other improvements.⁶ 

“Daily disposable lenses transformed the industry,” says Dr. Grant. “You’re producing 730 lenses for one person compared to 104 for weekly disposable lenses.

“That is a massive increase in volume and normally you trade off some quality for quantity,” he explains, who notes that this was not the case for daily disposable lenses. “These lenses were extraordinary in the quality that they delivered.”  

This was achieved through automation and cast molding, according to Dr. Grant. Up until this point, spin casting and lathing were predominantly the two technologies used to manufacture soft contact lenses. “Even with automation, lathing is quite inefficient,” he notes. “You cut away more than you leave behind.”

Ongoing efforts dedicated to the advancement of manufacturing techniques—both with small changes and significant innovations—have led the industry to where it is today, allowing for the production of soft lenses on a scale that could hardly be imagined 50 years ago. 

“Over the course of decades, the machines used to produce contact lenses have become much more automated and precise,” notes Tony Hough, MBA, BA, a longtime industry consultant. “Around the ’70s/’80s, almost all lens cutting was done with manual equipment, eventually moving to semi-automatic and later on, highly automatic. At the same time, underlying technology, such as air bearing spindles, allowed for an improvement in the quality of lenses produced. Together, we have the ability to mass produce high-quality lenses to meet the growing demands of the market.”

Entering the Market 

In an industry dominated by major players, gaining a foothold can prove challenging for a new manufacturer. Are the barriers to entry too high? It may be difficult, but not impossible if the company can fill a gap in the market.

One example of this is Eyeris, a new contact lens company that puts the doctor/patient relationship at the forefront of their mission. Dr. Sonsino, co-founder of the company, attributes Eyeris’s success to its unique business model and growing concerns around industry practices that are removing ODs from the equation.  

“It all comes back to patients and doctors,” notes Dr. Sonsino. “Certain direct-to-consumer companies are seemingly operating outside of prescription requirements and the law. As practitioners, we’re seeing the direct results of this bad behavior with patient complications.” Dr. Sonsino recalled a patient who purchased lenses from an online retailer for three years without that company requiring a valid prescription. This patient ultimately needed a corneal transplant.

At Eyeris, the doctor is in control of the process from start to finish. “Patients can purchase online directly from Eyeris, but doctors know that patients are receiving only the type of lens and quantity that they prescribe, all while realizing the margin on those sales,” Dr. Sonsino explains. “This is a better model not only for doctors, but also patients. We give consumers the cost convenience and comfort they desire, while requiring regular visits to their optometrists.”

As a growing start-up, how does Eyeris offer affordable options while contending with the costs of manufacturing and distribution? “One of the ways that we were able to produce lenses at a much lower cost than the big four was to work around them,” says Dr. Sonsino. “We produce Eyeris lenses with our own manufacturing lines in Asia.”

The quality control is held to the same standards as American manufacturers and the company uses the same techniques, he explains. For example, Eyeris uses UV crosslinking of monomers instead of heat as many Asian manufacturers do. Additionally, the company does not invest in a national sales force or rebates, according to Dr. Sonsino, who notes that these practices significantly raise the cost of a lens.

What Comes Next?

As advancements continue, how will manufacturing processes continue to evolve? According to Mr. Hough, there will be a focus on refining current technologies and an ongoing shift toward further automation. 

“If you look forward 20 years from now, I believe the majority of lenses will be made using exactly the same methods we employ today,” he notes. “We may run a bit quicker and jump a bit higher, but you’ll see the same core technologies.”

But processes will certainly keep evolving. “We continue to see improvements and more manufacturers making lenses for more complex prescriptions,” Mr. Hough continues. “The large companies now have very sophisticated, specialized manufacturing units that are filling in the ends of ranges. That’s the type of investment that I think we will see more of, as well as further emphasis on automation and some robotics.”

Shifting the Industry Mindset While ongoing advancements are crucial, so is a shift in mindset and industry practices, according to Dr. Sonsino.  “Manufacturing techniques are not going to fix the current problems in the industry; what we need is a change in manufacturer behavior,” he elaborates, noting that for the most part, the contact lens manufacturing industry has forgotten the importance of speaking to consumers. As a result, direct-to-consumer companies have filled this void and are trying to work around the doctor, Dr. Sonsino notes. “If nothing is done to counter this irresponsible messaging, there will be a tipping point where consumers no longer understand the need for legitimate eye care.”  The demand for soft contact lenses will continue. What could change, according to Dr. Sonsino, is how lenses are delivered to patients. Will it be doctors or online middlemen who act as the voice to the patient? He emphasizes the importance of treating contact lenses as a medical device, not a widget. “Without intervention, large, direct-to-consumer companies will continue to lobby for the deregulation of prescription requirements,” Dr. Sonsino says. “As doctors, we know this will result in more ocular complications, but the question is, can we properly educate regulators?”

Improvements in manufacturing processes will allow companies to address those patients with specialty needs, emphasizes Dr. Grant. “While high-volume molding processes can produce very large quantities of lenses, it is not flexible,” he explains. “For instance, in the case of toric lenses, where you have a sphere power, cylinder and an axis, the number of stock-keeping units goes up exponentially.”

“Developing manufacture processes that can better cope with this is important,” he continues. “A few things have been done, such as semi-molding—a combination of precision molding and lathe cutting.”

Another avenue that has possibilities for the future is 3D printing. This technology could potentially allow for more customizable lenses without the need for post-processing, such as grinding or polishing.⁸ However, this approach remains largely unexplored and will likely not be a viable innovation in the immediate future.

“3D printing is something I don’t think we have fully explored in the way that we could,” notes Dr. Grant. “Theoretically, you could have someone sit in front of a machine that connects to a 3D printer and creates a lens. While I believe we are several years from this becoming a reality, this approach does have possibilities for patients with specialty needs.”

In an industry committed to innovation, ongoing refinement of current technologies as well as new developments will allow consumers to access cutting-edge products, no matter how unique an individual’s needs.

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