A Brief History of Lens Corrective Solutions

For thousands of years we have sought solutions to poor and deteriorating vision. Ancient Egyptians performed operations for cataracts by couching -- dislocating a cataractous lens into the vitreous cavity, or piercing so it may reabsorb. This procedure is still practiced in some countries with poor access to advanced eye care.

Corrective glasses were used as early as 1284 to improve focus. And in 1949, the first lens designed to replace the natural human lens was developed by an English eye doctor named Harold Ridley. These early lenses were made of a hard plastic called polymethyl-methacrylate, and were implanted through a large incision. All patients received the same lens power, which left most with thick glasses.

Beginning in the 1960s, alternatives to lens replacement were developed that modified the structure of the eye.

The first corneal refractive surgery, which is surgery on the clear dome structure on the surface of the eye for the purpose of eliminating the need for glasses, was Radial Keratotomy (RK). A 90+ percent corneal depth incision made in a radial fashion causes the central cornea to flatten and push the focal point of light backwards towards the retina. This technique creates tremendous instability and ‘warping’ of the cornea that can never be repaired. Many patients experience poor vision subject to time of day, barometric pressure, altitude and temperature.

Two other alternative attempts to fix myopia (nearsightedness) are Photorefractive Keratectomy (PRK), which began in 1995, and Laser in Situ Keratomileusis (LASIK), introduced in 2000. Stability of vision is better than that of RK, but other problems persist. As with RK, these two procedures modify the cornea to change how light focuses in the eye, instead of replacing the lens, which is truly the culprit of poor focus.

Other attempts to flatten the cornea have proven unreliable. These include Intrastromal Rings – plastic bands inserted into the thickness of the cornea, and Conductive Keratoplasty – heat from ultrasound used to shrink the outer cornea.

All of the procedures developed as alternatives to lens replacement fail to one degree or another for many reasons. They cannot provide reading or near vision, the results are inconsistent, and in many cases the effects are short-term. Glare, halos, excess tearing, and “dry eyes” are common problems. Bulging and distorted corneas are now occurring eight to ten years after LASIK and PRK.

In contrast to corneal surgery, lens replacement surgery directly replaces the human lens with a man-made lens of a specific power, like a contact lens inside the eye.

Lens replacement increased in frequency in the 1960s. By the 1990s, using new technologies, intraocular lenses changed dramatically.

During the 1990's, a new generation of intraocular lenses attempted to provide both distance and near vision. But even two of the more advanced designs provided no significant reading vision, and one caused severe glare and halo problems. Problems with these lenses led others to pursue new lens designs.

In 2005 after 10 years and 10 million man-hours of research and development, the largest ophthalmic company worldwide, Alcon, developed the first successful distance and reading intraocular lens The ReSTOR®.

ReSTOR® is a breakthrough, and while not as perfect as the lens of a young adult, it allows anyone with an otherwise healthy eye to conquer nearsightedness, farsightedness, and presbyopia (inability to focus near when distance vision is corrected).

The ReSTOR® lenses are made of soft and flexible acrylic, and can be folded and inserted into the eye through a small incision. There, it gently unfolds into its permanent position. Glare and halos have been alleviated with a patented design using apodization – tiny incremental steps between focal zones.

For thousands of years we have sought a permanent solution for poor vision. Only in the past few years have we had the technology to make the solution a reality. The result of lens replacement using the ReSTOR® intraocular lens is exactly what we’ve been waiting for.