Monthly Archives: November 2014
By Dr. William F. Keeling, Ophthalmologist
Cataract Surgery is one of the oldest known surgical procedures, first described in ancient Egypt as a cataract “couching” operation. In the 5th century BC, the surgery consisted of pushing the cataractous lens into the back of the eye with a blunt object; later, they used a sharpened pencil-like instrument. In some cases limited vision would return, but without a lens of any kind. The eye was severely defocused and vision was blurry. Over many centuries, there was little advancement in the basic goal of cataract surgery, which was to leave the eye without a lens.
In the late 1940s Dr. Harold Ridley of London was caring for the many RAF pilots injured in World War II. He observed a number of pilots with fragments of the aircraft windshield still lodged inside the eye. The RAF Spitfire canopy was made of a plastic material, polymethylmethacrylate (PMMA). [envira-gallery id=”7701″]
Surprisingly, PMMA caused little trouble inside the pilots’ eyes. His observations led him to question whether it would be possible to make an intraocular lens out of this material and implant it into the eye at the time of surgery.
In 1949, Dr. Ridley commissioned a lens manufacturer and plastics company to create the first Perspex CQ PMMA intraocular lens. And in 1950 he performed the very first intraocular lens implant. Through the 1970s Dr. Ridley went on to perform over 1,000 such operations. It would take more than 25 years for intraocular lens (IOL) implantation to become the standard of cataract surgery in the U.S.
PMMA implants are still manufactured and used today, although there have been many significant advancements in intraocular lens (IOL) materials and design. The invention of an implantable, inert and technically feasible IOL was a revolution in cataract surgery.
Interestingly, IOLs were nearly banned in the U.S. in the 1970s. It was only through the efforts of actor Robert Young, who starred on “Marcus Welby, M.D.” and was an implant patient himself. Young used his star power, particularly with fans of his show over age 60, to testify before an FDA committee, which resulted in the approval of their use under investigational status.
Initial IOLs were one-piece rigid plates of clear plastic. Such lenses required large incisions and sutures to close the surgical site. In 1984 a new flexible silicone lens was produced, nicknamed he“Mazzocco taco” after its inventor, which could be folded and implanted through a very small incision, and then unfolded in the eye. This ushered in the era of small incision surgery.
In the 1990s, the shape of IOLs were modified to create a 3-piece model: a central optic (lens) with thin plastic positioning loops (haptics) anchored to the edge of the lens. These newer lenses could be implanted into the back of the eye, behind the iris and pupil.
Historically, many materials have been used to make IOLs including true glass, stainless steel and nylon. Today modern lenses are manufactured from one of three basic materials: silicones, hydrophobic acrylics and hydrophilic acrylics (aka hydrogel), all of which are flexible polymers. As of 2004 there were nearly 1,548 types of IOLs available from 33 different manufacturers throughout the world.
Today, the Indiana Eye Clinic uses the most modern, proven intraocular lenses and techniques. These IOLs include Aspheric (aberration free), Multifocal, Accomodating (focusing) and Toric (astigmatism correcting) designs. During cataract surgery/IOL implantation, we are able to utilize the most modern in-house surgical equipment, including eight different lasers (including excimer, and femtosecond) and the Ora Intraoperative Wavefront scanner. Surgical approaches are custom-designed for each patient according to their needs.