In the 1940s, Harold Ridley noticed plastic splinters sitting quietly in pilots’ eyes, and it wasn’t just wartime debris: It changed cataract surgery

When WWII broke out, there was another group of British soldiers, the Royal Air Force (RAF) pilots, whose canopies were destroyed as a result of attacks from the enemy's forces, and as a result, debris entering the pilots' eyes became a major problem. Normally, doctors would have expected any foreign material in the eyes to cause either an inflammatory or infectious reaction. However, the observations Ridley made on the RAF pilots were different. It is evident that some pieces of Perspex plastic used in aircraft canopies remained in patients' eyes without causing any adverse reactions. It is said that Ridley's experience of having observed such a phenomenon was among the most important discoveries in the ophthalmology of modern times, according to the Royal College of Ophthalmologists. What Ridley realized was not the eye injury itself, but the eye's tolerance to plastic implantation.

One particular example that is usually mentioned is that of RAF pilot Gordon Cleaver, whose plane's canopy cracked during a battle, sending Perspex shards into his eyes. As described on the Science Museum London site, what caught Ridley's attention about such incidents was how the acrylic bits seemed to remain biologically inert despite surgeons' expectations of their dangerous effects on patients. Ridley did not forget about that phenomenon even after World War II was over. In the past, when treating cataracts, doctors removed the affected lenses without providing any prosthetics to patients. Patients could regain partial sight using thick glasses.

Ridley’s idea challenged one of ophthalmology’s deepest assumptions

The idea came across as very radical in its time, since it had been the norm for surgeons to remove foreign matter from the eye rather than deliberately place it into it. As noted by the American Academy of Ophthalmology, many ophthalmologists had reacted by rejecting Ridley’s invention as potentially hazardous, since any procedure involving the placement of foreign matter inside the eye went against everything doctors knew. Nonetheless, Ridley did not give up on his idea. Partnering with manufacturers who specialized in working with the plastic PMMA, he developed an artificial lens intended to replace the patient's damaged natural lens.


Ridley is said to have conducted the first implantation of an artificial lens in 1949 at St Thomas’ Hospital, London, according to the Moorfields Eye Hospital History Archive, which was significant since the cataract procedure had stopped being one that simply aimed to extract the faulty lens from the eye; it had become one that aimed to restore vision as well. As seen in various academic reviews cited by the National Library of Medicine, Ridley’s initial models had several issues; nonetheless, the theory remained viable due to its biological soundness. The eye could accommodate acrylic material under specific circumstances.

The wartime observation became the foundation of modern cataract surgery

Indeed, IOLs are so commonplace nowadays that cataract sufferers do not appreciate the revolutionary nature of the procedure. As reported by the National Eye Institute, cataract removal procedures nowadays always involve replacing the natural eye lens with an artificial intraocular lens, directly following in Ridley’s footsteps. The influence of this invention is hard to exaggerate. As noted on the website of the World Health Organization, cataracts are one of the main reasons why people suffer from vision loss throughout the globe, meaning that countless patients each year are aided by a technique pioneered during the war. As reported by Britannica, Ridley’s groundbreaking work eventually won international acclaim despite the initial opposition he faced.

Ridley’s discovery was not based on his plan to revolutionize the field of cataracts; he saw something interesting when he realized that the minuscule plastic shards from shattered canopy glass did not respond as expected based on medical science. Most doctors would just write the observation down and let it go, but Ridley took a different approach. This approach resulted in one of the greatest contributions to the field of ophthalmology. His wartime experience revealed that the body could accept this type of plastic, leading to the use of artificial lenses today to restore eyesight.