When you ask historians who invented the first corneal contact lenses, the usual answers are Eugène Kalt, MD (1800s), and Kevin Tuohy (1940s). Therefore, it is logical that our story should begin with Eugène Kalt, MD.

Experimenting with Treating Keratoconus

In 1888, Kalt (Figure 1) was a young ophthalmologist and Chief Clinical Assistant at the Department of Ophthalmology, Hôtel-Dieu Hospital in Paris under the tutelage of Professor Photinos Panas. In March of that year, Panas presented his young colleague’s work with “coque de verre” (glass shells) in the lecture “Optical Treatment of Keratoconus” to the French Academy of Medicine (Pearson, 1989).

Further clarity on Kalt’s work was provided by French ophthalmologist Emile Haas. Through personal communication with Kalt in 1937, Haas learned that the initial patient described was a young nun who suffered from bilateral keratoconus and had visual acuity of only count fingers. Following application of the lenses, her visual acuity immediately improved to 3/10 and 4/10. Kalt later wrote to Haas that these lenses could only be tolerated for approximately two hours.

The historical record shows that from 1888 to 1893, Kalt experimented with 16.0mm to 22.0mm blown glass shells and later with ground glass scleral lenses. He also experimented with ground glass lenses that had overall diameters of 11.0mm, 11.5mm, and 13.0mm.

In his 1938 report “Les Verres de Contact” (Contact Glasses), Haas wrote that Kalt had asked an unknown optician to grind the thin glass contact lenses “having a radius of curvature the same as that of a normal cornea according to the measurements taken with the Javal keratometer and verified with a mold of a cadaver eye.”

Haas had an opportunity to examined Kalt’s three experimental ground glass lenses and found them to have a single curvature (monocurve) on the posterior surface, differentiated only by their total diameters of 11.0mm, 11.5mm, and 13.0mm. The anterior optical zone radius was 7.90mm, and the refractive powers were between +1.50D and +2.00D. These numbers indicate that the posterior base curve radius (BOZR) was flatter/longer than 7.90mm.

The legendary claim is that Kalt experimented with corneal lenses cut from the bottoms of test tubes. While this makes for wonderful folklore, no historical record has ever validated the story.

Unfortunately, Kalt did not publish the results of his observations with the experimental corneal contact lenses, and we must rely on the personal communication and evidence provided by Haas in his 1938 report.

Ophthalmic historian Robert F. Heitz, MD, PhD, wrote in The History of Contact Lenses that “In reducing the diameter of the scleral lenses to the diameter of the cornea Kalt went down a hitherto untraveled path which is another way of saying that he was the inventor of the corneal contact lenses as we would know them in the second half of the twentieth century.” However, it is unknown whether Kalt ever used his corneal contact lenses to manage keratoconus. These lenses were made from ground and polished glass and therefore were too heavy to be retained by the effect of surface tension alone, a problem that would not be overcome until the introduction of plastic (PMMA) corneal lenses in the 1940s. CLS

For references, please visit www.clspectrum.com/references and click on document #293.