Origin of the Capsular Tension Ring (2001)

I am writing to correct some misinformation that was published in this journal regarding the inventor of the capsular tension ring (CTR).1 I believe that I was the first to design (in 1990), report at an academic meeting (in 1991), and publish a paper (in 1994) on the development of a poly(methyl methacrylate) open ring for use as a CTR. The original aim of my ring was to maintain the circular contour of the capsular bag and to prevent decentration and deformation of soft intraocular lenses (IOLs). Soon after I developed the ring, I found that it could also be used to reconstitute a round capsular bag in cases of zonular rupture. I initially developed the ring in 1990 with Pharmacia (now Pharmacia & Upjohn), and I hold the Japanese patent for the ring (patent no. 2129249, intraocular ring; registered on November 16, 1990). The original name for my ring was the capsular bag supporting ring, and I presented a video on its use in cadaver eyes at the film festivals of the American Society of Cataract and Refractive Surgery (ASCRS) and the European Society of Cataract & Refractive Surgeons (ESCRS) meetings in 1991. I also presented experimental studies using the ring at the film festivals of the 1991 ESCRS and 1992 ASCRS meetings. Both films, entitled “Lens Epithelial Expansion to the IOL Optics” and “Lens Epithelial Expansion Onto the Posterior Capsule,” respectively, received the grand prize. A scientific paper describing my experimental studies of the ring was published in JCRS in 1994.2 I also conducted extensive research regarding the use of the ring for zonular rupture in 1992 and presented my results at a video session of the 14th Congress of the Japanese Society of Ophthalmic Surgeons in February 1993. My capsular bag supporting ring and the subsequently reported and clinically used CTR are the same in principle. The only difference is that the latter has eyelets and the former does not. While I wanted to put my ring to clinical use, Pharmacia had no interest in pursuing this for commercial sale. The first presentation on the CTR made by Witschel and Legler was given at the ASCRS meeting in May 1993. They have not published scientific papers on the use of the ring. However, many papers by other authors have subsequently stated that the first report of the ring was the presentation by Witschel and Legler at the 1993 ASCRS meeting.1,3,4 This is clearly not correct, as my evidence shows. However, this misinformation has now spread worldwide and I respectfully request the assistance of JCRS in correcting this. A similar device, the equator ring,5 was independently designed by Hara at almost the same time I developed the capsular bag supporting ring. Although the 2 rings are made of different materials and therefore have different physical properties, they share the same purpose; that is, maintenance of the circular contour of the capsular bag. Specifically, the equator ring is a closed ring made of a soft material, while the capsular bag supporting ring is an open ring made of a rigid material. I strongly believe that Dr. Hara and I should receive appropriate acknowledgment as being the original inventors of the equator ring and the CTR, respectively. Toshiyuki Nagamoto MD aTokyo, Japan