Charles Kelman, MD, a clinical professor at New York Medical College, worked closely with Tekia, Inc. (Irvine, CA), to develop the Kelman Duet Implant, currently CE Mark-approved but unavailable in the US. This two-piece lens design comprises a PMMA haptic and a separate, foldable optic. The surgeon first places the haptic within the anterior chamber, then injects the 6.3-mm lens optic, and finally secures the optic to two tabs located on the haptics to create a tripod-shaped IOL. The lens standard package configuration contains one optic and three haptics in sizes of 12.0, 12.5, and 13.0 mm, with 13.5 mm available upon special request. This innovative lens may be inserted through an incision 2 mm long. Although currently designed for myopic correction, in the future, hyperopic, toric, and multifocal designs will be available.
IMPLANTATION TECHNIQUE
In the first human implantations of the Kelman Duet Implant, we placed the optic inside a cartridge for injection into the eye. We created a calibrated incision of 2.5 mm and injected cohesive viscoelastic solution into the anterior chamber before implanting the haptic. After inserting the optic, we assembled the lens within the eye using Lester hooks (Figure 1). In the case depicted on the enclosed CD-ROM, we created a 2.5-mm incision (the principle incision) in the positive corneal meridian through which to insert the optic and 1-mm incisions located 170º apart. If pupil ovalization occurred, we assumed the reason was an oversized haptic, and we explanted and replaced it with a smaller one to correspond better with the internal dimensions of the patient's eye. In the near future, it will be possible to substitute a multifocal or customized optic to address the needs of the eye over the patient's lifetime.
LINICAL STUDY RESULTS
This postmarket study included 40 eyes of 26 patients. The patients had a mean age of 28.6 ±5.8 years. Their preoperative refractions ranged between -10.00 and -20.00 D with astigmatism of up to -2.00 D. The patients' mean preoperative spherical equivalent was-13.50 ±3.40 D. The minimum anterior chamber depth required was 2.8 mm. The patients' mean preoperative UCVA was 20/400, the BCVA was 20/50, and the mean endothelial cell count was 2,659 ±428 cell/mm2.
Postoperatively, the patients' mean UCVA was 20/32, the BCVA was 20/25, and the mean spherical equivalent was -1.73 ±1.20 D. Twenty-nine of all eyes gained one or more lines of BCVA, and none of the eyes has lost any lines of BCVA to date. The endothelial cell loss was 5% to 8%, including the cases of haptic exchange.
CONSIDERATIONS
Two eyes experienced a movement of the lens optic due to short haptics, and two other eyes received long haptics that caused pupil ovalization. In all cases, the haptics were exchanged safely with no need to explant the optic (Figure 2).
CONCLUSION
The Kelman Duet Implant is the only phakic lens that can be implanted through a 2-mm incision and assembled inside the anterior chamber. Our study showed that the optic centration of this lens is excellent and the optic/haptic relation is stable. This lens offers a unique surgical solution of a separate and exchangeable optic and haptics, and the efficacy of the exchange was proven in this study.
José Luis Rodriguez-Prats, MD, is a senior refractive surgeon in the Department of Refractive Surgery, Instituto Oftalmológica de Alicante in Alicante, Spain. He holds no financial interest in the product discussed herein. Dr. Rodriguez-Prats may be reached at +34 96 515 00 25; jlrodriprats@coma.es.
Ahmed Galal, MD, MSc, is a fellow in the Department of Refractive Surgery, Instituto Oftalmológica de Alicante, and Ophthalmology Department, Miguel Hernández University Medical School, in Alicante, Spain. He holds no financial interest in the product discussed herein. Dr. Galal may be reached at +34 96 515 00 25; dr_ahmgalal@hotmail.com.
