1 December 1991 Improved PMMA single-piece haptic materials
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Abstract
During the past fifteen years, Intraocular lens (IOL) haptic preferences have shifted from a variety of multi-piece haptic materials to single-piece PMMA. This is due in part to the research of David Apple, M.D., and other who have suggested that All-PMMA implants result in reduced cell flare and better centration. Consequently, single-piece IOLs now represent 45% of all IOL implants. However, many surgeons regard single-piece IOL designs as nonflexible and more difficult to implant than multipiece IOLs. These handling characteristics have slowed the shift from multi-piece to single-piece IOLs. As a result of these handling characteristics, single-piece lenses experience relatively high breakage rates because of handling before insertion and during insertion. To improve these characteristics, manufacturers have refined single-piece IOL haptic designs by pushing the limits of PMMA's physical properties. Furthermore, IOL manufacturers have begun to alter the material itself to change its physical properties. In particular, two new PMMA materials have emerged in the marketplace: Flexeon trademark, a crosslinked polymer and CM trademark, a material with molecularly realigned PMMA. This paper examines three specific measurements of a haptic's strength and flexibility: tensile strength, plastic memory and material plasticity/elasticity. The paper compares with Flexeon trademark and CM trademark lenses to noncrosslinked one-piece lenses and standard polypropylene multi-piece lenses.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Donald D. Healy, Christopher D. Wilcox, "Improved PMMA single-piece haptic materials", Proc. SPIE 1529, Ophthalmic Lens Design and Fabrication, (1 December 1991); doi: 10.1117/12.50483; https://doi.org/10.1117/12.50483
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