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Characteristics and Materials of Artificial Corneas

Learn about the key features and materials used in artificial corneas, such as PMMA and PHEMA hydrogels, for surgical applications. References and insights provided.

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Characteristics and Materials of Artificial Corneas

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  1. ARTIFICIAL CORNEAS MEEN 3344 Presentation by: Aditi Bandyopadhyay

  2. CHARACTERISTICS OF AN ARTIFICIAL CORNEA • Withstand intraocular pressure • Be transparent • Have an appropriate curvature • Have a suitable refractive index • Have sufficient tensile strength to allow surgical manipulation and fixation. 1 Figure 1. Dohlman Device

  3. MATERIALS USED TO MAKE ARTIFICIAL CORNEAS • Poly (methyl methacrylate) (PMMA) • Poly 2-hydroxyethyl methacrylate (PHEMA) hydrogels • Poly(vinyl alcohol) (PVA) Figure 2. Artificial cornea Photo credits: National Research Council of Canada

  4. CHARACTERISTICS OF PMMA • Transparent and colorless • 92% transmission of visible light • Glassy polymer with an amorphous structure • Very low water absorption capacity • The refractive index ranges from 1.49 to 1.51 depending on the type. • High mechanical strength • High Young's modulus • Good hardness with low elongation at break. • Does not shatter or rupture • Highly scratch resistant. 3 Figure 3. Chemical structure of PMMA

  5. REFERENCES • Chirila. T. V., Hicks C. R., Dalton. P.D., Vijayasekaran. S., Lou. X., Hong. Y., Clayton. A.B., Ziegelaar. B W., Fitton. J.H., Platten. S., Crawford. G.J., Constable. I.J. Aritificial Cornea, Prog. Polym. Sci., 1998, 23, 447-473 • Kobayashi. H., Kato. M., Taguchi. T., Ikoma. T., Miyashita. H., Shimmura. S., Tsubota. K., Tanaka. J., Collagen immobilized PVA hydrogel-hydroxyapatite composites prepared by kneading methods as a material for peripheral cuff of artificial cornea, Material Science and Engineering C, 2004, 24, 729-735 • http://www.tangram.co.uk/. Last updated on 08/28/06 • Hicks. C. R., Fitton. J. H., Chirila. T V., Crawford. G. J., Constable. I.J., Keratoprostheses: Advancing toward a true artificial cornea, Survey of ophthalmology, 1997, 42 • http://depts.washington.edu/chemeng

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