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ARTIFICIAL CORNEAS. MEEN 3344 Presentation by: Aditi Bandyopadhyay. CHARACTERISTICS OF AN ARTIFICIAL CORNEA. Withstand intraocular pressure Be transparent Have an appropriate curvature Have a suitable refractive index

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artificial corneas

ARTIFICIAL CORNEAS

MEEN 3344

Presentation by:

Aditi Bandyopadhyay

characteristics of an artificial cornea
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

materials used to make artificial corneas
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

characteristics of pmma
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

references
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