Computer assisted design and finite element analysis of contact lenses.

Contact lenses are an attractive alternative for vision corrections. Their improvement can be achieved by optimizing the geometry, use of new materials, and application of high precision processing technologies. The optimized design can be obtained by computer-aided design, considering the principles of geometrical optics. Inventor Professional and other similar advanced 3D CAD software allows complex approaches, selection of suitable materials with better mechanical/ optical properties. This is useful for the preparation of the virtual design for 3D printing or CNC fabrication. A finite element analysis is also of interest for testing the best design/ material choice. In this paper, the finite element analysis for a tri-curve contact lens was applied. The selected materials were PMMA and polycarbonate. The applied compressive loads were in the range from 10 to 100MPa. Our results showed that the best scenario was for the polycarbonate, but PMMA also had a high safety factor. The maximum compression load with a reasonable safety factor (of 7-9 depending on materials) was 12MPa.