Custom Corneas: 3D-Printed Lenses Adapt to Each Eye in Minutes

A team of scientists at the University of Waterloo in Canada has developed an experimental system capable of manufacturing rigid contact lenses tailored to each patient's cornea in under 20 minutes.

3D Printing Overcomes Conventional Limitations

Conventional contact lenses are fabricated within a limited range of sizes and curvatures, making it challenging for individuals with irregular corneas to find a lens that fits correctly. However, the 3D printing process allows for a personalized approach, starting with a detailed map of the eye's geometry and converting it into a custom-designed lens.

The process begins with obtaining a high-resolution map of the cornea. Software then uses these data to design the inner surface of the lens, which must adapt to the unique shape of the eye, while the outer surface is modified to direct light correctly to the retina. This separation enables both precise fitting and the necessary correction for conditions like myopia or hypermetropia.

3D printing also offers the flexibility to vary the curvature, thickness, and geometry of different areas, particularly useful for irregular corneas. The lenses require transparent, resistant materials that allow oxygen passage, as the cornea relies on this exchange for health. However, conventional silicones often don't work well in 3D printers.

To overcome this challenge, the researchers developed a silicone-acrylate blend that solidifies with light. The lens is built up layer by layer, following the digital model, enabling the reproduction of complex shapes without the need for a specific mold for each patient.

While the printing process takes around 12 minutes, the subsequent washing, treatment, and finishing steps bring the total time to around 15-20 minutes. The team has also addressed potential surface irregularities by applying an ultra-fine coating without direct contact, which smooths the surface without altering the personalized shape or optical correction.

Lab tests showed good transparency, mechanical resistance, oxygen permeability, and compatibility with corneal cells. While still in the experimental phase, this technology could revolutionize contact lens manufacturing, especially for those who struggle to find a comfortable, effective fit with standard lenses.