More than meets the eye

The contact lens began as a glimmer in the multifaceted mind of Leonardo da Vinci in the 1500s. Then, before the turn of the 20th century, a German ophthalmologist crafted a lens from glass that covered the entire front surface of the eye. Considering the divergence between the latest silicone hydrogel lenses of today and their glass-blown ancestors, it is difficult to predict whether the contact lenses of the future will bear anything more than a fleeting family resemblance. Manufacturers are continually refining the materials that contact lenses are made from to boost wearer comfort, while the range of applications that contact lenses are applied to is extending beyond vision correction alone.

Here are three innovative contact lens developments to follow.

1. Drug delivery

Using a technique that is similar to a tiny game of Tetris, researchers from China Pharmaceutical University and Southeast University developed a contact lens that
changes colour as medication is released into the eye. The lens is loaded with the glaucoma medication, timolol, through molecular imprinting which involves creating cavities within the lens that match the size and shape of a specific compound. As the  lens is exposed to tears, the medication is released into the eye and the architecture of the lens alters – prompting a colour change.

2. Measuring IOP

Moorfields Eye Hospital and the Royal Liverpool University Hospital have conducted a small study with a contact lens that is capable of measuring intraocular pressure (IOP). The contact lens contains a pressure sensor that detects IOP changes and then transmits them wirelessly to a portable external controller the size of a mobile phone. The soft silicone hydrogel device was found to accurately measure changes in IOP with little discomfort to the patient in a small clinical trial involving 12 volunteers.

3. Combating colour blindness

A contact lens saturated with dye has been developed by University of Birmingham researchers to assist those with red-green colour blindness. Scientists used a non-toxic dye derived from rhodamine to stain inexpensive soft commercial contact lenses. Researchers found that the dye blocks the band that lies between the red and green wavelengths, enabling better differentiation between red and green colours.

Image credit: Getty