Colour Changing Contact Lens Monitors Drug Levels in Eye

Thursday, October 25 2018 | 05 h 27 min | Vision Science

Contact lenses that can deliver drugs to the eye, and also provide a real-time indication of the rates of drug delivery have been developed by researchers at the China Pharmaceutical University in Nanjing.

Delivering drugs to the eye is a difficult challenge. Studies show that less than five percent of active drugs in eye drops are actually absorbed, and much of the drugs go into the bloodstream where they are ineffective.

Drug-delivering contact lenses can be a useful method to have drugs absorbed by the eye, but there are challenges in monitoring the rate of drug delivery in real-time.

The research team lead by Dawei Deng and Zhouying Xie created their prototype contact lenses using molecular imprinting, a method of creating lenses that have tiny cavities capable of holding medical compounds. These cavities were then loaded with the glaucoma drug timolol.

The researchers then immersed the contact lens in artificial tears and monitored the drugs being released from the contact lens.

As the timolol is released, the structure of the polymer material of the contact lens changes, resulting in a colour change in the material that is visible by both the naked eye and a fiber optic spectrometer.

The result is a safe method of monitoring drug release from contact lenses in real time, without the use of a dye.

The researchers said, “The contact lens can be further used for controlling release of many ophthalmic drugs and has high potential to be a new generation of functional contact lenses.”

This research was published in the October issue of ACS Applied Materials & Interfaces.