A contact lens that can measure intraocular pressure and deliver a glaucoma treatment when needed has been reported in the journal Nature Communications.
Glaucoma is a group of eye diseases which can lead to irreversible vision loss. According to Glaucoma Australia, two in 100 Australians will develop glaucoma in their lifetime, and there is no known cure.
Vision loss in glaucoma is usually caused by changes to intraocular pressure (IOP) due to abnormal circulation of the aqueous humour – a clear fluid that circulates within the eye. High intraocular pressure can damage the optic nerve which carries signals from the eye to the brain, leading to vision loss.
Currently, the main treatments for glaucoma management include prescription eyedrops and surgery, which both work to reduce the intraocular pressure. However, intraocular pressure also varies from person to person and over time depending on, for example, our circadian rhythm.
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According to the report, scientists have developed a contact lens that uses electrical sensing to measure real-time intraocular pressure. When the pressure reaches a high-risk threshold, a drug delivery module in the contact lens can apply an anti-glaucoma drug to the eye as needed.
The contact lens is an example of a so-called “theranostic device” – one that combines diagnostics and therapeutics – in other words, both recognising and treating the disease.
The design includes an intraocular pressure sensor and a wireless transfer power circuit sandwiched between upper and lower contact lenses, allowing the lens to function without wires or batteries.
The contact lens has so far been tested in pig and rabbit eyes, while clinical applications in humans still require further research.
“This smart system provides promising methodologies that could be expanded to other ophthalmic diseases,” the authors write in the new paper.