BCLA CLEAR – Contact lens technologies of the future

Abstract

Contact lenses in the future will likely have functions other than correction of refractive error. Lenses designed to control the development of myopia are already commercially available. Contact lenses as drug delivery devices and powered through advancements in nanotechnology will open up further opportunities for unique uses of contact lenses.This review examines the use, or potential use, of contact lenses aside from their role to correct refractive error. Contact lenses can be used to detect systemic and ocular surface diseases, treat and manage various ocular conditions and as devices that can correct presbyopia, control the development of myopia or be used for augmented vision. There is also discussion of new developments in contact lens packaging and storage cases.The use of contact lenses as devices to detect systemic disease has mostly focussed on detecting changes to glucose levels in tears for monitoring diabetic control. Glucose can be detected using changes in colour, fluorescence or generation of electric signals by embedded sensors such as boronic acid, concanavalin A or glucose oxidase. Contact lenses that have gained regulatory approval can measure changes in intraocular pressure to monitor glaucoma by measuring small changes in corneal shape. Challenges include integrating sensors into contact lenses and detecting the signals generated. Various techniques are used to optimise uptake and release of the drugs to the ocular surface to treat diseases such as dry eye, glaucoma, infection and allergy. Contact lenses that either mechanically or electronically change their shape are being investigated for the management of presbyopia. Contact lenses that slow the development of myopia are based upon incorporating concentric rings of plus power, peripheral optical zone(s) with add power or non-monotonic variations in power. Various forms of these lenses have shown a reduction in myopia in clinical trials and are available in various markets.

Novel Contact Lenses Embedded with Drug-Loaded Zwitterionic Nanogels for Extended Ophthalmic Drug Delivery

“…Contact lenses have been widely used by millions of people worldwide for decades for vision correction [ 5 ]. They are biocompatible, safe, durable and comfortable, thus providing a new route for ophthalmic drug delivery [ 6 ]. Numerous animal studies demonstrated that ophthalmic medications delivered by therapeutic contact lenses could prolong the time a drug stays on the cornea and increase its bioavailability by at least 50%, compared with eye-drop formulations [ 1 , 7 ].…”

Commercial and Scientific Solutions for Blood Glucose Monitoring—A Review

“…Tears also carry information and show similar glucose concentration to blood [30,52]. Tears contain organic molecules, which reflect the health status [46].…”

“…A potential way to increase the performance of prediction is by taking additional influence factors such as temperature into account. This can be carried out by sensor fusion [52,87,157]. For example, Geng et al [87] were able to improve their results significantly by combining the impedance spectroscopy-based glucose sensing system with temperature, humidity and optical sensors.…”

Characterization and analysis of extended‐wear silicone hydrogel contact lenses utilizing novel silicone macromers

“…Aside from improving the properties of commercial contact lenses or the manufacturability of contact lenses, there is also a need for advanced contact lens properties that current contact lens materials cannot fully or adequately support. Some examples of the newest contact lens advancements are ocular drug delivery via contact lenses, 11 contact lenses acting as biosensors for disease, contact lenses with advanced embedded electronics, and specialty lenses that could help patients prevent the development of myopia 12–14 . As new technologies are developed, the materials that serve as a platform for these advancements as well as knowledge of structure–property relationships must also advance.…”

“…Some examples of the newest contact lens advancements are ocular drug delivery via contact lenses, 11 contact lenses acting as biosensors for disease, contact lenses with advanced embedded electronics, and specialty lenses that could help patients prevent the development of myopia. [12][13][14] As new technologies are developed, the materials that serve as a platform for these advancements as well as knowledge of structure-property relationships must also advance. Thus, there is a significant need for the study and development of new silicone monomers and macromers and more robust silicone hydrogel formulations-mixtures that can handle the addition of new components or molecules without disrupting the oftendelicate balance of hydrophilic and hydrophobic phases and associated polymer phase morphology that affects lens properties.…”