A Microfluidic Contact Lens to Address Contact Lens‐Induced Dry Eye

Abstract

The contact lens (CL) industry has made great strides in improving CLwearing experiences. However, a large amount of CL wearers continue to experience ocular dryness, known as contact lens-induced dry eye (CLIDE), stemming from the reduction in tear volume, tear film instability, increased tear osmolarity followed by inflammation and resulting in ocular discomfort and visual disturbances. In this article, to address tear film thinning between the CL and the ocular surface, the concept of using a CL with microchannels to deliver the tears from the pre-lens tear film (PrLTF) to the post-lens ocular surface using in vitro eye-blink motion is investigated. This study reports an eye-blink mimicking system with microfluidic poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogel with integrated microchannels to demonstrate eye-blink assisted flow through microchannels. This in vitro experimental study provides a proof-of-concept result that tear transport from PrLTF to post-lens tear film can be enhanced by an artificial eyelid motion in a pressure range of 0.1-5 kPa (similar to human eyelid pressure) through poly(HEMA) microchannels. Simulation is conducted to support the hypothesis. This work demonstrates the feasibility of developing microfluidic CLs with the potential to help prevent or minimize CLIDE and discomfort by the enhanced transport of pre-lens tears to the post-lens ocular surface.

Recent developments and future perspectives of microfluidics and smart technologies in wearable devices

“…Zhu et al addressed this issue by developing an eye-blink mimicking system using a microfluidic hydrogel with integrated microchannels. 214 Their in vitro study demonstrated that the system could enhance tear transport from the pre-lens tear film to the post-lens tear film by simulating the motion of an artificial eyelid in a pressure range similar to that of human eyelid pressure. The microchannels were made of poly(2-hydroxyethyl methacrylate) (poly(HEMA)).…”

Toward the Next Generation Human–Machine Interaction: Headworn Wearable Devices

“…Water-soluble glue was employed to secure the poly(HEMA) film onto the planner substrate, enabling the production of high-quality microfluidic channels. 68,69 Light or heat mediated therapy is an important application of smart contact lenses in the treatment of eye diseases, and the preparation of component materials in this respect is also a hot spot of scientific research. 70−72 Figure 4d shows the main device used for ocular hyperthermia.…”

“…This microfluidic contact lens utilizes a UV-curable biomaterial with excellent biocompatibility, mechanical properties, and hydrophilicity, enabling automatic collection and monitoring of tears. 40,69,95 ■ THE INTEGRATION OF MICROFLUIDICS Microfluidics has the advantages of excellent stretchability, a fine microstructure, high integration of multiple functions, and low cost and has been widely used in wearable devices. Welldesigned microfluidic devices enable outstanding versatility in wearable applications, including sample collection, processing and storage, sample analysis, signal conversion and amplification, mechanical sensing, and power supply.…”

Screen-Printed Textile-Based Electrochemical Biosensor for Noninvasive Monitoring of Glucose in Sweat

“…Skin surface contamination, old and new sweat mixing problems: The skin may be contaminated by dead skin cells, sebum, the condensate from trans-epidermal water loss, and other contaminants induced by human activities or environmental exposure. The combination of flexible microfluidics with well-sealed microchannels or microchambers has been applied to harvest sweat to decrease contamination and evaporation of sweat samples (similar to wearable tear analysis) [60][61][62]. In addition, patterned hydrophilic fillers were designed to realize rapid sweat uptake at low secretion rates.…”