Smart soft contact lenses stand sentry for glaucoma

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Smart soft contact lens developed by Purdue research team to detect glaucoma. (Purdue University photo/Rebecca McElhoe)

Glaucoma is a group of eye conditions characterized by damage to the optic nerve, which transmits visual information from the eye to the brain. The cause is elevated intraocular pressure (IOP). Often referred to as the “silent thief of sight,” it can lead to progressive vision loss with no early warning signs or pain, making early detection and treatment crucial.

Typically, glaucoma is diagnosed by measuring IOP, as well as evaluating the optic nerve head and visual field. IOP fluctuates over the course of a day and by postural changes. For instance, overnight IOP in the supine position generally is 10 to 20 percent higher than IOP during the day, making overnight fluctuations a major risk factor for progressive vision loss.

However, clinicians are limited to using one or two static data points obtained during daytime office visits when making important disease management decisions — which necessitates recurring daily, weekly or monthly clinic visits. Vision loss can happen during sleep, without the patient being aware of it, even if IOP is within the normal range (10–21 mmHg) according to daytime clinic assessments. Thus, continuous, frequent IOP measurement over 24 hours on a daily, weekly or monthly basis can greatly benefit glaucoma patients.

Over the past two decades, researchers have explored various 24-hour IOP monitoring devices, but such devices have not gained market acceptance because they are not user-friendly. For example, wearable ocular tonometers (eye-pressure measuring devices) aim for continuous monitoring. However, their long-term use has been limited due to discomfort and safety concerns, including foreign body sensation; eye pain; corneal epithelial defects; and conjunctival redness, especially during sleep. Wearable ocular tonometers also have an integrated circuit chip that can cause discomfort and pose safety risks.

Another development, smart contact lenses incorporating functional nanomaterials into biocompatible polymers, has shown promise, but practical implementation has been impeded by lack of durability, stability, oxygen transmissibility, and ergonomic design.

Our team has a better solution to address the unmet need for 24-hour IOP monitoring at home and during sleep. We have developed a unique class of smart soft contact lenses exhibiting superior wearer tolerance and accuracy in comparison with other wearable ocular tonometers.

The innovation pairs a highly-soft, thin, stretchable, and wirelessly-accessible IOP sensor with a commercial, off-the-shelf soft contact lens. This approach preserves inherent lens properties, such as lens power, biocompatibility, softness, transparency, wettability, oxygen transmissibility, and ability to be worn overnight. The lenses for IOP measurement work by capturing corneal curvature changes in response to IOP.

Our technology will be highly impactful in early diagnosis and management of glaucoma, by virtue of its 24-hour monitoring of glaucoma progression or treatment effectiveness on a regular basis, as well as immediate notification of increased IOP, facilitating preparation of personalized treatment plans.

This project encompasses a wide range of disciplines, from wearable sensor design to development of wet adhesives, to clinical validation — requiring a collaborative team with expertise to augment my experience with wearable biomedical sensors. Team members include Bryan Boudouris, the R. Norris and Eleanor Shreve Professor of Chemical Engineering at Purdue, for his in-depth knowledge of macromolecular materials; Dr. Shin Ae Park, assistant professor of ophthalmology in Purdue’s College of Veterinary Medicine, who specializes in ophthalmology and glaucoma; and Dr. Peter Kollbaum, director of the Borish Center for Ophthalmic Research at the Indiana University School of Optometry, who provided vital clinical feedback.

Drs. Peter Kollbaum (right) and Dawn Meyer from Indiana University School of Optometry demonstrate smart contact lenses and how they can be used to identify glaucoma. (Purdue University photo/Rebecca McElhoe)

As our project objective aligns with the mission of the National Eye Institute (NEI) at the National Institutes of Health (NIH) — to protect and preserve human vision — we have submitted a proposal to the NIH NEI. Our team also has developed intellectual property for smart soft contact lenses, with four U.S. patents issued or pending through the Purdue Office of Technology Commercialization.

In addition, we are working with a spin-out company, BVS Sight, Inc., to bring the technology to market. BVS Sight is evaluating market potential, risk, and IP position, while working with contractors and consultants to ensure Food and Drug Administration (FDA) approval and reimbursement. The company will conduct biocompatibility testing with the help of a third-party regulatory consultant. To accelerate the translation to clinical commercialization, BVS Sight also has submitted a Small Business Innovation Research (SBIR) proposal to the NIH NEI.

I envision wearable devices such as we’ve developed being seamlessly integrated into people’s lives, offering real-time monitoring of vital signs and other health indicators to alert users and healthcare providers of potential issues before they become serious. The technology can be highly personalized, considering individual differences in anatomy, lifestyle and health status to provide customized health recommendations and support.

Information generated by these wearable devices would be securely transmitted and stored, allowing for remote access and communication with healthcare providers — particularly useful for patients who live in rural areas and/or have mobility limitations. Bigger picture, our innovation could help pave the way for development of at-home treatments and cures, and foster a proactive, preventive, and more accessible approach to healthcare.

Glaucoma is a significant global health issue, affecting an estimated 80 million people worldwide and incurring healthcare costs in the range of $6 billion to $8 billion. As a biomedical engineer, my ultimate objective is to empower patients and help them take control of their health. By leveraging the capabilities of our soft contact lens technology and other wearable biomedical devices, I aim to enable individuals to live longer, healthier, and more fulfilling lives.

Chi Hwan Lee, PhD

Leslie A. Geddes Associate Professor of Biomedical Engineering

Associate Professor of Mechanical Engineering

Associate Professor of Materials Engineering (by courtesy)

College of Engineering

Associate Professor of Speech, Language, and Hearing Sciences (by courtesy)

Purdue University

Adjunct Professor of Optometry

Indiana University

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