Experts Address Dangers of Inappropriate Contact Lens Substitution in New Contact Lens and Anterior Eye Paper

WATERLOO, ONTARIO, October 4, 2021—A newly published review paper addresses the dangers and consequences of inappropriate soft contact lens substitution by consumers and resellers, offering objective, evidence-based perspective on a globally proliferating issue. All soft contact lenses are not created equal (Efron N, et al.; is now in press from Contact Lens and Anterior Eye, the peer reviewed journal of the British Contact Lens Association.

Its authors represent some of the most prominent researchers in the contact lens field: Nathan Efron, Phillip Morgan, Jason Nichols, Karen Walsh, Mark Willcox, James Wolffsohn, and Lyndon Jones, who is director of the Centre for Ocular Research & Education (CORE).

The paper details the multifactorial reasons that qualified eye care professionals choose a particular contact lens, including a patient’s anterior ocular anatomy and physiology, lens handling, appearance, lifestyle, and affordability. However, those critical considerations may be ignored when purchasing from unregulated suppliers or even regulated suppliers who fail to understand that all soft contact lenses are not the same.

The research considers 16 independent material, design, optical and other properties of soft contact lenses, evaluating the reasons why these properties might be appropriate for a given lens wearer. These include surface treatment, internal wetting agents, oxygen permeability, water content, modulus, total diameter, back optic zone radius, thickness, edge profile, back surface design, optical design, power, color (tint), ultraviolet protection, wearing modality and replacement frequency.

The paper subsequently highlights problems likely experienced when using contact lenses other than those which have been specifically prescribed. Substitution of all but one of the properties considered (back surface design) was found to be related to at least one—and as many as six—potential sources of patient dissatisfaction and adverse ocular events.

The authors write that “Given the wide range of parameters and properties available, few soft contact lenses are identical in their clinical performance. The consequences of inappropriate substitution of soft contact lenses can vary from physical or visual discomfort to significant physiological complications.”

“While highly trained eye care professionals appreciate the differences between soft contact lenses, that is not well understood by some regulatory bodies, various retailers, and the public at large. My co-authors and I believe there are substantial opportunities to better illustrate those variations and the very real consequences of inappropriate substitution. We hope this paper will serve as a benchmark for advancing that discussion,” said Dr. Jones.

# # #

About the Centre for Ocular Research & Education (CORE)
The Centre for Ocular Research & Education (CORE) was established in 1988 at the University of Waterloo’s School of Optometry & Vision Science. Over the next three decades, the organization evolved from a three-person operation into a thriving hub of basic and applied research, collaborating with sponsors, agencies and academia on advanced biosciences, clinical research and education. Its uncompromising independence and results of the highest quality have been at the heart of many of the most prominent advances in eye health. Today, its approximately 50-person team serves a range of ophthalmic sectors, including medical devices, ocular pharmaceuticals, digital technology and others, with a focus on the anterior segment. For more information, please visit


Aimee J. Lewis or Mike McDougall, APR, Fellow PRSA, McDougall Communications for CORE +1.585.414.9838  | +1.585.545.1815