Vision: The Real Reason for Contact Lens Wear
point TOPIC: Vision or Comfort
Vision: The Real Reason for Contact Lens Wear
BY JOSEPH B. STUDEBAKER, OD, FAAO
The ancient Greeks possessed a rudimentary but fairly accurate understanding of the structure of the human eye and even performed surgery on it, but functional aspects of the eye and visual system mystified and confused even the most esteemed Athenian scholars. Just before the time of Hippocrates, attempts to logically explain the concept of vision took an odd mystical detour with the fairly broad acceptance that human beings and other creatures saw by virtue of “light-like rays,” which were believed to emanate from the eyes to make contact with objects in the universe and, thus, make them visible. Even great minds such as Euclid and Ptolemy accepted the very popular “emanation theory” of the interaction of light and the visual system. A few skeptics, among them Aristotle, questioned conventional thinking by asking why people couldn't see in total darkness if their eyes were, indeed, the source of such rays. Curiously, such questioning was essentially disregarded for the next two millennia until astronomers such as Johannes Kepler and Christopher Scheiner, through mathematical computation and direct experimental verification, respectively proved that the primary step in the visual process of converting “light into sight” began inside the eye.
More than four centuries later, human beings continue their relentless efforts to convert light into sight. Witness the revolutionary developments of the past few decades: space telescopes, surveillance satellites, adaptive optics, non-optical night vision devices, electro-optical vision aids, specialty contact lenses, intraocular lenses, custom-wavefront-guided refractive surgical procedures and ophthalmic lens fabrication, not to mention revolutionary inventions in the entertainment world, such as highdefinition television. More than any other single variable associated with any method of optical correction, quality of vision remains “nearest and dearest” to the heart of any spectacle or contact lens wearer.
Much of today's contact lens advertising trumpets the consumer and practitioner benefits of comfortable contact lenses with promises of “maximum comfort” and so on. Other advertisements seem to entice patients and practitioners alike with the assurance of “convenient” (thus perhaps psychologically comfortable?) lens wear or care. In fact, much of today's ophthalmic industry advertising would lead one to believe that “comfort is king” with regard to contact lens wear. But is it?
To be certain, contact lens comfort and cosmesis are important aspects of “successful” contact lens wear. But all of us — patients, manufacturers and clinicians — would be wise to remember that for most patients, vision is the primary motivating factor for most individuals who wear contact lenses. Except in infrequent cases when contact lenses are prescribed for purposes of ocular protection or delivery of pharmaceutical agents, vision enhancement is the preeminent reason why more than 125 million human beings on this planet continue to tolerate the presence of these amazing little medical devices in their precorneal tear films. As practitioners, we're faced with the fundamental challenges of delivering “the complete package” of safety, comfort and vision to the patients we serve. It's not always easy, but it's getting easier with new contact lens technologies.
Because of a variety of patho-physiological, optical, psychological and financial factors, not everyone is a suitable candidate for contact lens wear. The two variables of vision and comfort aren't always synonymous components of contact lens correction for all patients. However, the good news is that today's increasingly sophisticated materials and designs are greatly reducing the number of clinical instances in which comfort and vision are mutually exclusive qualities of contact lens wear. CLS
Dr. Studebaker is a clinical assistant professor at The Ohio State University College of Optometry. He has received research funding from Ciba Vision and CooperVision and is also a consultant to Bausch + Lomb and Compulink Business Systems. He is an Administrator for Vision Source and practices at Northwest Optometry, LLC in Englewood, OH.
The Case for Comfort
The Case for Comfort
BY ANDREW J. EMCH, OD, MS
The three basic tenets of successful contact lens wear are vision, comfort and health. In prioritizing this list, ocular health unequivocally goes at the top, but is comfort or vision more deserving of attention in today's contact lens practice? Poor vision will limit wear, but the case is the same for poor comfort. The fundamental question at hand is: Which is more bothersome to wearers — comfort problems or vision problems?
A basic approach to solving this dilemma is to survey those who have discontinued wear of contact lenses — the dropouts. Several studies have addressed this over the last two decades. In the 1990s, multiple international studies by Weed, Schlanger and Pritchard supported the claim that discomfort in lenses was overwhelmingly the number-one reason for contact lens dropout.
The new century ushered in new contact lens technologies, but in 2002, a multicenter study (Young, et al) noted the most common reason patients initially stopped lens wear was discomfort. After subjects were refit with new lens materials, poor vision was the main reason for discontinuation at the 1-month follow-up. However, 6 months after the fitting, comfort was again the main determinant in lens dropout.
Basic logic would argue that if patients were truly interested in the very best vision that refractive modalities offer, gas permeable lenses would comprise more than 10 percent of the current U.S. contact lens market. It would seem the massive shift over the last 35 years from hard to soft contact lens materials speaks volumes to the public appeal of comfort over vision. Perhaps this simply illustrates that the attainable vision in current soft lens materials is adequate enough that comfort becomes the limiting factor for contact lens success.
In 2005, Nichols and colleagues surveyed 893 subjects, 393 of whom were contact lens wearers. Of the contact lens wearers, 53 percent reported dry eye and 15 percent experienced “very intense” dryness at the end of the day. The same study reported wearers were five times more likely than spectacle wearers to report dry eye.
More recently, Richdale and colleagues (2007) showed in a cross-sectional survey that ocular symptoms, namely dryness, were the most common reasons for dissatisfaction with contact lenses. Poor vision with contact lenses was the least common reason for dissatisfaction or discontinuation.
Accordingly, the industry push over the last 5 years has been toward lens materials designed to enhance patient comfort and strategically marketed to convey this message. Names among these products are Acuvue 1-Day Moist (Vistakon), Dailies Aqua Comfort Plus (Ciba Vision), Acuvue Oasys (Vistakon), Biofmity (Cooper-Vision). Packaging and promotional media portray the perfect symbiosis of contact lens wear, contact lens comfort and ocular health. The message of quality vision seems to have fallen by the wayside.
While stable vision is of utmost importance, it's a given or expected feature of contact lenses, and it doesn't reconnect with contact lens dropouts for the very reason that these studies have shown. We've all experienced the occasional visually dissatisfied toric or multifocal contact lens patient, but the simple truth remains that patients have dropped out of lenses for the last 20 years primarily due to comfort issues, so that has to be the angle to get them back into lenses. Comfort trumps vision.
Perhaps even more powerful than the statistics are the anecdotes we all have from direct patient care; those individuals whose wear-time is consistently reduced due to comfort even in the highest Dk, lowest modulus, most wet-table lens on the market. The data seem to indicate that the vision is adequate, these patients are just waiting on a cure for comfort. CLS
For references, please visit www.clspectrum.com/references.asp and click on document SE2010.
Dr. Emch graduated from The Ohio State University College of Optometry in 2008 and completed a residency in cornea and contact lenses at the University of California, Berkeley School of Optometry. He is a clinical assistant professor at The Ohio State University College of Optometry, where he also serves as a research optometrist in the Contact Lens and Tear Film Laboratory.
Contact Lens Spectrum, Issue: April 2010