Q: Are the more expensive brands of contacts for dry eyes (e.g., Acuvue Oasys® vs. Sofmed®) really any better (or different) than the cheaper ones?
Answer: The sale price alone does not necessarily determine superiority of certain contact lenses compare to another. However, due to the advancements in the materials employed to make contact lenses, some contact lenses are more apt to improve the comfort among contact lens wearers with dry eyes.
Contact lenses vary in regards to their level of water content, lens composition, and oxygen transmission, which all can contribute to determining patient’s subjective level of comfort while wearing contacts.
In regards to the effects of different water content of contacts on dry eyes, low water content contact lenses generally provide better comfort compare to high water content contact lenses. This is contrary to the general misconception that high water content contact lenses may be better for dry eyes. Contact lenses with more than 50 percent water content are considered “high water,” and less than 50 percent water content are considered to be “low water”. High water content contact lenses tend to lose their moisture to the dry environment through dehydration. In order to compensate this loss, the contact lens material draws tears from the corneal surface to retain their wetness, thereby worsening dry eye symptoms and consequently increasing discomfort while wearing the lens.
As to the influence of lens material on dry eyes, soft contact lenses are traditionally made with hydrogel lens material (e.g. Sofmed®) which is made in combination with hydrophilic, i.e. “water-loving” polymers that help to preserve water and maintain the moisture. In these contact lenses, the percentage of water content fluctuates, depending on the brand. In comparison, the newer lens material, silicone hydrogel lenses (e.g. Acuvue Oasys®, Sofmed® Breathables®) generally contain lower water content than the traditional hydrogel lenses along with higher level of oxygen transmission, which is crucial in maintaining good ocular health. Subjective symptom of dryness tends to occur less frequently with low water content silicone hydrogel lenses, thereby increasing comfort and tolerance towards the end of the day.
Depending on the lens composition, some contact lenses absorb components (e.g. lipids, proteins and mucins) from the tear film more readily than others, which can also have an effect on subjective comfort and dry eye symptoms. For example, contact lenses made with non-ionic polymers with high water content tend to be prone to lipid deposition and contact lenses made with ionic polymers with high water content tend to be prone to protein deposition. In comparison, most of the silicone hydrogel lenses are non-ionic, low water content materials which are less susceptible to deposition, dryness, and discomfort at the end of the day.
In addition to the different contact lenses, there are other patient related factors which can influence contact lens related dry eye symptoms, including patient’s gender, nature of dry eyes, environment, lens care solutions and rewetting drops used. Some FDA approved brands also have been found to be particularly helpful to improve comfort for contact lens wearers with dryness symptoms, and you should consult with your eye doctor for specific recommendations.
Grace M. Kim, O.D.
Clinical Advisor Panel Chair for America’s Best Contacts & Eyeglasses
Dr. Kim received her Doctorate from the Pennsylvania College of Optometry. Prior to entering optometry school, she worked as a research biologist at the Department of Microbiology and Immunology of the Uniformed Services University of the Health Sciences. She was involved in electron microscopy, ultramicrotomy and immunocytochemistry, in which fields she received acknowledgements and co-authored presentations, abstracts, and articles which were published in the Journal of Eukaryotic Microbiology. Following graduation, Dr. Kim joined National Vision’s America’s Best Contacts and Eyeglasses. Since 2007, Dr. Kim served as Chairperson on Clinical Advisory Panel. She is also a Doctor Mentor in which position she trains newly hired doctors and assist in conducting performance reviews on the Peer Review Committee.