Resolving Filmy GPs, Part 2
By Edward S. Bennett, OD, MSED, FAAO; Robert M. Grohe, OD, FAAO; Marlane J. Brown, OD, FAAO; Susan Resnick, OD, FAAO; Michael A. Ward, MMSc, FAAO; & Derek Louie, OD, FAAO
In our last column (October 2011), the members of the GP Lens Institute Advisory Committee discussed three reasons why new GP lenses may become cloudy or filmy. This month, we discuss two more reasons for filmy GPs and how to address them.
Care and Compliance
Lanolin, mineral oil and other moisturizers in liquid soaps, although good for the skin, can cause fogging and filming of lens surfaces. These products quickly contaminate fluorosilicone acrylate lenses by hydrophobic interaction, resulting in clusters of disseminated dry spots. Patients apply their lenses and when they fog up, remove them, rub them with tap water, rewet and reapply, only to discover the filming has reappeared. They often repeat this ritual of cycle cleaning. The problem is easily avoided by using nonmoisturized hand soaps, such as Purpose by Johnson & Johnson. These over-the-counter products are available in bar or liquid pump forms.
Figure 1. Moisturizer on GP lens surface. Photo courtesy of Robert M. Grohe, OD.
Remember also that patients wearing plasma-treated lenses should avoid using liquid alcohol hand soaps, because these can disrupt the surface treatment and cause spotting.
Another way to address filmy lenses is to have the patient switch to a hydrogen peroxide care system. Often, one month of care with a system such as Clear Care (Ciba Vision) will resolve or remove any protein, mucus or waxy pitch buildup from new (or existing) contact lenses, and the patient may like the result so much that he decides to continue using the system.
Lens-to-Cornea Fitting Relationship
A lens that decenters inferiorly can disrupt the normal blink process and result in drying of the tear film over the lens surface. If this is the case, it is important to determine if the new lens has a greater center thickness than the previous lens. Remember that every laboratory has ultrathin designs available.
It is also vital to evaluate the edge clearance with fluorescein. Excessive edge clearance can disrupt the blinking process and cause drying of the peripheral cornea. Likewise, low edge clearance can result in dryness due to insufficient tear exchange peripherally, while possibly resulting in sealoff and debris buildup behind the lens.
As discussed here and in our previous column, numerous factors can cause cloudy or filmy GP lenses, including lens material, fit and care products, a patient's age, sex and eye health, and seemingly unrelated lifestyle choices, such as cosmetics and hand soaps. Systematically addressing these factors and explaining their impact to patients should quickly alleviate these problems and restore clear, comfortable vision. CLS
Dr. Bennett is assistant dean for Student Services and Alumni Relations at the University of Missouri-St. Louis College of Optometry and is executive director of the GP Lens Institute. You can reach him at firstname.lastname@example.org. Dr. Grohe specializes in contact lenses and anterior segment in his suburban Chicago practices while also being associated with the Northwestern University School of Medicine. Dr. Brown is an associate of Minnesota Eye Consultants, a specialty care anterior segment practice in Minneapolis, Minn. She works with contact lens patients who have challenging corneas as well as pre-operative and post-operative patients. Dr. Resnick is a principle in the New York City-based contact lens specialty practice, Drs. Farkas, Kassalow, Resnick and Associates P.C. She's a Diplomate in Cornea and Contact Lenses, AAO, and is a frequent author and lecturer. She is a consultant or advisor to Vistakon, has received lecture or authorship honoraria from Alcon, Alden Optical, and Ciba Vision, and she has a licensing agreement with Safigel, Inc. Mr. Ward is an instructor in ophthalmology at Emory University School of Medicine and director, Emory Contact Lens Service. You can reach him at email@example.com. Dr. Louie is an assistant professor of ophthalmology at Casey Eye Institute, Oregon Health & Science University, Portland, Ore. A large portion of his practice is focused on providing contact lens services for patients who have challenging corneal topography.