contact lens care
Soft Contact Lens Deposition — Part I
BY SUSAN J. GROMACKI, OD, MS, FAAO

Figure 1. Lipid deposition on a soft contact lens. Photos courtesy of Dr. Ron Watanabe.

Soft lens complications are often a result of contact lens deposition. The use of disposable lenses — especially daily and two-week replacement modalities — has helped in decreasing deposition and the problems associated with it. When using yearly or three-month replacement modalities, however, patients must perform proper lens care to provide a clean lens surface. Hydrogel lenses deposit secondary to their hydrophilic surface, patient tear film, environment and lens handling. Here are some common types of soft contact lens deposits and how to manage them.

Protein Deposits

One of the more common deposits, protein deposits originate primarily from albumin, globulin and lysozyme in the tears. A protein deposit has an opaque, white filmy appearance and may have cracks when the film is thick. It's found primarily on the front surface of soft contact lenses and on both surfaces of GP lenses. Deposition begins immediately after lens application. The deposits may bind solution preservatives. Protein deposition is most common in high-water-content hydrogels, followed by low-water-content HEMA materials. Silicone hydrogels tend to accumulate protein the least.

Practitioners should direct patients prone to heavy protein deposition to daily disposables. If this can't be done, recommend an enzymatic cleaner once each week or more. Extended wear patients should switch to daily wear. It's also helpful to refit into a more protein deposit-resistant material such as silicone hydrogel.

Lipid Deposits

Lipid deposition has a smeared, greasy whitish appearance (Figure 1). The lipid arises from the meibomian glands of the lids. Patients more prone to deposition include those with tear film potassium deficiency, dry eye, high fat diets and high alcohol consumption. Silicone hydrogel materials tend to accumulate more lipids than some conventional materials. Management includes thoroughly rubbing or rinsing lenses with solution; using an alcohol-based daily cleaner, which dissolves lipids; and/or using lenses with a two-week or less replacement schedule.

Microorganisms

Figure 2. Close-up of a fungus imbedded in a soft contact lens.

These are gray, black, brown or white growths in the lens matrix. Microorganisms are usually fungi or yeast and appear in a filamentary pattern (Figure 2). They're common in patients who neglect daily disinfection or who use non-preserved saline, high-water-content lenses and/or lenses dam-
aged or deposited with protein.

Lenses contaminated with microorganisms need to be replaced. Careful patient instruct-
ion is necessary regarding good personal hygiene and proper daily disinfection. It's also important to avoid prolonged lens storage without disinfecting lenses.

Dr. Gromacki has served as a faculty member at the University of Michigan Department of Ophthalmology and Visual Sciences.