contact lens case reports

Identifying Contact Lens Surface Deposits (Part 2)

BY PATRICK CAROLINE, FAAO, & MARK ANDRE, FCLSA
JULY 1998

Last month, in Part 1 of our two-part series on soft lens deposits, we described the etiology and management of protein deposits, lipid deposits and lens calculi. Here, we complete our review with a discussion of

with a discussion of inorganic films, rust-colored spots and microorganism growths.

Inorganic Films

An inorganic film manifests as round, coalesced, microscopic lesions similar in color and appearance to a protein film. Electron microscopy examination reveals slightly elevated, granular lesions embedded into the anterior lens matrix (Fig.1). The deposit consists predominantly of calcium phosphate, which is a component of tears. A peculiar feature of the deposit is that it tends to isolate itself to the thickest portions of soft lens designs, such as the thick lenticular cap of plus lenses or the thick ballast of a toric soft lens. In the past, inorganic films were best managed through the use of a calcium sequestering saline with thermal disinfection. Today, however, more frequent lens replacement appears to be warranted.

FIG. 1: Inorganic film. Right -- microscopy view.

Rust-Colored Spots

Rust-colored spots are small, raised, orange or red spots most commonly related to metallic foreign particles embedded into the anterior lens surface (Fig. 2). The metallic particles oxidize to form corrosive iron salts which penetrate the lens matrix. Rust-colored spots are most common among patients with occupations or recreational activities in which airborne metallic particles are present.

FIG. 2: Rust-colored spot. Right-- microscopy view.

Since the lesions are small and essentially inert, they usually don't require immediate intervention other than a review of the patient's environment, with emphasis on prevention.

Microorganism Growths

Microorganism growths are either fungi or yeast. Under high magnification, the colonies exhibit filamentary tentacles known as hyphae, which penetrate and grow throughout the lens matrix. The colonies are frequently colored off-white, brown, pink, orange or black (Fig. 3). Since the colonies cannot be removed from the lens, immediate lens replacement is indicated.

FIG. 3: Microorganism growth. Right -- microscopy view.

Microorganism growths are most commonly related to inadequate lens disinfection and storage procedures. Therefore, it is important to emphasize to your patients proper lens care and handling techniques. CLS

Patrick Caroline is an assistant professor of ophthalmology at the Oregon Health Sciences University and an assistant professor of optometry at Pacific University. Mark Andre is director of contact lens services at the Oregon Health Sciences University.