dry eye dx and tx
GP Plasma Treatment and Dry Eye Patients
BY ANN LAURENZI, OD, FAAO
Patients with confirmed dry eye, whether it is from systemic disease, medications or ocular disease, can be some of the most challenging patients to work with in our contact lens practices.
Such patients want good visual acuity, comfort and long wearing time. These are usually our goals as well, but we're also concerned with a good fit and physiological compatibility. Plasma treatment of GP lenses is one tool we can use to help us achieve these results with dry eye patients at the initial dispensing visit and during the adaptation process.
Plasma treatment influences the surface property of a GP lens, making it more hydrophilic. In general, a GP lens is placed in a vacuum chamber where the surface is bombarded by pressurized/ionized gases that remove contaminants and chemical residues from the lens surface.
Plasma treatments reduce the wetting angle and improve on-eye wettability. Treatments also can improve the compatibility of the on-eye lens/tear film interaction, which translates into better comfort and visual acuity.
Figure 1 shows a lens that has not been plasma treated. As you can see, the lens has large areas where the tear film is not wetting the anterior surface. The lens will usually look dull and have a beading, non-wetting appearance.
If beading persists and moves around the lens with the blink, this indicates that it's due to poor tear film from the dry eye condition. In such cases, vision is decreased and comfort is reduced. However, be cautious. Although infrequent, GPs can arrive from the laboratory with a lens material flaw, and you can have a non-wetting spot due to lens material/manufacturing quality.
Figure 1. A non-treated GP lens.
Figure 2. A plasma-treated GP lens.
You can determine whether a GP has a material flaw by focusing on the surface; if the non-wetting area of the lens is in exactly the same spot, even when the patient blinks and the lens rotates on the eye, this is a surface flaw from material, manufacturing or storage of the lens. The lens should be remade.
Figure 2 shows a plasma-treated lens with improved wettability and lubricity.
Many laboratories are plasma treating lenses routinely — without increased cost or delivery time. However, for the treatment to be of benefit, patients need to properly care for the treated surface. Nonabrasive cleaning systems are required; Boston Simplicity (Bausch & Lomb) and Optimum (Lobob Laboratories) are two systems that are compatible with treated lenses.
Although the treatment loses effectiveness over time — from weeks to months — the initial wettability and lubricity of the lens surface may allow the patient's tear film to adapt to the lens and improve its on-eye compatibility. CLS
Dr. Laurenzi practices at the Cole Eye Institute in Cleveland, Ohio where she specializes in refractive surgery co-management, contact lenses and clinical research.