contact lens exam
How to Be a Hero to Your Patients
BY MARJORIE J. RAH, OD, PHD
Figure 1: Epithelial disruption due to contact lens wear.
An annual contact lens examination is much like a comprehensive primary vision care exam with the addition of a contact lens fitting evaluation. Standard tests performed during a primary exam include subjective refraction and over-refractions, intraocular pressures and dilated fundus examinations when indicated. However, certain procedures that may be omitted in a primary vision care examination are critical in a contact lens evaluation.
All annual examinations begin with a case history. In addition to the standard medical information requested during a primary care examination, you should obtain a thorough contact lens history. This is one of the most important aspects of the contact lens exam and should address:
Wearing time. Ask about average wearing time and how long the patient has been wearing his lenses that day. Ideally, patients should be wearing their lenses when they arrive for the examination so you can observe characteristics that are not always apparent upon initial application, such as lens movement, rotational stability and comfort, all of which can change over time.
Lens care systems. In addition to asking what products a patient is using, find out how he's using them. If a patient uses a multipurpose solution, find out if he's rubbing his lenses before disinfecting. If not, ask if he rinses them for the required amount of time before continuing to the disinfecting step. Patients who wear silicone hydrogel contact lenses may not realize proper care includes rubbing their lenses with multipurpose solution.1
While you're on the subject of lens care, discuss or observe the condition of a patient's contact lens storage case. (For more on this topic, see "Making a Case for Clean Cases" on page 12.)
|Figure 2: Corneal topography showing corneal molding associated with flat-fitting GP contact lenses (left side) and resolution after discontinued lens wear (right side).|
Replacement schedule. Determine if the patient is complying with the prescribed wearing regimen by asking how long he's been wearing his current contact lenses and how often he replaces them.
Examine the Ocular Surface
Even with recent advances in lens materials and care systems, changes in the ocular structures still can occur. A thorough slit lamp examination is critical for proper care of contact lens patients. Although you may be tempted to omit certain tests to save chair time, always include eyelid eversion and fluorescein staining. Without these procedures, detecting early signs of contact lens complications can be difficult or impossible. For example, the epithelial disruption shown in Figure 1 may have been detectable with white light, but it's certainly more visible and appears more pronounced with fluorescein staining.
Another essential component of the annual contact lens exam is corneal curvature measurement, whether by manual keratometry or computerized corneal topography. This information will help you diagnose corneal irregularities, troubleshoot complicated cases and monitor long-term disease progression.
The maps in Figure 2 show corneal molding caused by a flat-fitted gas permeable lens, which can mimic early signs of keratoconus, and the same eye after abstaining from lens wear.
In another case, corneal topography helped a practitioner determine why a pre-teen patient wasn't achieving the desired results with corneal reshaping treatment despite the report from both the mother and the patient that the child was wearing the lenses. Topography showed the child had either discontinued treatment or the lenses were positioned incorrectly on the eye during sleep (Figure 3). Without corneal topography, reaching this conclusion would have been much more difficult.
Figure 3: Baseline topography (bottom right) of a patient fitted with corneal reshaping contact lenses. Initial treatment showed good progress ( bottom left), but subsequent evaluations show the cornea returned to baseline (top row).
The procedures I've outlined here are critical for monitoring the well-being of contact lens patients. New lens designs and materials continue to emerge, but we will always need to be vigilant to preserve our patients' corneal health. By maintaining the highest standards of care, you can become your patients' "Hero for Healthy Eyes."
Dr. Rah is an assistant professor at the New England College of Optometry where she works primarily in the Cornea and Contact Lens Service in patient care, teaching and research.
1. Ward MA. Re-educate silicone hydrogel patients about lens care. CL Spectrum. 2005;11:26.