the
contact lens exam
How
to Be a Hero to Your Patients
BY
MARJORIE J. RAH, OD, PHD
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Figure 1: Epithelial disruption due to contact
lens wear.
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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.
Take Notes
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.)
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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.
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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).
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Stay Alert
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.
REFERENCE
1. Ward MA. Re-educate silicone hydrogel patients about
lens care. CL Spectrum. 2005;11:26.
Contact Lens Spectrum, Issue: February 2006