Download New Noninvasive Method of Assessing the Tear Film Uses Corneal

CORNEA/EXTERNAL DISEASE
New Noninvasive
Method of Assessing
the Tear Film Uses
Corneal Topography
Graphic data greatly facilitate consultations with patients.
BY CONNI BERGMANN KOURY, EXECUTIVE EDITOR
E
ye care practitioners increasingly recognize the
importance of identifying and treating underlying problems with the tear film to ensure optimal
visual acuity and visual outcomes for surgical
patients. In the setting of premium cataract surgery with
advanced-technology IOLs, the health of the ocular surface is paramount.
Most established methods of examining the tear film
are based on the observation of induced tear film reflections. These include determining the height of the tear
meniscus, assessing interference phenomena, and observing noninvasive tear film breakup time (TBUT). A limitation of these examinations is their subjective nature.1 In
2007, the Report of the Diagnostic Methodology
Subcommittee of the International Dry Eye WorkShop2
provided recommendations for the standardization of
methods to examine the tear film and report data in clinical studies of dry eye disorders to improve their comparability. The article indicated that objective methods of
analysis might supplement the currently standard tests
for examining the precorneal tear film.3
To this end, some manufacturers have begun using
imaging technology specifically to obtain dry eye
measurements.
NONINVASIVE ASSESSMENT
The Oculus Keratograph (Oculus, Inc., Lynnwood, WA)
has scanning software that can noninvasively assess the
tear film, providing both qualitative and quantitative
assessments. The test is reportedly quick and relatively
comfortable for the patient.
36 ADVANCED OCULAR CARE MAY/JUNE 2011
“The data are produced
in an image showing the areas
of tear film instability
or dry spots.”
—Paul Karpecki, OD
The Keratograph 4 topographer measures up to
22,000 points using 22 Placido rings and has a true builtin keratometer, according to the product information.
Changes in the projected Placido rings (edge shift of the
rings) show where the tear film is breaking up (quality of
the tear film) within a certain number of seconds of a
blink. The data are produced in an image showing the
areas of tear film instability or dry spots, said Paul
Karpecki, OD, in an interview with Advanced Ocular Care.
Dr. Karpecki is clinical director of corneal services at
Koffler Vision Center in Lexington, Kentucky.
The device also noninvasively measures the height of
the tear meniscus (quantity of the tear film). Normative
data suggest that the height in a normal eye is greater
than 0.2 mm, Dr. Karpecki said. That measurement combined with the noninvasive tear breakup scan can point
to dry eye syndrome.
Physicians can use the color representation of the tear
film’s status to facilitate the consultation and better educate patients, according to Sheri Rowen, MD. She is the
founder and medical director of the Eye & Cosmetic
Surgery Center at Mercy Medical Center and the Rowen
CORNEA/EXTERNAL DISEASE
“A picture is worth a thousand
words, and the graphic
can confirm for patients that
their dry eye is a real condition.”
—Sheri Rowen, MD
Laser Vision & Cosmetic Center in Baltimore. “A picture is
worth a thousand words, and the graphic can confirm for
patients that their dry eye is a real condition,” she said in an
interview with Advanced Ocular Care. “The examination is
reproducible by clinical staff, and follow-up testing can confirm the patient’s progress or setbacks with treatment.”
The software is also networkable and compatible with
electronic medical records.
CLINICAL EXPERIENCE
When to Use the Keratograph
In her clinical practice, Dr. Rowen employs the
Keratograph 4 when she encounters a patient who has
dry eyes. “Often, my staff will pick up corneal staining,
which they are instructed to look for prior to administering drops,” she said. “They will use a fluorescein strip with
balanced salt solution and first check the cornea and
draw any staining patterns. If they see staining, they will
also use a lissamine strip. Then, they would perform the
examination using the Keratograph 4 examination, and
that way, baseline TBUT is established.”
Dr. Karpecki recommends using the device to assess all
patients who present with dry eye symptoms when initially taking their history. Both Drs. Karpecki and Rowen
employ the technology to examine patients with a history of ocular surface disease and those who are considering any surgical procedure.
Dr. Rowen said that, in her practice, these patients are
measured with the keratograph every 3 to 6 months to
evaluate the effectiveness of treatment. “We see if the
TBUT correlates with an improvement in the corneal surface and the patient’s symptoms,” she said.
Counseling Patients
The data and images obtained with the machine are
highly effective for counseling patients, according to
Dr. Rowen. “They have something to see, and they know
red colors are bad for them,” she said. “They seem to accept
treatment regimens more easily and adhere to them with
better compliance. The test also helps to pinpoint surface
issues preoperatively, so patients might understand a lessthan-perfect outcome if it is due to their tear film.”
Dr. Karpecki added that the ability to show patients
their images and discuss the height of their tears (tear
meniscus) or the rate at which or area where their tear
film breaks up is instrumental in gaining their confidence.
“It definitely helps to explain the condition in a way they
can understand based on images from the Keratograph
4,” he said. “It increases patients’ compliance with the recommended treatment/management knowing that we
will compare the images after treatment.”
Learning Curve
The learning curve associated with the device is not
daunting, according to Dr. Rowen. She added that it provides a quantitative measurement of how much the tear
film breaks up and when, making the interpretation of
the data much easier. Dr. Karpecki agreed. “The dry eye
evaluation is relatively self-explanatory, given eye care
professionals’ existing knowledge of the tear meniscus
height and TBUT,” he said.
The only limiting factor is that it can sometimes be difficult for dry eye patients to hold their eyes open for
long. “We still can identify their early TBUT, however,”
Dr. Rowen noted.
CONCLUSION
According to Dr. Karpecki, new diagnostic modalities
such as imaging technology and other sensitive topography systems can greatly increase the accuracy of dry eye
diagnosis. “Because the ocular surface is key to accurate
refractions and successful outcomes after cataract and
refractive surgery, more accurate early diagnoses of dry
eye syndrome will lead to prompt treatment and happier
patients,” he said.
“I have found [a] very significant correlation among
the Keratograph 4, corneal staining, and TBUT, so the
device has helped me to better manage these patients,”
Dr. Rowen said. ■
Paul Karpecki, OD, is a member of the speakers’ bureau for Oculus, Inc., but acknowledged
no financial interest in the product mentioned
herein. Dr. Karpecki may be reached at
[email protected].
Sheri Rowen, MD, is an assistant clinical professor of ophthalmology at the University of
Maryland. She acknowledged no financial interest in the product or company mentioned herein. Dr. Rowen may be reached at (410) 332-9500
or (410) 821-5333; [email protected].
1. Lemp MA,Marquardt R.The Dry Eye.A Comprehensive Guide. Berlin,Germany:Springer-Verlag;1992.
2. Methodologies to diagnose and monitor dry eye disease:report of the Diagnostic Methodology Subcommittee of
the International Dry Eye WorkShop (2007). Ocul Surf. 2007;5(2):108-152.
3. Sickenberger W.Klassifikation von Spaltlampenbefunden.Großostheim:
Bezug über Ciba Vision Vertriebs GmbH;2001.
MAY/JUNE 2011 ADVANCED OCULAR CARE 37