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FEATURE ARTICLE ON LINE
Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8)
and Opinion of Contact Lens Performance
Robin L. Chalmers*, Carolyn G. Begley
†
, Kurt Moody*, and Sheila B. Hickson-Curran
‡
ABSTRACT
Purpose. To report on the development and validation of a short form of the Contact Lens Dry Eye Questionnaire (the
CLDEQ-8) to enable it to reflect status of and change in overall opinion (“opinion”) of soft contact lenses (SCLs).
Methods. Item reduction for the CLDEQ was achieved by correlation with overall opinion of SCLs at follow-up visits in a
sample of 38 SCL wearers at one academic clinical site. The CLDEQ-8 score (frequency plus late day intensity of dryness,
discomfort, and “blurry vision”; frequency of “closing eyes to rest them” and “removing CLs to relieve discomfort”) was then
tested in 379 SCL wearers in a multicenter study with analysis stratified by opinion ratings at baseline and 2 weeks
postrandomization to new silicone hydrogel SCLs. The sum of CLDEQ-8 scores (maximum 37) was correlated with opinion by
Spearman’s rank correlation coefficient and analyzed for change in opinion by analysis of variance (ANOVA).
Results. The CLDEQ-8 scores in the validation sample were highly correlated with habitual baseline opinion (⫺0.44, p ⬍
0.0001) and responsive to change in opinion postrandomization (⫺0.58, p ⬍0.0001). Baseline CLDEQ-8 scores by
opinion status were as follows: Fair: 17.4 ⫾8.7, Good 13.7 ⫾6.4, Very Good 9.1 ⫾4.7, and Excellent 6.4 ⫾3.7
(ANOVA, F ⫽291.1, p ⬍0.0001). After 2 weeks, change in CLDEQ-8 scores by improvement status was as follows:
Much Improved: ⫺16.7 ⫾10.0, Unchanged: ⫺2.3 ⫾5.0, to Much Worse ⫹8.5 ⫾5.8 (ANOVA, F ⫽16.5, p ⬍0.001).
Conclusions. The CLDEQ-8 score significantly reflected baseline status and change in overall opinion after refitting with
two types of silicone hydrogels. The CLDEQ-8 score is a valid outcome measure in SCL clinical trials to reflect opinion
of SCLs.
(Optom Vis Sci 2012;89:1435–1442)
Key Words: soft contact lens, symptoms, dryness, questionnaire, Contact Lens Dry Eye Questionnaire, CLDEQ
Although soft contact lenses (SCLs) have changed significantly
over the past 10 years with the introduction of silicone hydro-
gel materials and newer designs, discontinuation of wear
remains an important factor that limits the number of successful wear-
ers.
1,2
Ocular surface symptoms such as discomfort and dryness are
most often reported as the chief cause of discontinuation for both
hydrogel and silicone hydrogel lenses.
2–4
In a cross-sectional survey of
patients presenting for eyecare,
4
⬎40% of former SCL wearers cited
dryness as their primary reason to discontinue use of lenses, and this
ranking has been confirmed in other recent studies.
2
Dryness and discomfort with SCL use are very common. The
prevalence of discomfort and dryness symptoms among SCL wear-
ers is high, approximately 50%, which is at least double than that
reported by subjects of similar age who were not using contact
lenses.
4,5
Even though so many SCL wearers report dryness and
discomfort, there is no established level of symptoms that is con-
sidered clinically significant. Definitive diagnosis of SCL-related
dryness remains a significant challenge, in part, because it is not a
disease, per se, but is a symptomatic condition that is amenable to
changes in SCL material
6–8
or lens care products
9,10
that can ame-
liorate symptoms. Finally, the SCL wearer may choose to cease lens
wear altogether as a remedy for dryness symptoms.
4
Recently the report from the 2007 Dry Eye Workshop included
contact lens-related dry eye in the evaporative category.
11
Soft
contact lens wear is associated with reversible changes in corneal
and conjunctival sensitivity and inflammation that may impact
dryness symptoms.
12–15
The potential to reverse SCL-related dryness
creates a considerable need for a well-designed validated questionnaire
for SCL-related dryness that is capable not only of assisting in diag-
nosis but also in measuring change in the condition that can be
improved by available treatments. A number of questionnaires
exist, but have not been validated so that the user knows the clinical
*OD, FAAO
†
OD, MS, FAAO
‡
BSc(Hons), MCOptom, FAAO
Clinical Trial Consultant, Atlanta, Georgia (RLC), Indiana University School
of Optometry, Bloomington, Indiana (CGB), and Johnson & Johnson Vision
Care, Inc., Jacksonville, Florida (KM, SBH-C).
1040-5488/12/8910-1435/0 VOL. 89, NO. 10, PP. 1435–1442
OPTOMETRY AND VISION SCIENCE
Copyright © 2012 American Academy of Optometry
Optometry and Vision Science, Vol. 89, No. 10, October 2012
meaning of scores or change in scores. A valid questionnaire should
be able to identify SCL wearers who are struggling with clinically
significant SCL-related dry eye complaints
16
and be sensitive
enough to track their progress when treated with products de-
signed to reduce those symptoms.
17,18
The Contact Lens Dry Eye Questionnaire (CLDEQ) was devel-
oped more than a decade ago to measure dryness symptoms among
contact lens wearers.
19,20
The CLDEQ instrument was originally
designed in parallel to the Dry Eye Questionnaire (DEQ) for use in
patients who do not wear contact lenses. The long forms of both
the CLDEQ and DEQ instruments query contact lens-wearing
history, frequency and diurnal intensity, and intrusiveness of nine
ocular surface symptoms, along with questions about treatments,
computer use, and environmental triggers. Recently, a validated
five-item short form of the Dry Eye Questionnaire, the DEQ-5,
was developed for patients who do not wear contact lenses.
21
The
DEQ-5 instrument uses a scoring system that is anchored by the
patient’s self-assessment of dry eye severity and contains five items.
The purpose of this study was to develop and validate a short
version of the CLDEQ for SCL wearers by identifying a set of
questions that reflected satisfaction and overall opinion of SCLs
that was also responsive to change among wearers of modern SCL
materials.
METHODS
The development of the short form of the CLDEQ was conducted
in two phases. Both phases of this clinical research were conducted
after institutional review board approval. All subjects signed informed
consent before enrollment, and the studies were conducted in com-
pliance with the Declaration of Helsinki and local Health Insurance
Portability and Accountability Act guidelines.
This study took place in two phases, an item reduction phase and
aknown groups validity phase. Table 1 shows the lenses used in each
phase of the research, although results were analyzed and displayed
regardless of lens type. Subjects in both phases were included if
they were at least 18 years old, if they needed bilateral correction,
were in good general health, were willing and able to follow
instructions, and were a current full-time and adapted wearer of
SCLs. Subjects were not enrolled into the study if they were
using monovision correction, were wearing rigid gas-permeable
lenses, had clinically significant (grade 3 or 4) anterior segment
abnormalities (or any iritis or any infection of the eye, lids, or
adnexa), had ocular or systemic disease that would preclude SCL
wear, or best-corrected Snellen visual acuity of ⬍20/30 in either
eye, or were pregnant or lactating females.
Item Reduction Phase
The purpose of the item reduction phase was to determine
which symptoms and SCL-wearer coping mechanisms most highly
correlated with the subjects’ overall opinion of the SCLs at all study
visits. This step was completed with data from a small study sample
at the Indiana University School of Optometry. After signing con-
sent documents, 38 (n ⫽38) frequent replacement SCL wearers
completed a prospective randomized, cross-over SCL clinical trial
that lasted for 4 weeks. Subjects were randomized at baseline to
daily wear of either senofilcon A (Johnson & Johnson Vision Care,
Inc, Jacksonville, FL) or balafilcon A (Bausch & Lomb, Rochester,
NY) and then crossed over to the other lens at the 2-week visit
(Table 1). All subjects were given OPTI-FREE EXPRESS MPDS
(Alcon Laboratories, Ft. Worth, TX) with a screw-top lens case,
and OPTI-FREE EXPRESS Rewetting Drops (Alcon Laborato-
ries, Ft. Worth, TX) as needed.
At each visit (baseline, 1, and 2 weeks after each cross over for a
total of five visits), responses to the long form of the CLDEQ were
analyzed to identify items with the highest correlation to overall
opinion of the SCLs at that visit (Poor, Fair, Good, Very Good,
and Excellent). Groups of items that were most often highly cor-
related with overall opinion were tested in versions of the short
form of the CLDEQ instrument after checking for redundant
information (high inter-item correlation). Items with low correla-
tions were not included in the combinations of questions that were
tested. Items were removed in order of lower to higher correlation
until there was no further impact on the analysis of variance
(ANOVA) for the overall relationship to overall opinion of SCLs.
Known Groups Validity Phase
The purpose of the known groups validity phase was to val-
idate the short CLDEQ-8— consisting of eight questions—by
testing the sum scores for their ability to reflect overall opinion of
TABLE 1.
Study products
Feature
Item Reduction Phase n ⫽38
Treatment arm A Treatment arm B
Lens material Senofilcon A Balafilcon A
Brand name ACUVUE OASYS Contact Lens with
HYDRACLEAR
BAUSCH & LOMB PureVision Visibility
Tinted Contact Lens
Power range ⫺0.50 to ⫺6.00 DS
Base curve 8.4 mm, 8.8 mm 8.3 mm, 8.6 mm
Diameter 14.0 mm
Lens care system OPTI-FREE EXPRESS MPDS
Screw top lens case
OPTI-FREE EXPRESS Rewetting Drops as needed
Wearing schedule Daily wear
1436 Dry Eye Questionnaire and Overall Opinion of Contact Lenses—Chalmers et al.
Optometry and Vision Science, Vol. 89, No. 10, October 2012
habitual SCLs at baseline and for the score’s responsiveness to
change in overall opinion after randomization to two silicone hy-
drogel SCL materials. To accomplish this, the short form of the
CLDEQ-8 was fielded to a much larger convenience sample in 24
North American clinical sites as part of a larger randomized pro-
spective clinical trial. Subjects (n ⫽379) in an institutional review
board-approved, multicenter, randomized parallel group trial
completed the short form of the CLDEQ-8, and anchoring ques-
tion on overall opinion of SCLs, and other questionnaires at
baseline and 2 weeks after randomization to daily wear of either
senofilcon A or lotrafilcon B silicone hydrogel lenses (Table 1). In
this validation phase, subjects were allowed to continue to use their
habitual care system (if appropriate) with the following distribution:
OPTI-FREE RepleniSH 31%, ReNu MPDS 17%, OPTI-FREE
EXPRESS MPDS 11%, and Clear Care 11%. Thirty percent
(30%) of subjects were not using an appropriate care system (saline
only or unknown system) and were given COMPLETE Multipur-
pose lens care kits at the baseline visit.
Change in overall opinion was measured by comparing the over-
all opinion rating (“Which statement best describes your overall
opinion of your current contact lenses?” with response options of
Poor, Fair, Good, Very Good, and Excellent) of habitual lenses to
lenses to which the subject was randomized in the trial. For exam-
ple, change in a worse direction would exist if the subject reported
Very Good with habitual lenses and Good with new lenses.
Change in assessment by two steps was considered “Much Worse”
if it was in the worsening direction and “Much Better” if there were
two levels of improvement in the overall opinion.
Only subjects with complete data sets (n ⫽309) were included
in this analysis. Summed CLDEQ-8 scores (possible 0–37) were
tested for correlation with overall opinion of habitual lenses
(Spearman’s rank correlation coefficient) and then for responsive-
ness to change in overall opinion after randomization by ANOVA.
Statistical significance was assumed if p ⬍0.05.
RESULTS
Subject Demographics
Table 2 shows the demographics of the subject sample in each
phase of the research and the distribution of habitual SCLs and
care systems for subjects in each phase. Note that habitual lens care
system was not queried in the item reduction phase of the research.
Item Reduction Phase
A number of CLDEQ questions were significantly correlated
with overall opinion of contact lenses, with more questions show-
ing significant correlations at visits after randomization than at
baseline. Correlations between individual CLDEQ symptom
questions at all visits are listed in Table 3.
Ranking of these correlations was used to model the best mix of
questions for the short form of the CLDEQ. A strategy that chose
TABLE 2.
Subject demographics
Factor
Item Reduction
Phase n ⫽38
Known Groups
Validity Phase
n⫽379
Gender
Female: N (%) 29 (76%) 261 (69%)
Male: N (%) 9 (24%) 118 (31%)
Age (yr)
Mean (SD) 24.4 (3.4) 29.5 (6.9)
Range 19–34 18–45
Habitual CL power
Mean (SD) ⫺3.56 (1.57) ⫺3.17 (1.40)
Keratometry reading
Horizontal/vertical in DK 43.80/44.50 43.81/44.52
Habitual contact lens type
Silicone hydrogel 29 (76.3%) 246 (64.9%)
Hydrogel (reusable) 9 (23.7%) 99 (26.1%)
Hydrogel (daily disposable) — 34 (9.0%)
Contact lens solution type
MPS 305 (80.4%)
Hydrogen peroxide Not queried 44 (11.6%)
None 29 (7.7%)
Unknown 1 (0.3%)
TABLE 1.
(Continued)
Feature
Known Groups Validity Phase n ⫽379
Treatment arm A Treatment arm B
Lens material Senofilcon A Lotrafilcon A
Brand name ACUVUE OASYS Contact Lens with
HYDRACLEAR
AIR OPTIX Aqua
Power range ⫺1.00 to ⫺6.00 DS
Base curve 8.4 mm 8.6 mm
Diameter 14.0 mm 14.2 mm
Lens care system Continue Habitual System
(31% OPTI-FREE RepleniSH, 17% ReNu MPDS, 11% OPTI-FREE EXPRESS, 11% ClearCare)
OR 30% AMO COMPLETE Multi-Purpose if no appropriate system at baseline
Wearing schedule Daily wear
Dry Eye Questionnaire and Overall Opinion of Contact Lenses—Chalmers et al. 1437
Optometry and Vision Science, Vol. 89, No. 10, October 2012
questions with the highest correlations and highest proportions of
significant correlations was put into a sequence that was then tested to
reduce redundancy. Some questions, such as burning/stinging,
showed very high statistically significant correlations with other items
that also had high correlation to overall opinion. Those questions were
eliminated from the final CLDEQ-8 short form, as they did not affect
the overall performance of the instrument’s ability to discriminate by
the wearer’s overall opinion of the SCLs they were wearing at that visit.
The CLDEQ-8 questions are shown in Fig. 1.
Known Groups Validity Phase
Fig. 2 shows the mean and distribution of CLDEQ-8 scores by
overall opinion of habitual lenses at baseline for the known groups
validity phase. The distribution of CLDEQ-8 scores by overall opin-
ion of lenses was as follows: Fair: 17.4 ⫾8.7, Good: 13.7 ⫾6.4, Very
Good: 9.1 ⫾4.7, and Excellent: 6.4 ⫾3.7, and the overall distribu-
tion was significant (ANOVA, F ⫽291.1, p ⬍0.001). There were no
subjects who reported Poor overall opinion at baseline.
TABLE 3.
Correlation of CLDEQ questions with overall opinion of lenses in Item Reduction Phase
Item Baseline
1 week
Arm A
2 weeks
Arm A
1 week
Arm B
2 weeks
Arm B
Discomfort—frequency ⴚ0.43
a
ⴚ0.65
a
ⴚ0.67
a
ⴚ0.72
a
ⴚ0.62
a
AM severity 0.00 ⫺0.35
b
⫺0.68
a
⫺0.44
a
⫺0.37
b
PM severity ⫺0.34
b
ⴚ0.57
a
ⴚ0.64
a
ⴚ0.59
a
ⴚ0.59
a
Bother ⫺0.35
b
⫺0.37
b
⫺0.66
a
⫺0.57
a
⫺0.56
a
Dryness—frequency ⫺0.26 ⴚ0.58
a
ⴚ0.49
a
ⴚ0.59
a
ⴚ0.68
a
AM severity 0.002 ⫺0.45
a
⫺0.71
a
⫺0.36
b
⫺0.27
PM severity ⫺0.19 ⴚ0.48
a
ⴚ0.59
a
ⴚ0.42
a
ⴚ0.61
a
Bother ⫺0.26 ⫺0.42
a
⫺0.58
a
⫺0.50
a
⫺0.63
a
Blurry vision—frequency ⫺0.17 ⴚ0.43
a
ⴚ0.42
a
⫺0.27 ⫺0.26
AM Severity 0.03 ⫺0.42
a
⫺0.39
b
⫺0.22 ⫺0.15
PM severity ⫺0.17 ⴚ0.46
a
ⴚ0.52
a
ⴚ0.35
b
⫺0.30
Bother ⫺0.13 ⫺0.36
b
⫺0.52
a
⫺0.27 ⫺0.21
Burning, stinging—frequency ⫺0.14 ⫺0.27 ⫺0.47
a
⫺0.48
a
⫺0.49
a
AM severity 0.14 ⫺0.28 ⫺0.47
a
⫺0.52
a
⫺0.41
b
PM severity ⫺0.15 ⫺0.36
b
⫺0.52
a
⫺0.37
b
⫺0.49
a
Bother ⫺0.09 ⫺0.32 ⫺0.47
a
⫺0.42
a
⫺0.48
a
Grittiness—frequency ⫺0.13 ⫺0.44
a
⫺0.27 ⫺0.40
b
⫺0.58
a
AM severity 0.07 ⫺0.36
b
⫺0.28 ⫺0.26 ⫺0.41
a
PM severity ⫺0.26 ⫺0.37
b
⫺0.29 ⫺0.40
b
⫺0.48
a
Bother ⫺0.21 ⫺0.37
b
⫺0.28 ⫺0.34
b
⫺0.55
a
Tired eyes—frequency ⫺0.03 ⫺0.18 ⫺0.25 ⫺0.34
b
⫺0.47
a
AM severity 0.27 ⫺0.30 ⫺0.38
b
⫺0.12 ⫺0.21
PM severity ⫺0.04 ⫺0.22 ⫺0.06 ⫺0.34
b
⫺0.43
a
Bother ⫺0.002 ⫺0.21 ⫺0.08 ⫺0.42
a
⫺0.41
b
Other questions
Red eyes—frequency 0.21 ⫺0.35
b
⫺0.11 0.001 ⫺0.34
b
Watery eyes—frequency 0.01 ⫺0.33
b
⫺0.24 0.007 ⫺0.47
a
Crusty eyelids—frequency 0.03 ⫺0.15 ⫺0.06 0.007 ⫺0.09
Coping questions
Close eyes for relief—frequency ⫺0.25 ⫺0.29 ⴚ0.49
a
ⴚ0.50
a
ⴚ0.64
a
Remove lenses for relief—frequency ⴚ0.35
b
ⴚ0.38
b
ⴚ0.59
a
ⴚ0.52
a
ⴚ0.65
a
Artificial tear use 0.04 ⫺0.50
a
⫺0.41
b
⫺0.35
b
⫺0.41
b
Environmental triggers
Cigarette smoke ⫺0.19 ⫺0.16 0.02 ⫺0.10 ⫺0.18
Air conditioning ⫺0.20 ⫺0.10 ⫺0.17 ⫺0.55
a
⫺0.49
a
Malls ⫺0.30 0.04 ⫺0.04 ⫺0.26 ⫺0.11
Self-assessment of dry eye
Think dry eye? 0.17 0.17 0.23 ⫺0.10 0.10
Bolded question titles indicate items that were included in CLDEQ-8.
Bolded figures in those rows show significant items.
a
p⬍0.001,
b
p⬍0.05.
1438 Dry Eye Questionnaire and Overall Opinion of Contact Lenses—Chalmers et al.
Optometry and Vision Science, Vol. 89, No. 10, October 2012
FIGURE 1.
CLDEQ-8 questionnaire.
Dry Eye Questionnaire and Overall Opinion of Contact Lenses—Chalmers et al. 1439
Optometry and Vision Science, Vol. 89, No. 10, October 2012
The distribution of change in overall opinion by change in
CLDEQ-8 score is shown in Fig. 3. Note that a lower CLDEQ-8
score indicates fewer symptoms and less need for coping actions. In
general, the 73 subjects who reported a worse overall opinion status
had an 8.5 ⫾5.8 point increase in the CLDEQ-8, the 218 in the
unchanged group had a decrease of ⫺2.3 ⫾5.0 points, and the 11
subjects with improved status had a change of ⫺16.7 ⫾10.0 points in
CLDEQ-8 scores. The distribution was significantly related to change
in overall opinion of SCLs (ANOVA, F ⫽16.5, p ⬍0.001).
DISCUSSION
Although numerous questionnaires have been developed to as-
sess dry eye symptoms without contact lens use,
22–25
and others to
assess quality of life across refractive correction,
25–29
the CLDEQ
is one that was developed to assess dry eye symptoms among con-
tact lens wearers in particular. A population-specific SCL question-
naire is required because SCL wearers report a distinctly different
pattern of symptoms compared with people who do not wear
SCLs.
16
For example, in an age-matched sample of SCL wearers
and non-wearers, more than twice as many SCL wearers reported
intense dryness, especially late in the day, but these symptoms were
nearly eliminated when they removed lenses.
4
In that study, symp-
tom patterns also differed between SCL wearers and age-matched
non-wearers; in SCL wearers, dryness intensity was not correlated
with gender although it was inversely correlated with age among
contact lens wearers, differing significantly from the pattern
among non-lens wearers in which females and older patients report
more dryness.
Because SCL-related dryness is not a disease, we developed a
responsive tool to measure its recovery. The CLDEQ-8 was able to
reflect improvement and worsening of overall opinion after ran-
domization to new lenses. The SCL wearer’s opinion can change
after refitting with new lens designs, materials, lens care products,
and with new replacement schedules; thus, the score to reflect that
opinion should be developed by methods that sample patients’
symptoms during the refitting process.
The CLDEQ-8 is a short form of the CLDEQ questionnaire
that was designed to describe symptoms among SCL wearers. The
short form was developed by selecting items that related to the
wearer’s global opinion of the SCLs they were wearing across all
study visits. The number of items was then reduced to avoid re-
dundancy owing to very high inter-item correlation. The eight
remaining items were also capable of reflecting change in this opin-
ion after randomization to new lens brands in the second phase of
the study. Scores from an earlier short CLDEQ version relied on
the response to the question “Do you think you have dry eye?,”
which was useful as a stratifying question in dry eye patients with-
out SCL wear.
30
Reliance on the Gestalt “Do you think you have
dry eye?” question may not be a good approach with SCL wearers,
as many of them have few symptoms while not wearing lenses.
4
Therefore, SCL wearers with dry eye complaints may not globally
consider themselves to have dry eye separately from SCL wear. The
overall opinion question used in this study focuses on the SCLs and
not on the patient’s underlying condition of eye dryness. In addi-
tion, the earlier short CLDEQ formula was less intuitive and pos-
sibly more cumbersome for clinician users to implement.
The CLDEQ-8 score shows an excellent dose–response rela-
tionship to the subjects’ overall opinion of SCLs, making it a
potentially useful tool for capturing the patient-reported opinion
of new SCL treatments. There was a slight dampening of linearity
FIGURE 2.
CLDEQ-8 score by overall opinion of habitual lenses; known groups validity phase.
FIGURE 3.
CLDEQ-8 score against change in overall opinion; known groups validity
phase. (Much Worse, n ⫽73; No Change, n ⫽218; Much Better, n ⫽11).
1440 Dry Eye Questionnaire and Overall Opinion of Contact Lenses—Chalmers et al.
Optometry and Vision Science, Vol. 89, No. 10, October 2012
in the scale when we related it to change in opinion after refitting
with new lenses. Subjects showed larger change in score when they
reported an improvement in overall opinion (mean decrease of
16.7 points) compared with when they had a lower overall opinion
of the new lenses (mean increase of 8.5 points). Other researchers
have shown that the structure of the DEQ questions showed lin-
earity by Rasch analysis.
31
In this sample, we were unable to assess
the lowest end of the scale, as none of the subjects presenting for
the clinical trial had an estimation of “Poor” for their habitual
SCLs. Contact lens-related dryness differs from dry eye disease
(fortunately for the lens wearers) in that the patient is able to cease
wear if the lenses are so uncomfortable that they would warrant a
poor rating. Inability to test that end of the scale is a limitation in
the development of the instrument. Repeatability of the instru-
ment should also be established in other patient populations in the
future.
For diagnostic use and categorization, a valid and useful instru-
ment must be able to distinguish between groups that are otherwise
identifying themselves as different, a feature referred to as having
construct validity. The items in the CLDEQ-8 were selected from
the ocular surface symptoms, environmental triggers, and coping
items in the longer CLDEQ questionnaire. Also, the selection was
based on patient opinion of SCLs after changes between marketed
lens brands, so the CLDEQ-8 is scaled to perform well to reflect
changes of a magnitude that are clinically achievable through
change in available products.
Ideally, we would like to understand the underlying biological
basis of SCL-related dryness symptoms and have means of measur-
ing those specific factors. However, with or without that basic
understanding, a gold standard, or highly repeatable clinical tests,
it remains important to be able to measure symptoms as assessed by
individual SCL wearers in the clinical or clinical trial setting. The
CLDEQ-8 allows a standardized quick means to measure this
symptom-based condition from the wearer’s point of view. Note
that two vision (frequency and late day intensity) and two coping
(removing lenses early and closing eyes for relief) questions are
included in the CLDEQ-8 but were not the most discriminating
questions in the short form of the DEQ-5.
21
With SCL wear, the
prelens tear film is significantly less stable with SCLs compared
with the precorneal tear film in patients without SCLs
32,33
; there-
fore, changeable blurry vision has been cited as a more prominent
symptom in the SCL population. Blurry vision that clears with a
blink is the third most common symptom among SCL wearers,
close behind discomfort and dryness. This complaint of transient
blurry vision most likely stems from the tear break up that occurs
between blinks in SCL wearers.
34
This recent study of blinking
patterns during different cognitive tasks with and without SCL
wear showed that the unstable prelens tear film, and symptoms
associated with it, drove an increase in blink frequency during SCL
wear compared with no wear.
The two coping questions included in the CLDEQ-8, the need
to close the eyes and early lens removal, capture the wearer’s strug-
gle with uncomfortable lenses. Subjects in this study with lowest
overall opinion of SCLs were more likely to frequently close their
eyes for a prolonged time or to finally capitulate and remove lenses
before the desired time. It is clear that these symptoms alter the
SCL-wearing experience and reflect a significant impact on the
wearers who experience them.
In this study, we validated the eight-item short form of the
CLDEQ as a means of testing the SCL wearer’s symptom-related
experience with their contact lenses. The sum of scores for the eight
items was significantly related to overall opinion of lenses and was
also able to reflect change in overall opinion in prospective treat-
ment trials. The CLDEQ-8 will be useful for identification of SCL
wearers who may benefit from lenses or lens care products designed
to reduce symptoms of dryness with SCL wear and to track their
progress in treatment trials.
ACKNOWLEDGMENTS
This study was funded by Johnson & Johnson Vision Care, Inc., and designed
by RLC, CGB, and KM. We thank Graeme Young, PhD, MPhil, FCOptom,
DipCL, FAAO, and Chris Hunt, MSc, and the staff at Visioncare Research for
their assistance in fielding the CLDEQ-8 in the Known Groups Validity
Phase.
Received March 5, 2012; accepted June 6, 2012.
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Robin L. Chalmers
Clinical Trial Consultant
2097 East Lake Road
Atlanta, Georgia 30307
e-mail: Chalmers2097@gmail.com
1442 Dry Eye Questionnaire and Overall Opinion of Contact Lenses—Chalmers et al.
Optometry and Vision Science, Vol. 89, No. 10, October 2012
