1. Epidemiologic Analysis of Change in Eyelash
Characteristics With Increasing Age in a Population of
Healthy Women
Dee A. Glaser, MD,* Derek Jones, MD,†
Jean Carruthers, MD,‡
Antoinette Campo,x
Susan Moench, PhD,x
Greg Tardie, PhD,x
Joan Largent, MPH, PhD,k
and Carrie Caulkins, PhDk
BACKGROUND Observations that eyelashes become thinner, shorter, and lighter, as women age has not
been previously quantified.
OBJECTIVE This study was conducted to investigate associations between eyelash characteristics and age.
MATERIALS AND METHODS The upper natural eyelashes of 179 subjects were photographed and analyzed
(digital image analysis); length, thickness, and darkness (intensity: 0 = white and 255 = black) were calculated.
Linear regression, including race as a potentially confounding factor, was used to assess the association
between age and mean eyelash characteristics.
RESULTS Subjects’ mean age was 40.3 (610.3) years; 46.1% were white, 36.5% Asian, 9.0% Hispanic, 5.1%
East Indian, and 3.4% black. Mean eyelash length ranged from 6.39 (61.02) to 7.98 (61.15) mm (subjects aged
50–65 years and 22–29 years, respectively). Mean thickness ranged from 1.17 (60.42) to 1.62 (60.56) mm2
(subjects aged 50–65 years and 20–29 years, respectively). Mean intensity ranged from 118.2 (619.8) to 129.4
(617.3) (subjects aged 30–39 years and 50–65 years, respectively). Adjusted for race, eyelash length, thickness,
and darkness decreased significantly with increasing age (p < .000, p = .0090, and p < .05, respectively).
CONCLUSION Advancing age among an ethnically diverse population of healthy women is associated with
significant decreases in eyelash length, thickness, and darkness.
D. A. Glaser, D. Jones, and J. Carruthers are consultants and investigators for Allergan, Inc. J. Largent and C.
Caulkins are employees and stockholders of Allergan, Inc. At the time of manuscript preparation, A. Campo, S.
Moench, and G. Tardie were employees of Scientific Communications and Information, which received
compensation from Allergan, Inc. for medical writing and editorial services.
Perceived age is a valued socially relevant
characteristic to many individuals, as evidenced by
the large and global cosmetics industry.1
Previous
studies of facial aging of the skin have reported that
increased sun damage, pattern baldness, under eye
wrinkles and bags, pigmented spots, alterations in skin
topography (i.e., skin microtexture and wrinkles), and
reduced skin color uniformity are associated with an
appearance of aging that is not necessarily consistent
with an individual’s chronologic age.1–4
The
perception of older age is also frequently associated
with both genetic and environmental determinants
that result in the graying of hair and hair loss.1
The eye region is similarly subject to the consequences
of aging and exerts a particularly distinct influence on
*Department of Dermatology, Saint Louis University, St. Louis, Missouri; †
Division of Dermatology, David Geffen School
of Medicine, University of California, Los Angeles, Los Angeles, California; ‡
Department of Ophthalmology and Visual
Sciences, University of British Columbia, Vancouver, British Columbia; x
Scientific Communications and Information,
Parsippany, New Jersey; k
Allergan, Inc., Irvine, California
Supported by Allergan, Inc. Writing and editorial assistance provided by Scientific Communications and Information.
© 2014 by the American Society for Dermatologic Surgery, Inc.
·Published by Lippincott Williams & Wilkins
·ISSN: 1076-0512 ·Dermatol Surg 2014;40:1208–1213 ·DOI: 10.1097/DSS.0000000000000170
1208
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2. perceived age.4
However, although it is documented
that foundational changes can occur in hair loss, hair
cycling, hair density, hair diameter and pigmentation,
and possibly even in the structural qualities of hair
fibers, these age-related changes have only been
documented for scalp hair loss.5,6
It is reasonable to
expect that age-related follicular changes may also
manifest as hypotrichosis of the eyelashes. However,
to date, no empirical data have been reported to
quantify this phenomenon in eyelashes. Therefore,
this study was undertaken to investigate how eyelash
characteristics (i.e., length, thickness, and darkness)
correlate with advancing age.
Methods
This was a single-center, cross-sectional, observa-
tional study of healthy adult females with natural
eyelashes. One study visit was performed during
which qualified subjects provided demographic
information, and digital imaging of their eyelashes was
performed. For this visit, subjects were instructed to
remove all eye makeup (including any makeup around
the periorbital area) before photography.
The primary objective of the study was to quantify the
association between age and eyelash length. Second-
ary objectives included to quantify the association
between age and eyelash thickness and darkness
(intensity), characterization of eyelash length, thick-
ness, and darkness by age group, and to compare
eyelash length, thickness, and darkness in age groups
stratified as <35 and $35 years.
Female subjects of any race, 18 to 65 years of age, were
eligible for inclusion in the study. To qualify for par-
ticipation, subjects must not have met any of the
following exclusion criteria: no visible eyelashes, per-
manent eyeliner or eyelash implants of any kind,
semipermanent eyelash tint, dye, or extensions (use
within 3 months), or prescription eyelash growth
products (use within 6 months).
Digital Image Analysis
The prospectively defined secondary end point meas-
ures were assessed by digital image analysis based on
superior-view digital eyelash photographs taken with
standardized equipment, lighting, and subject prepa-
ration, as previously described. Digital image analysis
was used to assess upper eyelash length, thickness, and
darkness (intensity). Digital image analysis was pro-
vided by Canfield Scientific, Inc. (Fairfield, NJ), using
a methodology that was developed and validated by
Canfield Scientific, Inc., and was demonstrated to be
reliable and reproducible within the acceptance crite-
ria (<0.5% of mean coefficient of variance) (Allergan,
Inc., Irvine, CA). For eyelash darkness, the mean
intensity was based on a continuum of 0 (black; i.e.,
darker-colored eyelashes) and 255 (white; i.e., ligh-
ter-colored eyelashes) intensity units, such that
a lower intensity score is consistent with darker
eyelashes. Canfield Scientific, Inc. is well recognized
in the clinical dermatology community for quantita-
tive image analysis related to hair and skin
conditions.
TABLE 1. Demographic Characteristics
Total
(N = 179)
Age: 20–29
Years (n = 27)
Age: 30–39
Years (n = 63)
Age: 40–49
Years (n = 52)
Age: 50–59
Years (n = 30)
Age: 60+
Years (n = 7)
Age, years 40.3 (10.3) 26.8 (2.1) 33.5 (2.8) 44.5 (2.8) 54.1 (2.9) 62.1 (2.0)
Race, n (%)
White 82 (46.1) 10 (37.0) 23 (36.5) 23 (45.1) 21 (70.0) 5 (71.4)
Black 6 (3.4) 0 (0.0) 2 (3.2) 3 (5.9) 1 (3.3) 0 (0.0)
Hispanic 16 (9.0) 2 (7.4) 6 (9.5) 7 (13.7) 1 (3.3) 0 (0.0)
Asian 65 (36.5) 14 (51.9) 26 (41.3) 17 (33.3) 7 (23.3) 1 (14.3)
East Indian 9 (5.1) 1 (3.7) 6 (9.5) 1 (2.0) 0 (0.0) 1 (14.3)
Missing 1 0 0 1 0 0
Values are presented as mean (SD).
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3. Statistical Analysis
Correlation of eyelash length, thickness, and darkness
variables to age was analyzed with linear regression
analysis, which was also conducted adjusting for race
(white and non-white) as a potential confounding
variable. The slope of the regression line obtained was
tested, with the null hypothesis assuming a slope equal
to 0. Eyelash measurements were also calculated by
age group and compared using analysis of variance
(ANOVA)/Kruskal–Wallis test. Comparison between
subjects younger than 35 years and those 35 years or
older was performed using a t-test or a Wilcoxon
rank-sum test, according to the normality of the
variable distribution (determined by the
Shapiro–Wilk test). A 2-sided p-value #.05 was
considered statistically significant. Descriptive statis-
tics (mean, standard deviation [SD]) were calculated
for all continuous variables collected in this study.
Results
A total of 179 subjects aged 22 to 65 years were
enrolled, with a mean (SD) age of 40.3 (10.3) years.
Racial distribution of subjects was: white (46.1%),
Asian (36.5%), Hispanic (9.0%), East Indian (5.1%),
and black (3.4%) (Table 1). Because there were only
7 subjects in the age group 60 to 65 years, these
individuals were combined with the group aged 50 to
59 years.
Eyelash Characteristics
The mean (SD) maximum eyelash length of subjects
ranged from 6.39 (1.02) mm in subjects aged 50 to 65
years to 7.98 (1.15) mm in subjects aged 22 to 29 years
(p < .0001; ANOVA). Mean (SD) eyelash thickness
ranged from 1.17 (0.42) mm2 in subjects aged 50 to
65 years to 1.62 (0.56) mm2 in subjects aged 22 to 29
years (p = .0090; Kruskal–Wallis). Mean (SD) eyelash
Figure 1. Eyelash characteristics. Mean (SD) maximum
eyelash length compared across age groups (A). Mean (SD)
maximum eyelash thickness compared across age groups
(B). Mean (SD) maximum eyelash intensity compared
across age groups (C).
Figure 2. Representative photographs of eyelash charac-
teristics. Eyelash length (mm) (A), eyelash thickness (mm2)
(B), and eyelash darkness using intensity scale from 0–255,
wherein 0 = black, 255 = white (C).
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4. intensity ranged from 118.2 (19.8) in subjects aged 30
to 39 years to 129.4 (17.3) in subjects aged 50 to 65
years (p # .0475; ANOVA; Figure 1). Representative
photographs of eyelash characteristics are presented
in Figure 2.
Age Stratification (Aged <35 and $35 Years)
When subjects were grouped by age in strata of <35
and $35 years, mean eyelash length (p < .0001; t-
test) and thickness (p = .0057; Wilcoxon rank-sum
test) were significantly greater for the subjects aged
<35 years as compared with subjects aged $35
years. Mean eyelash darkness was less pronounced
for subjects aged $35 years; however, the difference
was not significant (p = .2878, t-test; Figure 3).
Linear Regression Analysis of Eyelash
Characteristics and Age
In this population of healthy women, advancing
age was associated with significant decreases in eye-
lash length, thickness, and darkness (Figures 4–6).
After adjusting for race, mean eyelash length and
eyelash thickness significantly decreased with
increasing age, and mean eyelash intensity signifi-
cantly increased with increasing age (Table 2),
Figure 3. Eyelash characteristics by age groups: <35 and $35.
Mean (SD) maximum eyelash length (A), mean (SD) eyelash
thickness (mm) (B), and mean (SD) eyelash darkness (C).
Figure 4. Correlation of mean eyelash length by age: linear
regression analysis. N = 177. Simple linear regression
model. Dependent variable = mean maximum eyelash
length; independent variable = age. Note: length = 9.6164–
0.0568 age. L95M = lower limit 95% CI; U95M = upper limit
95% CI. R-squared = 0.23.
Figure 5. Correlation of mean eyelash thickness by age:
linear regression analysis. N = 153. Simple linear regres-
sion model. Dependent variable = mean maximum eyelash
thickness; independent variable = age. Note: thickness =
2.0472–0.0166 age. L95M = lower limit 95% CI; U95M =
upper limit 95% CI. R-squared = 0.10.
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5. suggesting that the correlation of these eyelash
characteristics and age is independent of ethnicity.
Discussion
It has been established that eyelashes are a key
contributor to facial beauty, such that eyelashes
exhibiting aesthetically pleasing length, thickness,
and darkness are highly valued attributes.7
Decades
before the concept of age-related hypotrichosis, the
majority of women relied on daily applications of
makeup or over-the-counter cosmetics to enhance
the appearance of their eyelashes. Other current
options include long-lasting treatments such as
eyelash extensions and transplants8,9
or bimatoprost
ophthalmic solution 0.03% (Latisse; Allergan, Inc.),
the only synthetic prostaglandin analog treatment
approved by the U.S. Food and Drug Administration
to increase the length, thickness, and darkness of
eyelashes in people with hypotrichosis of the
eyelashes.10
This study was undertaken to describe the eyelash
characteristics of individuals across several decades
of age and to quantify the correlation of age-related
and race-related interactions with the eyelash charac-
teristics of length, thickness, and darkness. The
results from this study confirm anecdotal observations
that significant decreases in eyelash length, thickness,
and darkness occur with advancing age among an
ethnically diverse population of healthy women.
The linear regression best-fit lines demonstrate that
each year of advancing age, on average, is associated
with a 0.059 mm decrease in eyelash length, a 0.018
mm2 decrease in eyelash thickness, and a mean
increase of 0.32 in eyelash intensity score (where
0 intensity = black and 255 = white), implying
lightening of eyelash color.
There were several limitations that should be
acknowledged for this study. The overall sample size
of the study was relatively small (n = 179), and
although diverse, represents only a small selection
of women from a single regional location. Certain
age and racial groups were constrained by small
TABLE 2. Predicted Annual Age-Related Changes in Eyelash Characteristics, White/Non-White Women*
White Non-White
Dependent
Variable
Independent
Variable
Race-Adjusted Change in
Eyelash Characteristic
Eyelash
length, mm
Length =
9.7058 2 0.0562
(age)
Length =
9.7485 2 0.0629
(age)
Mean maximum
eyelash length
Age Decrease Slope:
b = 20.059,
p < .0001
Eyelash
thickness,
mm2
Thickness =
2.3354 2 0.0214
(age)
Thickness =
1.8985 2 0.0144
(age)
Mean eyelash
thickness
Age Decrease Slope:
b = 20.018,
p < .0001
Eyelash
darkness
(intensity
score)
Intensity =
105.55 + 0.4777
(age)
Intensity =
114.8 + 0.1313
(age)
Mean eyelash
intensity spline
area of interest
Age Increase Slope: b = 0.32,
p < .05
Eyelash intensity scale is based on a continuum of 0 (black) and 255 (white), such that a lower intensity score is consistent with darker
eyelashes.
*These results were obtained using linear regression modeling length, thickness, and darkness, with age as a continuous independent
variable.
Figure 6. Correlation of mean eyelash intensity by age:
linear regression analysis. N = 154. Simple linear regres-
sion model. Dependent variable = mean eyelash intensity
spline area of interest; independent variable = age. Note:
intensity = 107.87–0.3639 age. L95M = lower limit 95% CI;
U95M = upper limit 95% CI. R-squared = 0.04.
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6. sample sizes, especially in those older than 60 years.
The overall effect on the study findings is undeter-
mined. Furthermore, as the inclusion criteria extended
only to age 65, the sample size for the 60-and-over age
group represents only half a decade and may have
precipitated the small number of study participants for
this age group. This led to combining this age group
with participants aged 50 to 59 years.
The results from this study represent the first attempt to
quantify the age-related decrement of eyelash charac-
teristics in a healthy, racially diverse population. How-
ever, questions remain thatwarrant further exploration.
In this study, eyelash characteristics were described for
white and non-white groups, but eyelash characteristics
among subpopulations of non-whites warrant further
study. In addition, althoughthese observations establish
correlations between eyelash characteristics and
advancing age, the mechanisms of the growth cycle of
eyelashes, and any heterogeneities, remain unexplored.
New research that focuses on these questions would be
a welcome addition to the literature.
Conclusion
The findings suggest that advancing age in an
ethnically diverse population of healthy women is
correlated with significant decreases in eyelash length,
thickness, and darkness.
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Address correspondence and reprint requests to: Dee A.
Glaser, MD, Department of Dermatology, Saint Louis
University, 4th Floor, 1755 S Grand Boulevard, St. Louis,
MO 63104, or e-mail: glasermd@slu.edu
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