The Turkish Journal of Pediatrics
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Tear secretion and ferning patterns among premature and full-term newborns
Ümit Beden1, Deniz Turgut-Çoban1, Canan Aygün2, İnci Ulu-Güngör1, Yüksel Süllü1, Dilek Erkan1, Şükrü Küçüködük2
1Departments of Ophthalmology, Ondokuz Mayıs University Faculty of Medicine, Samsun, Turkey
2Departments of Pediatrics, Ondokuz Mayıs University Faculty of Medicine, Samsun, Turkey
|Beden Ü, Turgut-Çoban D, Aygün C, Ulu-Güngör İ, Süllü Y,
Erkan D, Küçüködük Ş. Tear secretion and ferning patterns among premature
and full-term newborns. Turk J Pediatr 2008; 50: 155-159.|
In this study, we aimed to assess the quality and quantity of tears among
premature and term newborns. Tear ferning and Schirmer’s tests were
conducted over the first 10 days of life. Correlations between tear ferning
patterns, Schirmer’s scores, post-conceptional age, and birth weight were
evaluated. Forty-six newborns (23 preterm, 23 term) were enrolled, with a
mean post-conceptional age of 36.6 weeks and a mean weight of 2598.2 g.
Mean total, basal and reflex Schirmer’s test results were 13.5 mm, 6.7 mm
and 6.8 mm, on the right and 14.0 mm, 7.1 mm and 6.9 mm on the left
eye, respectively. Median ferning score was 2 (range 1-3) bilaterally. Schirmer
scores were correlated with ferning capacity and post-conceptional age. Our
study shows that newborns secrete moderate quantity, good quality tears.
Ferning capacity, Schirmer scores and post-conceptional age are correlated.
newborn, premature, tear secretion, ferning, Schirmer
|The ferning phenomenon is a dendritic growth
pattern of dried tear fluid. Its pattern is
influenced by the electrolyte, protein and mucus
contents of secretions. Initially developed by
Papanicolau and utilized in gynecology, this
test more recently has been used to assess the
quality of tear mucus, based upon the pioneering
studies of Tabbara and Okumoto.|
Despite there being many published studies
concerning tear production in newborns, tear
ferning pattern has not been investigated in
premature or even term newborns. Moreover,
studies of human tear secretion in term and
premature newborns, by means of Schirmer’s
test, have yielded conflicting results[3-5].
Consequently, in this study we aimed to assess
the mucus quality and secretion potential of
premature and term babies’ tears, using both
mucus ferning and Schirmer’s tests, and to
explore any correlation between these two
|Material and Methods |
|After obtaining informed consent from families,
23 preterm and 23 term newborns were
included in the study. Babies with systemic
and ocular anomalies or with local or systemic
infections were excluded from the study.|
Tear ferning and Schirmer’s tests were performed
during the first 10 days of life and while babies
were in a quiescent state. Basal and reflex
Schirmer’s measurements and tear ferning tests
were used to evaluate tear quality.
In order to assess ferning capacity, a few
microliters of tear fluid was collected using an
osmotic tube, blown onto a light microscopy
slide, and then allowed to dry by evaporation
at room temperature. Mucus crystallization
was observed within 10 minutes of collection,
using a light microscope at 40x magnification.
This process was performed without applying
any topical medication and before Schirmer’s test measurements, in order to prevent any
alteration in tear composition or ferning
pattern. The ferning patterns were classified
according to a grading system proposed by
Rolando (Fig. 1). In this system, Type I and II
patterns are seen in normal tears and classified
as good ferning capacity, while type III and
IV patterns are seen in abnormal tears and
classified as poor ferning capacity.
| ||Fig 1: Ferning patterns according to Rolando’s
classification scheme (light microscopy x 40).|
After an assessment of ferning pattern, a
sterile Schirmer’s test strip was placed in both
eyes in the inferotemporal conjunctival fornix,
avoiding contact with the cornea. After five
minutes, the strips were removed and wetting
was measured in millimeters and recorded as
total (basal + reflex) tear secretion. In order to
measure basal tear secretion, a drop of topical
anesthetic agent (Oxybuprocain 0.4% Thilo,
Alcon, Belgium) was instilled in both eyes and
the measurements were repeated. Reflex tear
secretions were then calculated as the difference
between total and basal Schirmer’s results.
Chi-square, Student’s t test, and Pearson
correlation analyses were used for statistical
analysis. A p-value of <0.05 was considered
statistically significant. Correlation was described
as weak, moderate, strong, and very strong when correlation coefficient (r) was 0.000 to 0.250,
0.250 to 0.500, 0.500 to 0.750, and 0.750 to
|The clinical characteristics of 46 babies enrolled
in the study are summarized in Table I.|
| ||Table I: Clinical Characteristics of the Babies Enrolled in the Study (values given as means ± SD [min–max])|
The mean basal, reflex and total Schirmer’s
test results for the right and left eyes are
presented in Table II. There was a very strong
correlation between all the Schirmer’s scores
in the right and left eye (p<0.001), and a
moderate correlation between Schirmer’s scores
and post-conceptional age (p<0.05). Birth
weight was also moderately correlated with
basal and total (p<0.05), but not with reflex
(p>0.05) Schirmer’s scores.
| ||Table II: Schirmer’s Scores of the Right and Left Eyes in Preterm and Term Babies (*: significant)|
Schirmer’s scores for both eyes and in both
term and preterm babies are given in Table
and in Figures 2 and 3. These results show
that the total and basal Schirmer’s test results
are significantly different in term and preterm
babies, while the reflex Schirmer’s scores are
not. The reflex secretion level was also higher
in the terms, albeit not to a degree that was
| || II|
| ||Fig 2: Schirmer’s test scores (mm) of the right eye,
in term and preterm babies.|
| ||Fig 3: Schirmer’s test scores (mm) of the left eye,
in term and preterm babies.|
During the ferning pattern evaluation, bilateral
lacrimal sampling was performed on 36 babies,
but only unilateral lacrimal sampling on 10
babies due to the loss of a quiescent state, in
order to obviate the effect that crying could have
on tear composition and ferning capacity. The
ferning results for both eyes, in both term and
preterm babies, are given in Table III. Out of 82
eyes among 46 patients, 77 (94%) showed good
ferning capacity (Grade 1 or 2), in accordance
with the system proposed by Rolando.
| ||Table III: Grade of Ferning Patterns in Both Eyes in Term and Preterm Newborns|
The ferning test was neither affected by the sex
of the baby nor the time interval between birth
and the test, while it was weakly correlated
with all the Schirmer’s scores (p<0.003).
Moreover, there was no correlation between
ferning capacity and post-conceptional age of
Mean total, basal and reflex Schirmer’s results
among babies with good and poor ferning
capacities are presented in Table IV. Although
the total and basal Schirmer’s scores for eyes
with good ferning patterns are higher than
those for eyes with poor ferning patterns, no
comparison could be performed due to the low
number of subjects in the Rolando Grade 3
and 4 groups, since most babies demonstrated good ferning capacity. On the other hand,
comparisons performed in groups with very
good (Grade 1) and good (Grade 2) ferning
patterns revealed that all the Schirmer’s scores
are significantly higher in the former group,
indicating an improving effect of Schirmer’s
score on the ferning pattern (p<0.005).
| ||Table IV: Schirmer’s Scores (mm) of the Right and Left Eyes with Good or Poor Ferning Capacity|
|The tear ferning test is often used to assess the
effects of drugs like N-acetylcysteine, topical
retinoic acid, antioxidants and hyaluronic acid on tear quality, as well as the efficacy
of tear substitutes. It has been used to
assess tear quality in ocular surface diseases
like pterygium and during different phases
of the menstrual cycle in healthy women.
Just like Schirmer’s test, the ferning test is
accepted as part of the diagnostic protocol in
the evaluation of dry eye symptoms. Hence,
tear ferning capacity usually is considered a
reflection of the quality of tears[7,8-14]. In this
respect, we wanted to combine tear ferning
capacity and Schirmer’s tests in our evaluation
of newborn tear properties, since prior studies
using only Schirmer’s test results have yielded
Diminished basal and reflex tear secretion
among newborns may mask the symptoms of
congenital nasolacrimal duct obstruction, and
increase the local and systemic side effects of
topical medications used in newborns. It is
also necessary for newborns to have adequate
basal and reflex tear secretion, in order to
have good ocular antibacterial protection and
maintain corneal clarity while being examined
ophthalmoscopically. In spite of this, should
newborn babies exhibit low Schirmer’s test
readings, they would be expected to present
signs of insufficient ocular surface protection,
which usually is not the case. This might
imply that, in addition to tear quantity, tear
quality is also an important feature that can be
evaluated easily by means of ferning capacity
testing, even in newborns.
Puderbach et al., while investigating tear
ferning, Schirmer’s tests, break-up time and
protein composition in subjects between 4
months and 85 years old, reported a positive
correlation between tear ferning patterns and
low Schirmer’s test values, and between ferning
patterns and tear break-up time. They stated
that ferning pattern was not influenced by
single tear proteins, but by the quantity of
watery secretion. They also stated that ferning
patterns of higher degree were significantly
more frequent with increasing age. We have also revealed that ferning capacity is correlated
with higher Schirmer’s test results but were
unable to reveal a correlation between ferning
pattern and the post-conceptional age of the
babies. In our study, we additionally found
that total, reflex and basal Schirmer’s results
are higher in newborns with very good ferning
capacity (Grade 1) than in those with good
ferning capacity (Grade 2). This correlation
might become stronger, as Puderbach has
reported, with improved tear secretion and
quality with advancing age.
The results of our study imply that tear ferning
pattern and Schirmer’s test results, albeit exhibiting
two different properties of tears, are positively
correlated in newborns in spite of the fact that
tear ferning patterns deteriorate as temperature
and humidity increase, a characteristic not shared
by Schirmer’s tests.
Spiegler et al. evaluated tear secretion in
newborns by means of the Schirmer-1 test.
They reported that basal tear secretion was
5 mm ± 3 mm in 5 min. They stated that
tear secretion was independent of the baby’s
age, birth weight, degree of maturity, and sex,
findings that are partially supported by the
results of our study. Our basal Schirmer’s test
results were 6.7 mm for the right eye and
7.1 mm for the left eye, both highly consistent
with the results of Spiegler’s study. Apt and
Cullen established that full-term newborns
produce tears normally, and that preterm infants
also exhibit the capacity to secrete tears. They
showed that 82% of non-crying full-term infants
had normal tearing (defined as at least 15 mm of
wetting of the tear test strip in 5 min) at 1 day
of age, and that this percentage decreased to 14-
63% for premature newborns, these results being
correlated with body weight. This correlation
between maturity and tear secretion level was
also apparent in our study. Similarly, Patrick
reported that 84% of term infants display normal
tearing; however, he was unable to determine
any difference between term and premature
newborns with respect to tear secretion.
Toker et al. reported that mean total tear
production was 16.3 mm in term and 7.4 mm
in preterm infants. They also demonstrated that
total, but not basal tear secretion, is correlated
with birth weight and post-conceptional age.
However, they were unable to detect any
correlation between Schirmer’s scores and birth
weight or post-conceptional age.
The variability of Schirmer’s test results can
be attributed to increases in reflex secretion
induced by eye blinking, which cannot be
prevented in newborns, unlike in adults in
whom the test can be employed with the
patient’s eyes closed. In addition, topical
anesthesia is not absolute enough to test
basal Schirmer’s levels, because eyelid margins
and cilia are still sensitive to irritation by
the Schirmer’s strip, which is relatively large
for newborns. This raises disagreement with
respect to basal and reflex tearing, because
even using topical anesthesia, we still irritate
eyelid margins and lashes and, hence, basal
secretion cannot be measured without at least
some degree of test interference. It also seems
obvious that a normal test strip, which in
adults can be positioned at the temporal margin
of the lower eyelid so as not to irritate the
cornea but in newborns will touch the cornea
wherever it is placed because of its relative
size, will cause more irritation and tearing in
newborns than in adults. Consequently, we
believe that Schirmer’s tests are not accurate
enough in newborns to evaluate tear properties
and that additional tests, like measurement of
tear ferning patterns, are warranted.
We hypothesized that any correlation between
tear secretion and tear ferning pattern could
be helpful in evaluating tearing capacity in
newborns, because using the ferning test alone
would be as accurate as Schirmer’s test for the
newborn, and our study confirmed a positive
correlation between these two tests. In fact,
we believe that they represent two different
parameters of tear secretion (tear quality and tear
quantity), which are affected by each other.
In conclusion, newborns secrete good quality
tears in moderate quantity, and ferning patterns
are affected by Schirmer’s test scores. Tear
secretion levels are correlated with postconceptional
age and birth weight. Given
further that tear ferning can be assessed easily
in newborns and that Schirmer’s tests are already done in this population, perhaps both
tear ferning capacity and Schirmer’s tests could
be utilized in the evaluation of newborns’ tear
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