Evaluation of the Schirmer Tear Test in two Turkish breeds of

Evaluation of the Schirmer Tear Test in two Turkish breeds of

Evaluation of the Schirmer Tear Test in two
Turkish breeds of Shepherd dogs
° F. ALKAN, ° C. IZCI, °° C. TEPELI and ° Y. KOC
° Assistant Professor, Department of Surgery, Collage of Veterinary Medicine, University of Selcuk, Konya, Turkey
°° Assistant Professor, Department of Animal Breeding, Collage of Veterinary Medicine, University of Selcuk, Konya, Turkey
Corresponding author : Dr. Fahrettin Alkan, Departman of Surgery, College of Veterinary Medicine, The University of Selcuk, 42031 Kampus, Konya, Turkey
Tlf: 00 90 332 2410041 / 2746 ; Fax: 00 90 332 2410063 ; e-mail: [email protected]
SUMMARY
RÉSUMÉ
The Schirmer tear test 1 and 2 (STT-1 and STT-2) were performed to evaluate tear production in 20 Turkish Akbas Shepherd Dogs and 21 Turkish
Kangal Shepherd Dogs. The mean values for STT-1 and STT-2 in Turkish
Akbas and Kangal Shepherd Dogs were 20.7 ± 2.9 mm/min and 21.5 ± 3.8
mm/min, and 9.8 ± 2.3 mm/min and 9.8 ± 3.0 mm/min, respectively. It was
determined that neither body weight nor age had a statistically significant
effect on these values. There were significantly differences in both STT-1
and STT-2 values between females and males in Shepherd dogs of both
breeds (p < 0.05). There were significant fluctuations daily, weekly, or over
time for STT-1and STT-2 values for each breed (p < 0.05). This study has
shown that the STT-1 and STT-2 values in both Turkish Akbas Shepherd
Dogs and Turkish Kangal Shepherd Dogs are normally distributed and are
significantly affected by breed, sex, or measurement sequences.
Évaluation du test de Schirmer chez deux races de chiens berger turcs.
Par F. ALKAN, C. IZCI, C. TEPELI et Y. KOC.
KEY-WORDS : Turkish Akbas shepherd dog - Turkish
Kangal shepherd dog - Schirmer tear test - tear production.
MOTS-CLÉS : Chien Turc berger de Kangal - Chien Turc
berger d’Akbas - test de Schirmer - production de
larmes.
Introduction
provide specific and nonspecific antimicrobial actions [9, 14,
15, 18].
Deficiency in tear production results in inflammation of the
conjunctiva and cornea known as dry eye, xerophthalmia, or
keratoconjunctivitis sicca [1, 7,10,17]. Clinical signs of keratoconjunctivitis sicca (KCS) include mucoid discharge, blepharospasm, conjunctival hyperemia, chemosis, corneal
ulceration, vascularization, and pigmention. KCS may be difficult to detect clinically, which can lead to more serious ocular damage by the time an accurate diagnosis is made [8, 10,
14, 15, 18].
Traditionally, the diagnosis of KCS, xerophthalmia, or dry
eye is based on clinical signs, laboratory analyses and on
results of Schirmer tear test (STT). The STT values in healthy dogs tend to cluster between 14 and 24 mm. wetting/
minute [2, 3, 4, 5, 6, 9, 11, 14, 19]. Dogs with wetting of
The preocular tear film comprises the secretions of several
glands [1, 7, 8, 14]. The outermost lipid layer is produced by
the Meibomian and Zeis glands in the upper and lower eyelids. The middle aqueous layer is produced by the orbital
lacrimal gland and the gland of the third eyelid. The inner
mucoprotein layer is produced by conjunctival goblet cells
and corneal epithelial cells [3, 15, 17, 18]. The preocular tear
film distribution occurs as a result of the movements of the
upper and lower eyelids, and the third eyelid. It plays an
important role in maintaining the health and normal function
of the conjunctiva and cornea. Tears help remove foreign
substances, provide moisture, lubrication, and essential
nutrients (oxygen and glucose) to the avascular cornea, and
contain immunoglobulins, enzymes and other proteins that
Revue Méd. Vét., 2004, 155, 2, 67-70
Des tests de Schirmer 1 et 2 (STT-1 et STT-2) ont été réalisés pour évaluer la production de larmes chez 20 chiens turcs berger d’Akbas et 21
chiens turcs berger de Kangal. Les valeurs moyennes pour STT-1 et STT-2
chez les chiens turcs berger d’Akbas et Kangal étaient 20.7 ± 2.9 mm/min
et 21.5 ± 3.8 mm/min, et 9.8 ± 2.3 mm/min et 9.8 + 3.0 mm/min, respectivement. Il est montré que ni le poids corporel ni l’âge n’a eu un effet statistiquement significatif sur ces valeurs. Des différences significatives
(p < 0.05) dans les valeurs de STT-1 et STT-2 entre femelles et mâles chez
les chiens de berger des deux races ont été trouvées. Des fluctuations significatives (p < 0.05) dans le temps (jour, semaine...) pour des valeurs de STT-1
et STT-2 ont été mises en évidence pour chaque race. Cette étude a prouvé
que les valeurs des STT-1 et STT-2 chez les chiens turcs de berger d’Akbas
et les chiens turcs de berger de Kangal sont normalement distribuées et sont
sensiblement affectées par la race, le sexe, ou les ordres de mesure.
68
10 to 14 millimeters may have xerophthalmia or keratoconjunctivitis sicca [1, 8, 14, 15, 18]. In the presence of typical
clinical signs and less than 8 or 10 millimeters of wetting per
minute is diagnostic for the disease. More severe clinical
signs are usually evident with STT values of 0 to 5
mm/minute [1, 9, 10, 18]. However, significant differences
are found in both Schirmer tear test values between dogs of
different breeds [4, 5, 12, 13]. Thus, what is considered normal tear production in the former would be deficient in the
latter. Therefore, it would be most difficult to rule out KCS as
a differential diagnosis for those breeds in which normal
values are not known [5, 8]. It is very important to establish
mean baseline values because keratoconjunctivitis has been
diagnosed in dogs of different breeds [9, 10, 15, 17]. In the
literature, however, very little was known on the STT-1 and
STT-2 values in Shepherd dogs of different breeds. The purpose of this study was to determine the normal values for the
STT-1 and STT-2 in Turkish Akbas Shepherd Dogs and
Turkish Kangal Shepherd Dogs ; to determine the values between normal tear and tear deficiency status on the basis of
the KCS ; to determine whether the age of dogs has any effect
upon Schirmer values or not, and to attempt to identify the
variables that might influence these findings.
Materials and Methods
ANIMALS
Turkish Akbas Shepherd Dogs and Turkish Kangal
Shepherd Dogs reared at the Veterinary Faculty Farm of
Selcuk University were used in this study. All dogs were used
following general physical and ocular examination to rule out
pre-existing ocular or physical abnormalities. Breed, age, body
weight and sex were recorded for each dog within each breed.
They were housed inside room temperature 17 °C, humidity
55 ± 10 %, and fed once a day between 10 a.m. and noon.
EXPERIMENTAL DESIGN
The experimental protocol was approved by the managerial board of the animal farm of the Veterinary Faculty,
University of Selcuk in Turkey. The Schirmer tear testing
paper (Clement Clarke International Limited) was used for
the Schirmer test. The STT-1 was measured by inserting a
bent portion of the test paper into the anterior medial onethird of the conjunctival sac. The test paper was removed
after the eyelids were closed for 60 seconds and the wet portion of the test paper was measured as mm. For STT-2, 0.4 %
oxybuprocaine hydrochloride (Benoxinate 0.4 % Thilo, Liba
A.S) was instilled on the surface of the eye, and a second
drop was instilled 30 seconds later. After 5 minutes residual
tear in the conjunctival sac was gently dried with a cotton-tipped swab (Soffio, Sogedv, Brascia) and the STT-2 was performed as described for the STT-1 [4, 5, 9, 11, 15]. The STT1 and STT-2 measurements were performed between 8 and
10 a.m. and again between 3 and 5 p.m. twice daily for seven
consecutive days and twice for 14th, 21th, and 28th days
(weekly) on each eye of each dog. All tests were performed
by the same investigators (F.A. and C.I.). For data analyses,
dogs within each breed were divided into three age categories
ALKAN (F.) AND COLLABORATORS
which are young (6 months to 18 months), middle-aged (two
to five years), and old (older than five years).
STATISTICAL ANALYSES
The experimental analyses of the data were carried out by
one-way analysis of variance (ANOVA). The differences between groups were compared using the Duncan’s multiple
range test. Statements of statistical significance are based on
P < 0.05. These analyses were accomplished by using statistical analysis system configured for computer (SPSS, Relase
10.0, SPSS. Inc).
Results
Twenty Turkish Akbas Shepherd Dogs and twenty one
Turkish Kangal Shepherd Dogs were used in the study.
Turkish Akbas Shepherd Dogs (10 females and 10 males)
ranged from 6 months to 8 years old (mean, 3.3 ± 2.3 years),
and the mean body weight was 30.2 ± 8.7 kg (range 16 to
42 kg). The mean values for STT-1 and STT-2 are shown in
table II.
The mean STT-1 and STT-2 values in Turkish shepherd
dogs of both breeds were 21.1 ± 3.4 mm/min and 9.8 ± 2.7
mm/min, respectively (Table I). There were significant fluctuations daily and weekly for STT-1 and STT-2 values for
each breed (P < 0.05) (Table I).
The young age group contained seven Turkish Akbas
Shepherd Dogs (4 females, and 3 males), ranging from
6 months to 1.5 years old (mean 1,1 years) and weighing
20.6 ± 3.8 kg (range 16 to 26 kg). The mean values for STT-1
and STT-2 are shown in table II.
The middle age group contained seven Turkish Akbas
Shepherd Dogs (3 females and 4 males), ranging from 2 to 5
years old (mean 3.1 years) and weighing 33.0 ± 6.2 kg (range
25 to 41 kg). The mean values for STT-1 and STT-2 are
shown in table II.
The old age group contained six Turkish Akbas Shepherd
Dogs (3 females, 3 males) ranging from 5 years to 8 years old
(mean 6.2 years ) and weighing 38.2 ± 2.6 kg (range 35 to
42 kg). The mean values for STT-1 and STT-2 are shown in
table II.
Turkish Kangal Shepherd Dogs (10 females and 11 males)
ranged from 6 months to 8 years old (mean 3.6 ± 2.6 years),
and the mean body weight was 37.0 ± 12.5 kg (range 18 to
TABLE II. — Values of STT-1 and STT-2 of different age groups in Turkish
Akbas Shepherd Dogs and Turkish Kangal Shepherd Dogs.
Revue Méd. Vét., 2004, 155, 2, 67-70
EVALUATION OF THE SCHIRMER TEAR TEST IN TWO TURKISH BREEDS OF SHEPHERD DOGS
abcd
69
Values in the same column with different superscripts are significantly different (P < 0.05). Data expressed as mean ± SEM mm wetting minute.
TABLE I. — Values of STT-1 and STT-2 in Turkish Akbas Shepherd Dogs and Turkish Kangal Shepherd Dogs.
57 kg). The mean values for STT-1 and STT-2 are shown in
table II.
The young age group contained seven Turkish Kangal
Shepherd Dogs (4 females, and 3 males), ranging from 6 to
18 months old (mean 11 months) and weighing 22.7 ± 3.4 kg
(range 18 to 28 kg). The mean values for STT-1 and STT-2
are shown in table II.
The middle age group contained seven Turkish Kangal
Shepherd Dogs (3 females, and 4 males), ranging from 2 to 4
years old (mean 3.0 ± 0.7 years) and weighing 39.1 ±7.6 kg
(range 28 to 52 kg). The mean values for STT-1 and STT-2
were shown in table II.
The old age group contained seven Turkish Kangal
Shepherd Dogs (3 females and 4 males), ranging from
5 years to 8 years old (mean 6.8 ± 1.1 years) and weighing
49.0 ± 6.6 kg (range 40 to 57 kg). The mean values for STT1 and STT-2 are shown in table II.
The mean values for STT-1 and STT-2 in the female and
male dogs of both breeds were shown in table III. There were
significant differences in both STT-1 and STT-2 values between females and males in both Turkish Akbas and Kangal
Shepherd Dogs (P < 0.05), (Table III). The mean values for
STT-1 and STT-2 in the morning and afternoon in Turkish
Akbas Shepherd Dogs and Turkish Kangal Shepherd Dogs
are shown in table IV. There were significant differences at
over time in both STT-1 and STT-2 values for each breed
(P < 0.05) (Table IV).
Discussion
The Schirmer tear test that is a semiquantitave method can
be performed with or without topical anesthesia. The STT-1
is performed in clinical setting to determine baseline and
reflex lacrimation. The STT-2, which is performed after the
instillation of a topical anesthetic evaluates solely basal tear
production in dogs [2, 4, 8, 11, 13]. The mean values for the
STT-1 and STT-2 in healthy dogs have been established as
19.8 ± 5.3 mm/min and 11.6 ± 6.1 mm/min, respectively [3,
7, 11]. However, in our study, we determined that the mean
values for STT-1 and STT-2 in the shepherd dogs of both
breeds were 21.1 + 3.4 mm/min, and 9.8 + 2.7 mm/min, respectively (Table I). The mean STT-2 value has been reported
to be approximately 30.5 % to 58.5 % [1, 5, 8, 12, 13], which
is nearly consistent with our mean values relating to STT-2
(46.5 %). These results are due to the effect of the local anesthetic drop on the corneal and conjunctival nervous system
ab
Values in the same column with different superscripts are significantly different
(P < 0.05). Data expressed as mean ± SEM mm wetting per minute.
ab
TABLE III. — Values of STT-1 and STT-2 in female and male Turkish Akbas
Shepherd Dogs and Turkish Kangal Shepherd Dogs.
TABLE IV. — Values of the STT-1 and STT-2 in morning and afternoon in
Turkish Akbas Shepherd Dogs and Turkish Kangal Shepherd Dogs.
Revue Méd. Vét., 2004, 155, 2, 67-70
Values in the same column with different superscripts are significantly different
(P < 0.05). Data expressed as mean ± SEM mm wetting per minute.
70
which control the reflex tear production as reported earlier [5,
9, 14, 15].
It has been reported that body weight [11, 19], head shape
[11] and age [5, 11, 19] have no effect on STT values in dogs.
However, BERGER and KING [2] reported that the values of
the STT-1 and STT-2 may be influenced by the dog’s weight.
In our study, there was no statistically significant difference in
both STT-1 and STT-2 values related to body weight or to the
age groups for each dog of both breeds (Table II), howewer,
the related-values have been found to be a little higher in dogs
of each breed with both old age and higher body weight than
in the other groups. These results revealed that the dogs with
small body weight may predispose to KCS in further years.
The STT values have been reported to be higher in females
than in males [4, 19], but not to be influenced by sex [11].
The findings of this study are consistent with those of the former two (P < 0.05), (Table III). Regarding the related-findings, we have suggested that female sex hormones may
have a protective function on lacrimation.
It has been suggested that the STT-1 and STT-2 values in
dogs may be influenced by dog’s breed [4, 5, 7, 12, 13].
Howewer, another author denied such a variation [11].
Previous reported STT-1 values in various breeds include 20.2
± 2.5 mm/min in the Beagle, 22.9 ± 4.1 mm/min in the
Labrador Retriever, 20.7 ± 3.2 mm/min in the English Spinger
Spaniel, 21.8 ± 3.7 mm/min in the Golden Retriever, and 15.8
± 1.8 mm/min in Shetland Sheepdog [5]. In this study, we showed that the mean STT-1 value was 20.7 ± 2.9 mm/min in
Turkish Akbas Shepherd Dogs and was 21.5 ± 3.8 mm/min in
Turkish Kangal Shepherd Dogs. In our study, the mean STT-1
values in dogs of both breeds was found to be consistent with
breeds mentioned above. We have suggested that the breed
differences of the dogs with healthy and KCS should be taken
into consideration as a contributing factor during clinical examinations. Previous reported STT-2 values in various breeds
are 3.8 ± 2.7 mm/min in the Beagle, 9.6 ± 3.8 mm/min in the
Labrador Retriever, 5.4 ± 3.4 mm/min in the English Spinger
Spaniel, 8.8 ± 3.1 mm/min in the Golden Retriever, and 3.6 ±
2.8 mm/min in Shetland Sheepdog [5]. In the present study,
the mean STT-2 values in both Turkish Akbas Shepherd Dogs
(9.8 ± 2.3 mm/min) and Turkish Kangal Shepherd Dogs (9.8
± 3.0 mm/min) were similar or higher than those reported for
any other breeds. We suggest that the mean STT-1 and STT-2
values in Turkish Akbas Shepherd Dogs and Turkish Kangal
Shepherd Dogs are similar because of the very close relationship between breeds.
It has previously been reported that there are daily and
weekly fluctuations in the STT-1 and STT-2 values in healthy
dogs [2, 4, 7]. Results of the present study indicated that the
dogs of both breeds had typical fluctuations in daily and
weekly tear production. In other hand, significant differences
were detected in both the STT-1 and the STT-2 values over
time (P < 0.05). SMITH et al. [16] have shown that there was
a diurnal variation with the lowest values at midday and the
highest values in the late afternoon, which is consistent with
our findings. The results from our study have proposed that
repetitive testing may affect changes in both STT-1 and STT2 values daily, weekly and within over time, by means of irritation, stress, physical condition.
ALKAN (F.) AND COLLABORATORS
This study has shown that the STT-1 and STT-2 values in
both Turkish Akbas Shepherd Dogs and Turkish Kangal
Shepherd Dogs are normally distributed and are significantly
affected by breed, sex, or measurement sequences. Howewer,
we have suggested that the age, body weight, sex, head type,
breed and ecological conditions should be considered for all
mesurements so that tear production can be accurately determined. We think that further studies are needed to properly
appreciate the differences among the shepherd dogs of
various breeds, and to avoid the misdiagnosis of KCS.
Acknowledgements
The authors thank the students of the veterinary medicine
who helped us during the study.
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