Lacrimostimulants and lacrimomimetics

Precorneal retention time of ocular lubricants measured with fluorophotometry in healthy dogs

OBJECTIVE

Determine the precorneal retention time of five different ocular lubricants commonly used in dogs.

ANIMALS STUDIED

Six healthy Beagle dogs (n = 12 eyes).

PROCEDURES

Five ocular lubricants were studied: Artificial Tears Solution® (1.4% polyvinyl alcohol), I-Drop® Vet Plus (0.25% hyaluronate), Optixcare® Eye Lube Plus (0.25% hyaluronate), Systane® Ultra (0.4% polyethylene glycol 400 and 0.3% propylene glycol), and Artificial Tears Ointment® (mineral oil/white petrolatum). Each lubricant was mixed with 10% sodium fluorescein to achieve 1% fluorescein formulations. Following topical administration of 35 mg in each eye, tear fluid was collected with capillary tubes at selected times (0, 1, 5, 10, 20, 30, 40, 50, 60, 90, 120, 180 min) and fluorescein concentrations were measured with a computerized scanning ocular fluorophotometer.

RESULTS

Tear fluorescence was significantly greater with Artificial Tears Ointment® compared with other lubricant formulations from 1 to 20 min post-administration. Median (range) precorneal retention times were significantly different among the 5 lubricants, ranging from 40 minutes (20-90 min) for Artificial Tears Ointment®, 35 min (20-90 min) for Systane® Ultra, 30 min (10-60 min) for I-Drop® Vet Plus, 25 min (10-60 min) for Optixcare® Eye Lube Plus, and 10 min (10-20 min) for Artificial Tears Solution®. Precorneal retention time was significantly lower for Artificial Tears Solution® compared with the other 4 formulations.

CONCLUSIONS

This study established normative data for the retention time of common lubricants on the ocular surface of dogs, which may be used to guide clinicians with their choice of lubricant and frequency of administration.

Neurogenic keratoconjunctivitis sicca in 34 dogs: A case series

OBJECTIVE

To describe the clinical findings, imaging features, underlying conditions, treatment, and progression of dogs presented between 2010 and 2019 with neurogenic keratoconjunctivitis sicca (NKCS).

METHODS

Dogs diagnosed with NKCS were searched in the clinical database. Inclusion criteria were STT-1 readings <15 mm/min, clinical signs of KCS with concurrent ipsilateral xeromycteria.

RESULTS

Thirty-four cases were identified. Mean age at presentation was 8.2 years, median 8.9 years (0.3-14.7). Twenty dogs were male, and 14 dogs were female. Concurrent neurological deficits included facial neuropathy (n = 13, 38%), peripheral vestibular syndrome (n = 10, 29%), and Horner's syndrome (n = 5, 15%). Advanced imaging was acquired in 53% of cases (n = 18). Etiologies included idiopathic (n = 18, 53%), endocrinopathy (n = 6, 18%), otitis interna (n = 4, 12%), head trauma (n = 3, 9%), iatrogenic (post-TECA-LBO, n = 1, 3%), brainstem mass (n = 1, 3%), and an area of inflammation in the pterygopalatine fossa (n = 1, 3%). Treatment for NKCS was initiated in most cases (n = 30, 88%) including: oral pilocarpine 2% and lacrimostimulant (n = 19), oral pilocarpine 2% only (n = 3), or lacrimostimulant only (n = 8). A mean time follow-up of 3.7 months, median 3 months (1-14) was available in 23 cases (68%). Eleven cases with follow-up were responsive (48%) with resolution of the clinical signs in a median time 4 months (1-10), and all of them were treated with oral pilocarpine (±lacrimostimulant).

CONCLUSIONS

Most cases presented as idiopathic NKCS; in others, an underlying cause of facial neuropathy was identified. All responsive cases were treated with oral pilocarpine 2%.

Corneal protective effects of novel tear substitutes containing sodium hyaluronate and dodecahydrosqualene, squalane, in a porcine dry eye model

To develop a novel tear substitute (TS) containing sodium hyaluronate (SH) and dodecahydrosqualene (DHS, squalane), we improved the prescription of a previously developed TS containing saline, 0.5% SH and 1% castor oil (CO), which had corneal protective effects against 60-min desiccation in a porcine dry eye model and viscosity of 106.8 mPa·S. Fresh porcine eyes were treated with a TS containing saline, 0.1%, 0.25%, 0.3% or 0.5% SH, and 1% CO or 1%, 2.5% or 5% DHS, and TS-treated eyes were desiccated for up to 180 min. The corneal damage was evaluated by the staining score of methylene blue (MB), absorbance of MB extracted from the cornea, the staining density of lissamine green (LG) and histopathology. The viscosities of the examined TS were also measured. A saline/0.5% SH/1% DHS solution had corneal protective effects for 90 min under desiccation and a viscosity of 110.0 mPa·s. A TS with saline, 0.1%, 0.25% or 0.3% SH and 1% or 2.5% DHS did not have better protective effects than a saline/0.5% SH/1% DHS solution, although a saline/0.3% SH/5% DHS solution exhibited greater corneal protection against 180-min desiccation on MB and LG staining and histopathological examination, and its viscosity was 34.5 mPa·s, which was similar to the 29.5 mPa·s of 0.3% SH. The saline/0.3% SH/5% DHS solution is available as a novel 3-hr long-lasting TS containing mucinomimetic and liquid oil components to treat and relieve dry eye symptoms in animals and humans.

Schirmer tear test and strip meniscometry in healthy cats

Background:

The surface of the eye is covered by the preocular tear film, which is critical for maintaining a normal, healthy, visual, and comfortable vision. The Schirmer tear test (STT) and, more recently, strip meniscometry (SM) are used to evaluate tear production.

Aim:

To establish the normal values for STT and SM in healthy cats and to discover the correlation between these tests.

Methods:

A total of 25 mixed breed cats, aging from 8 months to 13 years of both genders (10 females and 15 males) were included in the study. All the cats were assigned to the study as being both clinically and ophthalmologically healthy. For the SM test, the tip of the strip was used to evaluate the meniscus without touching the eyelid or the cornea for 5 seconds. After a full tear washout period of 10 minutes, the STT was performed using a standard STT strip.

Results:

In the right eyes, the mean ± standard deviation (SD) of SM was 4.32 ± 2.27 mm/5 seconds, and in the left eyes it was 5.04 ± 2.24 mm/5 seconds (for both eyes combined: 4.68 ± 2.26 mm/5 seconds), with a median of 4 in both eyes; the reference values ranged from 4.04 to 5.32 mm/5 seconds. No significant differences were recorded in the SM between the right and left eyes of the cats when using the SM (p > 0.05). When the STT was used, the mean ± SD for the cats’ right eyes was 12.16 ± 4.04 mm/minute, and for the left eyes, it was 12.76 ± 4.1 mm/minute (for both eyes combined: 12.46 ± 4.20 mm/minute), with a median of 13.50 for both eyes. Reference values were calculated and ranged from 11.27 to 13.65 mm/minute. No significant differences were recorded between the STT for the right and left eyes (p > 0.05).

Conclusion:

Both tests can, therefore, be used to assess tear production in cats. For more precise results, SM should be evaluated according to the cat’s eye position—whether it is a brachiocephalic cat or a normaloid cat—and according to the age. In all cases, STT and SM should be evaluated according to the animal’s clinical status and the results of other diagnostic tools.

Clinical comparison of tear film breakup time measurements in normal dogs using three different methods of fluorescein solution administration

OBJECTIVE

To evaluate whether the method of fluorescein administration affects the results of tear film breakup time (TFBUT) measurement in normal dogs.

ANIMALS STUDIED

Thirty-seven client and hospital staff owned dogs over 1 year of age with no known comorbidities or administration of systemic or topical ophthalmic medications.

PROCEDURES

A prospective randomized three-way crossover study was conducted. All dogs received an abbreviated ophthalmic examination to rule out ocular surface disease. Using a 30-min washout interval period, each dog's right eye was received: (a) direct application of fluorescein stain strip with one drop of sterile eyewash, (b) direct application of fluorescein stain strip with two drops of sterile eyewash, or (c) application of one drop from a premade fluorescein solution (dilution of one strip in 0.3 mL sterile eyewash). Eyes were assessed using the cobalt blue filter of a slit lamp biomicroscope. TFBUT measurements were summarized as means ± standard deviation. The methods were compared using mixed model analysis of variance. All analyses were performed using sas version 9.4.

RESULTS

Thirty-seven dogs met the inclusion criteria. Mean TFBUT ± standard deviation (SD) for the three described methods were: (a) 16.58s ± 6.9, (b) 15.98s ± 7.1, and (c) 16.43s ± 8.1. No differences between fluorescein stain application techniques were observed (p = .92).

CONCLUSION

The technique of fluorescein solution administration did not affect TFBUT measurement in this population of healthy dogs.

Osmolarity of basal and reflex tears of normal dogs

OBJECTIVE

To compare basal and reflex tear osmolarity in healthy dogs and to evaluate for correlation among tear film osmolarity, tear production, and tear fern pattern.

ANIMALS STUDIED

The population consisted of 22 healthy adult dogs.

PROCEDURES

Reflex tear osmolarity was measured in both eyes using the I-PEN^®  VET osmometer 30 minutes following the Schirmer tear test (STT-1) measurement. Subsequently, two minutes following topical anesthetic application, the lacrimal lake and conjunctival fornices were dried, and 3 minutes later, basal tear osmolarity was measured. Tears were extracted from the dye-free STT-1 strip by centrifugation, placed on a glass slide, and the ferning pattern was determined by light microscopy. Comparisons between basal and reflex tears were performed with one-way ANOVA. Correlations between tear osmolarity, STT-1, and tear ferning were verified by Pearson's correlation coefficient.

RESULTS

No statistical difference was found between right and left eyes for STT-1, tear fern pattern, and osmolarity of reflex or basal tears (P < .05). There was no statistical difference between osmolarity of basal and reflex tears among individuals (P < .05). No correlation was detected between tear fern pattern and osmolarity of reflex tears. A weak positive correlation was detected between STT-1 values and osmolarity of reflex, but not basal tears.

CONCLUSIONS

The osmolarity of basal tears did not differ from that of reflex tears. A positive weak correlation exists between tear production and osmolarity of reflex tears. No correlation was detected between tear osmolarity measured by handheld osmometer and tear ferning.

The use of tear ferning test in cats for evaluation of ocular surface

Background

The tear film is a trilaminar fluid composed mainly of lipids, electrolytes, proteins and water. It is responsible for lubrication, nutrition and protection against microbial and toxic agents. Disruption of any these components may weaken the ocular surface, making it more susceptible to disease. Increasing evidence suggests that qualitative tear film deficiencies are an important predisposing factor or cause of some of the most common and challenging ocular diseases in cats, including conjunctivitis, corneal ulcer, spontaneous chronic corneal epithelial defects (SCCED), pigmentary keratitis, corneal sequestrum and dry eye syndrome. The aim of this study was to describe the tear ferning test in healthy cats and to compare the results by using two grading scales for humans. Tear samples were collected using Schirmer tear test (STT) strips from 60 healthy cats, and, after centrifuging the strips to obtain the samples, the aliquot was placed on clean microscope glass until it dried and the tear ferning patterns were observed under a polarized light microscope and classified according to the Rolando and Masmali grading scales.

Results

Ferning patterns in the lower grades showed full crystallization with high density, without gaps between the ferns and branches, forming several nuclei that were easily distinguished. According to the Rolando scale, 50% (60/120), 46.6% (56/120) and 3.4% (4/120) of eyes showed type I, II and III patterns, respectively. According to the Masmali scale, 15% (18/120), 56.6% (68/120 eyes) and 28.4% (34/120) of eyes showed grade 0, 1 and 2 patterns, respectively. No difference was observed between the right and left eyes for both Rolando (P = 0.225) and Masmali (P = 0.683) scales.

Conclusions

The tear ferning test is a qualitative test that can be used in cats as a complementary evaluation of the ocular surface. While the Rolando scale showed an increased prevalence of types I and II, the Masmali scale showed an increased prevalence of grades 1 and 2. This can be attributed to the species-specific differences between human and feline tear film. So Masmali grade 2 can be considered a normal tear pattern for the species, because all the cats used in study were clinically healthy. For this reason, future complementary studies are necessary for comparing healthy eyes and eyes with different ocular surface disease in cats. Both scales can be feasible options for grading tear crystallization in cats, but as Rolando scale included 96.6% of the samples in the 2 types that are considered normal for humans, we think that this scale seemed to be more precise to classify crystallization pattern in cats. The crystallization patterns observed in this study can form the basis for standardizing ocular surface parameters in cats.

Evaluation of tear production using the Schirmer tear test I in healthy cats; effect of age, life stage, sex, breed and neuter status

BACKGROUND

The purpose of this study was to evaluate the values of Schirmer tear test (STT) and determine effects of age, life stage, sex, breed and neuter status on tear production in healthy cats.

METHODS

Three hundred and forty-three domestic shorthair (DSH) and Persian cats, 50 days through 18 years old, were examined in this study. STT I was used to measure tear production in both eyes of each cat.

RESULTS

A mean STT 14.9±4.8 mm/min was calculated for the eyes of all cats. There was a significant difference between STT values in kittens (≤6 months old) and cats of other age groups (P<0.001). A substantial number of cats with clinically normal eyes had STT values less than 10 mm/min. No significant difference was found between males (14.7±5.0 mm/min) and females (15.1±4.5 mm/min) in STT values (P=0.46). Significant differences were found between entire (14.4±4.2 mm/min) and neutered (16.2±4.1 mm/min) cats (P=0.001), and between STT values of DSH (14.6±5.0 mm/min) and Persian (16.5±3.1 mm/min) cats in the study population (P=0.001).

CONCLUSIONS

This study documents the average STT values for a sizeable feline population demonstrating that, in contradistinction to the situation in dogs, a number of cats with clinically normal eyes have STT values below 10 mm/min.

Pilot evaluation of the circadian rhythm of tear production in a population of healthy adult cats

OBJECTIVES

The purpose of this study was to determine if a circadian rhythm exists in Schirmer's tear test (STT-1) values in a group of healthy adult cats.

ANIMALS STUDIED

Twenty adult neutered Domestic Short-haired cats (DSH) were used in the study.

PROCEDURES

Tear production was measured with the Schirmer tear test (STT-1) at 12 different time points over a 48-hour period.

RESULTS

A significant difference (approximately 4.3 mm/min) was noted between STT-1 values measured between 4 pm (lowest) and 12 am (highest) on both day 1 (P = 0.02) and day 2 (P = 0.01), and substantial variation in STT-1 values was observed at different times during the 48-hour period.

CONCLUSIONS

Significant variation in mean STT-1 values demonstrates that there is a circadian rhythm in tear production in cats and thus shows the importance of taking the time of day into account when measuring STT-1 in cats.

Comparative efficacy of topical oclacitinib 0.1% and tacrolimus 0.01% in canine keratoconjunctivitis sicca

OBJECTIVE

To assess the efficacy of 0.1% oclacitinib as a single agent, and in combination with tacrolimus 0.01%, for the control of ophthalmic signs of keratoconjunctivitis sicca (KCS) in dogs.

ANIMALS STUDIED

Thirty-two dogs (57 eyes) diagnosed with idiopathic KCS were included. Inclusion criteria were Schirmer Tear Test 1 (STT-1) values <15 mm/min and concurrent clinical signs such as ocular hyperemia and discharge.

PROCEDURES

The animals were submitted to a randomized, open-label, 5-week study and divided into 3 treatment groups treated with the following ophthalmic solutions: (a) 0.1% oclacitinib, (b) 0.1% oclacitinib +0.01% tacrolimus, and (c) 0.01% tacrolimus. Eye drops were instilled twice daily (12-hour intervals). At each follow-up examination, STT-1, clinical signs, and potential drug side effects were assessed.

RESULTS

Oclacitinib did not significantly improve STT-1 values or clinical scores. Tacrolimus alone and in combination with oclacitinib increased mean STT-1 values by 11.84 ± 5.2 and 12.46 ± 5.3 mm/min, respectively (P = 0.0001). Clinical scores of ocular discharge and hyperemia also improved significantly in both groups receiving treatment with tacrolimus (P < 0.05). However, addition of oclacitinib to tacrolimus provided no additional improvement over tacrolimus alone.

CONCLUSIONS

Topical 0.1% oclacitinib twice daily is not effective in controlling the ocular signs of KCS in dogs. 0.01% tacrolimus increased STT-1 values significantly and could potentially be used as a treatment for mild-to-moderate cases of KCS. Synergism between drugs did not occur, and therefore the use of oclacitinib is not justified in cases of canine KCS.

Comparison of the Schirmer tear test I values after placement in ventral and dorsal conjunctival fornices in healthy cats

OBJECTIVES

The objective of this study was to compare the Schirmer tear test I values obtained from placement of Schirmer tear test (STT) strips in ventral and dorsal conjunctival fornices and to investigate any correlation between age, body weight and STT values in clinically normal cats.

METHODS

Twenty-eight intact adult domestic shorthair and Persian cats were used in this study. The cats were gently physically restrained in a sternal position, and a Schirmer tear strip was placed on each eye in the ventral conjunctival fornix at one-third of the distance from the temporal to nasal canthus for 60 s. Then, the wetted portion of the strips was measured as mm/min (L-STT I). After 48 h, the same procedure was performed on each eye in the dorsal conjunctival fornix (U-STT I).

RESULTS

Mean ± SD STT values of the ventral and dorsal conjunctival fornices were 20.80 ± 2.25 mm/min (range 14-25 mm/min; 95% confidence interval [CI] 19.92-21.67) and 18.28 ± 2.27 mm/min (range 15-22 mm/min; 95% CI 17.39-19.16) in all of the study population, respectively. A significant difference was found between STT values obtained from the ventral and dorsal conjunctival fornices ( P <0.001). There was no correlation between the age and body weight of the animals and STT I values.

CONCLUSIONS AND RELEVANCE

This study compared the STT I values of the dorsal and ventral conjunctival fornices in cats. The difference was significant between the L-STT I and U-STT I values; however, the L-STT I and U-STT I values were within normal reference intervals. The U-STT I data have diagnostic value that might be of benefit in cases where there is a problem in the ventral conjunctival fornix.

Eficácia dos colírios ciclosporina e tacrolimo no tratamento de ceratoconjuntivite seca em cães

RESUMO O objetivo deste estudo foi avaliar os efeitos do tacrolimo e da ciclosporina na produção lacrimal de cães com ceratoconjuntivite seca (CCS) durante 90 dias. Para tanto, foram utilizados colírios de tacrolimo 0,02% (TcL) e ciclosporina 0,1% (CsA) em 14 cães com CCS. Os animais foram distribuídos em dois grupos e avaliados antes do início do tratamento (T0) e aos 15 (T1), 30 (T2), 45 (T3), 60 (T4), 75 (T5) e 90 (T6) dias após o início do tratamento. Na avaliação clínica, observou-se maior redução da secreção ocular, da opacidade e do edema corneano e da vascularização conjuntival. no grupo tacrolimo. No teste de Schirmer, verificou-se produção basal de 6(4,07 e 5,86(2,85mm/min no TcL e CsA, respectivamente, com aumento significativo da produção lacrimal em ambos os grupos, contudo houve aumento significativo da produção lacrimal a partir dos 15 dias de tratamento no grupo TcL (17,88(5,51mm/min), mas apenas a partir dos 45 dias no grupo CsA (11,86(4,74mm/min). Conclui-se que o uso do colírio tacrolimo aumentou em 68,83% a produção lacrimal em 90 dias de tratamento, comparado com a ciclosporina (56,82%), além de diminuir as manifestações clínicas inerentes à CCS, quando comparado à terapia com ciclosporina.

Tear ferning test in healthy dogs

PURPOSE

To evaluate and compare three tear sampling methods using two grading scales for administering the tear ferning test (TFT) to healthy dogs.

METHODS

In total, 90 dogs (180 eyes) were subjected to tear sampling using millimetered strips, reused after the Schirmer tear test (STT) (Schirmer group, SG). Then, the dogs were subdivided into three groups according to sampling approach: micropipette (MPG), microcapillary (MCG), and Schirmer sample 2 (S2G). The collected tears were dried on a clean microscope glass slide at room temperature and humidity. The ferning patterns were observed under a polarized light microscope and classified according to the Rolando and Masmali grading scales.

RESULTS

Although all three methods were feasible, the STT was easier to perform in clinical settings. Type I and Grade 1 were the most commonly observed (64.17% and 61.7%, respectively) regardless of collection method. There was no significant difference between the STT median values and the TFT classifications.

CONCLUSIONS

The TFT is appropriate for dogs and can be performed using the three suggested sampling methods, with a higher frequency of Type I and Grade 1. Thus, it is possible to use both grading scales in the classification of tear ferning in dogs.

Comparison between fish and linseed oils administered orally for the treatment of experimentally induced keratoconjunctivitis sicca in rabbits

The objective of this study was to compare the efficacy of two sources of omega 3 and 6, fish oil (FO) and linseed oil (LO), orally administered, alone or in combination, for treating experimentally induced keratoconjunctivitis sicca (KCS) in rabbits. Twenty-eight New Zealand rabbits were used in this study. Seven animals were allocated to the C group (negative control), and KCS was induced in 21 animals by topically applying 1% atropine sulfate drops for 7 days. Treatment with atropine was maintained throughout the study period (12 weeks). The rabbits were divided into 3 treatment groups containing 7 animals each: FO group, LO group and FLO group (FO and LO). The animals were evaluated using the Schirmer Tear Test I (STT I), Rose Bengal Test (RBT), fluorescein test (FT), tear film break-up time (TBUT), and conjunctival and histopathological analysis. There was a significant increase in STT I and TBUT values in treatment groups, but the increase occurred earlier in the FO group. The results of the RBT and FT were similar among treatment groups, except FT, in the FLO group, negative staining was only in 12 weeks. There was a significant decrease in the number of goblet cells in the FLO group compared with the other groups. The results demonstrated that orally administered of FO and LO improved the clinical signs of KCS. However, improvement occurred earlier in the FO group. Using oils in combination did not provide additional benefits. These results contribute to the future development of new oral formulations as adjuvant therapies for KCS.

Corneal-protective effects of an artificial tear containing sodium hyaluronate and castor oil on a porcine short-term dry eye model

The corneal-protective effects of an artificial tear containing sodium hyaluronate (SH) and castor oil (CO) were evaluated on a porcine short-term dry eye model. Fresh porcine eyes with an intact cornea were treated with an artificial tear of saline, SH solution (0.1%, 0.5% or 1%), CO solution (0.5%, 1% or 5%) or a mixture solution containing 0.5% SH and 1% CO and then desiccated for 60, 90 or 180 min. To assess corneal damage, the eyes were stained with methylene blue (MB) or lissamine green (LG). The staining score of MB, absorbance of MB extracted from the cornea and staining density of LG increased significantly with increasing desiccation time in untreated and all artificial tear-treated eyes, although there were no significant differences in staining scores and absorbance of MB between eyes treated continuously with saline and 1% SH-treated ones at 60 and 90 min of desiccation or the mixture-treated eyes at 60 min of desiccation. No significant differences in the staining density of LG were also found between continuous saline-treated eyes and ones desiccated for 60 min and treated with 1% SH and the mixture. Mild cytoplasmic vacuolations were histopathologically observed in the basal and wing cells in eyes desiccated for 60 min and treated with 1% SH and the mixture. The mixture solution containing 0.5% SH and 1% CO has protective effects against corneal desiccation similar to those of 1% SH and would be helpful as an artificial tear.

Canine neurogenic Keratoconjunctivitis sicca: 11 cases (2006-2010)

OBJECTIVE

  To describe the clinical data of dogs with neurogenic Keratoconjunctivitis sicca (KCS) and an ipsilateral dry nose without other neurologic deficits.

PROCEDURE

  The retrospective case study included 11 dogs diagnosed with neurogenic KCS and an ipsilateral dry nose between 2006 and 2010. Medical records were reviewed for breed, age, sex, history, suspected cause of neurogenic KCS, clinical signs, and treatment modalities. Follow-up information was obtained by re-examination of patients or completion of a telephone survey with the referring veterinarian or the owners.

RESULTS

  Mean age of the dogs was 6.6 ± 4.5 years. Neurogenic KCS was diagnosed in three females, five spayed females, one male, and two castrated males representing 10 different breeds. Ophthalmic signs of KCS (mean Schirmer tear test [STT] value of 1.9 ± 2.9 mm/min) combined with an ipsilateral dry nose were diagnosed in seven left and four right eyes. The suspected cause of neurogenic KCS was idiopathic in nine and trauma in two cases. Systemic therapy consisted of oral pilocarpine 1-2% eye drops combined with case-specific topical treatment with cyclosporine 0.2% and tear substitutes. Duration of systemic treatment with pilocarpine until healing was 125 days (range 84-204, median 98 days) for five dogs. One dog was lost to follow-up, and the remaining five dogs are still under systemic treatment with pilocarpine.

CONCLUSIONS

  Neurogenic KCS with an ipsilateral dry nose seems to be a predominantly idiopathic disease of middle-aged female dogs without breed predisposition, which may be self-limiting in some cases.

Evaluation of tear production with modified Schirmer tear test-1 during the neonatal period in cats

The study aimed to evaluate tear production by means of modified Schirmer tear tes-1 (mSTT-1) in neonate cats. Likewise, correlation between mSTT-1 and STT-1 was assessed in vitro. Standard SST strips were cut in half and after eye lid opening, tear production of neonates (n=15) was daily measured in both eyes (mSTT-1), until the 7th day, and at day 14, 21, and 28. Animals were daily weighted until 28 days of age. Results were compared statistically (P<0.05). During the first 7 days, the overall mSTT-1 mean was 0.76 wetting/minute. Significant differences between right and left eyes were not observed at any time point (P=1.00). Tear secretion increased significantly, from the 14th to 28th day, in comparison with 7 first days (P<0.05). Positive correlation between maturity parameters and tear secretion was observed (P<0.0001). Distance between slopes of each strip changed significantly (P<0.0001). It was concluded that tear secretion in the neonatal period of cats is very below the reference values described for young and adults of the same species. It is not possible to extrapolate results obtained with mSTT-1 to standard STT-1.

Measurement of phenol red thread tear test in Arabian and throughbred horses

OBJECTIVE

To determine physiologic levels of tear production in Arabian (AH) and throughbred horses (TH) by using phenol red thread test (PRT).

ANIMALS STUDIED

The study was performed on 16 AH and 14 TH, ranging from 2.5 to 24 years of age, housed in a stable situated in the Sanliurfa of Turkey.

PROCEDURES

For the measurement of PRT, the strip was placed under the lower eyelid approximately one-third the distance from the temporal to nasal canthus and left for 15 s. The length of the wet area was measured in mm and compared among breed, sex, and age groups and between eyes of both sides.

RESULTS

The mean length of the wet area was in AH and TH were 30.22 +/- 0.99 mm ranging from 16 to 41 and 31.00 +/- 1.4 mm ranging from 14 to 47, respectively. There were no significant differences in tear production among breed, sex, or age groups. The values measured for left eyes were significantly higher than those for right eyes (P < 0.05).

CONCLUSIONS

Phenol red thread test measurement is easily used, with no pain, and a comfortable method. PRT can be used in equine ophthalmology on a routine basis to the measurement of tear production. These normal PRT values help diagnosis keratoconjunctivitis sicca in horses.

Use of phenol red thread tests to evaluate tear production in clinically normal Amazon parrots and comparison with Schirmer tear test findings

OBJECTIVE

To determine phenol red thread test (PRTT) values in eyes of clinically normal Hispaniolan Amazon parrots before and after topical application of an ophthalmic anesthetic agent and compare findings with Schirmer tear test (STT) values.

DESIGN

Evaluation study.

ANIMALS

24 Amazona ventralis parrots from a research colony.

PROCEDURES

On 4 occasions (1-week intervals), all birds underwent a thorough ophthalmic examination of both eyes, which included (in sequence) performance of a PRTT and an STT; topical ocular application of proparacaine hydrochloride; and performance of another PRTT and another STT. Correlations between PRTT and STT values recorded with and without topical anesthesia were assessed.

RESULTS

Without topical anesthesia, mean +/- SD PRTT value was 12.5 +/- 5.0 mm/15 s (range, 1 to 25 mm/15 s). With topical anesthesia, the PRTT value was 12.6 +/- 5.4 mm/15 s (range, 2 to 24 mm/15 s). Without topical anesthesia, mean STT value was 7.9 +/- 2.6 mm/min (range, 0 to 13 mm/min). With topical anesthesia, the STT value was 5.1 +/- 3.3 mm/min (range, 0 to 18 mm/min). The correlation of PRTT and STT values recorded with or without topical anesthesia was weak (r = 0.51 and r = 0.32, respectively).

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that the PRTT and STT were both viable methods for measurement of tear production in Hispaniolan Amazon parrots. Topical application of an ophthalmic anesthetic agent did not have a significant effect on the PRTT values but significantly decreased the STT values.