Objective—To evaluate effects of daily topical ocular
administration of latanoprost solution on intraocular
pressure (IOP) in healthy cats and dogs.
Animals—9 domestic shorthair cats and 14 dogs.
Procedure—Latanoprost solution (0.005%) was
administered topically to 1 eye (treated) and vehicle to
the other eye (control) of all animals once daily in the
morning for 8 days. Intraocular pressure was measured
twice daily for the 5 days preceding treatment,
and IOP, pupillary diameter, conjunctival hyperemia,
and blepharospasm were measured 0, 1, 6, and 12
hours after the first 4 treatments and 0 and 12 hours
after the final 4 treatments. Measurements continued
twice a day for 5 days after treatment was discontinued.
Aqueous flare was measured once daily during
and for 5 days after the treatment period.
Results—Intraocular pressure and pupillary diameter
were significantly decreased in the treated eye of
dogs, compared with the control eye. Mild conjunctival
hyperemia was also detected, but severity did not
differ significantly between eyes. Blepharospasm and
aqueous flare were not detected in either eye.
Intraocular pressure in cats was not significantly
affected by treatment with latanoprost. However,
pupillary diameter was significantly decreased in the
treated eye, compared with the control eye.
Conjunctival hyperemia, aqueous flare, and blepharospasm
were not detected in either eye.
Conclusions and Clinical Relevance—Once-daily
topical ocular administration of latanoprost solution
(0.005%) reduced IOP in healthy dogs without inducing
adverse effects but did not affect IOP in healthy
cats. Latanoprost may be useful for treating glaucoma
in dogs. (Am J Vet Res 2000;61:1220–1224)
Objective—To compare inhibitory effects of topically applied 1% prednisolone acetate suspension, 0.03% flurbiprofen solution, 0.1% dexamethasone suspension, and 0.1% diclofenac solution on paracentesis-induced blood-aqueous barrier breakdown in cats.
Animals—9 healthy cats.
Procedures—Paracentesis of the anterior chamber was performed in both eyes of each cat. One eye of each cat was treated with a topically administered anti-inflammatory medication (1% prednisolone [n = 7 cats], 0.03% flurbiprofen , 0.1% dexamethasone , or 0.1% diclofenac ) immediately following paracentesis and at 6, 10, and 24 hours after paracentesis. The contralateral untreated eye served as the control eye. Each cat had a 6-day washout period between experimental drugs. Breakdown of the blood-aqueous barrier was quantified by use of laser flaremetry.
Results—Topical administration of 1% prednisolone significantly reduced aqueous humor flare at 4, 8, and 26 hours after paracentesis. Topical administration of 0.1% diclofenac significantly reduced aqueous humor flare at 8 and 26 hours after paracentesis. Topical administration of 0.1% dexamethasone and 0.03% flurbiprofen did not significantly decrease flare at any time point. There were significant differences in intraocular pressures between NSAID-treated eyes and untreated contralateral eyes.
Conclusions and Clinical Relevance—Topical administration of 1% prednisolone and 0.1% diclofenac significantly reduced intraocular inflammation in cats with paracentesis-induced uveitis. Topical administration of 1% prednisolone or 0.1% diclofenac may be appropriate choices when treating cats with anterior uveitis. Topical administration of diclofenac and flurbiprofen should be used with caution in cats with a history of ocular hypertension.
OBJECTIVE To compare the efficacy of various concentrations and combinations of serum, EDTA, 3 tetracyclines, and N-acetylcysteine (NAC) for collagenase inhibition in an in vitro corneal degradation model.
SAMPLE Grossly normal corneas from recently euthanized dogs and horses and fresh serum from healthy dogs and horses.
PROCEDURES Serum was pooled by species for in vitro use. For each species, sections of cornea were dried, weighed, and incubated with clostridial collagenase (800 U/mL) in 5 mL of a 5mM calcium chloride-saline (0.9% NaCl) incubation solution and 500 μL of 1 of 19 treatments (homologous serum; 0.3%, 1.0%, or 2% EDTA; 0.1%, 0.5%, or 1.0% tetracycline, doxycycline, or minocycline; 0.5%, 1.0%, or 5.0% NAC; serum with 0.5% tetracycline; serum with 1.0% EDTA; or 1.0% EDTA with 0.5% tetracycline). Positive and negative control specimens were incubated with 5 mL of incubation solution with and without collagenase, respectively. Each control and treatment was replicated 4 times for each species. Following incubation, corneal specimens were dried and reweighed. The percentage corneal degradation was calculated and compared among treatments within each species.
RESULTS Treatments with tetracyclines at concentrations ≥ 0.5%, with EDTA at concentrations ≥ 0.3%, and with NAC at concentrations ≥ 0.5% were more effective at preventing corneal degradation than serum in both species. The efficacy of each combination treatment was equal to or less than that of its components.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested EDTA, tetracyclines, and NAC may be beneficial for topical treatment of keratomalacia, but in vivo studies are required.
Objective—To determine whether oral administration
of L-lysine to cats would lessen the severity of conjunctivitis
caused by feline herpesvirus (FHV-1).
Animals—8 healthy young adult cats.
Procedure—Cats received oral administration of
lysine monohydrochloride (500 mg, q 12 h) or placebo
(lactose) beginning 6 hours prior to inoculation of
virus. The left conjunctival sac received a 50-µl suspension
of FHV-1 grown in cell culture (1.8 X 108 tissue
culture infective dose50) on day 1. Cats were evaluated
and scores given for clinical signs each day for 21
days. Samples for virus isolation were collected from
the eye and throat every third day. Plasma lysine and
arginine concentrations were measured prior to the
study and on days 3, 14, and 22.
Results—Cats that received lysine had less severe
conjunctivitis than cats that received placebo. Virus
isolation results did not differ between the groups.
Plasma lysine concentration was significantly higher
in cats that received lysine, compared with control
cats, whereas plasma arginine concentrations did not
differ between groups.
Conclusion and Clinical Relevance—Oral administration
of 500 mg of lysine to cats was well tolerated
and resulted in less severe manifestations of conjunctivitis
caused by FHV-1, compared with cats that
received placebo. Oral administration of lysine may be
helpful in early treatment for FHV-1 infection by lessening
the severity of disease. (Am J Vet Res
Objective—To develop a reverse transcriptase-polymerase
chain reaction (RT-PCR) assay to detect feline
herpesvirus-1 (FHV-1) latency-associated transcripts
(LATs) in the corneas and trigeminal ganglia of cats
that did not have clinical signs of ocular disease.
Sample Population—Corneas and trigeminal ganglia
obtained from 21 cats necropsied at the Indiana
Animal Disease Diagnostic Laboratory and 25 cats
euthanatized at a humane shelter; none of the cats
had a recent history of respiratory tract or ocular disease,
and all had normal results for ophthalmic examinations.
Procedure—Both corneas and both trigeminal ganglia
were harvested from each cat. An initial PCR assay
detected FHV-1 DNA in the corneas and trigeminal
ganglia. The RNA was then isolated from samples
positive for FHV-1 DNA, and an RT-PCR assay was
used to detect LATs.
Results—FHV-1 DNA was detected in 45 of 92
(48.9%) corneas and 38 of 92 (41.3%) trigeminal ganglia.
In many samples, the RNA had degraded and RTPCR
assay was not possible. Of the samples subjected
to RT-PCR assay, none of the 39 corneas but 4 of
16 trigeminal ganglia had positive results when tested
Conclusions and Clinical Relevance—Analysis of
the results indicated that a high percentage of cats
that did not have clinical signs of ocular disease had
detectable FHV-1 DNA in their corneas and trigeminal
ganglia. This study documents that the RT-PCR assay
can successfully identify LATs and may serve as a
tool to better understand the biologic characteristics
of FHV-1 and its relationship to clinical disease. ( Am J Vet Res 2004;65:314–319)
Objective—To evaluate the effect of topical application
of a 1% morphine sulfate solution (MSS) on signs
of pain and wound healing in dogs with corneal ulcers
and examine normal corneas immunohistochemically
for the presence of µ and δ opioid receptors.
Procedure—A 7-mm superficial corneal ulcer was
surgically created in the right eye (OD) of 10 dogs,
after which gentamicin solution and 1% MSS (n = 6)
or saline solution (4) was administered topically OD 3
times daily. Blepharospasm, tearing, conjunctival
hyperemia, aqueous flare, esthesiometer readings,
and pupil size were recorded before and 30 minutes
after treatment in all dogs. Ulcer size and days to
completion of healing were recorded. Corneas from 4
treated and 3 control dogs were evaluated histologically.
Normal canine corneas from 2 dogs not used in
the study were evaluated immunohistochemically for
the presence of µ and δ opioid receptors.
Results—Dogs treated with MSS had significantly
less blepharospasm and lower esthesiometer readings
than did control dogs. Duration of ulcer healing
and findings of histologic evaluation of corneas did
not differ between groups. Numerous δ and infrequent
µ opioid receptors were identified in the
corneal epithelium and anterior stroma of normal
Conclusions and Clinical Relevance—Topical use of
1% MSS in dogs with corneal ulcers provided analgesia
and did not interfere with normal wound healing.
Both µ and δ opioid receptors were identified in normal
corneas of dogs, although the µ receptors were
present only in small numbers. (Am J Vet Res 2003;64:813–818)
Objective—To evaluate the in vitro antifungal properties of silver sulfadiazine (SSD) and natamycin against filamentous fungi isolated from eyes of horses with keratomycosis.
Sample Population—Filamentous fungal isolates obtained from eyes of keratomycosis-affected horses.
Procedures—Fungal culture of ocular samples yielded 6 Fusarium spp; 7 Aspergillus spp; and 1 isolate each of Curvularia, Scopulariopsis, Penicillium, and Chrysosporium. For each fungal isolate, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of SSD and natamycin were determined.
Results—For all 17 fungal isolates, SSD MIC distribution ranged from ≤ 1 to > 64 μg/mL; MIC50 and MIC90 (MICs at which 50% and 90% of organisms were inhibited) were 4 and 32 μg/mL, respectively. The SSD MFC distribution for all isolates was ≤ 1 to > 64 μg/mL; MFC50 and MFC90 (MFCs at which 50% and 90% of organisms were killed) were 8 and > 64 μg/mL, respectively. For all fungal isolates, natamycin MIC distribution ranged from 256 to > 1,000 μg/mL; MIC50 and MIC90 were 512 and > 1,000 μg/mL, respectively. The natamycin MFC distribution for all isolates ranged from 512 to > 1,000 μg/mL; MFC50 and MFC90 were each > 1,000 μg/mL.
Conclusions and Clinical Relevance—These in vitro data suggest that SSD is fungicidal against the fungal isolates that were obtained from eyes of horses with keratomycosis and that natamycin is fungicidal against some of the isolates at the drug concentrations evaluated. Silver sulfadiazine may be a therapeutic option for equine keratomycosis.
Objective—To report values for tear production, central corneal touch threshold (CTT), and intraocular pressure (IOP) in healthy guinea pigs and determine results of aerobic bacterial culture and cytologic examination of conjunctival swab specimens.
Animals—31 healthy guinea pigs (62 eyes) of various ages and breeds.
Procedures—Tear production was measured by the phenol red thread tear test (PRT) and Schirmer tear test (STT) before and after topical anesthetic application, CTT was measured with an esthesiometer, and IOP was measured by applanation tonometry.
Results—Combining data from all eyes, mean ± SD PRT values before and after topical anesthetic administration were 21.26 ± 4.19 mm/15 s and 22.47 ± 3.31 mm/15 s, respectively, and mean IOP was 18.27 ± 4.55 mm Hg. Median STT values before and after topical anesthetic administration were 3 mm/min (range, 0 to 12 mm/min) and 4 mm/min (range, 0 to 11 mm/min), respectively, and median CTT was 2.0 cm (range, 0.5 to 3.0 cm). Values did not differ between eyes for any test, but significant differences were identified for PRT values between males and females and between values obtained before and after topical anesthetic administration. Common bacterial isolates included Corynebacterium spp, Streptococcus spp, and Staphylococcus spp. Cytologic examination of conjunctival swab specimens revealed mainly basal epithelial cells; lymphocytes were common.
Conclusions and Clinical Relevance—Results provided information on values for PRT, STT, CTT, and IOP in healthy guinea pigs and on expected findings for aerobic bacterial culture and cytologic examination of conjunctival swab specimens.
OBJECTIVE To compare the anticollagenase efficacy of fresh feline, canine, and equine serum and plasma on in vitro corneal degradation.
SAMPLE Grossly normal corneas from recently euthanized dogs, cats, and horses and fresh serum and plasma from healthy dogs, cats, and horses.
PROCEDURES Serum and plasma were pooled by species and used for in vitro experiments. Corneas were collected and stored at −80°C. Sections of cornea were dried, weighed, and incubated in saline (0.9% NaCl) solution with clostridial collagenase and homologous fresh serum or plasma. Corneal degradation was assessed as the percentage of corneal weight loss and hydroxyproline concentration, compared with results for positive and negative control samples.
RESULTS Homologous fresh serum and plasma significantly reduced the percentage of corneal weight loss, compared with results for positive control samples. No significant difference was found in percentage of corneal weight loss between incubation with serum or plasma for feline, canine, and equine corneas. Canine serum and plasma significantly reduced hydroxyproline concentrations, whereas inclusion of feline and equine serum or plasma did not, compared with results for positive control samples. Hydroxyproline concentrations were moderately correlated with percentage of corneal weight loss for feline samples and weakly correlated for equine samples, but they were not correlated for canine samples.
CONCLUSIONS AND CLINICAL RELEVANCE In this study, the anticollagenase efficacy of fresh feline, canine, and equine serum was not different from that of plasma. Plasma should be an acceptable substitute for serum in the topical treatment of keratomalacia.
OBJECTIVE To evaluate species differences and effects of storage duration and temperature on the anticollagenase efficacy of canine, feline, and equine serum on in vitro corneal degradation.
SAMPLES Corneas and serum from dogs, cats, and horses.
PROCEDURES Clinically normal corneas from dogs, cats, and horses were harvested within 2 hours after euthanasia. Serum samples from dogs, cats, and horses were collected and pooled by species. Corneal specimens were incubated with collagenase derived from Clostridium histolyticum, 5mM calcium chloride in saline (0.9% NaCl) solution, and feline, canine, or equine serum that had been stored for 0, 30, 90, or 180 days at −20° or −80°C. Following incubation, the corneal weight loss percentage and hydroxyproline concentration in the incubation fluid were calculated and compared among experimental combinations.
RESULTS Feline serum was more effective than canine or equine serum for minimizing corneal weight loss. Incubation with feline or equine, but not canine, serum significantly reduced hydroxyproline production. Serum storage duration did not affect corneal weight loss, but the hydroxyproline concentration was greater for corneal specimens that were incubated with serum that was stored for 90 days, compared with that for corneal specimens incubated with serum that was stored for 0, 30, or 180 days. Serum storage temperature did not affect corneal weight loss or hydroxyproline concentration.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that serum reduced corneal degradation in vitro, and the duration and temperature at which serum was stored did not affect its anticollagenase efficacy.