Objective—To determine density of corneal endothelial
cells, corneal thickness, and corneal diameters in
normal eyes of llamas and alpacas.
Animals—36 llamas and 20 alpacas.
Procedure—Both eyes were examined in each
camelid. Noncontact specular microscopy was used
to determine density of corneal endothelial cells.
Corneal thickness was measured, using ultrasonographic
pachymetry. Vertical and horizontal corneal
diameters were measured, using Jameson calipers.
Results—Values did not differ significantly between
the right and left eyes from the same camelid. There
was no significant effect of sex on density of corneal
endothelial cells or corneal thickness in either
species. Mean density of endothelial cells was 2,669
cells/mm2 in llamas and 2,275 cells/mm2 in alpacas.
Density of endothelial cells decreased with age in llamas.
Polymegathism was observed frequently in both
species. Mean corneal thickness was 608 µm for llamas
and 595 µm for alpacas. Corneal thickness and
density of endothelial cells were negatively correlated
in llamas. Older (> 36 months old) llamas had significantly
larger horizontal and vertical corneal diameters
than younger llamas, and older alpacas had a significantly
larger vertical corneal diameter than younger
Conclusions and Clinical Relevance—Density of
corneal endothelial cells is only slightly lower in
camelids than other domestic species. Density of
endothelial cells decreases with age in llamas. Age or
sex does not significantly affect corneal thickness in
normal eyes of llamas and alpacas. Specular
microscopy is useful for determining density of
corneal endothelial cells in normal eyes of camelids.
(Am J Vet Res 2002;63:326–329)
Objective—To determine the effect of 0.005%
latanoprost solution on intraocular pressure (IOP) of
eyes of clinically normal horses and establish the frequency
of adverse effects of drug administration.
Animals—20 adult clinically normal horses.
Procedure—IOP was recorded (7, 9, and 11 AM; 3, 5,
and 7 PM) on days 1 and 2 (baseline), days 3 to 7 (treatment),
and days 8 to 9 (follow-up). Latanoprost was
administered to 1 randomly assigned eye of each
horse every 24 hours during the treatment period, following
the 7 AM IOP recording. Pupil size and the
presence or absence of conjunctival hyperemia,
epiphora, blepharospasm, blepharedema, and aqueous
flare were recorded prior to IOP measurement.
Results—IOP was reduced from baseline by a mean
value of 1.03 mm Hg (5%) in males and 3.01 mm Hg
(17%) in females during the treatment period. Miosis
developed in all treated eyes and was moderate to
marked in 77% of horses, with the peak effect
observed 4 to 8 hours after drug administration.
Conjunctival hyperemia, epiphora, blepharospasm,
and blepharedema were present in 100, 57, 42, and
12% of treated eyes, respectively, 2 to 24 hours following
drug administration. Aqueous flare was not
observed at any time point.
Conclusions and Clinical Relevance—Although IOP
was reduced with every 24-hour dosing of
latanoprost, the frequency of prostaglandin-induced
adverse events was high. Because recurrent uveitis
appears to be a risk factor for glaucoma in horses,
topical administration of latanoprost may potentiate
prostaglandin-mediated inflammatory disease in
affected horses. (Am J Vet Res 2001;62:1945–1951)
Objective—To determine effects of topical antimicrobial
and antimicrobial-corticosteroid preparations on
the ocular flora of horses.
Procedure—One eye was treated 3 times daily for 2
weeks with one of the following ointments: 1) neomycinbacitracin-
polymyxin B, 2) 0.6% prednisolone-0.3% gentamicin,
3) neomycin-polymyxin B-0.05% dexamethasone,
or 4) treated (artificial tears) control. Contralateral eyes of
treated control eyes served as untreated control eyes.
Corneal and conjunctival specimens for bacterial and fungal
cultures were collected prior to initiation of treatment,
after 1 and 2 weeks of treatment, and 2 weeks after concluding
treatment. Changes in culture growth quantity
scores of bacterial and fungal species were analyzed.
Results—The most common species before treatment
were the following: gram-positive bacteria included
Streptomyces spp (66%) , Staphylococcus spp (46%) ,
Bacillus spp (32%) , and Streptococcus spp (32%); gramnegative
bacteria included Moraxella spp (28%) ,
Escherichia coli (24%) , Acinetobacter spp (18%), and
Enterobacter spp (14%); and fungi included Aspergillus
nidulans (56%) , Cladosporium spp (32%), and
Aspergillus fumigatus (22%). In all groups, the percentage
of positive bacterial culture results, growth quantity
score of gram-positive bacteria, and number of bacterial
species isolated decreased at week 1 and increased at
week 2, whereas growth quantity score of gram-negative
bacteria decreased throughout treatment. Differences
were not significant among groups. Fungal growth quantity
score decreased during treatment in all groups.
Repopulation of bacterial and fungal species occurred.
Conclusions and Clinical Relevance—All interventions
decreased the number of microorganisms.
Repopulation of normal flora occurred during and after
treatment. (Am J Vet Res 2005;66:800–811)
Objective—To evaluate the effect of topical administration
of 2% dorzolamide hydrochloride or 2% dorzolamide
hydrochloride-0.5% timolol maleate on intraocular
pressure (IOP) in clinically normal horses.
Animals—18 healthy adult horses without ocular
Procedure—The IOP was measured at 5 time points
(7 AM, 9 AM, 11 AM, 3 PM, 7 PM) over 11 days. On days
1 and 2, baseline values were established. On days 3
through 5, horses received 2% dorzolamide HCl
(group D, n = 9) or 2% dorzolamide HCl-0.5% timolol
maleate (group DT, 9) in 1 randomly assigned eye
every 24 hours immediately following each daily 7 AM
IOP measurement. On days 6 through 9, each drug
was given every 12 hours (7 AM and 7 PM) in the treated
eye. Measurements on days 10 and 11 assessed
return to baseline. Mixed linear regression models
compared mean IOP difference for each drug at each
Results—Mean IOP decreased significantly in all
eyes during the 2 dose/d period, compared with the
baseline, 1 dose/d, and follow-up periods.
Conclusions and Clinical Relevance—Administration
of either drug every 24 hours for short-term
treatment does not reduce IOP significantly.
Administering either drug every 12 hours induced a
significant reduction of IOP; however, controlling for
all variables, the reduction was less than 2 mm Hg.
(Am J Vet Res 2001;61:709–713)
Objective—To estimate intraocular pressure (IOP) in
eyes of healthy camelids, using applanation tonometry.
Animals—The eyes of 34 camelids (16 llamas [Lama
glama] and 18 alpacas [L pacos]) that did not have
major abnormalities of the ocular surface or intraocular
Procedure—Tonometry measurements were
obtained from each eye 3 times during a 24-hour period.
Each measurement was the mean of several
corneal applanations obtained by use of an applanation
tonometer. Data were analyzed, using an ANOVA
for a repeated-measures design.
Results—Mean (± SEM) IOP of llamas and alpacas
was 13.10 ± 0.35 and 14.85 ± 0.45 mm Hg, respectively.
Range of IOP was 7 to 18 mm Hg for llamas
and 11 to 21 mm Hg for alpacas. Mean IOP of llamas
was significantly less than the mean IOP of alpacas.
Significant differences in IOP were not detected
between the right and left eye of animals. Significant
differences in IOP were not attributed to sex, age, or
time of measurement within llamas or alpacas.
Conclusions and Clinical Relevance—Establishing
the mean and range of IOP of clinically normal llamas
and alpacas provides a frame of reference that is
important for use in a complete ophthalmic examination
of camelids, which can assist clinicians in the
diagnosis of glaucoma and uveitis. Reasons for the
difference in mean IOP between llamas and alpacas
are unknown. Although the difference may be unimportant
clinically, this finding reiterates the fact that
caution must be used when extrapolating IOP among
species. (Am J Vet Res 2000;61:1542–1544)