Ocular effects of topical 0.03% bimatoprost solution in normotensive feline eyes

OBJECTIVE: The current study was undertaken to evaluate the effects of topically applied bimatoprost, an ocular hypotensive lipid, on intraocular pressure (IOP) and pupil size (PS) in healthy cats. ANIMAL STUDIED: Nine European Shorthair cats free from clinically relevant ocular abnormalities were used in the study. PROCEDURES: Pretreatment baseline measurements of IOP and PS were obtained bilaterally at 8 am, 2 pm, and 8 pm for five consecutive days (days 1 to 5). Then the cats received one drop twice daily (10 am and 6 pm) of bimatoprost ophthalmic solution 0.03% (Lumigantrade mark, Allergan Inc., Irvine, CA USA), in one randomly selected eye and one drop of artificial tears in the fellow eye (control eye) for 5 days (days 6 to 10). Values for IOP and PS were obtained under the same conditions as in the pretreatment phase. The potential for ocular irritation following bimatoprost application was also evaluated. RESULTS: During the pretreatment period, the mean IOP and mean PS were not significantly different between the eyes subsequently treated with bimatoprost and those subsequently determined as controls. During the treatment period, the mean IOP in bimatoprost-treated eyes was not significantly lower than in control eyes (14.2+/-2.3 vs. 14.5+/-2.8 mmHg). Mean IOP in control eyes was not significantly changed at any time during the study period. A marked reduction of PS was seen in all bimatoprost-treated eyes, but no other clinically relevant side effects were observed. CONCLUSION: Twice daily topical applications of bimatoprost produced miosis but had no significant effect on IOP in healthy cats.     

The effect of 0.12% unoprostone isopropyl (rescula) on intraocular pressure in normotensive dogs

Rescula (0.12% unoprostone isopropyl) is the first docosanoid compound approved for treatment of glaucoma in humans. It is commercially available in Japan, and is undergoing clinical testing elsewhere. The aim of this study was to evaluate the effect of Rescula on intraocular pressure (IOP) in normotensive dogs. After establishing a baseline diurnal IOP curve, six dogs were unilaterally treated with Rescula while the contralateral eye was treated with a placebo. Applanation tonometry was performed in both eyes, and pupil size was evaluated, 30 min after treatment, and at 1-hr intervals for the next 9 hr. Rescula caused a significant (p=0.014) and long-lasting decrease in IOP, from 20.49+/-2.02 mm Hg in control eyes to 15.49+/-0.69 mm Hg in treated eyes. These results suggest that Rescula is potentially efficacious in treatment of canine glaucoma.     

Effects of topical 0.5% tropicamide on intraocular pressure in normal cats

The objective of the study was to determine the effect of topical 0.5% tropicamide on intraocular pressure (IOP) in normotensive feline eyes. IOP was measured bilaterally in 70 clinically healthy cats and gonioscopy (and goniophotography) was performed. Thereafter, 50 cats were treated unilaterally with one drop of 0.5% tropicamide. The contralateral, left eye served as a control. In the placebo group consisting of 20 cats, one drop of physiologic saline solution was administered to the right eye. In all cats, IOP of both eyes was measured 30, 60 and 90 min after topical administration. After unilateral tropicamide application, IOP increased significantly both in the right and in the left eye. Maximum average IOP increase was observed at the control measurement performed 90 min after treatment, with an elevation of 3.8 +/- 4.2 mmHg in the right eye and 3.5 +/- 3.6 mmHg in the left eye. Maximum IOP increase after treatment was 18.0 mmHg in the treated eye and 17.0 mmHg in the left eye. Measurements made at 60 min after treatment revealed a significantly higher increase in IOP in the right eye as compared to the left eye (P60 < 0.05), whereas the differences between right and left eye in IOP increase were not significant at 30 and 90 min after mydriatic application (P30 = 0.123; P90 = 0.305). Although tropicamide-induced mydriasis was observed in the treated eye, the contralateral eye did not show any changes in pupillary function at any time. With increasing age of the cats, IOP increase was found to be more moderate, whereas the gender of the cats did not have any significant influence on IOP changes. In the 20 cats in the placebo group, no significant changes in IOP were observed. We conclude that topical 0.5% tropicamide causes a significant elevation of IOP in the treated and untreated eye in normal cats.     

Effects of mydriatics on intraocular pressure and pupil size in the normal feline eye

OBJECTIVE: To determine the effect of various mydriatics (1% atropine, 1% cyclopentolate, 0.5% tropicamide, 10% phenylephrine) on intraocular pressure (IOP) and pupil size (PS) in normal cats. ANIMALS STUDIED: The mydriatics were tested in 10 adult ophthalmoscopically normal European Domestic Short-haired cats. Procedure Single-dose drug studies were divided into placebo (vehicle of phenylephrine), 10% phenylephrine, 0.5% tropicamide, 1% cyclopentolate and 1% atropine. After measurement of IOP and pupil size (PS) at 8 a.m. on the first day, one drop of the tested drug was applied to one randomly selected eye. The IOP and PS were measured for a minimum of 36 h until the pupil returned to pretest size. RESULTS: Ten per cent phenylephrine had no significant effect on IOP, and the effect on the pupil size was minimal (相似文献   

Effects of topical administration of 2.0% pilocarpine on intraocular pressure and pupil size in cats

Effects of topical administration of a single dose of 2% pilocarpine on intraocular pressure (IOP) and pupil diameter were evaluated in normotensive eyes of 10 clinically normal cats over 12 hours. Mean (+/- SEM) normal IOP was 17.1 (+/- 1.1) mm of Hg and, diurnal fluctuation was observed, with the highest IOP seen in the evening. Mean (+/- SEM) normal pupil diameter was found to be 10.1 (+/- 0.5) mm. Topical treatment with pilocarpine resulted in reduction of IOP in treated and nontreated eyes. This effect was time-dependent and was first observed at 4 hours after treatment. Mean reduction of IOP was 15.2% in the treated eye and 9.3% in the nontreated eye. The treated eye had reduced pupil diameter at 30 minutes after treatment, and miosis persisted throughout the 12 hours of the study. Mean reduction in pupil diameter was 28.5% in the treated eye and 14.2% in the nontreated eye. Topically administered pilocarpine results in reduction of IOP and pupil diameter in treated and contralateral eyes, which supports the use of pilocarpine for treatment of glaucoma in cats.     

Effects of systemic administration of 0.5% tropicamide on intraocular pressure, pupillary diameter, blood pressure, and heart rate in normal cats

OBJECTIVE: The objective of the study was to determine the effects of systemic 0.5% tropicamide on intraocular pressure (IOP), pupillary diameter (PD), blood pressure, and heart rate (HR) in normal felines with normotensive eyes. PROCEDURES: Intraocular pressure, PD, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), and HR were measured in 18 clinically healthy cats. Each of the previously mentioned parameters was measured every 30 min during the trial period. At T(60), each cat was treated with one to two drops of 0.5% tropicamide ophthalmic solution placed on the dorsal aspect of the tongue. Changes in SBP, DBP, MBP, and HR were evaluated using one-way repeated measures analysis of variance, with time as the repeated factor. IOP and PD were evaluated using two-way repeated measures analysis of variance, with time and side (OD vs. OS) as the repeated factors. P values less than or equal to 0.05 were considered statistically significant. RESULTS: After lingual tropicamide administration, the mean PD at T(60) was 3.53 mm OD and 3.53 mm OS. The mean PD at T(90) was 6.36 mm OD and 6.31 mm OS. The mean PD at T(120) was 8.25 mm OD and 8.19 mm OS. This change in PD from T(60), T(90), and T(120) was statistically significant, demonstrating a linear increase in PD over time after tropicamide application on the tongue (P<0.0001). There was no statistically significant difference in PD when comparing the right to the left pupils (P=0.10). The mean IOP at T(60) was 14 mmHg OD and 12.94 mmHg OS. The mean IOP at T(90) was 14.5 mmHg OD and 14.23 mmHg OS. The mean IOP at T(120) was 14.94 mmHg OD and 14.89 mmHg OS. This change in IOP from T(60), T(90), and T(120) was statistically significant, demonstrating a linear increase in IOP over time after tropicamide application on the tongue (P=0.034). There was no statistically significant difference in IOP when comparing the right eye to the left eye (P=0.28). There were no statistically significant differences in SBP, DBP, MBP, and HR values over time for the duration of the study. CONCLUSIONS: We conclude that although lingual application of tropicamide appears to result in systemic absorption, causing significant pupillary dilation and elevations in IOP, systemic effects on SBP, DBP, MBP, and HR were not observed.     

Effect of single and multiple doses of 0.2% brimonidine tartrate in the glaucomatous Beagle

The objective of this study was to evaluate the changes in intraocular pressure (IOP) in glaucomatous dogs after instillations of 0.2% brimonidine once, twice and three times daily in single day studies, and after twice and three times daily for 4 days in multiple dose studies. We studied eight Beagles with inherited primary open angle glaucoma. Applanation tonometry (IOP), pupil size (PS) and heart rate (HR) measurements were obtained at 8 am, 10 am, 1 pm, 3 pm and 5 pm. The studies were divided into: eight glaucoma dogs and five of the eight dogs that demonstrated greater response to 0.2% brimonidine. Single-dose drug studies are divided into placebo (0.5% methylcellulose), 0.2% brimonidine administered once daily (8 am); twice daily (8 am and noon); and three times daily (8 am, noon and 5 pm). The 5-day multiple-dose studies included: day 1, no drug; and 4 days, 0.2% brimonidine instillations either twice daily (8 am and 2 pm) or three times daily (8 am, 2 pm and 9 pm). Statistical comparisons between drug groups included control (nondrug) and treated (placebo/0.2% brimonidine) eyes for both single- and multiple-dose studies. The mean +/- SEM diurnal decrease in IOP in the eight glaucomatous Beagles for the control and placebo eyes were 3.4 +/- 4.7 and 5.4 +/- 2.8 mmHg, respectively. The mean +/- SEM diurnal decrease in IOP after 0.2% brimonidine once, twice and three times daily was 6.4 +/- 3.5, 8.0 +/- 6.1 and 9.8 +/- 8.1 mmHg, respectively; this trend was not significant statistically. Significant miosis occurred starting 2 h postinstillations, and the resultant mean +/- SD pupil size was 2.7 +/- 0.3 mm. A significant decrease in heart rate also occurred (12%). In the five most responsive dogs the changes in PS and HR during these studies were similar to the larger group, but significant decreases in IOP occurred at most measurement times. In the multiple-dose study with 0.2% brimonidine twice daily the mean +/- SEM decrease in IOP for day 1 to day 4 was 5.0 +/- 1.3, 5.7 +/- 1.3, 1.4 +/- 3.3 and 4.9 +/- 1.3 mmHg, respectively. When 0.2% brimonidine was instilled three times daily the mean +/- SEM diurnal IOP decrease was from day 1 to day 4 and was 0.75 +/- 1.3, 2.4 +/- 1.5, 1.2 +/- 2.7 and 1.4 +/- 1.8 mmHg, respectively. The mean change in pupil diameter was 1.3 +/- 0.5 mm. Decrease in HR averaged 22%. In the same single-dose studies with the five most responsive dogs, PS and HR were similar, but the decreases in IOP were significant at more measurement intervals. We conclude that 0.2% brimonidine produces a decrease in IOP in dogs, a statistically significant miosis, and a reduced heart rate (12-22%). However, because of the limited drug-induced ocular hypotension, brimonidine should be combined with other drugs when used for the glaucomas in the dog.     

Effect of single- and multiple-dose 0.5% timolol maleate on intraocular pressure and pupil size in female horses

OBJECTIVE: To determine the effect of single and multiple-dose 0.5% timolol maleate on intraocular pressure (IOP) and pupil size between 8 AM and 8 PM. Animals Nine female horses with normotensive eyes. Procedure IOP, horizontal and vertical pupil size were measured on a single day, between 8 AM and 8 PM at hours 0, 0.5, 1, 2, 4, 6, 8, 10, and 12. A single dose of 0.5% timolol maleate was applied to both eyes immediately after the first measurement at 8 AM. IOP and pupil size were measured at 8 AM and 4 PM in a 5-day experiment of twice-daily application of 0.5% timolol maleate. RESULTS: A significant decrease in IOP from 24.9 +/- 4.2 mmHg prior to application of timolol maleate to 20.7 +/- 3.1 mmHg (4.2 mmHg = 17%) was observed 8 h after single-dose application. A significant decrease in horizontal pupil size (2.0 mm = 11%) was present 6 h after single-dose application. In the multiple-dose experiment, a significant decrease in IOP was present on days 4 and 5 as compared to IOP measured prior to application of timolol maleate. A significant decrease in horizontal and vertical pupil size was present throughout the 5-day study as compared to the values obtained prior to treatment. CONCLUSIONS: 0.5% timolol maleate significantly decreased IOP and pupil size in normo-tensive eyes of this group of female horses in both single and multiple twice daily applications.     

Effects of topical administration of timolol maleate on intraocular pressure and pupil size in cats

Effects of topical administration of a single dose of timolol maleate, a nonselective beta-adrenergic blocking agent, on intraocular pressure (IOP) and pupil diameter were evaluated in the normotensive eyes of 10 clinically normal cats over 12 hours. Mean (+/- SEM) normal IOP was 17.1 (+/- 1.1) mm of Hg and diurnal fluctuation was observed, with the highest IOP seen in the evening. Mean (+/- SEM) normal pupil diameter was 10.1 (+/- 0.5) mm. Topical treatment with 0.5% timolol resulted in reduction of IOP in treated and nontreated eyes. This effect was time-dependent and was first observed at 6 hours after treatment. Mean reduction of IOP was 22.3% in the treated eye and 16.3% in the nontreated eye. The treated eye had reduced pupil diameter at 30 minutes after treatment, and miosis persisted throughout the 12 hours of the study. Mean reduction of pupil diameter was 38.7%. A contralateral effect on pupil diameter was not seen in the nontreated eye. Topical administration of timolol maleate results in a reduction of IOP in treated and contralateral eyes, which supports the use of timolol for treatment of glaucoma in cats. In addition, the treated eye becomes miotic. This effect may indicate beta-adrenergic inhibition or alpha-adrenergic activation of the iris sphincter muscle. beta-Adrenergic blockade would then result in miosis.     

Effects of unilateral topical administration of 0.5% tropicamide on anterior segment morphology and intraocular pressure in normal cats and cats with primary congenital glaucoma

Objective To determine the effects of topical 0.5% tropicamide on anterior segment morphology (ASM) and intraocular pressure (IOP) in normal and glaucomatous cats. Animals used Normal cats and cats with inherited primary congenital glaucoma (PCG). Procedures Control IOP curves were performed in untreated normal and PCG cats. In the first experiment, tropicamide was applied OD in eight normal and nine PCG cats. IOP and pupillary diameter (PD) were measured at 0, 30, and 60 min, then hourly until 8 h post‐treatment. In a second experiment, six normal and seven PCG cats received tropicamide OD. High‐resolution ultrasound images were obtained at 0, 1, 5, and 10 h post‐treatment to measure ASM changes. IOP and PD were measured OD at 0, 1, 2, 3, 5, 7, and 9 h. Results In untreated normal cats IOP OU decreased throughout the day. In PCG cats IOP OU had wide fluctuations over time. In normal cats IOP response varied in the treated eye but did not change significantly in untreated eyes. IOP significantly increased from baseline in both eyes of all treated PCG cats. Increases in IOP were associated with some ASM changes. Cats with PCG had a significantly smaller angle recess areas, diminished ciliary clefts and decreased iris‐lens contact. ASM changes were not strongly correlated with IOP in all cats. Conclusions The ASM of PCG cats is markedly different from normal cats, and clinically significant increases in IOP OU occur in cats with PCG after tropicamide treatment. The mechanism for this increase remains unclear.     

Effect of Coherin™ on intraocular pressure,pupil size and heart rate in the glaucomatous Beagle: a pilot study

Objective To evaluate effects of Coherin? on intraocular pressure (IOP), pupil size (PS), and heart rate (HR) in glaucomatous Beagles in single‐dose studies in a pilot study. Materials and methods Intraocular pressure, PS, and HR were measured in eight glaucomatous Beagles. One randomly chosen eye received single 50 μL doses of differing concentrations of Coherin? (treated eye) or vehicle (placebo‐treated eye), and the fellow eye served as the untreated control. After the first measurements, a single dose of either Coherin? or sterile water vehicle was instilled in the drug and placebo eyes, respectively. Results The mean ± SEM diurnal changes in IOP after 0.005%, 0.01%, 0.2%, 0.284%, 1%, 2%, and 4% topical Coherin? once daily were 7.6 ± 3.2 mmHg, 15.5 ± 5.3 mmHg, 11.2 ± 4.4 mmHg, 11.8 ± 4.4 mmHg, 19.1 ± 3.8 mmHg, 5.0 ± 1.8 mmHg, and 8.8 ± 2.8 mmHg, respectively. The declines in IOP were significantly different (P < 0.05) from the untreated control eyes with the 0.2% and 0.284% Coherin?‐treated eyes and suggestive for 1% Coherin? concentrations. No signs of irritation, significant PS, and HR changes were detected in the Coherin?‐treated eyes. Conclusion Of seven different concentrations, 2% and 0.248% Coherin? produced significant declines in IOP in the glaucomatous beagle in single‐dose studies when compared to both untreated control and placebo‐treated eyes. One percent Coherin? solution produced significant IOP decreases compared with the placebo‐treated eye but not the untreated control eyes. No local ocular irritation, PS and HR changes were observed in Coherin?‐treated eyes. This pilot study suggests that topical Coherin? has potential as an ocular hypotensive agent.     

Effects of 0.005% latanoprost solution on intraocular pressure in healthy dogs and cats

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.     

Intraocular pressure measurements obtained as part of a comprehensive geriatric health examination from cats seven years of age or older.

OBJECTIVE: To determine intraocular pressure (IOP) in cats > or = 7 years of age undergoing a routine comprehensive geriatric health examination. DESIGN: Prospective study. ANIMALS: 538 cats (1,068 eyes). PROCEDURE: IOP was measured by applanation tonometry following instillation of 0.5% proparacaine. RESULTS: Mean +/- SD IOP for all eyes was 12.3 +/- 4.0 mm Hg (range, 4 to 31 mm Hg). Mean age was 12.3 +/- 2.9 years. Intraocular pressure did not vary significantly cross-sectionally with age. However, in 78 cats, IOP was measured more than once, and follow-up measurements were significantly less than initial measurements (mean time between measurements, 9.4 +/- 3.0 months). The most useful tonometric criteria for identifying ocular abnormalities on the basis of IOP was an IOP > or = 25 mm Hg (mean + 3 SD) or a difference in IOP between eyes > or = 12 mm Hg. Eight cats met these criteria, and 5 of these cats had ophthalmic abnormalities. Low IOP was a nonspecific indicator of the presence of ocular abnormalities, as 111 cats had an IOP < or = 8 mm Hg, but only 2 had uveitis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that IOP measurements can be a useful addition to a comprehensive geriatric health examination in cats > or = 7 years of age, especially when combined with an ophthalmic examination. Cats without ocular abnormalities that have lOP > or = 25 mm Hg or a > or = 12 mm Hg difference in IOP between eyes should have tonometry repeated or be referred to an ophthalmologist for further evaluation before beginning antiglaucoma treatment.     

Effects of topical administration of 1% brinzolamide on normal cat eyes

Objective To evaluate the effect of short‐term daily topical administration of 1% brinzolamide on the intraocular pressure (IOP) of healthy domestic cats with normotensive eyes and to assess the potential for negative side effects of drug administration. Animals Twelve privately owned adult domestic cats without physical or ocular abnormalities. Procedure Normal variation in IOP was determined on day 1. Cats were then treated on days 2–8 with a topical placebo (artificial tear solution) OU q 12 h. On days 9–15 the cats were treated q 12 h with 1% brinzolamide in one randomly selected eye and the placebo in the contralateral eye. All medications (drug and placebo) were administered twice daily at 7 a.m. and 7 p.m. On days 16–22 the cats received no topical medications. IOP, horizontal pupil size in mm and assessment of conjunctival hyperemia were noted OU on days 1, 8, 15 and 22 at 5 time points (9 a.m., 11 a.m., 1 p.m., 3 p.m. and 5 p.m.). Mixed linear regression models were used to compare the IOP of each eye at all time periods for each cat, controlling for age and weight. Results Mean IOP was not significantly altered in any eye at any time point during the treatment period compared with pretreatment, baseline, or follow‐up evaluations. Conjunctival hyperemia and miosis were not detected in either eye at any time point. Conclusions and clinical relevance Short‐term q 12 h administration of 1% brinzolamide did not significantly reduce IOP in this small sample population of normotensive cats under these study conditions. No clinically relevant side effects were noted with brinzolamide administration.     

Cullen frontal sinus valved glaucoma shunt: preliminary findings in dogs with primary glaucoma

PURPOSE: To evaluate the efficacy of a novel, professionally manufactured, frontal sinus valved glaucoma shunt in maintaining normal intraocular pressure (IOP) and vision in dogs with primary glaucoma. METHODS: Three eyes of three dogs diagnosed with primary glaucoma were included in this prospective clinical study. A Cullen frontal sinus valved glaucoma shunt was implanted into each glaucomatous globe. Dogs were treated postoperatively with topical neomycin/polymyxin B/0.1% dexamethasone and 0.03% flurbiprofen every 6 h tapered over 8-12 weeks, and meloxicam at 0.1 mg/kg orally every 24 h for 7-10 days. IOP, intracameral shunt position and apparent patency, and vision were assessed twice daily for up to 4 (n= 3 eyes) and 10 (n= 2 eyes) days postoperatively, and then at re-examination periods of up to 36 weeks (n= 1 eye). Postoperative complications were recorded and documented photographically. RESULTS: Normal IOP was maintained in all shunted globes (range 10-29 mmHg; mean = 16.7 mmHg at 24 h; IOP = 23 mmHg at 36 weeks) postoperatively for 2 days (3/3 eyes), 8 weeks (2/2 eyes), and 36 weeks (1/1 eye) without additional antiglaucoma therapies. Photopic vision and shunt position and patency were maintained in all shunted globes for all follow-up periods. Postoperative complications included mild aqueous flare and fibrin (n= 3 eyes for 3-10 days postoperatively); intracameral shunt occlusion with fibrin (n= 1 eye at days 2 and 4); partial anterior chamber tube extrusion (n= 1 eye at day 4), and focal corneal edema (n= 1 eye at 18 weeks). Tissue plasminogen activator injected intracamerally through the silicone tube near the frontal sinus effectively resolved the fibrinous shunt occlusion. CONCLUSIONS: The Cullen frontal sinus valved glaucoma shunt shows promise for the management of canine primary glaucoma.     

Effects of the topically applied calcium-channel blocker flunarizine on intraocular pressure in clinically normal dogs

OBJECTIVE: To determine effects of the topically applied calcium-channel blocker flunarizine on intraocular pressure (IOP) in clinically normal dogs. ANIMALS: 20 dogs. PROCEDURES: Baseline diurnal IOPs were determined by use of a rebound tonometer on 2 consecutive days. Subsequently, 1 randomly chosen eye of each dog was treated topically twice daily for 5 days with 0.5% flunarizine. During this treatment period, diurnal IOPs were measured. In addition, pupillary diameter and mean arterial blood pressure (MAP) were evaluated. Serum flunarizine concentrations were measured on treatment day 5. Intraday fluctuation of IOP was analyzed by use of an ANOVA for repeated measures and a trend test. Changes in IOP from baseline values were assessed and compared with IOPs for the days of treatment. Values were also compared between treated and untreated eyes. RESULTS: A significant intraday fluctuation in baseline IOP was detected, which was highest in the morning (mean +/- SE, 15.8 +/- 0.63 mm Hg) and lowest at night (12.9 +/- 0.61 mm Hg). After 2 days of treatment, there was a significant decrease in IOP from baseline values in treated (0.93 +/- 0.35 mm Hg) and untreated (0.95 +/- 0.34 mm Hg) eyes. There was no significant treatment effect on pupillary diameter or MAP. Flunarizine was detected in serum samples of all dogs (mean +/- SD, 3.89 +/- 6.36 microg/L). CONCLUSIONS AND CLINICAL RELEVANCE: Topically applied flunarizine decreased IOP in dogs after 2 days of twice-daily application. This calcium-channel blocker could be effective in the treatment of dogs with glaucoma.     

Changes in intraocular pressure associated with topical dorzolamide and oral methazolamide in glaucomatous dogs

Objective To compare the reduction in intraocular pressure (IOP) by topical 2% dorzolamide to oral methazolamide (5 mg/kg) in dogs, and determine if the combination of both drugs would reduce IOP more than either drug administered alone. Animals studied Thirteen glaucomatous beagles. Procedures Measurements, including applanation tonometry, pupil size and heart rate, were obtained at 8 am, 12 noon, and 5 pm on days 1, 3 and 5. The 5‐day drug studies included placebo (0.5% methylcellulose); 2% dorzolamide administered in one eye twice daily (8 am and 5 pm), and repeated again in one eye three times (8 am, 12 noon and 5 pm) daily; methazolamide (5 mg/kg per os administered at 8 am and 5 pm); 2% dorzolamide instilled twice daily (5 days) combined with oral methazolamide on the last 3 days, and methazolamide (5 days) combined with 2% dorzolamide on the last 3 days and instilled twice daily. Statistical comparisons between drug groups included control (nondrug) eye and treated (placebo/drug) eyes for days 1, day 3 and 5. Results Topical 2% dorzolamide, administered twice and three times daily, significantly decreased IOP (mean ± SEM) in glaucomatous dogs on the first day (twice daily 7.6 ± 2.4 mmHg, and three times daily 16.4 ± 3.6 mmHg) that was even greater by day 5 (twice daily 10.4 ± 2.0 mmHg, and three times daily 13.9 ± 2.7). Oral methazolamide also significantly lowered IOP in both eyes. Oral methazolamide (administered from day 1 through to day 5) combined with 2% topical dorzolamide (instilled in the drug eye for day 3 through to day 5) also significantly lowered IOP of both eyes for all days, and for day 5 the mean ± SEM IOP was decreased by 7.9 ± 1.7 mmHg (methazolamide plus dorzolamide) and 7.5 ± 2.6 mmHg (methazolamide only). Topical dorzolamide (instilled in the drug eye for day 1 through to day 5) combined with oral methazolamide (administered from day 3 through to day 5) significantly lowered IOP in the drug eye on day 1 (5 pm: 9.6 ± 1.9 mmHg), for day 3 (11 am and 5 pm) and for all of day 5 for both eyes (5 pm: control eye 9.5 ± 1.8 mmHg; drug eye 9.2 ± 1.9 mmHg). Topical dorzolamide (2%) instilled three times daily produces similar IOP declines compared to the combination of oral methazolamide and 2% dorzolamide administered twice daily. Conclusions Dorzolamide (2%) instilled twice or three times daily causes significant decreases in IOP in glaucomatous dogs. Twice daily instillations caused progressive declines in IOP from day 1 to day 5. Dorzolamide (2%) combined with oral methazolamide (5 mg/kg per os twice daily) produces similar but not additional declines in IOP.     

Effect of different dose schedules of latanoprost on intraocular pressure and pupil size in the glaucomatous Beagle

Objective To evaluate the changes in intraocular pressure and pupil size in glaucomatous dogs after instillation of 0.005% latanoprost (Xalatan, Pharmacia and Upjohn, Kalamazoo, MI, USA) once in the morning, or once in the evening, or twice daily in five‐day multiple‐dose studies. Animals studied Eight Beagles with the moderate stage of inherited primary open‐angle glaucoma. Procedures Applanation tonometry (IOP) and pupil size (PS) measurements were obtained at 8 am, 10 am, 12 noon, 2 pm, and 4 pm in eight glaucoma dogs. Methylcellulose (0.5% as placebo) was instilled in the control eye, and 0.005% latanoprost was instilled in the opposite drug eye. Control and drug eyes were selected using a random table. For these three studies, 0.5% methylcellulose and 0.005% latanoprost were instilled the second through the fifth days with instillations in the morning (8.30 am), or evening (8 pm), or twice daily (8.30 am and 8 pm). Statistical comparisons between drug groups included control, placebo, and treated (0.005% latanoprost) eyes for three multiple‐dose studies. Results In the 8‐am latanoprost study, the mean ± SEM diurnal declines in IOP for the placebo and drug eyes for the first day were 6.5 ± 3.6 mmHg and 8.4 ± 4.0 mmHg, respectively. The mean ± SEM diurnal changes in IOP after 0.005% latanoprost at 8 am once daily for the next four days were 23.3 ± 5.0 mmHg, 25.4 ± 2.1 mmHg, 25.7 ± 1.7 mmHg, and 26.1 ± 1.7 mmHg, respectively, and were significantly different from the control eye. A significant miosis also occurred starting 2 h postdrug instillation, and the resultant mean ± SD pupil size was 1.0 ± 0.1 mm. In the first day of the second latanoprost study, the mean ± SEM diurnal changes in the placebo and drug eye IOPs were 11.6 ± 3.8 mmHg, and 12.0 ± 4.4 mmHg, respectively. For the following four days with latanoprost instilled at 8 pm, the mean ± SEM diurnal changes in IOP in the drug eyes were 24.9 ± 2.1 mmHg, 22.4 ± 1.8 mmHg, 21.6 ± 1.9 mmHg, and 26.6 ± 2.2 mmHg, respectively. Compared to the fellow placebo eyes, the diurnal changes in IOP were significantly different. Significant changes in pupil size were similar to the IOP changes, with miosis throughout the day and return to baseline pupil size the following morning before drug instillation. In the last study, the mean ± SEM diurnal changes in IOP for the placebo and drug eyes for the first day were 6.6 ± 2.1 mmHg and 9.4 ± 2.8 mmHg, respectively. For the four subsequent days with latanoprost instilled twice daily, the mean ± SEM diurnal IOP changes were 19.6 ± 1.5 mmHg, 19.1 ± 1.4 mmHg, 19.9 ± 1.7 mmHg, and 20.3 ± 0.7 mmHg, respectively, and were significantly different from the placebo eyes. The mean changes in PS were 3.1 ± 0.7 mm. Conclusion 0.005% latanoprost instilled once daily (am or pm) as well as twice daily produces significant decreases in IOP and PS in the glaucomatous Beagle. The evening instillation of 0.005% latanoprost produced less daily fluctuations in IOP than when the drug was instilled in the morning. 0.005% latanoprost instilled twice daily produced the greatest decline in IOP with the least daily fluctuations, but longer duration miosis.     

Evaluation of two applanation tonometers in cats.

Comparisons of the MacKay-Marg and Tono-Pen applanation tonometers in open and closed in vitro systems were made for the eyes of cats. Both instruments significantly underestimated intraocular pressure (IOP) vs direct manometry (P less than 0.001), but in readily predictable manner, with high coefficients of determination (r2 = 0.99). For tonometer 1 (MacKay-Marg), calculated actual IOP = 1.36 x (MacKay-Marg measurement) - 1.67 mm of Hg; and for tonometer 2 (Tono-Pen), calculated actual IOP = 1.37 x (Tono-Pen measurement) + 0.8 mm of HG, using measurements from 11 enucleated eyes. In vivo comparisons were initially made in 81 clinically normal eyes (n = 41 cats) by applying the Tono-Pen first followed by the MacKay-Marg. Compared with the MacKay-Marg, the Tono-Pen significantly (P less than 0.001) underestimated IOP in these cats. When the order of tonometer applanation was subsequently reversed in 73 clinically normal eyes (n = 37 cats) the Tono-Pen again significantly (P less than 0.001) underestimated IOP, compared with the MacKay-Marg. Alterations in tonometer order did not result in significant differences in measured IOP for the MacKay-Marg when compared with itself, but Tono-Pen measurements were significantly (P less than 0.05) less when its use followed, rather than preceded, that of the MacKay-Marg. Mean (+/- SD) IOP in clinically normal cats when each tonometer was used first was 22.6 +/- 4.0 mm of Hg (range, 14 to 32 mm of Hg) for the MacKay-Marg and 19.7 +/- 5.6 mm of Hg (9 to 31 mm of Hg) for the Tono-Pen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of topical 1% atropine sulfate on intraocular pressure in normal horses

OBJECTIVE: To determine the effect of topical 1% ophthalmic atropine sulfate on intraocular pressure (IOP) in ocular normotensive horses. Animals Studied Eleven clinically healthy horses. Procedures IOP was measured bilaterally twice daily, at 8 AM and 4 PM, for 5 days. No medication was applied for the first 2 days of the study. Thereafter, one eye of each horse was treated with 0.1 mL of topical 1% atropine sulfate ointment twice daily (7 AM and 7 PM) for 3 days. The contralateral eye served as a control. In eight of the horses, an additional IOP reading was taken 3 days following cessation of the atropine treatment. RESULTS: There was no significant difference in the IOP of control vs. treatment eyes in the pretreatment period, days 1 and 2 (P = 0.97 and 0.55, respectively). During the treatment period, treated eyes of 10 of the horses had significantly lower IOP than control eyes (P = 0.03). The mean IOP reduction in treated eyes, relative to untreated eyes, was 11.2%. One horse had a significant rise in IOP in the treated eye compared to the remaining study animals. The IOP of control eyes did not vary significantly over the observation period (P = 0.27). There was no significant variation in IOP between the 8 AM and 4 PM measurement (P = 0.9). CONCLUSIONS: Topical 1% atropine sulfate causes a small, but significant decline in IOP in most ocular normotensive horses. Because topical atropine may elevate IOP in some horses, it should be used with caution in the treatment of glaucoma in this species.