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K N Gelatt

Publications and source records attributed to K N Gelatt.

At least 19 recordsLinked to original sources
PubMed2003

Progressive changes in ophthalmic blood velocities in Beagles with primary open angle glaucoma.

OBJECTIVE: To measure changes in the ocular and orbital blood flow velocities by color Doppler imaging (CDI) in beagles with primary open angle glaucoma as the disease progressed from early to advanced stages. METHODS: CDI measurements were performed periodically on 13 glaucomatous Beagles during the nontreated mild, moderate and advanced stages of POAG over the course of 4 years. CDI was performed with the dogs lightly anesthetized (butorphanol 0.1 mg/kg IV, acepromazine maleate 0.02 mg/kg IV, and atropine sulfate 0.05 mg/kg) while the CD transducer was placed directly on the cornea anesthetized with 0.5% tetracaine hydrochloride. Intraocular pressure (IOP) by pneumatonography or TonoPen XL, heart rate and mean arterial blood pressure were measured at the beginning, middle and end of each study. The ophthalmic vessels examined included: external ophthalmic arteries and veins, long and short posterior ciliary arteries, anterior ciliary arteries and veins, primary retinal arteries, and vortex veins. Recordings of each vessel included peak systolic velocity (PSV), end diastolic velocity (EDV) and time averaged velocity (TAV), and when possible the resistive index (RI) and pulsatility index (PI) were computed. RESULTS: CDI abnormalities were present before intraocular pressure exceeded the normal range. As the animals aged, and the glaucoma progressed with higher levels of IOP, significant changes occurred in nearly all vessels, and generally included a major increase in RI (P < 0.001) and an increase in the PI (P < 0.001). Mean arterial blood pressure (105 +/- 18 mmHg) and heart rate (118 +/- 33/min) remained reasonably constant. The IOP gradually increased as the disease progressed (early and normotensive: 19.4 +/- 3.9 mmHg; moderate: 29.7 +/- 2 mmHg; and advanced: 44.5 +/- 6 mmHg). The ocular veins seemed most influenced early on in the disease. Late in the disease, ocular venous blood flow could not be consistently demonstrated. An increase in the PI of ocular veins occurred in the moderately and severely affected glaucomatous Beagles. As the IOP increased, there were trends of increasing resistive index and pulsatility index in most arteries, and periods of marked decreased velocities of the vortex and external ophthalmic veins in severe cases. CONCLUSION: CDI measurements in Beagles with primary open angle glaucoma during the course of 4 years indicate easily measurable and repeatable progressive blood flow abnormalities before the elevation of IOP and, thereafter, with gradually increased levels of IOP.

Animals↗
PubMed2003

Localization of smooth muscle actin in the iridocorneal angle of normal and spontaneous glaucomatous beagle dogs.

PURPOSE: To date, our knowledge of the canine trabecular meshwork (TM) with regard to contractility is incomplete. It is important to understand the potential contractile capability within the TM and possible changes associated with spontaneous hypertensive glaucoma. To that end we have examined the presence of actin, including smooth muscle (SM) actin, in the normal and glaucomatous canine iridocorneal angle (ICA) morphologically and immunohistochemically. METHODS: Sections from the ICAs of 12 Beagles with inherited glaucoma (3 months to 6 years old) and age-matched normal Beagles were treated with target retrieval, protein and power blocked and sequentially incubated with the primary antibody (rat anticanine SM actin) and the secondary antibody (rabbit antirat immunoglobulin), followed by peroxidase labeled streptavidin and incubation with substrate-chromogen solution (AEC). Smooth muscle fibers that lined an artery within canine heart tissue were used as positive controls. Separate specimens were prepared for ultrastructual observation. RESULTS: Ultrastructurally, cells within the inner, posterior region of the corneoscleral TM and outer, posterior region of the uveal TM contained many microfilaments, 6 nm in diameter (i.e. actin). Immunohistochemistry demonstrated that cells within these regions possessed SM actin, having been greatest posteriorly, but extended anteriorly to a lesser extent. In the preglaucomatous affected dog the localization pattern for SM actin was identical to that seen in the normal dogs. With the progression of the disease the pattern disappeared. CONCLUSIONS: The interior presence of myofibroblastic cells within the canine ICA suggests that these cells and the smooth muscle cells of the ciliary body along the same plane of orientation function to facilitate the removal of aqueous humor and are likely to be influenced by vascular mediators. The contractile apparatus for the ICA in the dog with inherited glaucoma appeared identical to that of the normal dog prior to expression of the disease, but weakened as the disease progressed.

Actins↗
PubMed2003

Changes in antibiotic resistance in equine bacterial ulcerative keratitis (1991-2000): 65 horses.

OBJECTIVE: To document changes in antibiotic resistance of organisms in cases of equine bacterial ulcerative keratitis over a 10-year time period. DESIGN: A retrospective study. PARTICIPANTS: Medical records of equine patients with bacterial ulcerative keratitis seen at the University of Florida's VMTH for the years 1991-2000 were reviewed. MATERIALS AND METHODS: All cases of equine bacterial ulcerative keratitis for the above mentioned years were examined. Bacterial isolates were identified and subjected to Kirby-Bauer disc diffusion method sensitivity tests. Antibiotics used in the sensitivity tests included bacitracin, ampicillin, gentamicin, chloramphenicol, polymyxin B, trimethoprim-sulfa, neomycin, kanamycin, carbenicillin, tobramycin and enrofloxacin. RESULTS: A total of 65 bacterial isolates were subjected to sensitivity testing. Of these isolates, Pseudomonas aeruginosa accounted for 14 of the bacterial isolates (22%), Streptococcus equi subspecies zooepidemicus accounted for 13 of the bacterial isolates (20%), and Staphylococcus aureus accounted for four of the isolates (6%). A statistically significant increase in resistance of Pseudomonas aeruginosa isolates to the antibiotics gentamicin and tobramycin was found between the isolates from 1992 to 1998 and those from 1999 to 2000. An increase in resistance of Streptococcus equi subspecies zooepidemicus to gentamicin was found between the isolates from 1993 to 1997 and those from 1998 to 2000. CONCLUSIONS: Streptococcus equi subspecies zooepidemicus and Pseudomonas aeruginosa were the most common organisms isolated from cases of equine bacterial keratitis referred to the University of Florida's VMTH for the years 1991-2000. There appears to be an increase in resistance of Streptococcus equi subspecies zooepidemicus to gentamicin over the past 10 years. In addition, there is a significant increase in resistance of Pseudomonas aeruginosa to both gentamicin and tobramycin over the same time period.

Animals↗
PubMed2003

Effect of topical tropicamide on tear production as measured by Schirmer's tear test in normal dogs and cats.

OBJECTIVE: To evaluate the effect of a single dose of topical 1% tropicamide on tear production as measured by the Schirmer tear test (STT) in the normal dog and cat. MATERIAL AND METHODS: Twenty-eight dogs and 32 cats received 50 micro l : l of 1% tropicamide in one eye and the opposite eye served as the control. STTs were performed immediately before instillation of tropicamide and then at 1, 4, 8 and 24 h post drug instillation. STT results were compared between the control and treated eyes at the different times. RESULTS: Aqueous tear production in dogs, measured by STT, was not significantly reduced. The mean +/- SEM STTs for the baseline time for control and tropicamide-treated eyes were 19.9 +/- 0.8 and 20.3 +/- 0.8 mm wetting/min, respectively. For the control eyes, the subsequent mean +/- SEM STT levels were 20.3 +/- 0.9 (1 h), 21.1 +/- 0.8 (4 h), 20.1 +/- 0.9 (8 h), and 18.7 +/- 0.7 (24 h). For the tropicamide-treated eyes, the subsequent mean +/- SEM STT levels were 19.4 +/- 0.9 (1 h), 19.3 +/- 0.9 (4 h), 20.0 +/- 0.9 (8 h), and 18.4 +/- 0.8 (24 h). Aqueous tear production of both eyes was significantly reduced in cats at 1 h but returned to baseline by 4 h post tropicamide instillation. The mean +/- SEM STT levels for the baseline time in cats for control and tropicamide-treated eyes were 14.9 +/- 0.8 and 14.7 +/- 0.8 mm wetting/min, respectively. Subsequent mean +/- SEM STT levels for the control eyes were 6.4 +/- 1.1 (1 h), 11.9 +/- 1.0 (4 h), 13.9 +/- 0.8 (8 h), and 16.4 +/- 1.0 (24 h). For the tropicamide-treated eyes, the subsequent mean +/- SEM STT levels were 5.3 +/- 0.8 (1 h), 10.2 +/- 0.8 (4 h), 14.7 +/- 1.0 (8 h), and 16.6 +/- 1.0 (24 h). CONCLUSION: Single dose 1% tropicamide does not significantly lower tear production rates, as measured by the STT, in normal dogs. However, in normal cats single doses of 1% tropicamide in one eye cause significant reductions in tear production of both eyes at 1 h that recovered to baseline levels by 4 h.

Administration, Topical↗
PubMed2001

The relationship of cataract maturity to intraocular pressure in dogs.

OBJECTIVE: To determine the distribution of intraocular pressure, as measured by applanation tonometry, in dogs with cataracts, and compare these tonometric results to the different stages of cataract formation (incipient, immature, mature, and hypermature). Animals studied Retrospection study of canine clinical patients (86 dogs). PROCEDURES: All records of dogs presented from 1991 to 1996 to the university veterinary medical teaching hospital for diagnosis of cataracts and evaluation for cataract surgery were reviewed. The tonometric measurements from the initial ophthalmic examination were selected in cataractous and nonglaucomatous eyes either receiving no topical or no systemic medications. The stage of cataracts was based on the degree of opacification, tapetal reflection, clinical vision, and visibility of the ocular fundus by indirect ophthalmoscopy. The distribution of tonometric results were grouped by the cataract maturity, and compared by anova and Tukey's general linear tests. RESULTS: Intraocular pressure with incipient cataracts ranged from 9 to 17 mmHg (mean 12.7 +/- 1.2 mmHg). Intraocular pressure with immature cataracts ranged from 3 to 27 mmHg (mean 13.6 +/- 0.6 mmHg). For the mature cataracts, IOP ranged from 5 to 22 mmHg (mean 11.9 +/- 0.7 mmHg). For the hypermature cataract group, IOP ranged from 4 to 23 mmHg (mean 10.8 +/- 0.6 mmHg). Comparison of the tonometric results among the different stages of cataract formation indicated a significant difference (P = 0.0086) between only the immature and hypermature groups. CONCLUSIONS: Intraocular pressure in lens-induced uveitis (LIU) is lowered but the relationship to the stage of cataract maturity is less clear. Significant tonometric differences were present between the immature and hypermature cataract groups, but these differences are too small to be clinically useful. Decreased intraocular pressure of dogs with all stages of cataract formation suggests concurrent LIU during all stages of cataract formation, especially with the mature and hypermature stages. The average tonometric measurements in dogs with these cataracts were about two standard deviations below the mean IOP reported in normal dogs.

Animals↗
PubMed2001

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.

Animals↗
PubMed2001

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.

Administration, Oral↗
PubMed2001

Enrofloxacin-associated retinal degeneration in cats.

OBJECTIVE: The objective of this study was to evaluate the possible relationship between the administration of parenteral and/or oral [corrected] enrofloxacin and the onset of acute retinal degeneration in cats. The animals studied included 17 cats that received systemic enrofloxacin and developed retinal degeneration soon thereafter. PROCEDURES: In this retrospective clinical study, cats that received parenteral and/or oral [corrected] enrofloxacin and developed acute blindness were identified. Parameters recorded included breed, age, sex, enrofloxacin dosage (daily dose and number of days administered), medical condition for which the antibiotic had been prescribed, ophthalmic signs, examination results, and the visual outcome. Fundus photographs were obtained in seven cats, and electroretinography was performed in five cats. Histopathology was performed on two eyes from one cat (case 1) that received enrofloxacin 5 months previously and developed retinal degeneration. RESULTS: All cats were the domestic shorthair breed; seven were females (one neutered) and ten were males (seven castrated). Ages ranged from 3 to 16 years old (mean +/- SD; 8.8 +/- 4.6 years). The medical disorders for which enrofloxacin was administered ranged from lymphoma and pancreatitis to otitis and dermatitis, and eight cats had urinary diseases. The daily and total dosage of enrofloxacin and number of days of administration were also highly variable. Presenting clinical signs were most often mydriasis and acute blindness. All cats had diffuse retinal degeneration as evidenced by increased tapetal reflectivity and retinal vascular attenuation. Absence of recordable electroretinographic responses suggested diffuse and extensive outer retinal disease. Vision returned in a few cats, but the retinal degeneration persisted or even progressed. Histopathology of two eyes revealed primarily outer retinal degeneration, with diffuse loss of the outer nuclear and photoreceptor layers, and hypertrophy and proliferation of the retinal pigment epithelium. CONCLUSION: Parenteral and/or oral [corrected] enrofloxacin is potentially retinotoxic in some cats, and may result in acute and diffuse retinal degeneration. Blindness often results, but some cats may regain vision. Practitioners should adhere closely to the manufacturer's current enrofloxacin dosage recommendation (5 mg/kg q 24 h), and continue clinical observations for this drug toxicity in cats.

Acute Disease↗
PubMed2000

Development of glaucoma after cataract surgery in dogs: 220 cases (1987-1998).

OBJECTIVE: To examine postoperative ocular hypertension (POH) and other variables as predictors of the risk of developing glaucoma after cataract surgery in dogs. DESIGN: Retrospective study. ANIMALS: 220 dogs that had cataract surgery. PROCEDURE: Medical records of 220 dogs (346 eyes) that had extracapsular cataract removal or phacoemulsification of cataracts were reviewed. With respect to glaucoma development, 8 variables were analyzed, which included development of POH, breed, sex, age at time of surgery, eye (right vs left), phacoemulsification time, intraocular lens (IOL) placement (yes or no), and stage of cataract development. Eyes developed glaucoma within 6 or 12 months of surgery or did not have signs of glaucoma at least 6 or 12 months after cataract surgery. RESULTS: Of 346 eyes, 58 (16.8%) developed glaucoma after surgery. At 6 months, 32 of 206 (15.5%) eyes examined had glaucoma; at 12 months, 44 of 153 (28.8%) eyes examined had glaucoma. Median follow-up time was 5.8 months (range, 0.1 to 48 months). Mixed-breed dogs were at a significantly lower risk for glaucoma, compared with other breeds. Eyes with IOL placement were at a significantly lower risk for glaucoma, compared with eyes without IOL placement. Eyes with hypermature cataracts were at a significantly higher risk for glaucoma, compared with eyes with mature or immature cataracts. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple factors appear to contribute to the onset of glaucoma in dogs after cataract surgery. Complications prohibiting IOL placement during cataract surgery may lead to a high risk of glaucoma development.

Animals↗
PubMed2000

Diagnosis, treatment and outcome of orbital neoplasia in dogs: a retrospective study of 44 cases.

Forty-four dogs with confirmed orbital neoplasia were studied. Eighteen tumour types were represented and 95 per cent of the neoplasms were classified as malignant. The tumour types most commonly diagnosed were osteosarcoma, fibrosarcoma and nasal adenocarcinoma. Thirty-six per cent of the dogs had at least one clinical sign that was compatible with a diagnosis of orbital abscessation or cellulitis. Fifty-six per cent of the dogs, where follow-up information was available, were euthanased or had died within six months of diagnosis, while 19 per cent of the total were still alive after one year post-diagnosis. Cytological examination was diagnostic for orbital neoplasia in 49 per cent of the fine needle aspirates of the retrobulbar space. In contrast, 56 per cent of the non-surgical biopsies were diagnostic for orbital neoplasia. Of those dogs that had died or been euthanased within six months of diagnosis, only 22 per cent had undergone some form of therapy for orbital neoplasia. In comparison, 86 per cent of dogs surviving longer than six months post-diagnosis had undergone such therapy.

Adenocarcinoma↗
PubMed1998

The ocular hypertensive effects of topical 0.1% dexamethasone in beagles with inherited glaucoma.

Topical 0.1% dexamethasone(50 microl) instilled QID in glaucomatous Beagles increased intraocular pressure (IOP) by about 5 mm Hg within the first seven to ten days in a four week test. The elevated levels of IOP persisted until drug instillations ceased. Both drug eye and placebo eye IOP levels were increased significantly over the predrug (control) IOPs. Comparisons of the IOP changes associated with topical dexamethasone in beagles bred for glaucoma and less than seven months of age to older glaucomatous Beagles did not detect any significant differences. The magnitude of elevation in IOP in both age groups was about 4.8 mmHg. During the week after cessation of the topical dexamethasone instillations, IOPs of both the drug and placebo eyes declined toward predrug levels. Primary open angle glaucoma in the Beagle exhibits a significant and rapid elevation in IOP following unilateral or bilateral 0.1% dexamethasone instilled QID.

Administration, Topical↗
PubMed1998

Equine ulcerative keratomycosis: visual outcome and ocular survival in 39 cases (1987-1996).

The medical records of 39 horses treated for ulcerative keratomycosis over a 10 year period were reviewed. Records were evaluated to determine the medical and/or surgical treatment protocol, visual outcome, globe survival and whether the outcome was influenced by the fungal species isolated. Stromal abscesses and iris prolapses caused by fungi were not included. Twenty of the horses underwent medical treatment only, and 19 horses had combined medical and surgical treatment. Most horses had been treated with topical antibiotics (n = 32) and atropine sulphate (n = 23) prior to referral; topical antifungals had been employed less frequently (n = 14). Fungi were identified by cytology (n = 31), culture (n = 33) and/or surgical histopathology (n = 6). Aspergillus (n = 13) and Fusarium (n = 10) were the most commonly isolated fungi. Miconazole (n = 35) was the most common topical antifungal medication utilised. Median duration of treatment was 48 days (range 31-192 days). Associated bacterial infection (n = 13) was frequently encountered. Visual outcome was favourable in 36/39 (92.3%) eyes. All eyes (20/20) retained vision following medical management only, and 16/19 (84%) retained vision following combined medical and surgical therapy. All medically treated horses (20/20), and 17/19 (89%) of those treated medically and surgically retained their globes. Overall ocular survival was favourable in 37/39 (94.9 %) eyes. Aggressive therapy can result in successful results for equine ulcerative keratomycosis.

Animals↗
PubMed1997

Effects on intraocular pressure and pupil size in glaucomatous beagles after topical pilocarpine instilled with standard (pH 5) and buffer-tip (pH 7) droptainers.

Single doses (50 microliters) of 1% and 2% pilocarpine, instilled by a buffer-tip droptainer resulting in an approximate pH 7.0 solution, and 1, 2, and 4% pilocarpine, instilled by the standard droptainer, resulting a pH 5.0 solution, were evaluated in the glaucomatous Beagle model. Pupil size and intraocular pressure measurements were performed at 0, 1/4, 1/2, 3/4, 1, 2, 4, 6, and 8 hours. Signs of topical irritation (blepharospasm, conjunctival hyperemia and chemosis, and any corneal changes) were also monitored. Both solutions produced similar onset and duration of miosis and ocular hypotension, but the pH 5.0 solutions produced a brief elevation in intraocular pressure during the first hour post-drug instillation. Moderate blepharospasm, conjunctival hyperemia, and chemosis occurred with only the pilocarpine solutions with pH 5.0.

Administration, Topical↗
PubMed1997

Visual disturbance: where do I look?

Visual disturbances often signal serious ophthalmic disease. Comprehensive general medical and ophthalmic histories are most helpful. Information about the animal's vision, based on its performance in familiar and unfamiliar environments, should be obtained from the owner. As bilateral involvement and visual disturbances are often associated with systemic diseases, a complete physical examination is indicated. The ophthalmic examination consists of a series of diagnostic procedures to isolate and define the ophthalmic disorder. Several clinical tests can be performed easily in the examination room, including the light-induced pupillary reflex, the dazzle or photic reflex, the menace reflex, the obstacle course test and, if indicated, the flash electroretinogram, the visual evoked response and, recently, the pattern electroretinogram. Ophthalmic diseases that produce visual disturbances in dogs often affect the cornea, aqueous pathways, lens and ocular fundus; in cats, they usually affect the uveal tract and are associated with serious systemic diseases. Orbital diseases are not usually associated with visual disturbance unless the optic nerve is involved. Corneal diseases and cataract formation that involve the visual axis and pupillary aperture often cause visual disturbance. Inflammations of the Iris and ciliary body can produce both acute and long-term visual disturbance and even blindness. Diseases of the retina and optic nerve usually present as visual disturbances in the absence of pain.

Animals↗
PubMed1997

Visual outcome and ocular survival following iris prolapse in the horse: a review of 32 cases.

The medical records of 32 horses treated for iris prolapse (IP) during an 8 year period, at the University of Florida Veterinary Medical Teaching Hospital, were reviewed. Iris prolapse was associated with perforated corneal ulcers in 15 horses (47%), ruptured stromal abscesses in 2 horses (6%), and full thickness corneal lacerations in 15 horses (47%). Initial ophthalmic examinations revealed IP with severe iridocyclitis in all eyes and keratomalacia in 8 eyes with corneal ulcers, one with a stromal abscess and 1 with a corneal laceration. Hyphema was present in 7 eyes with corneal lacerations. Thirty horses were managed with combined medical and surgical therapy. Two horses were only treated medically with topically administered antibiotics. Of the 24 perforations surgically repaired, 21 were closed primarily and 13 were then covered with a conjunctival graft. After combined therapy and a minimum of 4 months of follow-up, vision was retained in 6 of the horses (40%) with perforating corneal disease and 5 of the horses (33%) with perforating corneal lacerations. Post operatively, of the 11 (37%) horses blind at discharge, 6 (55%) subsequently developed phthisis bulbi. Enucleations were performed in 4 cases with extensive keratomalacia and/or endophthalmitis, 2 cases with limbal rupture and total hyphema, and one case with a chronic IP. One horse was subjected to euthanasia after 3 surgical treatments failed to stabilise stromal melting. Horses presented with ulcerative keratitis of fewer than 15 days duration, or horses with corneal lacerations less than 15 mm in length, tended to have a favourable visual outcome. Keratomalacia, hyphema, corneal lacerations longer than 15 mm and lacerations extending to, along, or beyond the limbus, adversely influenced visual outcome. Iridectomy did not appear clinically to exacerbate anterior uveitis or adversely affect visual outcome. Ocular survival following combined therapy was 80% (12/15) in horses with corneal lacerations and 67% (10/15) in horses with ulcerative keratitis.

Animals↗
PubMed1997

In vitro flow characteristics of the Ahmed and self-constructed anterior chamber shunts.

OBJECTIVE: To compare in vitro opening pressures (OP) and closing pressures (CP) of the Ahmed VS-1 and VS-2 glaucoma valves with those of several self-constructed valve 'prototypes,' and to assess their ability to maintain perfusion pressures between 6 and 21 mm of Hg. SAMPLE POPULATION: Ahmed VS-1 (n = 6), 2 groups of Ahmed VS-2 (group 1: n = 12; group 2: n = 14), and self-constructed valves with linear incisions in the long axis of the tube wall (n = 6) or X-shaped incisions in the tube walls (n = 2). PROCEDURE: Valves were perfused with deionized water, lactated Ringer's solution (LRS), Dulbecco's modified Eagle's medium (DMEM), DMEM plus 50% equine serum (ES), and 100% ES. Flow rates of 2.85, 4.2, 6.0, 9.0, and 12.0 microliter/min were used for each perfusate. Valves were tested 3 times for reproducibility, and OP/CP were compared for each system. RESULTS: OP/CP of the VS-1, VS-2 (group 1), VS-2 (group 2), and linear 1.0-cm incisional valves with thick tubing consistently increased with increasing perfusion rate. Linear 0.5-cm (thick tubing) and 1.0-cm (thin tubing) incisional valves had increasing OP/CP with increasing perfusion rate in all but a few instances. Mean OP/CP decreased with increasing perfusate osmolarity for all perfusates except LRS, using the VS-1 and V-2 (group 2) valves. Mean OP/CP were consistently lower for VS-1 than VS-2 (group 1) valves at any given flow rate and for any given perfusate. Mean OP/CP were consistently lower for VS-2 (group 1) than VS-2 (group 2) valves at any given flow rate and for any given perfusate. The linear 0.5-cm incisional valves with thick and thin tubing induced the highest mean OP/CP, maximizing at > 30 mm of Hg. CONCLUSIONS: Only the VS-2 (group 2) valves consistently had mean OP/CP between 6 and 21 mm of Hg for all perfusates and at all flow rates. CLINICAL RELEVANCE: Anterior chamber shunts, although imperfect, appear to offer a physiologically sound alternative for glaucoma management.

Animals↗