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Abstract

Objective—To determine whether an applanation tonometer and rebound tonometer can be used to detect similar intraocular pressure (IOP) measurements in eyes of dogs undergoing phacoemulsification.

Animals—24 dogs (40 eyes) undergoing elective phacoemulsification.

Procedures—IOP measurements were obtained from each eye by use of both the rebound tonometer and applanation tonometer. Central corneal thickness was measured by use of an ultrasonic pachymeter 3 hours before surgery and 2 and 24 hours after surgery. Statistical analysis was performed by use of paired t tests.

Results—Mean ± SD IOP 3 hours before surgery, 2 hours after surgery, and 24 hours after surgery was 11.9 ± 4.7 mm Hg, 15.5 ± 11.7 mm Hg, and 10.9 ± 6.7 mm Hg, respectively, as measured with the rebound tonometer and 12.2 ± 5.3 mm Hg, 15.7 ± 12.5 mm Hg, and 12.4 ± 5.4 mm Hg, respectively, as measured with the applanation tonometer. Measured IOP did not differ significantly between the 2 tonometers 3 hours before surgery and 2 hours after surgery, but measured IOP differed significantly between the tonometers 24 hours after surgery.

Conclusions and Clinical Relevance—Use of a rebound tonometer underestimated IOP, relative to results for use of an applanation tonometer, by 1.65 mm Hg in eyes 24 hours after phacoemulsification. Caution should be used when IOP measurements obtained with a rebound tonometer are in the high part of the reference range, and verification of these values with an applanation tonometer would be advised.

Full access
in American Journal of Veterinary Research

Summary

Topically administered tissue plasminogen activator (tPA) was evaluated for its penetration into aqueous humor of clinically normal dogs. Two concentrations of tPA (5 mg/ml and 10 mg/ml) were evaluated in a single-dose study, and a concentration of 5 mg of tPA/ml was used for a multiple-dose study. The contralateral eye served as a nontreated control. Enzyme substrate analysis of aqueous humor was used to determine tPA activity. The activity of tPA in aqueous humor was significantly (P ≤ 0.05) greater in treated eyes of all dogs, compared with that in control eyes. Significant differences in activity of tPA were not detected at different doses in treated eyes.

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate effects of intracameral injection of preservative-free 1% and 2% lidocaine hydrochloride solution on the anterior segment of the eyes in dogs.

Animals—16 adult healthy dogs (8 male and 8 female) judged to be free of ocular disease.

Procedure—Dogs were randomly assigned to 2 groups of 8 dogs each. Group 1 dogs received an intracameral injection of 0.10 mL of preservative-free 1% lidocaine solution in the designated eye, and group 2 dogs received 0.10 mL of preservative-free 2% lidocaine solution in the designated eye. After injection, intraocular pressure was measured every 12 hours for 48 hours and then every 24 hours until 168 hours after injection. Slit-lamp biomicroscopy was performed preceding intracameral injection, 8 hours after injection, and then every 24 hours until 168 hours after injection. Ultrasonic pachymetry and specular microscopy were performed preceding intracameral injection and 72 and 168 hours after injection. Corneal thickness and endothelial cell density and morphology were compared with baseline measurements.

Results—No significant differences were found in intraocular pressure, corneal thickness, endothelial cell density, and morphologic features in either group, compared with baseline. A significant difference in aqueous flare was found for treated and control eyes 8, 24, and 48 hours after injection, compared with baseline. No significant difference in aqueous flare was found between treated and control eyes within either group.

Conclusions and Clinical Relevance—No adverse ocular effects were detected after intracameral injection of preservative-free 1% or 2% lidocaine solution; thus, its use would be safe for intraocular pain management in dogs. (Am J Vet Res 2004;65:1325–1330)

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in American Journal of Veterinary Research

Summary

Contact wide-field specular microscopy was performed on eyes of 16 healthy dogs after tissue plasminogen activator at a concentration of 25 μg/100 μl (group 1, n = 8) or 50 μg/100 μl (group 2, n = 8) was injected into 1 anterior chamber of each dog. The contralateral eye served as a nontreated control. Applanation tonometry was used to measure intraocular pressure in both eyes for up to 168 hours. By use of computerized morphometric analysis and pachymetry, changes from baseline values in endothelial cell density, cell morphologic features, and corneal thickness were evaluated at postinjection hours 24, 48, and 168. Significant mean differences in intraocular pressure were not detected between treated eyes of group-1 dogs and those in group 2 at designated times, or between treated and nontreated eyes of dogs in either group. Mean corneal thickness of treated and nontreated eyes was similar in both groups through postinjection hour 168. Changes in mean percentage of endothelial cell sides were observed only in treated eyes of group-2 dogs, with the mean percentage of hexagons at postinjection hour 168 decreasing by 18%, a decrease that was significantly (P < 0.05) greater than the decrease in nontreated eyes. The mean percentage of 6-sided cells in treated eyes of group-2 dogs was significantly (P < 0.05) less than that in treated eyes of group-1 dogs at postinjection hour 168.

Free access
in American Journal of Veterinary Research

Summary

Fibrin clots were induced in eyes of dogs by injection of autogenous citrated plasma into the anterior chamber. Twenty-four hours after clot formation, 0.01 ml of tissue plasminogen activator at a concentration of 1 μg/100 μl (group 1, n = 5) or 25 μg/100 μl (group 2, n = 5) was injected into 1 anterior chamber of each dog. The contralateral eye served as a nontreated control. Serial photographs were taken of the fibrin clots after intracameral injection of tissue plasminogen activator. Computerized morphometric analysis was then used to evaluate changes in cross-sectional surface area of the fibrin clot. Significant (P < 0.001) fibrin-clot lysis was detected in treated eyes of group-2 dogs, but was not found in treated eyes of group-1 dogs. A mean decrease of > 90% in clot surface area was detected by 120 minutes after injection in treated eyes of group-2 dogs.

Free access
in American Journal of Veterinary Research

Objective

To evaluate clinical signs of ocular blastomycosis in dogs, to determine response of blastomycosis-infected eyes to treatment with systemically administered amphotericin B and ketoconazole, and to identify prognostic indicators of successful antifungal treatment.

Design

Retrospective study.

Animals

73 dogs.

Procedure

Medical records were reviewed for all dogs with confirmed blastomycosis and ocular disease seen at our hospital between 1985 and 1993.

Results

6 eyes had anterior segment disease, 24 had posterior segment disease, and 78 had endophthalmitis. 40 eyes were treated with a combination of amphotericin B and ketoconazole, and 16 of the 40 responded favorably. However, 16 of the 24 eyes that were not severely affected responded favorably, but none of the 16 eyes that were severely affected did.

Clinical Implications

Dogs with blastomycosis had posterior segment disease, without complete retinal separation, had a good prognosis for retaining vision. Results of histologic examination suggested that secondary glaucoma was a manifestation of endophthalmitis and was indicative of a grave prognosis for response to antifungal and antiglaucoma treatment. (J Am Vet Med Assoc 1996;209:1271–1274)

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

Contact in vivo wide-field specular microscopy was performed on right eyes of 20 healthy dogs after sodium hyaluronate (1%, n = 5), sodium chondroitin sulfate (4%) and sodium hyaluronate (3%, n = 5), hydroxypropyl methylcellulose (2%, n = 5), or balanced salt solution (control, n = 5) was injected into the anterior chamber. Using computerized morphometric analysis and pachymetry, changes in endothelial cell density, cell morphologic features, and corneal thickness from baseline values were evaluated at postinjection hour (pih) 72 and pih 168. Changes were not seen in endothelial cell density or cell morphologic features in any treated eye. The mean corneal thickness of all treated eyes at pih 72 increased 6%, significantly greater than that of the nontreated eyes (P = 0.03). Mean corneal thickness of treated and nontreated eyes was similar at baseline and pih 168 in all treatment groups.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the electrodiagnostic and histologic response of short-term increases of intraocular pressure (IOP) on transient pattern electroretinograms (PERG) and flash electroretinograms (FERG) in the eyes of dogs.

Animals—8 healthy mixed-breed dogs.

Procedure—Transient PERG and FERG waveforms were recorded from dogs (while anesthetized) as IOP was increased from baseline (7 to 19 mm Hg) to 90 mm Hg. One hundred mean PERG responses and a single FERG response were recorded at each step during 3 recording sessions. Globes of each dog were enucleated after euthanasia on posttreatment day 7 and evaluated by a pathologist.

Results—Increases in spatial frequency resulted in decreased amplitudes of N2 (second negative PERG peak). Increases in IOP resulted in decreases in all 3 PERG waveforms and the FERG waveform. All values began to return to baseline after short-term increases in IOP on day 0, and waveforms were not significantly different on posttreatment days 3 and 7.

Conclusions—Data suggest that short-term increases in IOP affect PERG and FERG waveforms, and PERG waveforms are more sensitive to increases in IOP. Differences were not detected between treated and control eyes on histologic examination. Further studies are necessary to determine at what IOP permanent damage to ganglion and photoreceptor cells will develop and whether PERG is a reliable clinical diagnostic technique for use in dogs to reveal retinal damage that is secondary to increased IOP prior to changes in waveforms generated by FERG in dogs. (Am J Vet Res 2000;61:1087–1091)

Full access
in American Journal of Veterinary Research