Evaluation of intraocular pressure measurements obtained by use of a rebound tonometer and applanation tonometer in dogs before and after elective phacoemulsification.

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.

Outcome of retinal reattachment surgery in dogs: a retrospective study of 145 cases.

OBJECTIVE: To summarize the clinical outcomes and complications of pars plana vitrectomy with perfluoro-n-octane (PFO)-silicone oil exchange and endolaser retinopexy for treatment of retinal detachment (RD) in dogs, at one surgical center. PROCEDURE: Records of 145 dogs (168 eyes) that underwent retinal reattachment surgery (RR) between 2005 and 2009 were reviewed. All surgeries were performed by the same surgeon (SS). Data collected from the medical records included signalment, duration of time from diagnosis of RD to surgical intervention, if prior lensectomy was performed, time from surgery to restoration of vision, and postoperative complications. The data was analyzed to test the effect of breed, prior lensectomy, and time from diagnosis to surgery on visual outcome, tendency for complications, and time of complication onset. RESULTS: One hundred thirty pure-bred dogs (36 breeds) and 15 mixed-breed dogs were represented. One hundred fifty-five of 168 eyes (92%) were visual after surgery. Six of 155 eyes (3.8%) were visual before the procedure and retained vision; one hundred forty-nine of 155 eyes (96%) were nonvisual before and regained vision afterward. Thirteen of 168 eyes (8%) that were nonvisual prior to the procedure did not regain vision. The most common complications in order of occurrence included: cataract development, silicone prolapse into the anterior chamber, corneal ulceration, retinal degeneration, glaucoma, and uveitis. CONCLUSIONS: Pars plana vitrectomy with PFO-silicone oil exchange and endolaser retinopexy for treatment of RD in dogs is highly successful and associated with overall good visual outcome.

Effects of intracameral injection of preservative-free lidocaine on the anterior segment of the eyes in dogs.

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.

Alginate as a new biomaterial for the growth of porcine retinal pigment epithelium.

OBJECTIVE: Determine the effect of a 3-dimensional alginate matrix on the growth and differentiation of cells isolated from porcine retinal pigment epithelium (RPE). PROCEDURES: Porcine RPE cells were harvested from enucleated eyecups, isolated by differential gravity sedimentation and cultured in either alginate alone (Group 1) or on plastic tissue culture plates followed by alginate (Group 2). Group 1 cells were cultured in alginate to evaluate the efficacy of the matrix as a culture medium. Group 2 cells were initially cultured on plastic to induce dedifferentiation. The cells were then harvested, suspended in alginate beads, and incubated for a second culture period to determine if the induced dedifferentiation was reversible. RESULTS: The number of Group 1 cells was significantly greater (P < or = 0.01) at the end of the culture period. The amount of pigment and cell morphology of Group 1 cells at the end of the culture period was similar to that seen at initial cell isolation. The initial culture of Group 2 cells on plastic showed characteristic features of dedifferentiation marked by the loss of pigment and alterations in microscopic appearance. Secondary culture of dedifferentiated Group 2 cells in alginate beads resulted in a return to pigmentation and characteristic morphology for a majority of the cultured cells. CONCLUSIONS: Porcine RPE cells can be propagated in alginate culture with a significant increase in cell numbers while maintaining normal morphology. Under the conditions described in the present study, the dedifferentiation of porcine RPE induced by standard in vitro culture methods is reversible.

Survival of equine herpesvirus-4, feline herpesvirus-1, and feline calicivirus in multidose ophthalmic solutions.

OBJECTIVE: To determine survival over time of infectious equine herpesvirus-4, feline herpesvirus-1, and feline calicivirus in three commercially available and commonly used ophthalmic solutions (eyewash, fluorescein, and proparacaine HCl). SAMPLE POPULATION: Viruses used in this study were originally isolated from eyes of animals referred to the University of Illinois. Equine herpesvirus-4 was propagated in MDBK cells and feline herpesvirus-1 and feline calicivirus in CRFK cells. PROCEDURE: After separately inoculating a designated solution with a specific titer of an individual virus, solutions were incubated per manufacturer's recommendations, either at 4 degrees C or 25 degrees C. Virus titers within solutions were subsequently measured at 1, 8, and 24 h and 3, 5 and 7 days post inoculation using either plaque or TCID50 assays. RESULTS: Equine herpesvirus-4, feline herpesvirus-1, and feline calicivirus were present in eyewash for 7 days, 5 days, and 7 days, respectively. Eyewash did not decrease survival time of any virus when compared to controls. Equine herpesvirus-4 and feline herpesvirus-1, both enveloped viruses, were not recovered at any time > or = 1 h post inoculation in fluorescein. Feline calicivirus, a nonenveloped virus, was present in fluorescein for 7 days. Equine herpesvirus-4 and feline herpesvirus-1 did not remain infectious in proparacaine at any time > or = 1 h post inoculation, but feline calicivirus was recovered at up to 24 h post inoculation. CONCLUSIONS: Equine herpesvirus-4, feline herpesvirus-1, and feline calicivirus may be readily transmissible via the eyewash solution used in this study. Risk of iatrogenic transmission of the three viruses used in this study was significantly reduced in both fluorescein and proparacaine solutions. Feline calicivirus, the only nonenveloped virus evaluated, remained viable longer in both fluorescein and proparacaine solutions.