Evaluation for endotoxin in intraocular materials used during phacoemulsification surgery using a recombinant factor C assay.

OBJECTIVE: Cataract surgery remains the sole method to resolve blindness secondary to cataract formation. One complication includes fibrin web formation post-operatively. This study aimed to investigate the presence of endotoxin within materials used during cataract surgery as a possible cause of fibrin web phenomenon. METHODS: Preservative-free epinephrine, heparin, viscoelastic devices, and intraocular lenses were collected for evaluation. Various manufacturers and manufacturing lot numbers were used when available. Viscosity of viscoelastics was reduced by incubating samples with human recombinant hyaluronidase. Intraocular product (IOL) packaging fluid was collected and stored for testing. The IOLs were then washed with a sterile balanced salt solution, incubated at 37°C for 48 h, and then fluid was collected for testing to mimic intraocular placement. Samples were tested using a commercially available rFC kit. Fluorescence was measured at time zero and after 1 h using a fluorescence microplate reader. The change in fluorescence was corrected for blank fluorescence and plotted to a standard curve. RESULTS: Endotoxin levels were below the limit of detection (0.05 EU/mL) in all samples. Incubation of IOLs at intraocular temperature did not increase extraction of endotoxin. CONCLUSION: Endotoxin was not identified in any tested sample, including those used in cases of fibrin web formation post-phacoemulsification. As fibrin webs are often observed episodically, it is possible that endotoxin levels may vary between batches, or that endotoxin is not related to fibrin formation.

Unilateral invasive intraocular melanoma with choroidal and optic nerve involvement resulting in bilateral vision loss in a Labrador Retriever.

A 10-year-old male castrated Labrador Retriever cross was referred for evaluation of acute vision loss. Ophthalmic examination revealed mild left sided exophthalmos, bilateral resting mydriasis, an absent direct and reduced consensual PLR in the left eye and reduced direct and absent consensual PLR in the right eye. Examination of the cornea and anterior segment with slit lamp biomicroscopy was unremarkable. Indirect fundoscopy revealed a left optic nerve head obscured by a darkly pigmented lesion. Fundic examination in the right eye was unremarkable. Magnetic resonance imaging revealed a smoothly marginated, lobulated cone to irregularly shaped, strongly T1 hyperintense, T2 and T2 fluid-attenuated inversion recovery hypointense, strongly contrast enhancing mass closely associated with the entire left optic nerve, extending across the optic chiasm and into the right optic nerve ventrally. Full clinical staging revealed no evidence of metastasis. Exenteration of the left eye was performed. Histopathology revealed an unencapsulated, poorly demarcated, multilobulated and infiltrative pigmented mass that was effacing the posterior choroid and optic nerve. The mass was composed of a moderately pleomorphic population of heavily pigmented polygonal cells arranged in sheets and clusters, displaying moderate anisocytosis and anisokaryosis. The population of cells contained moderate amounts of abundant brown-black granular pigment consistent with melanin within the cytoplasm. Mitotic figures averaged approximately three per ten 400× fields (2.37 mm2 ). This is the first report of a melanocytic tumor invading along the optic nerve and tract to result in contralateral vision loss.

Comparison of ophthalmic loteprednol etabonate and prednisolone acetate effects on adrenocortical response to ACTH in dogs.

OBJECTIVE: This study served to compare the degree of adrenocortical suppression following a 2-week administration of loteprednol etabonate (LE) and prednisolone acetate (PA) ophthalmic drops. PROCEDURES: In this prospective double-masked triple-crossover study, 21 clinically healthy dogs were randomized to receive loteprednol etabonate ophthalmic suspension 0.5%, prednisolone acetate ophthalmic suspension 1%, or artificial tears (AT). Each group (LE, PA, and AT) received one drop in each eye every 12 h for 2 weeks, followed by a 3-week washout period between treatment blocks. ACTH stimulation tests were performed before and after each treatment block. Serum cortisol samples were drawn before and 60 min after administration of 1 µg/kg cosyntropin IV. Repeated-measurement ANOVA followed by a Tukey's multiple comparisons test (or a Friedman test followed by a Dunn's multiple comparisons test) were used to compare pre- and post-treatment cortisol values between each group. A p-value of ≤.05 was considered significant. RESULTS: A total of 18 dogs completed the study. Prestimulation cortisol values were lower in the PA group compared to the LE (p = .0106), but not AT (p = .0589) groups, and post-stimulation cortisol values were lower in the PA group than either LE (p = .0005) or AT (p = .0002) groups. There was no significant difference detected in pre- or post-stimulation cortisol values after the treatment periods between LE and AT. CONCLUSIONS: Based on the reduced suppression of cortisol values, LE caused significantly less hypothalamic-pituitary-adrenal axis suppression than PA. A topical steroid with minimal adrenocortical suppression, such as LE, may be favorable in patients where systemic glucocorticoid effects should be avoided.

Comparison of preoperative retrobulbar bupivacaine and postoperative subcutaneous liposome-encapsulated bupivacaine on postoperative analgesia in dogs undergoing enucleation.

OBJECTIVE: To compare the effectiveness of preoperative bupivacaine inferotemporal retrobulbar blocks to postoperative liposome-encapsulated bupivacaine (Nocita) line blocks for analgesia following enucleation. ANIMALS: 39 client-owned dogs (40 eyes) presenting to the Ophthalmology Service for enucleation. METHODS: Dogs were randomly assigned to receive either a preoperative inferotemporal retrobulbar block with 0.5% bupivacaine or a peri-incisional line block with liposome-encapsulated bupivacaine (Nocita) at closure. Patients underwent unilateral enucleation and were hospitalized for 24 hours after surgery. Pain scores were performed by a masked observer with the Glasgow Composite Measure Pain Scale and the University of Wisconsin Ocular Pain Scale at 0.25, 0.5, 1, 2, 4, 6, 8, and 24 hours following surgery. Intraoperative use of blood pressure and anesthetic support mediations as well as need for rescue pain control were recorded and compared between groups. RESULTS: There was no significant difference in rescue rates between treatment groups. When comparing the use of medical intraoperative heart rate, blood pressure, or anesthetic plane support, there were no significant differences in use between groups. CLINICAL RELEVANCE: Use of preoperative bupivacaine retrobulbar blocks and postoperative Nocita line blocks were equally effective at postoperative pain control with similarly low complication rates.