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Objective: To evaluate the intraocular reactivity to metallic and ethylene oxide (EO) contaminants of ophthalmic devices in rabbits., Design: Two experimental animal studies., Participants: Thirty-five New Zealand white rabbits., Methods: A metallic exposure study and an EO exposure study were performed. In the first study, both eyes of 25 rabbits were equally allocated to intracameral injections of alumina 0.2 μg, alumina 20 μg, copper sulfate 0.4 μg, copper sulfate 20 μg, or an aqueous control. In the second study, 10 rabbits were allocated (5 per group) to receive intracamerally an ophthalmic viscosurgical device (OVD) exposed to EO or not exposed to EO (control). All eyes were examined by slit lamp at baseline and 3, 6, 9, 24, 48, and 72 hours after exposure, with dilated indirect ophthalmoscopy being performed at 24 and 72 hours. Tonometry was performed only in the first study., Main Outcome Measures: Grade of corneal clouding, anterior chamber (AC) flare, AC cells, AC fibrin, iridal hyperemia, cell and fibrin on the lens surface, vitreous haze and cells, lens opacities, intraocular pressure, and onset time., Results: For metallic compounds at the study's low doses, mean inflammatory grades were 0.2 or less above the control for all responses at all time points. For the high-dose alumina, mean inflammatory grades peaked at 6 to 9 hours at 0.5 to 0.7 above the control responses for conjunctival congestion, iris hyperemia, AC cells, flare, and fibrin and declined over the remaining time points. For the high-dose copper sulfate, mean inflammatory grades peaked between 3 and 24 hours at 1.2 to 1.8 above the control responses for conjunctival congestion, iris hyperemia, AC cells, flare, fibrin, and corneal clouding, then subsequently declined. The intraocular pressure changes appeared significant for only high-dose copper sulfate, with mean declines of 4.3 to 7.5 mmHg at 6 to 72 hours. No clinically meaningful differences in ocular inflammation were observed between the OVD exposed to EO and the OVD not exposed to EO., Conclusions: Alumina and copper sulfate did not cause clinically meaningful ocular inflammation at the low study levels (levels expected with ophthalmic devices). Ethylene oxide exposure of an OVD was not associated with inflammation., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate whether enzymatic detergents used in cleaning ophthalmic surgical instruments can cause toxic anterior segment syndrome (TASS)-like responses in a rabbit model., Design: Randomized, investigator-masked, controlled experimental animal study., Participants: Thirty-five New Zealand white rabbits., Methods: The rabbit eyes were randomized into 7 treatment groups to receive intracameral injection of 1 of 3 different doses of Medline Dual Detergent or Enzol Detergent, or sterile limulus amoebocyte lysate reagent water as a control. The eyes were evaluated for anterior segment inflammation at baseline and at 1, 3, 6, 24, 48, and 72 hours after treatment by slit-lamp biomicroscopy., Main Outcome Measures: Anterior chamber (AC) inflammation, including cells, flare, fibrin, and iris injection; time course of inflammation; and residual detergent levels in luminated instruments., Results: Moderate to marked injection of the iris vessels was seen as early as 1 hour after treatment with the enzymatic detergents in 41 of 60 eyes, with the response being more severe in the Enzol Detergent-exposed eyes. Severe iris hemorrhages were accompanied by blood in the AC in 13 eyes, which usually persisted through 72 hours, with an associated increase in AC cell and flare. Corneal haze was present in 52 of 56 eyes 1 hour after treatment, but was mild and resolved within 24 hours in all but the Enzol 4.5%-exposed eyes. Median AC cell and flare peaked at 6 hours and resolved by 48 hours., Conclusions: Enzymatic detergents caused a severe but unusual response from the iris when injected intracamerally into rabbit eyes. This response has not been reported in humans with TASS. The time course of inflammation was faster (peak at 6 hours) and resolved more quickly (within 48 hours) than TASS. Simulated cleaning and extraction studies indicate that the level of residual detergent to which a patient could be exposed is significantly less than the lowest dose used in this study. Because that low dose caused no significant observations other than injection of the iris vessels, these results do not support residual enzymatic detergents on surgical instruments as a cause for TASS., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To describe the ocular reactivity of the rabbit to bacterial endotoxin contained in an aqueous medium and in a cohesive and a dispersive ophthalmic viscosurgical device (OVD)., Design: Experimental, randomized animal study., Participants: Seventy-five New Zealand white rabbits., Methods: This study was performed using 75 rabbits to evaluate the ocular reactivity to bacterial endotoxin contained in Dulbecco's phosphate-buffered saline (DPBS), a cohesive OVD, and a dispersive OVD. For each test material, 25 rabbits were randomized into 5 groups and were exposed to the test material containing 0.75 endotoxin units (EU), 0.25 EU, 0.08 EU, and 0.02 EU of endotoxin or the vehicle control. The rabbits in each group received bilateral intracameral injection of 0.05 ml of the same test material. All eyes were examined by slit-lamp biomicroscopy at baseline, 3, 6, 9, 24, 48, and 72 hours after injection. At 24 and 72 hours, slit-lamp biomicroscopy (and additionally indirect ophthalmoscopy) was performed through dilated pupils., Main Outcome Measures: Corneal clouding, anterior chamber (AC) flare, cells and fibrin, vitreous haze and cells, cells and fibrin on lens surface, lens opacities, and onset time., Results: The inflammation seen after exposure to the 3 endotoxin-spiked materials followed the same general time course. Anterior chamber cells, flare, iris hyperemia, and conjunctival congestion were seen as early as 3 hours. They started to diminish after 6 hours (DPBS eyes) and 9 hours (OVDs) and were not detectable at 48 and 72 hours, respectively. The AC inflammation was more severe in the OVD eyes than in the DPBS eyes. Anterior chamber fibrin was seen in the OVD eyes only, which persisted through 72 hours in many eyes. A trend toward a dose-response relationship was seen for AC cells and flare and the presence of cells and fibrin on the lens surface in all 3 treatment groups in the first 24 hours., Conclusions: Inflammation was seen after intracameral injection of as little as 0.02 and 0.08 EU in OVD and DPBS eyes, respectively. Observed responses to intracamerally injected endotoxin in OVDs were more severe and of longer duration than those in aqueous medium., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate the intraocular reactivity to organic contaminants of ophthalmic devices in the rabbit., Design: Experimental animal study., Participants: Fifty New Zealand white rabbits., Methods: The rabbits were allocated to 10 groups of 5 each to receive 2 different doses of human albumin and nonhuman nucleic acids and their respective vehicle controls, a denatured cohesive ophthalmic viscosurgical device (OVD) and a denatured dispersive OVD and their respective nondenatured controls. All 10 eyes in each treatment group received bilateral intracameral injection of the test materials. All the eyes in the study were examined by slit-lamp biomicroscopy at baseline and 6, 9, 24, 48, and 72 hours. Pachymetry was also performed on eyes exposed to albumin, protein vehicle control, and the OVDs at these time points., Main Outcome Measures: Corneal thickness, grade of corneal clouding, anterior chamber (AC), cells, flare and fibrin, iridal hyperemia, cell and fibrin on lens surface, and onset time., Results: There were no inflammatory signs in any eyes exposed to human albumin. Anterior chamber cells (1+ to 3+) and flare and fibrin (1+ to 2+), along with cells and fibrin on the lens surface, were seen in the eyes exposed to the nucleic acid samples, and they resolved in 24 hours. Mild (mostly 1+) conjunctival congestion, cells, flare, and fibrin were seen in a few eyes exposed to the 2 denatured OVDs and their controls, with the response durations being shorter in the denatured OVD eyes (24 hours) than in the nondenatured OVD eyes (48 hours). Anterior chamber inflammation was generally observed in fewer denatured OVD eyes than in nondenatured OVD eyes, particularly the dispersive OVD eyes., Conclusions: Intracameral injection of human albumin protein did not cause ocular inflammation. Nucleic acid intracamerally injected into rabbit eyes caused acute inflammation that quickly resolved. Cohesive and dispersive OVD denatured by drying and steam sterilization alone did not cause ocular inflammation., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)