Evaluation of Retinal Function and Pathology After Intravitreal Injection of Povidone-Iodine and Polyvinyl Alcohol-Iodine in Rabbits

Abstract

Citation: Shimada H, Kato K, Ishida K, Yamaguchi T, Shinoda K. Evaluation of retinal function and pathology after intravitreal injection of povidone-iodine and polyvinyl alcohol-iodine in rabbits. Trans Vis Sci Tech. 2020;9(5):5, https://doi.org/10. 1167/tvst.9.5.5 Purpose: This study compared intraocular toxicity of intravitreally injected povidoneiodine (PI) and polyvinyl alcohol-iodine (PAI) in rabbits. Methods:In each rabbit, 0.1 mL of PI or PAI solution was injected intravitreally into one eye and saline was injected into the other. PI was tested at available iodine concentrations of 0.05%, 0.1%, 0.2%, and 0.5%, and PAI at 0.05%, 0.1%, and 0.2% (n = 6 each). Electroretinograms were recorded before injection and 1, 7, and 14 days after injection. Pathological examinations of eyeballs were performed on day 15.Results: Mean b-/a-wave ratios of the electroretinograms did not change in eyes injected with 0.05%, 0.1%, or 0.2% PI (PI-0.05, PI-0.1, and PI-0.2, respectively) or in eyes injected with 0.05% or 0.1% PAI (PAI-0.05 and PAI-0.1, respectively) compared to salineinjected eyes, but was transiently impaired on day 1 in PAI-0.2 eyes. Histopathologically, no retinal abnormalities were observed in PI-0.05, PAI-0.05, or PAI-0.1 eyes. One PI-0.1 eye first showed localized inflammatory cell infiltration in the inferior retinal region. Two PI-0.2 eyes and one PAI-0.2 eye had retinal degeneration and inflammatory cell infiltration. In the PI-0.5 group, extensive inflammatory cell infiltration was observed in six eyes and inferior retinal detachment in five eyes.Conclusions: PI and PAI have equivalent retinal toxicity profiles, and retinal toxicity first affects the inner retinal layer in the inferior region. The highest non-retinotoxic vitreous concentration is 0.0033% available iodine from intravitreal injection of PI or PAI containing 0.05% available iodine.Translational Relevance: Low concentrations of PI or PAI can be used to wash the ocular surface during surgery or intravitreal injection to prevent endophthalmitis.

Safety Measures for Maintaining Low Endophthalmitis Rate after Intravitreal Anti-Vascular Endothelial Growth Factor Injection before and during the COVID-19 Pandemic

“…For this reason, we disinfect the eyelids, eyelashes, and conjunctival fornix with at least 10 mL of 0.25% povidone-iodine before draping; irrigate the ocular surface with several ml of povidone-iodine after placing the solid blade lid speculum; wait for 30 s; and then perform intravitreal injection while the povidone-iodine remains on the ocular surface. According to a study performed using rabbit eyes, there is no retinal damage associated with washing the ocular surface with 0.25% povidone-iodine during intravitreal injection [41]. After injection, the ocular surface is again disinfected with several ml of povidone-iodine to prevent endophthalmitis [42].…”

Cell death and barrier disruption by clinically used iodine concentrations

“…When cells were exposed to stable solutions of PVP carrier alone or I 2 , toxicity was solely caused by I 2 (Figs 1C-E and S1A-C). Above a threshold of free I 2 at 0.5 mM, elemental iodine is an irreversible respiratory poison, likely explaining topical toxicity such as retinal degradation (Shimada et al, 2020), and clinical sudden cardiovascular and metabolic collapse upon high-level systemic exposure (Glick et al, 1985;Kanakiriya et al, 2003;Ramaswamykanive et al, 2011), confirmed in animal models (Lores et al, 1981;Song et al, 2018). To translate these findings to a 3D environment, calcein AM-labelled epithelial spheroids were exposed to PVP-I or I 2 .…”

“…Former authors found only a range between 0.005% and 0.1% effective, as it caused only minor membrane damage ( Van den Broek et al, 1982 ). Others found the safe concentration range to vary with cell type, such as <0.033% for the retina ( Shimada et al, 2020 ), <0.05% for corneal endothelial cells ( Jiang et al, 2009 ), and <0.05% for corneal epithelial cells ( Swift et al, 2020 ).…”

Vitrectomy using 0.025% povidone-iodine irrigation for treating post-traumatic endophthalmitis due to intraocular foreign bodies: Two case reports

“…In addition, electroretinography (ERG) and histologic examinations of the retina were performed to verify that both 0.1% and 0.3% PI were tolerable. Furthermore, 0.025% PI-balanced salt solution (BSS) PLUS (Alcon Laboratories, Fort Worth, TX) is a bactericidal drug when used as an irrigation solution for vitrectomy in eyes with endophthalmitis (21). IVI of 1.25% PI followed by vitrectomy using 0.025% PI irrigation for treating endophthalmitis was proved to be effective (22).…”