Good to see people questioning standard practice. Also good to see recognition of the potential for a thyroid issue - though they do not seem to see any thyroid issues with the 5% solution.
In vitro efficacy of aqueous PVP-iodine solution below 5% as alternative to preoperative antisepsis in ophthalmology as the basis for an in vivo study
Paula Zwicker, Nevin Opitz, Julia Harris, Andreas Stahl, Ulrich Kellner, Ruth Koelb-Keerl, Philipp S. Muether, Anne Hunold & Axel Kramer
Abstract
Purpose
Pre-operative antisepsis of the conjunctiva is indicated prior to intraocular surgery to prevent post-interventional endophthalmitis. In Germany, antisepsis with 5% povidone-iodine (PI) aqueous solution is explicitly required prior to intravitreal injections (IVI), and also generally recommended for intraocular surgery. However, this concentration often leads to a foreign body sensation and an unpleasant burning in combination with dry eye symptoms. Postoperative eye pain, persistent corneal epithelial defects, and a risk of keratitis are further side effects. Due to the repetitive nature of IVI, these symptoms are particularly present in IVI patients. A reduced concentration may be favorable to decrease patient discomfort. A 1.25% PI solution does not increase the iodine concentration in the aqueous humor and is also used for prophylaxis of ophthalmia neonatorum and for preoperative antisepsis; in both cases the renal iodine excretion stays in a physiological range thus thyroid diseases are no contraindication for its use. Thus, the efficacy of reduced concentrations of PI should be evaluated in vitro.
Methods
PI with dilutions below 5% (0.625 − 2.5% serial 1:2 dilution) was tested in vitro in a quantitative suspension assay and in a quantitative carrier test without and with addition of matrices to identify their antimicrobial effect against Staphylococcus epidermidis, Pseudomonas aeruginosa, Cutibacterium acnes and Candida albicans.
Results
No differences in the antimicrobial effect was seen due to reduced concentrations of PI in comparison to a 5% solution. However, a trend was seen regarding the required contact time of the antiseptic solution.
Conclusion
The in-vitro tests have shown adequate antisepsis of 1.25% PI prior to intraocular surgery. However, it is important to pay attention to a sufficient contact time of the antiseptic of about 1 min before ophthalmologic intervention. In order to give final recommendations, in vivo testing is needed to build a robust data foundation.
Highlights
5% PVP-Iodine solution prior IVI leads to unpleasant side effects.
In vitro, antimicrobial effect of 5% PI is comparable to that of 1.25% PI.
Addition of matrices had no visible effects on antimicrobial activity.
Contact time of 1 min is necessary.
Unusually, an Open Access paper:
https://joii-journal.springeropen.com/articles/10.1186/s12348-025-00489-3
