“Iodine Allergy” and the Use of Povidone Iodine for Endophthalmitis Prophylaxis

Comparison of Endophthalmitis Rates after Alcohol-Based Chlorhexidine and Povidone-Iodine Antisepsis for Intravitreal Injections

OBJECTIVE

Intravitreal injections (IVIs) are the most frequently performed intraocular procedure in Canada. Povidone-iodine (PI) is the current gold standard for antisepsis for IVI and is widely used; chlorhexidine (CH) is a possible alternative antiseptic agent. This study aims to compare rates of endophthalmitis after IVI with 0.05% chlorhexidine with a 4% alcohol base antisepsis to rates of endophthalmitis after IVI with 10% PI antisepsis.

DESIGN

Retrospective cohort study.

SUBJECTS

Eyes that received IVI between May 2019 and October 2022 at a group retina practice in Edmonton, Canada.

METHODS

Eyes at a single center received focal conjunctival application of either 10% PI antisepsis or 0.05% CH in 4% alcohol antisepsis for 30 seconds before each IVI.

MAIN OUTCOME MEASURE

Rates of endophthalmitis between the PI and CH groups.

RESULTS

A total of 170 952 IVIs were performed during the study period. A total of 31 135 were performed using CH prophylaxis compared with 139 817 with PI prophylaxis. Among all IVIs there were 49 total cases of endophthalmitis, 29 in the PI group (0.021%) and 20 in the CH group (0.064%). There was a statistically significant difference in the rates of endophthalmitis between the 2 groups (P < 0.001). The odds ratio for developing endophthalmitis with CH antisepsis was 3.1 (95% confidence interval, 1.9-5.2) compared with PI antisepsis. There were increased odds of developing endophthalmitis with aflibercept injection compared with bevacizumab (odds ratio, 3.48; 95% confidence interval, 2.09-7.24).

CONCLUSIONS

There is a statistically significant difference in rates of endophthalmitis between alcohol-based CH and PI antisepsis for IVI in our patient population utilizing the methods discussed. In our center, alcohol-based CH is now considered a second-line antiseptic agent. Further studies are warranted to further assess the endophthalmitis rate utilizing these 2 antiseptic agents.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Intravitreal injections as a leading cause of acute postoperative endophthalmitis-a regional survey in England

BACKGROUND

To evaluate the characteristics, treatment patterns and outcomes of acute postoperative endophthalmitis.

METHODS

Patients presenting with acute postoperative endophthalmitis between January 2017 to December 2019 were identified from hospital records in this multicentre retrospective cohort study. Clinical records were reviewed for visual acuity (VA) at various timepoints, cause of endophthalmitis, microbiological results, treatments and complications.

RESULTS

Forty-six eyes of 46 patients were included. Intravitreal injections were the leading cause of acute postoperative endophthalmitis (n = 29; 63%), followed by cataract surgery (n = 8; 17%), vitreoretinal surgery (n = 7; 15%), and secondary intraocular lens insertion (n = 2, 4%). The absolute risk of endophthalmitis was 0.024% (1:4132) for intravitreal injections, 0.016% (1:6096) for cataract surgery, and 0.072% (1:1385) for vitreoretinal surgery. The majority of patients (n = 38; 83%) had better VA at 6 months compared to presentation, although fewer (n = 13; 28%) maintained similar or better VA compared to before the precipitating surgery. Twenty-four cases yielded positive culture results, of which staphylococcus epidermidis was the most commonly isolated organism. Microbiological yield was not associated with better final visual outcomes. Patients who underwent therapeutic vitrectomy (n = 15; 33%) had poorer VA at presentation, but subsequently achieved visual outcomes comparable to those who received medical treatment alone. There was no difference in time to presentation, visual outcome and retinal detachment rates among the different causative procedures.

CONCLUSION

Intravitreal injections were the most common cause of endophthalmitis in our region, primarily because of their higher frequency compared to other intraocular procedures. In this cohort, the primary procedure had no effect on presentation, management or visual outcomes.

Repurposing povidone-iodine to reduce the risk of SARS-CoV-2 infection and transmission: a narrative review

BACKGROUND

Accumulating data suggest antiviral effects of povidone-iodine against the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. This narrative review aims to examine the antiviral mechanisms of povidone-iodine, efficacy of povidone-iodine against the SARS-CoV-2 virus, and safety of povidone-iodine to human epithelial cells and thyroid function.

METHODS

We searched the electronic databases PubMed, Embase, Cochrane Library, ClinicalTrials.gov and World Health Organization's International Clinical Trials Registry Platform for articles containing the keywords "povidone-iodine", "SARS-CoV-2" and "COVID-19" from database inception till 3 June 2021.

RESULTS

Despite in vitro data supporting the anti-SARS-CoV-2 effects of povidone-iodine, findings from clinical studies revealed differences in treatment response depending on study settings (healthy vs. hospitalized individuals), treatment target (nasal vs. oral vs. pharynx), method of administration (oral rinse vs. gargle vs. throat spray) and choice of samples used to measure study endpoints (nasopharyngeal vs. saliva). One large-scale clinical trial demonstrated reduction in the incidence of SARS-CoV-2 infection among participants who administered povidone-iodine 3 times daily during an active outbreak. Povidone-iodine is also used to disinfect the oro-pharyngeal space prior to dental or otolaryngology procedures. Although existing data suggest minimal impact of povidone-iodine on thyroid function, high-quality safety data are presently lacking.

CONCLUSIONS

Povidone-iodine application to the oropharyngeal space could complement existing non-pharmacological interventions to reduce SARS-CoV-2 infection especially in high exposure settings.Key messagesAccumulating data suggest antiviral effects of povidone-iodine against the SARS-CoV-2 virus.Findings from clinical studies reveal differences in treatment response depending on study settings, treatment target, method of administration and choice of samples used to measure study endpoints. One large-scale clinical trial observed reduction in the incidence of SARS-CoV-2 infection among participants who administered povidone-iodine 3 times daily during an active outbreak.Povidone-iodine application to the oropharyngeal space could complement existing non-pharmacological interventions to reduce SARS-CoV-2 infection especially in high exposure settings.

The effect of punctal plugs in reducing ocular surface irritation after povidone-iodine preparation of intravitreal injection-a randomized trial

PURPOSE

To evaluate the utility of dissolvable collagen punctal plugs (CPP) in reducing ocular surface irritation after intravitreal injections (IVI).

METHODS

Sixty-four subjects in the experimental group received CPP after intravitreal injections. Sixty-two controls did not receive CPP. Reductions in the Ocular Surface Disease Index© (OSDI) and Standardized Patient Evaluation of Eye Dryness II (SPEED II) scores were analysed.

RESULTS

Dry eye symptoms, as measured by reductions from the pre- to post-injection OSDI (p = 0.137) and SPEED II (p = 0.381) scores, did not significantly differ between the two groups. In sub-group analysis, patients with objective findings of dry eyes had significant improvement in their symptoms (p = 0.046) with CPP. The effect of CPP is not significant in those without dry eyes (p = 0.27).

CONCLUSION

CPPs were not effective in reducing post-injection ocular irritation in patients with no or only mild dry eye symptoms. CPPs improved patients' post-injection comfort levels in those who had moderate-to-severe symptoms and objective findings of dry eye. Though costly CPP could be considered in selective patients. A standardized eye rinse could be a simple, efficacious, and cost-effective way to reduce post-injection ocular irritation; however, more studies are needed.

Chlorhexidine and other alternatives for povidone-iodine in ophthalmic surgery: review of comparative studies

Povidone-iodine (PVI) is a universally accepted antiseptic agent used in ophthalmic surgery. Insufficient antisepsis in patients with self-reported allergies to iodine has led to devastating complications. The aim of this study was to review the current evidence for alternatives to PVI in ocular surgery. Aqueous chlorhexidine has been used as a primary antiseptic agent in Sweden for several years and has proven efficiency and safety; in a study of a large series of intravitreal injections in Australia, the endophthalmitis rates were similar to those after the use of PVI. The evidence related to using other disinfectants such as picloxydine, hypochlorous acid solution, and polyhexanide is scarce. Single studies have shown lower patient discomfort after conjunctival lavage with chlorhexidine or hypochlorous acid than with PVI. No evidence was found to suggest changing from PVI to other antiseptic agents. Disinfectant solutions other than PVI or chlorhexidine will require further investigations to show their utility in ocular surgery.

Post-injection endophthalmitis rates with reduced povidone-iodine prophylaxis in patients with self-reported iodine sensitivity

BACKGROUND

Our objectives were (1) to report the post-injection endophthalmitis rate over 18 months, and (2) to determine any difference in the incidence of endophthalmitis in patients treated with reduced or no 5% povidone-iodine (PI) due to self-reported PI sensitivity.

METHODS

We performed a retrospective cohort study of all patients who received intravitreal injections (IVIs) from January 1st, 2018 to June 26th, 2019. Information on patients' age, gender visual acuities, the number of injections, drug administered, self-reported iodine sensitivity and injection protocols were obtained from electronic and paper records. For endophthalmitis cases, vitreous culture results and treatment were also noted. Patients were divided into three cohorts based on the injection protocol used for statistical analysis.

RESULTS

During the study period 22,046 IVIs were administered to 3332 eyes of 2709 patients. Intolerance to PI was reported by 2.4% of patients. The incidence of endophthalmitis was 0.02% (4/21,185) with the standard 5% PI protocol, 0.78% (6/769) with a reduced PI protocol involving fewer drops of 5% PI and chlorohexidine 0.05% for periorbital skin cleansing, and 1.09% (1/92) without any PI use. Receiving the standard PI protocol was associated with significantly lower rates of endophthalmitis compared to both the reduced PI and no PI protocols (p < 0.0001).

CONCLUSIONS

Patients who opt for less or no PI use are likely at significantly increased risk of developing post-IVI endophthalmitis. It is imperative to educate, counsel and consent these patients accordingly while exploring alternative antiseptic solutions.