Potential impact of oral flora dispersal on patients wearing face masks when undergoing ophthalmologic procedures

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.

Microbiological Profile of Infectious Keratitis During Covid-19 Pandemic

Purpose

The Covid-19 pandemic introduced significant changes in our daily life, including the widespread use of face masks. The purpose of this study was to assess if significant changes occurred in the microbiological profile of infectious keratitis.

Patients and Methods

A retrospective study was performed, based on a survey review of the electronic medical records of all patients with presumed infectious keratitis, between March 2020 and October 2021. The microbiological isolates in this sample (pandemic group) were compared with those obtained in our center between 2009 and 2018 (pre-pandemic group).

Results

A total of 194 samples were included in the pandemic group. We obtained a culture-positivity rate of 43.3%, which was significantly higher when compared with the pre-pandemic data (35.15%, p = 0.033). Several further significant differences were found between the pandemic and the pre-pandemic groups: the proportion of bacteria, including gram-positive and gram-negative groups, was higher in our sample (pre-pandemic vs pandemic: 76.78% vs 83.33%, p = 0.010; 53.35% vs 60.71%, p = 0.016; 23.43% vs 34.52%, p = 0.005, respectively); two populations of Gram-positive bacteria found in this study were not isolated in the pre-pandemic sample - Dolosigranulum pigrum and Propionibacterium spp.; and two bacterial isolates were significantly increased in our sample - Corynebacterium spp. (18.41% vs 29.76%, p = 0.003) and Pseudomonas aeruginosa (9.00% vs 16.66%, p = 0.012).

Conclusion

In conclusion, significant changes were found in the microbiological profile of infectious keratitis in our center during the Covid-19 pandemic. While these changes could be related to face mask use, more observational and experimental studies are needed to explore this possible association.

Legal obligation in the general population: face mask influence on endophthalmitis after intravitreal injection

PURPOSE

To investigate whether compulsory face masking in public life changes the incidence or pattern of post-injection endophthalmitis (PIE).

PATIENTS AND METHODS

All injections of bevacizumab, ranibizumab, aflibercept, dexamethasone or triamcinolone between 01/01/2015 and 12/31/2021 at the University Eye Clinic of Tuebingen were included in this retrospective analysis. The injection procedure itself was unchanged since 2015 and included the use of a sterile drape covering the head up to the shoulders which prevents airflow toward the eye. Furthermore, all staff wore a face mask and gloves at all times. The two study periods were defined by the introduction of a compulsory face masking rule in public life (01/01/2015 until 04/27/2020 vs. 04/28/2020 until 12/31/2021).

RESULTS

A total of 83,543 injections were performed in the tertiary eye clinic, associated with a total of 20 PIE (0.024%, 1/4177 injections). Of these, thirteen PIE were documented during the pre-pandemic period (0.021%, 1/4773 injections) and seven PIE during the pandemic period (0.033%, 1/3071 injections). No significant difference in PIE risk was observed (p = 0.49), and there was no case of oral flora associated PIE.

CONCLUSION

Although some potential confounders (wearing time, skin flora) could not be considered, there was no clear signal that the introduction of compulsory face masking in public life did alter the risk for PIE in our patient population. Three and six months after PIE, no difference in visual acuity was detectable between the two study periods.