Electroretinographic Evaluations Using Skin Electrode of Eyes with Bleb-Related Endophthalmitis Following Vitrectomy with 0.025% Povidone Iodine Irrigation

Abstract

Purpose

To determine whether 0.025% povidone-iodine (0.025% PI) in the irrigation solution during vitrectomy for endophthalmitis is safe.

Methods

Two cases of bleb-associated endophthalmitis were treated with vitrectomy using 0.025% PI in the irrigation solution. The RETevel electroretinographic (ERG) system with skin electrodes was used to assess the physiology of the retina pre- and postoperatively.

Case

Case 1 was a 46-year-old man who had atopic keratoconjunctivitis and underwent trabeculectomy with the creation of a bleb after there was a rise in the intraocular pressure. One month postoperatively, a mild filtering bleb-associated endophthalmitis developed, and the eye was treated with intravitreal and subconjunctival injections of vancomycin (VCM) and ceftazidime (CAZ). After three days, the fundus was not visible and B-mode echography showed an area of high brightness in the retina. Vitrectomy with irrigation with VCM and CAZ, and 0.025% PI was performed successfully. Pre- and postoperative ERGs showed an improvement in both the a- and b-wave amplitudes and the b/a ratio was stable at 2.0. Case 2 was a 63-year-old man who had undergone trabeculectomy for glaucoma. Five years later, the eye developed blebitis which was treated with topical and subconjunctival injections of VCM and CAZ. Three days later, vitreous opacities appeared and a high brightness area was seen in the B-mode echographic images. Vitrectomy with VCM and CAZ, and 0.025% PI irrigation was successfully performed. Comparisons of the pre- and postoperative ERGs found that the a- and b- wave amplitudes of the ERGs increased and the b/a ratio was stable at approximately 1.5.

Conclusion

Vitrectomy with 0.025% PI irrigation is safe and ERG recordings with skin electrodes can be used to evaluate the pre- and postoperative retinal physiology safely.

Plain Language Summary

We report our findings in two cases of bleb-related endophthalmitis that underwent pars plana vitrectomy (PPV) with irrigation with 0.025% povidone-iodine (PI)-Balanced Salt Solution (BSS) PLUS (Alcon Laboratories, Fort Worth, TX). The retinal function was evaluated by full-field electroretinograms (ERGs) recorded with skin electrodes before and after the vitrectomy.

At present, there is no consensus on whether patients with bleb-related endophthalmitis should be treated with PPV or treated solely by intravitreal antibiotics. It was recently reported that vitrectomy using an irrigation solution containing 0.025% PI followed by postoperative antibiotics was effective and safe for the treatment of endogenous endophthalmitis and postoperative endophthalmitis. However, iodine is known to be retinotoxic depending on its concentration.

Electroretinography is a useful method to evaluate the safety of medications because it represents the physiology of the entire retina. However, conventional recording procedures with contact lens electrodes cannot be used in eyes with bleb associated endophthalmitis. Therefore, we performed ERG using skin electrodes which were introduced relatively recently. As a result, electroretinographic response showed that retinal function was not altered after surgery in these two cases.

Keywords:

• blebitis
• electroretinography
• bleb-related endophthalmitis
• povidone iodine irrigation
• vitrectomy

Study Approval Statement

The study was conducted according to the guidelines of the Declaration of Helsinki. The vitrectomy using 0.025% povidone-iodine in irrigation solution for bleb-related endophthalmitis was approved by the Ethical Committee of Saitama Medical University (2021-073).

Data Sharing Statement

All data generated or analyzed during this study are included in this article. Further enquiries can be directed to the corresponding author.

Consent to Publish Statement

Written informed consent was obtained from participants after full explanation of the diagnosis and treatment. Institutional approval was waived because of the retrospective design of this study.

Acknowledgment

The authors thank Professor Emeritus Duco Hamasaki of the Bascom Palmer Eye Institute for discussions and editing this manuscript. This paper has been uploaded to Research Square as a preprint: [https://www.researchgate.net/publication/378186153_Electroretinographic_evaluations_of_bleb-related_endophthalmitis_after_vitrectomy_with_0025_povidone_iodine_irrigation/fulltext/65ccb8a71bed776ae35f2893/Electroretinographic-evaluationsof-bleb-related-endophthalmitis-after-vitrectomy-with-0025-povidone-iodine-irrigation.pdf].

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors have no conflicts of interest to declare in this work.

Additional information

Funding

This study was supported in part by a grant to KS from the Japan Society for the Promotion of Science (JSPS; KAKENHI grant number: 22K09838).