The relationship between MIGS procedures and endophthalmitis

Dr Yoshihiro Yonekawa from Wills Eye Hospital, Mid-Atlantic Retina, Thomas Jefferson University, Philadelphia, reported that the prevalence of endophthalmitis following minimally invasive glaucoma surgery (MIGS) is similar to the prevalence rates of endophthalmitis after other incisional glaucoma surgeries but warned of the potential risk of endophthalmitis with the use of implantable MIGS devices.

While endophthalmitis is a rare event after glaucoma surgery, ranging from 0.20% to 6.3%, little is known about the characteristics of endophthalmitis after various MIGS procedures, he emphasized.

To shed more light on this complication after MIGS, Dr Yonekawa and associates retrospectively reviewed bacterial endophthalmitis cases after MIGS that were diagnosed and treated at the Wills Eye Hospital from 1 October 2015, to 1 July 2020. In this study,¹ a MIGS procedure involved both implantable devices, i.e., the iStent (Glaukos Corp.), Hydrus device (Ivantis, Inc), Xen Gel stent (Allergan Plc), CyPass Microstent (Alcon), and MIGS procedures not involving an implantable device.

Factors associated with endophthalmitis

Dr Yoshihiro Yonekawa

Over the study course of almost 5 years, 979 cases of endophthalmitis were treated, of which 13 (1.3%) were diagnosed after a MIGS procedure and 4 of those were from Wills Eye Hospital or affiliated practices. A total of 3,055 MIGS procedures had been performed at Wills, which resulted in a prevalence rate of 0.13% (4/3,055; 95% Poisson confidence interval [CI], 0.04%-0.30%), or 1 in 769 patients, Dr Yonekawa reported.

Nine of the 13 cases were associated with the iStent (7 from external practices and 2 of 2,101 internal; 0.095%; 95% CI, 0.036%-0.29%), 3 cases with the Xen Gel stent (2 external and 1 of 406 internal; 0.25%; 95% CI, 0.014%-1.1%), and 1 case with the CyPass Microstent (0 external and 1 of 111 internal; 0.90%; 95% CI, 0.051%-3.97%). Endophthalmitis was not associated with the 437 MIGS procedures that did not involve an implantable device, i.e., goniotomy, trabeculectomy, gonioscopy-assisted transluminal trabeculotomy, trabectome, Kahook Dual Blade (New World Medical), or OMNI surgical system (Sight Sciences, Inc.).

Three cases of endophthalmitis had delayed presentation, and 2 of these were related to Xen Gel exposure.

Of 7 eyes with positive cultures, 2 eyes showed Staphylococcus epidermidis, 1 eye S. aureus, and 4 eyes various Staphylococcus species, findings that differed slightly from findings after cataract surgery, which is associated mostly with coagulase-negative staphylococcal species.

The investigators concluded, “The calculated prevalence of endophthalmitis in this study is similar to the reported incidences of endophthalmitis after other incisional glaucoma surgeries. Surgeons need to be cognizant of the potential risk of endophthalmitis with the use of implantable MIGS devices and the differences between endophthalmitis after MIGS procedures and endophthalmitis after standard cataract surgery. Not all MIGS devices are similar in their approach to lowering intraocular pressure, and thus each device and case of endophthalmitis may require unique management decisions.”

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Reference

Starr MR, Huang D, Israilevich RN, et al. Endophthalmitis after minimally invasive glaucoma surgery. Ophthalmology 2021;Jun 5 [Online ahead of print] DOI: 10.1016/j.ophtha.2021.06.004.

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