Editors Selection IGR 20-4


Brandon J. Wong

Comment by Brandon J. Wong on:

82885 Review of hygiene and disinfection Recommendations for outpatient glaucoma care: A COVID era update, Shabto JM; De Moraes CG; Cioffi GA et al., Journal of Glaucoma, 2020; 29: 409-416

See also comment(s) by Ningli Wang & Chunyan QiaoLuciano QuarantaClement Tham & Poemen ChanTin Aung & Rahat HusainPradeep RamuluMichele C. LimAndrew CampClement Tham & Poemen Chan

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In this timely review article, Shabto and coworkers describe disinfection practices relevant to the glaucoma clinic during the present COVID-19 pandemic, specifically practices concerning the clinic environment and commonly used equipment and instruments. The authors provide a comprehensive review of the varying manufacturer recommendations for disinfection of non-contact ancillary testing, such as perimetry and optical coherence tomography, and testing involving direct patient contact, such as applanation tonometry and gonioscopy. Clinicians and staff should be familiar and attentive to the proper disinfection practices of the clinic and equipment, especially as clinics reactivate and patient volumes increase. While different institutions may be at various stages of reactivation, our hospital-based academic glaucoma clinics are now re-opening with a limited clinic capacity to comply with local and state guidelines. Our approach to re-opening clinics includes adhering to all manufacturer recommendations for instrument disinfection as well as other environmental and engineering control measures. We have converted to the use of disposable tonometer prisms which obviates the need to disinfect reusable tonometer tips and are transitioning to single use lenses for gonioscopy and laser procedures, such as laser peripheral iridotomy and selective laser trabeculoplasty. Anecdotally, we have not had issues with the lens quality or visualization for these procedures.

Since the publication of this article, Zeiss has updated its recommended cleaning guidelines for the Humphrey Visual Field Analyzer to incorporate updated information regarding the perimeter's ventilation and guidance on how to clean the bowl, if deemed necessary. The HFA2, HFA2-i, and HFA3 perimeters have fans which circulate and exchange air in the bowl, and the HFA2-i, and HFA3 perimeters continuously push air out of the bowl and past the patient while the machine is powered on.1 It is not known if viral particles or respiratory droplets that accumulate on the bowl could potentially be aerosolized due to this fan mechanism. The updated Zeiss guidelines recommend the use of 70% isopropyl alcohol and a fine misting sprayer to sanitize the bowl surface if necessary.2 Importantly, the alcohol must dry (approximately 5-10 minutes) prior to the next test. For patients requiring perimetry, our clinic practice is to have all patients wear surgical masks for the duration of the test. Routine N95 masks for patients appears impractical given that the physical size of most N95 masks interferes with proper placement of the trial lens. The visual field technician in the room also wears a surgical mask, or N95 mask, if available. While Shabto and co-workers recommend deferring 'routine' perimetry, the risks and benefits of perimetry must be weighed with the individual patient and the stage of disease in mind, particularly if there is concern for disease progression.

In addition to clinic modifications for in-person visits, our institution has also actively moved to telemedicine visits to limit physical interactions between individuals. We are exploring 'testing-only' visits in which patients come for all ancillary testing with a technician (including an intraocular pressure check) with a subsequent follow-up telemedicine visit by the clinician. Satellite clinics may also employ drive-through intraocular pressure checks for certain high-risk patients or for those unwilling or unable to come for in-person visits. These drive-through visits could potentially incorporate even more clinical testing in the future, such as virtual reality visual field testing.

The pandemic has created the opportunity for our specialty to advance new and innovative methods of health care delivery and accelerate research into making glaucoma care safer, more convenient, and more accessible to our patients than ever before

While increased attention and adherence to proper disinfection practices are critical to mitigating risk of acquiring COVID-19, successful strategies will incorporate these and other clinic environmental controls in an integrated approach to make the delivery of glaucoma care safer. Prior to COVID-19, thriving glaucoma clinics relied upon significant patient volumes, arrays of imaging and testing, and circuitous clinic throughput with multiple, in-person, interactions to function. We cannot anticipate a return to that clinic model any time soon. Nonetheless, the pandemic has created the opportunity for our specialty to advance new and innovative methods of health care delivery and accelerate research into making glaucoma care safer, more convenient, and more accessible to our patients than ever before. The glaucoma clinic of the future will, and must, be different.


  1. Cleaning Guidance for the Humphrey Field Analyzer (HFA). Zeiss. https://www. en_31_025_0408i_hfa.12415_final.pdf. Published 2020. Updated May 1, 2020. Accessed May 18, 2020.
  2. Quickstart Guide COVID-19 guidance: Cleaning your HFA perimeter. Zeiss. en_31_025_0409ihfa12434_covid-19_hfacleaning_quickstart.pdf. Published 2020. Accessed May 18, 2020.

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