Glaucoma Appointment, Come In or Postpone? An Algorithm For Helping Ophthalmologists Triage.

July 21, 2020

University of Michigan researchers developed a simple algorithm to guide risk-benefit decisions for glaucoma patient coming in for visits.

COVID-19 has been a large, unplanned experiment in risk-benefit thinking and actions that follow. It is the same balancing act over and over again: Do the risks of X outweigh the benefits of Y?

The risk-balance balancing act for patients with chronic eye diseases is an especially high-stakes one. People with serious conditions like glaucoma could lose vision by skipping or postponing care. At the same time, people with glaucoma are disproportionately older and have comorbidities that put them in the COVID-19 high-risk category. Glaucoma is also a disease that

as does COVID-19..

Using data from the EHR system at the University of Michigan’s Kellogg Eye Center, researchers at the center developed a relatively simple, straightforward algorithm for assessing the COVID-19-era risk-benefit tradeoffs for glaucoma patients.

"This algorithm was developed to be easy to implement, given the urgency of the situation; scalable, so that it could assist clinicians with making determinations for large numbers of patients; and flexible enough to accommodate changes in guidance from the CDC or other agencies, which was anticipated, given the rapidly changing environment,” Nikhil K. Bommakanti, M.D., and his colleagues at the Kellogg Eye Center wrote in an their article published on July 17 on the JAMA Ophthalmology website.

One part of the algorithm assigned a “glaucoma severity” score to putting off an appointment; the greater the negative number, the greater the risk. The factors included in that score included incisional intraocular surgery in the past three months, records of high (≥30 mm Hg) or low (<6 mm Hg) intraocular pressure in the past year, considerable visual field loss in one or both eyes, and monocularity (having vision in just one eye).

The other part put a positive number to patients’ COVID-19 risk, and factored in their age, comorbidities, and a few other risks.

The two scores were added together to arrive at an overall score. Different thresholds (0, 25, and 50) yielded different results for how many patients would have been advised to come in for glaucoma care and how many would be told that it was safe enough to postpone their visit. For example, setting the threshold at 0 would have meant 94% (970 of 1,034) of the patients in the sample would have been told to postpone or reschedule their visits. But if is set 50, indicative of accepting more COVID-19 risk, the reschedule and postponement proportion drops to 26.6% (275 out of 1,034).

When Bommakanti and his colleagues tested the algorithm against the 3,303 glaucoma patients at the Kellogg center from March 16 to May 8, they found that it matched up reasonably well to what patients were told to do. About 80% of the patients with 0 or greater scores according to their algorithm were told by a glaucoma specialist that their appointment could safely be delayed. Of the 72 patients with scores of less 0 (indicative of a greater glaucoma risk), about 75% were told to keep their appointment or otherwise get care

Bommakanti and his colleagues said they view the algorithm as a “useful guide” for appointment scheduling while also emphasizing that it is only supposed to be a guide.

“We encourage readers to not rely exclusively on the scores of our algorithm but also consider patient-specific factors that may influence follow-up, such as travel distance, caregiver’s risk of exposure to SARS-CoV-2 when escorting patients to clinic appointments, and whether the patient resides in a skilled nursing facility,” they wrote in JAMA Ophthalmology.