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Selecting a Visual Field Analyzer for the Future

Aiming to address long-standing challenges without sacrificing accuracy

by Benjamin Gaddie, OD, FAAO

Visual field (VF) testing is a critical tool for evaluating vision loss and identifying and monitoring diseases such as glaucoma. For all its diagnostic virtue, it has long been a pain point for eye care professionals, their practices, and most especially, their patients.

Standard automated perimetry (SAP) consumes considerable time and physical space, negatively impacting practice efficiency. The test is difficult and uncomfortable, causing fatigue and frustration among patients and technicians. This can lead to poor, if not useless, results due to fixation losses, false positives, and other reliability issues with the field.

Recently, some practices within the Keplr Vision network needed new visual field analyzers, creating the perfect opportunity to explore new technologies that might address these long-standing issues. We evaluated the Tempo Binocular Perimeter (Topcon Healthcare). Introduced in November 2023, it is a tabletop device with a compact, ergonomic footprint that can be used in ambient room lighting, eliminating the need for a dedicated dark room. It is stand-mounted, which helps ensure proper patient positioning. Tempo can test the right and left eyes separately or use a binocular approach in which the patient does not know which eye is being tested. Based on the clinical evidence, Tempo performed 39% faster than SAP in clinical testing.^1,2

Through our evaluations, we found that Tempo provides the equivalent benefits of a wearable device in terms of ergonomics, but with the accuracy, sensitivity, and specificity of a traditional SAP. We are impressed with Tempo’s AIZE-Rapid algorithm with 24-2. It compares favorably to SITA Fast, which we have used.^3,4 Based on these findings, Tempo is the device we selected for our practices needing new VF platforms.

Experience in the clinic

Our experience with Tempo has been positive. I have received better results with Tempo than SAP because the increased efficiency means fewer test reliability issues. In some instances, I have found that defects identified and tracked over time on past VF instruments are not as pronounced simply because Tempo allowed us to obtain a reliable visual field — not because of a difference in the sensitivity of the testing but rather the speed of the test. For this same reason, I have also had cases in which I found VF defects where I had not before.

Many patients are poor VF takers due to the challenges inherent to traditional SAP. Many dread the test (and, in my experience, are not afraid to let you know). Since implementing Tempo, we have received positive feedback from many patients and technicians administering the test.

Tips and considerations

A tabletop VF analyzer is an appropriate choice for any practice, from a glaucoma specialty clinic to primary eye care offices focused on screening. Its speed is a benefit with any patient, but particularly children and patients with disability. I recently saw a patient with end-stage glaucoma who had broken her back and was in a movement-restrictive brace. Using the tabletop analyzer over a traditional bowl perimeter, she was able to put her head forward just enough to take the test, ensuring that I would be able to track her progression. The only limitation I have found is with amblyopes, for whom the dominant eye takes over, sometimes impacting the accuracy of the results. However, monocular testing is an option on Tempo.

Because Tempo has a small footprint, it can be placed on a counter or examination room desk. It is also portable enough to take off-site (for example, performing examinations in a nursing facility or screenings at a health fair). The Tempo can be connected to Topcon’s Harmony Clinical Image and Data Management Solution, which we utilize at Keplr. Reports are automatically exported upon test completion, making it very efficient.

If you are considering transitioning to a new VF device, keep copies of VF results captured with your previous perimeter so they can be compared. You are not going to have progression analysis immediately; you must have multiple visits for those data to aggregate and be comparable. I do not anticipate that there will be a bridge or fix for backwards comparison from older or previous visual fields. There is a transitionary period where you are going to have to rely on your own thinking/extrapolation, but after the first year, it becomes easy to track these patients over time. For the first six months, I often evaluated the Tempo results side by side with previously captured SAP results. Now, I estimate doing so on only 1 in 50 patients.

Conclusion

Considering the importance of accurate VF results and the challenges inherent in traditional SAP testing, it is worth evaluating the many innovative technologies now available. New technologies like Tempo offer a smaller, faster alternative without sacrificing accuracy. Your patients (and your staff) may just thank you for it.

References:

1. Eslani M, Nishida T, Moghimi S, et al. Comparison between new perimetry device (IMOvifa) and Humphrey Field Analyzer. Invest Ophthalmol Vis Sci. 2022;63(7):1272-A0412.

2. Nishida T, Eslani M, Weinreb RN, et al. Perimetric comparison between the IMOvifa and Humphrey Field Analyzer. J Glaucoma. 2023;32(2):85-92. doi:10.1097/IJG.0000000000002134

3. Nomoto H, Matsumoto C, Okuyama S, et al. A new static visual field test algorithm: the Ambient Interactive ZEST (AIZE). Sci Rep. 2023;13(1):14945. doi:10.1038/s41598-023-42266-z

4. Nishida T, Weinreb RN, Arias J, Vasile C, Moghimi S. Comparison of the TEMPO binocular perimeter and Humphrey field analyzer. Sci Rep. 2023;13(1):21189. Published 2023 Dec 1. doi:10.1038/s41598-023-48105-5