With the rise in telehealth appointments as a cause of COVID-19, many clinicians have been getting creative by using technologies to ensure glaucoma patients are attending follow-up visits.

Oluwatosin U. Smith, MD, of Glaucoma Associates of Texas in Dallas, explains that physicians have had to “change several aspects of clinical flow and patient interaction, especially regarding diagnostic testing and disease monitoring, with the emphasis on visual field (VF) testing.”

Diagnostic Methods

Initially, VF testing was being performed in the office, but the thorough cleaning of the technology between each appointment caused prolonged delays between appointments.

To eliminate the delay, virtual VF testing and at-home VF tests have been used. Some of the virtual VF tests used include commercial available head-mounted devices, referred to as virtual reality perimetry, such as:

• The VisuALL S for office use (from Olleyes)
• The VisuALL H for home use (from Olleyes)
• IMO (Crewt Medical Systems)
• The C3 Field Analyzer (Remidio).

Additionally, a visual acuity assessment is usually included in most of these systems, as is threshold/suprathresold testing. The VisuALL system in particular can be bought or rented, and patient instruction and training are required.

The Research on VisuALL vs. Standard Automated Perimetry

Dr. Smith referenced a study that compared Olleyes VisuALL with standard automated perimetry (SAP) using the Humphrey Field Analyzer (HFA) The researchers analyzed 102 eyes of 25 healthy patients and of 26 patients with mild to moderate glaucoma, all of whom were evaluated with both tests.

They found that:

• VisuALL test time was longer than with HFA used in SAP.
• The VisuALL mean sensitivity was greater than the HFA mean sensitivity for differentiating healthy eyes from glaucomatous eyes.
• The VisuALL system had lower peak brightness and lower background illumination than the HFA.
• The VisuALL system mimics the format of the HFA printouts, allowing one eye or both eyes to be evaluated simultaneously.

Benefits and Disadvantages of Using Virtual Reality

The benefits of using virtual reality field tests are:

• Lightweight and Portable
• Efficiency and Ease of Use
• Safety
• Ability to be Worn over Glasses

In contrast, the disadvantages include: 

• Potential for patient disorientation when wearing the goggle headset 
• Preference for standard perimetry
• Possible high cost for buying or renting the device
• Need for more clinical studies to test the device with advanced glaucoma and with size V stimulus

The Research on Melbourne Rapid Fields Device vs. SAP

The Melbourne Rapid Fields (MRF) device is a portable tablet-based perimetry for home-based testing (different from virtual reality) in which a patient can use their own glasses. They can perform the test via a link on their own device; there may be a slight learning curve in using the device.

 A study compared MRF with HFA in 12 normal eyes and 78 eyes with glaucoma, and found that there was “a high correlation between the two devices and comparable test-retest reliability.”

Benefits and Disadvantages of Home-Based VF Tests

The advantages of using home-based test, such as the portable tablet VF testing, is that:

• There are no upfront costs as the test can be performed on the patient’s own tablet or computer. 
• The patient can use their own glasses.

The disadvantages include:

• The size V stimulus test is not available.
• Patients may find discomfort with the positioning required.
• A home test requires calibration, which may be challenging to perform at home.

Dr. Smith believes that both virtual reality and at-home visual field tests are tools that will be valuable in offices and telemedicine for patient screening and monitoring.

“The devices have been correlated with the established perimetry method, the Humphrey VF test,” according to Dr. Smith. She notes that there is a need for improvement in the diagnostic and disease progression monitoring capabilities, and that home monitoring VF devices may assist in identifying rapid VF progression.

*Charters, L. (2021, June 1). Taking a step forward in glaucoma patient care. Ophthalmology Times. https://www.ophthalmologytimes.com/view/taking-step-forward-glaucoma-patient-care