SPOTLIGHT ON TECHNOLOGY & TECHNIQUE

Perimeter automates visual field testing

SVOP by i2eye Diagnostics tracks eye movements to map peripheral vision and guide patient treatment.

By Zack Tertel, Senior Associate Editor

Testing patients’ visual fields is crucial for diagnosing and monitoring conditions and diseases that affect peripheral vision, such as brain tumors or glaucoma.

However, traditional visual field (VF) testing methods are not ideal for all patients, making the SVOP automatic static perimeter by i2eye Diagnostics (Scotland, i2eyediagnostics.com/usa) a potential solution.

Patients using i2eye Diagnostics’ SVOP view a series of lights in various positions on the device’s LED monitor while eye movements are measured with a tracker below the screen.

IDEAL CANDIDATES

Traditional perimeters can be ineffective for patients who cannot participate, such as infants, toddlers and adults with traumatic brain injury, says Gena Heidary, MD, PhD, a pediatric ophthalmologist and neuro-ophthalmologist at Boston Children’s Hospital.

“In my field, I see young children who have neurologic and oncologic diseases that impact peripheral vision, but the ability to evaluate VF is currently limited. We use subjective methods that have a great deal of variability in terms of assessment and interpretation,” says Dr. Heidary.

“The SVOP device is a quantitative method of VF testing that may allow us to identify VF loss and VF progression over time.”

TAKING THE TEST

Patients view a series of lights in various positions on the SVOP’s LED monitor. Rather than responding when prompted, an eye tracker located below the monitor follows patients’ eye movements to determine whether they detect the light.

“The SVOP method is more flexible for our patients. They may sit in free space and the eye tracker monitors the VF response without need for a buzzer,” says Dr. Heidary.

The test averages four to five minutes per eye and at the completion of the test, a print out with the VF map is generated. This can be used to track changes over time.

“Many of my children are being treated for their brain tumors that affect the visual pathways. We have a great need for a tool that may help to determine whether current chemotherapy treatments are effective,” says Dr. Heidary.

Dr. Heidary says that accurate VF testing has benefits that extend to the educational setting, as VF loss may significantly impact a child’s mobility, safety, and ability to read.

“We may be able to more readily identify the need for accommodations to help children with VF loss in the classroom,” she says. “Further, the SVOP method has potential in adults with traumatic brain injury or glaucoma who may otherwise not be able to participate in current methods of VF testing.”

ANY QUESTIONS?

The user-friendly interface and setup make the device easy to incorporate in a practice. Once users choose the desired test on the device’s computer, they press start to begin the test.

When they have encountered problems with operating the device, Dr. Heidary says she has been satisfied with i2eye Diagnostics’ customer service when needed.

“Whenever we have questions we contact them, and it’s pretty immediate that we get a response,” she says.

BILLING AND BENEFITS

To report SVOP, use CPT code 92081 (limited perimetry with a single stimulus). Also, the 2013 national Medicare Physician Fee Schedule allowable for this code was $35.04, according to i2eye Diagnostics.

Dr. Heidary says the device is still imperfect, noting the SVOP device has difficulty with VF testing in patients with profound vision loss or with efferent dysfunction that interferes with accurate eye tracking. Further, she says no VF method is likely to work for the subset of patients who simply cannot attend to the test due to poor cooperation.

Still, for those who have struggled to obtain VF results with certain patients, this device provides practices with a tool that may enhance patient care by expanding the possibilities for VF testing.

Dr. Heidary adds that the SVOP device’s alternative method of VF testing is a game changer.

“The SVOP device offers great promise and opens a new beginning towards VF assessment,” she says. OM