New Multifunction Perimetry Device Combines Kinetic and Static Testing

Software and hardware advancements improve integration and clinical utility.

By E. Randy Craven, MD

Visual field testing is a routine part of the comprehensive eye examination, and its use is indispensible for following patients with suspected neurological, retinal, or optic nerve damage. In certain circumstances, visual field testing provides the key clinical data that define the diagnosis and/or disease progression. Its use in ophthalmology is well established, and it is a key diagnostic test for neurologists and neurosurgeons as well.

Some recent evidence has suggested that visual field testing is underutilized in the management of patients with glaucoma.1 Stein et al noted a simultaneous increase in the reliance on what they termed “other ocular imaging” in evaluating patients with open-angle glaucoma and a decrease in visual field testing. In reviewing claims data from a national managed care network, the authors found that the probability of a glaucoma patient undergoing visual field testing while under the care of an optometrist fell from 66% in 2001 to 44% in 2009. Meanwhile, the probability of undergoing “other ocular imaging” increased from 26% to 47% during the same time. The authors drew an interesting conclusion with regard to this trend in visual field testing: “Increased reliance on [other ocular imaging] technology, in lieu of [visual field] testing, may be detrimental to patient care.”

Automated visual field assessment has been an integral part of patient care since the early 1970s. Automated perimetry devices have evolved, and testing modalities have improved to provide clinicians the ability to assess patients’ visual function and track changes over time.

NEW PERIMETRY DEVICE

Perimetry testing exists in various forms to account for the many circumstances clinicians may encounter in caring for patients. Generally, visual field testing is categorized as either static perimetry or kinetic perimetry. The former is performed with automated equipment and is potentially the most widely used form for mapping the visual field, and the latter is appropriate for establishing the boundaries of peripheral vision in patients who are unable to perform automated testing.

A new perimetry device, the Octopus 900 Pro (Figure 1), offers clinicians the potential to perform both types of perimetry testing with a single device. This much-improved visual field device offers clinicians a new level of flexibility to analyze, track, and define patients’ visual fields using a separate Windows-based computer.

The Octopus 900 Pro offers a full range of visual field testing for diagnosis and follow-up by including standard white/white perimetry, computer-assisted Goldmann kinetic perimetry, short-wavelength automated perimetry, and flicker perimetry for early detection in a single device. These tests can be used for early detection, monitoring for progression, and looking for preservation of visual field. This variety of testing abilities makes the device useful for monitoring all forms of disease that can affect the visual pathway or the occipital lobe and for understanding diseases that are directly damaging the retina.

FUNCTIONALITY AND CLINICAL BENEFITS

The automatic eye tracking software and fixation control in the Octopus 900 combine to improve the data’s reliability. Using camera-to-monitor fixation, the unit recognizes when a patient is not fixated or has blinked and will automatically reproduce a stimulus that may have been missed. In addition, the device also offers automatic eye tracking to ensure central fixation. As is true with any types of visual field instrument, however, patients’ responses to the testing will vary, so caution should still be taken in interpreting results. Even with the improvements in technology inherent to the Octopus 900, it is still recommended that tests be repeated to improve testing accuracy.

FLEXIBILITY AND ACCESSIBILITY

The EyeSuite software in the Octopus 900 has unique features such as the ability to import visual field data from other visual field instruments like the Humphrey Perimeter (Carl Zeiss Meditec). This feature allows clinicians to continue testing patients on the patterns they have used in the past (such as a 30-2 threshold), and it permits a clinic to create a centralized database for its visual fields. Clinicians can compare several field tests using a customizable view of historical data, which helps improve the ability to track patients’ vision and aids in making accurate treatment decisions quickly (Figure 2).

VERSATILITY

Static Perimetry
Clinicians can perform a full range of testing patterns in static mode, including 32 point, 30-2, 24-2, and 10-2. The printout of the test can be made to resemble those produced by automated Humphrey perimeter (Figure 3). In addition to the standard linear testing patterns, the Octopus 900 also offers two unique testing patterns that are based on ocular physiology: the G program (a 30° field for glaucoma assessment) and the M program (a 10° field for analyzing the macula), the latter of which is correlated with a nerve fiber bundle map (Figure 4).

Goldmann Kinetic Perimetry The Octopus 900 Pro is the only computer-assisted perimeter that retains the capabilities and specifications of the original Goldmann Kinetic Perimeter. In a recent study by Rowe and colleagues, the Octopus 900 Pro was found to be equivalent in testing times and results to a manual Goldmann Perimeter.2

Features of the kinetic testing module include the ability to start a test from scratch and draw in any size stimulus using a predetermined vector speed. The 900 Pro also reduces subjectivity from variable test patterns by allowing the setup of standardized templates via EyeSuite’s automatic test capabilities. These tests are fully customizable to match the physician’s current testing methodologies. Even within these templates, the operator has the ability to add additional test vectors.

Other key features of the 900 Pro include special vectors to assess reaction time, measurement of the isopter area measurement, and the ability to export kinetic tests into an electronic medical record (EMR) or image management system. This allows clinicians to more accurately and efficienty monitor peripheral retinal conditions such as retinitis pigmentosa (Figure 5).

DIGITAL INTEGRATION

One limitation of many visual field testing devices on the US market is a limited capacity for network integration. Several devices still do not communicate with EMR systems used in eye care practices. This is not an insignificant problem, especially given that the Affordable Care Act has set incentives for EMR integration, and that practitioners without EMRs will start to see penalized Medicare reimbursement rates starting in 2015. The use of EMRs is more or less a requirement of modern medical practice, and so it is important that all of the testing modalities used in the office are compatible in this digital age of medicine. The advantage of digital integration is the ability to perform trend analysis over time easily and in a more efficient manner compared with printouts. The on-board EyeSuite Progression Analysis Software allows for seemless connectivity throughout the clinic.

Once testing is complete, the software can be customized to automatically send the image files of the visual fields to a centralized database, an EMR or image management system, and a server for data backup. These features help improve efficiency and patient throughput.

CONCLUSION

The improvement in visual field testing functionality and software combined with electronic integration will allow visual field testing to continue to be an essential diagnostic tool to assess patients and provide more advanced progression analysis. Moreover, the advancements in the Octopus 900 ease the burden on clinicians attempting to make treatment decisions when assessing several years of visual field testing for their patients.

Section Editor Eric T. Brooker, OD, is in private practice at the Advanced Vision Institute, Las Vegas. He is a consultant to AcuFocus, Inc. Dr. Brooker may be reached at (949) 241- 9077; drbrooker1@aol.com.

E. Randy Craven, MD, is the chief of glaucoma at the King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia, and an associate professor at Johns Hopkins Wilmer Eye Institute in Baltimore. He has received research funding from Haag-Streit. Dr. Craven may be reached at ercraven@yahoo.com.

  1. Stein JD, Talwar N, Laverne AM, et al. Trends in use of ancillary glaucoma tests for patients with open-angle glaucoma from 2001 to 2009. Ophthalmology. 2012;119(4):748-758.
  2. Rowe F, Hanif S. Uniocualr and binocular fields of rotation measures: Octupus versus Goldman. Graefes Arch Clin Exp Ophthalmol. 2011;249(6):909-919.