Why the Wise Eyes™ App Goes Beyond the Amsler Grid
Performing the Wise Eyes assessments daily can help patients catch changes quickly.
Static Field Testing Works When Amsler Fails.
The Amsler grid relies on straight lines, stable fixation, consistent viewing distance for accuracy, and conscious recognition of distortion and change. However, patients also often adapt to defects; in other words, they fill in distorted areas. They miss slow or subtle changes, and they overlook scotomas unless they are large and sudden. Static field testing bypasses some of these issues by reducing perceptual filling-in or adapting by stressing the temporal contrast processing in the visual system, and making abnormal areas stand out perceptually, even though patients cannot define distortions in lines like the Amsler. In essence, the retina reveals dysfunction more readily when challenged dynamically than when asked to judge static geometry.
A Combined Testing Approach
Static field testing is not new. But the ability to put it in a digital format is! The evidence shows that dynamic fields can reveal macular dysfunction earlier than static grids. Combining the static field with Amsler improves detection of exudative AMD for clinicians managing patients at risk of developing wet AMD. A combined functional testing approach offers a more complete picture of macular health versus the Amsler grid alone.
Real-World Challenges of Paper Amsler Grids
We’ve passed out hundreds, if not thousands, of Amsler grids over our careers. And let’s face it, most of grids don’t make it home or end up not getting used. If they are used, they are typically used incorrectly. But the Amsler grid has been the standard for decades. While it is simple and inexpensive, the limitations are well-documented. Particularly the low sensitivity for early, subtle changes, the reliance of patient’s fixation, having the patient hold the card consistently at the correct distance, remembering what the previous defect looked like and subsequently determining if it has changed, and most importantly, remembering to even perform task.
The Wise Eyes™ App Addresses All These Concerns.
The Wise Eyes™ app begins testing with the less widely known Static Field, also known as static field campimetry, white noise field, noise field perimetry, and TV static. It was first described in the late 1980s.
Aulhorn and Kost described it as a new form of perimetry. Patients viewed a field of “small black and white dots flickering randomly at a high frequency (such as the white noise field of a TV screen)”. This technique takes advantage of how the visual system processes dynamic stimuli. Static Field method offers a more sensitive way to detect functional changes in the macula, especially when used in combination of the traditional Amsler grid.
What Patients See During Static Field Testing
In normal retinas, the Static Field appears to be a uniform field of flickering dots. In patients with AMD or other macular pathologies, the field appears to have dark areas, often described as a cloudy or shadowy appearance. This occurs because the visual system is highly sensitive to temporal and contrast changes. Even small disruptions of the retinal pigment epithelium (RPE) can alter how the dynamic static field is perceived.
Macular degeneration starts with small, subtle distortions in the RPE. This produces relative scotomas, difficult to pick up on an Amsler grid. Relative scotoma can appear as distortions or metamorphopsia. This is prior to dense or absolute scotoma, which may occur later, and is easier to spot on an Amsler. The geometry-based Amsler grid may miss early changes. Static Field differentiates the subtle differences between healthy and diseased retinal areas.
Clinical Evidence Supporting Static Field Testing
The evidence for static field: Sensitivity and specificity increase dramatically when combined with the Amsler grid, according to a study by Moore and Choi in 2018. At that time, there were no digital platforms for the static field. In 2015 at an ARVO annual meeting, Koike et al. evaluated static field for screening and central scotomas and macular degeneration. Their key finding was “Combining noise field perimetry (Static Field) with Amsler-type testing increased sensitivity for detecting exudative AMD compared to either test alone.” The same year, a published PubMed by Schwartz and Loewenstein discussed the necessity of detecting AMD early. They compared the detection methods OCT, near vision charts, PHP, SDH, MMT, and Static field They concluded that Static Field with Amsler was superior to Amsler alone. Still, the disadvantage was that it was not available for frequent home monitoring.
Enter Wise Eyes™!
Wise Eyes™: Beyond Amsler
Two tests are better than one: Amsler Grid & Static Field
On-screen Marking
Distance Monitoring
Automated Reminders
Illustrated, Easy-To-Follow Instructions
Layered Results with subscription
Aulhorn E, Köst G. Rauschfeldkampimetrie. Eine neuartige perimetrische Untersuchungsweise [White noise field campimetry. A new form of perimetric examination]. Klin Monbl Augenheilkd. 1988 Apr;192(4):284-8. German. doi: 10.1055/s-2008-1050114. PMID: 3404938.
Schwartz R, Loewenstein A. Early detection of age related macular degeneration: current status. Int J Retina Vitreous. 2015 Dec 1;1:20. doi: 10.1186/s40942-015-0022-7. PMID: 27847613; PMCID: PMC5088451.
Moore L, Choi A. Macular Disease: Home Testing Options Reviewed. Mivision Eye Care, August 31, 2018
Koike K, Hohenberger M, Wannamaker K, Trivedi RH, Kylstra JA. Noise Field Perimetry for Screening Central Scotomas in Age-Related Macular Degeneration. ARVO Annual Meeting Abstract, June 2015
