Worldwide Accessible Comprehensive Visual Field Test and Diagnosis System
Purpose: To provide a worldwide accessible, comprehensive 3D threshold Amsler Grid test that allows for screening and examining people worldwide over the Internet and monitoring astronaut health in space. Further, to provide an automated, objective characterization of scotomas, offering a promising perspective towards modern computer-assisted diagnosis in medicine.
Methods: We have created an Internet-deployable version of the 3D computer-automated threshold Amsler grid test, recently introduced by Fink (JPL/Caltech) and Sadun (Doheny/USC) (see ). With one eye covered the patients are positioned at a fixed distance in front of a computer, equipped with either a touch-sensitive monitor or a regular monitor using a mouse. While focusing on a varying fixation marker the patients trace with their finger/mouse the areas on an Amsler grid that are missing from their field of vision. Various degrees of contrast of the Amsler grid are presented by repeating the test at different grayscale levels. The results are recorded and transmitted via the Internet to a central server, where a topographical contour map, a 3D depiction of the central hill-of-vision, and a comprehensive scotoma characterization (area, volume, and slope distribution of visual field loss, etc.) are generated and sent back to the client.
Results: The now Internet-deployable 3D computer-automated threshold Amsler grid test has shown, in multiple clinical pilot studies, to be innovative and successful for fast (4-5 minutes per eye), easy (use of finger, touch pen, or mouse), accurate (spatial resolution 1° to 15’), non-invasive, and comprehensive visual field testing. Conditions such as optic neuritis, AION, ARMD, glaucoma, and ocular hypertension have been successfully detected by the 3D visual field test. A software package has been developed for the automated, comprehensive evaluation of scotomas in 3D with respect to area of visual field loss as a function of contrast sensitivity, overall volume of visual field loss as compared to a “normal” hill-of-vision, and slope distribution of the scotoma boundaries.
Conclusions: This Internet-deployable automated test & diagnosis system is a significant step towards screening and examining people worldwide, monitoring astronaut health in space, and to assist physicians, both on Earth and in space, with an independent second opinion or provide expertise where otherwise not readily available.
Gamma calibration of examination monitor
Example of 3D Amsler grid test setup
Example of one Amsler grid contrast level
Boundary between vision and no vision
Filled in area of patient visual field
Patient visual field at lower contrast level
Example test result with analysis: ARMD
Analysis result: individual slope data
Analysis result: slope histograms
Example test result with analysis: glaucoma
Wolfgang Fink, Ph. D.
Senior Researcher at Jet Propulsion Laboratory (JPL)
Visiting Research Associate Professor of Ophthalmology at University of Southern California (USC)
Visiting Research Associate Professor of Neurosurgery at University of Southern California (USC)
Visiting Associate in Physics at California Institute of Technology (Caltech)
California Institute of Technology
Visual and Autonomous Exploration Systems Research Laboratory
15 Keith Spalding (corner of E. California Blvd & S. Wilson Ave)
Mail Code 103-33
Pasadena, CA 91125