Central Vision Analyzer
The Central Vision Analyzer (CVA), available through Visoptics, is designed for the practitioner’s office examination lane but can also be operated in a screening environment. Similar to other electronic charts, high and low contrast lettered charts can be presented for refraction or standard chart testing. So where is the difference you ask? The CVA also offers an interactive section that rapidly measures an individual’s central vision under conditions that simulate real world activities. At each presentation a Landolt C is tumbled one of four positions, and within 4 seconds the patient must respond recognition of the correct position via a joystick. The program adapts to patient response timing walking back and forth across the threshold with finer steps balancing the requirements of clinical expediency (requiring less than 2-3 minutes for testing both eyes with instructions) but approaching the true threshold of psychophysical testing with accuracies and reproducibility that are similar to or often better than those achieved with standard ETDRS chart testing. The Central Vision Analyzer is the only vision test that measures the threshold reproducibility for every patient during testing.
The CVA may test up to 6 environments, usually combining 3 mesopic and then 3 photopic (glare) environments; for example, restaurant dining or driving at dusk, playing golf or tennis in sun environments equivalent to visualizing a golf ball with the sun overhead and at 15o off-axis. The luminance and contrast conditions of the vision tasks have been extensively validated.
The CVA has been used to evaluate real-world functional vision in eyes with many types of pathology as well as for therapeutic trial outcomes; cataracts pre and post surgery with various IOL’s implanted, patients with AMD and HIV disease with and without retinopathy or in eyes of diabetics with retinopathy and macular edema undergoing a number of treatments. It has been used in screening settings including two Special Olympics, in which it performed well in children of all ages with mental difficulties, correlating better with the diagnosed ocular pathologies than the HOTV chart measurements.
This device is FDA approved for a practitioner’s supervised use.