The ESV-3000 ETDRS testing device is quickly becoming the worldwide standard for ETDRS testing. Like the CSV-1000, it uses patented (Patent # 5,078,486) self-calibrated test lighting. The ESV-3000 device incorporates highly advanced LED light source technology. The auto-calibration circuitry constantly monitors the LED light source and calibrates the test luminance to 85 cd/m2 or 3 cd/m2. Other ETDRS testers are not standardized and have no circuitry to control the test lighting. They use "off-the-shelf" non-standardized fluorescent bulbs that require a bulb "burn-in" period. The bulbs must be constantly replaced and each time a bulb is replaced, there is an additional "burn-in" period. No testing can be accomplished during the "burn-in" period.
The ESV-3000 is the only large-format standardized ETDRS testing device. The ESV-3000 allows testing up to 20/200 ETDRS Acuity at a test distance of 4 meters (The CSV-1000 has a smaller footprint and allows testing up to 20/200 at a test distance of 8 feet.). The device is operated by infrared remote control.
The ESV-3000 is designed specifically for clinical trials where large-format ETDRS testing (up to 20/200) is performed at 4 meters. Unlike other large-format back-lit devices for ETDRS evaluation, the light level is calibrated and held constant, allowing the automatic replication of testing light levels from different clinical trials locations or for evaluating before and after treatment. Other devices are not standardized and cannot provide constant test lighting for ETDRS evaluation between locations or over time. A wide variety of ETDRS LogMAR tests are available, including Chart R, Chart 1, Chart 2, Tumbling E and many others.