Contrast sensitivity provides the best method to evaluate the true visual capability of patients with poor vision. Virtually every low vision practitioner recognizes the problem of using visual acuity to measure the real-world visual capability of low vision patients. It is not uncommon for patients with the same level of standard acuity to have significantly different real-world visual capability and mobility. VectorVision offers a range of contrast sensitivity and letter contrast sensitivity tests that provide accurate and standardized evaluation for low vision patients.
Recommended test distance is 1 meter for these tests
The CSV-l000LV is designed for evaluating patients who have worse than 20/70 acuity. At a test distance of 1 Meter, the letter size is equivalent to 20/630 ETDRS LogMAR acuity. This test presents letters at 8 contrast levels.
The unique design of the CSV-l000LV matches the visual capability of low vision patients and provides for a more sensitive and reliable test.
The CSV-l000LV improves the office efficiency for evaluating low vision patients. The test is very fast because of the specific contrast levels chosen for the test and because row isolation eliminates the fixation problems encountered with other tests.
No special lighting or lighting calibration is required for the examination. Further, when needed, the test can easily be moved closer to the patient without adjusting the lighting.
The CSV-1000LV can also be used to test patients who have good acuity (better than 20/70). For these patients, the test distance should be 3 meters.
CSV-1000-1.5cpd Sine Wave Low Vision Test
The CSV-1000-1.5cpd is a special test face designed for low vision evaluation by testing one spatial frequency using a very large field size.
At the 8 foot test distance, the test presents gratings with a spatial frequency of 1.5 cycles/degree and at the 4 foot test distance the test presents a 0.75 cycles/degree grating.
ELCT (Evans Letter Contrast Test) For Use with the ESV-3000
VectorVision recently expanded the CSV-1000LV test to a new test that offers 16 contrast levels. This test, the ELCT, provides a substantial improvement over other letter contrast tests which are simply printed charts, such as Pelli Robson or the Mars Test, because the ELCT uses a LogMAR-related acuity letter and is tested in a standardized format. The ELCT is used for testing low vision patients in conjunction with the ESV-3000. The test is administered at 1 meter for low vision patients