contrast sensitivity 2 charts

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  • 1. CONTRAST SENSITIVITY(CHARTS)Jagdish Dukre

2. no international recommendation on how contrastof visual acuity charts should be defined. Therefore there are differences in the contrast oftests of different manufacturers. 3. Test results are marked on the recording sheet at the levelused (see example below) going along that level towardthe right until the visual acuity value, measured at thatcontrast (A at 1.2%, B at 2.5%), is reached. If the persons visual acuity was 20/20 (6/6, 1.0), the lineconnecting these three points, A, B and X, depicts theslope of the contrast sensitivity curve of this person. 4. Cambridge low contrastgratings It is a rapid and simple screening test for contrastsensitivity. Performed at a distance of 6m. It comprises of 12 pair of plates consisting ofstripes of varying contrast. First one is for demonstration and rest are for theproper testing and are numbered from 1-10. The plates are changed sequentially starting fromplate 1 till the patient fails to respond. 5. Cambridge low contrastg ratings Then a new series is begun starting 4 plates prior towhere the patient failed to respond. Four such series are completed and the score ofeach series is noted (numbered as per the numberof plate read) and added. The final total value is converted into contrastsensitivity from the provided table. 6. Functional Acuity Contrast Testing(FACT) FACT charts were developed by Dr. ArthurGinsburg. FACT comprises of a chart with sine-wave gratingsof varying contrast as well as varying spatialfrequencies. It is an accurate and comprehensive grating chartthat tests functional visual acuity. This test is performed at a distance of 10 feet. 7. The chart tests five spatial frequencies (sizes) and nine levelsof contrast. The Contrast varies in a row, decrease from left to right. And the spatial frequencies increase as one move down thevarious columns from top to bottom 8. The patient determines the last grating seen for each row (A,B, C, D and E) and reports the orientation of the grating: right,up or left. The last correct grating seen for each spatial frequency isplotted on a contrast sensitivity curve. 9. Vistech VCTS 6000 and 6500Contrast Sensitivity Tests There are two Vistech CS tests; model 6000 is used totest near (i.e., reading distance) sensitivity at 40 cm (16in), and model 6500 tests far sensitivity (3.05 m = 10ft). Both tests use charts with 5 rows of sine-wave gratings. The rows increase in spatial frequency from the top tobottom of the chart, and on each row the gratingsdecrease in contrast from left to right. 10. Vistech VCTS 6000 and 6500Contrast Sensitivity Tests The observers task is to indicate each grating'sorientation (leaning left, vertical or leaning right); The lowest contrast grating determines the sensitivityscore for that spatial frequency. The sensitivity at each spatial frequency can be used toplot a csf for the observer, and can also be compared tothe age norms provided for the test. 11. Vistech VCTS 6000 and 6500Contrast Sensitivity Tests 12. CSV-1000E It is widely used in theworld This test provides four rowsof sine-wave gratings The test distant 2.5 meters, Gratings test the spatialfrequencies of 3,7,12,and 18cycles/degree $250.00 13. CSV-1000E Useful for the evaluation of ocular disease(particularly cataracts, glaucoma, optic neuritis,diabetes, and macular degeneration), contact lenses,and refractive surgery. For cataract documentation, a functional acuity scorecan be obtained directly from the test scoring sheet.$250.00 14. CSV-1000-S This test presents standard visual acuity from20/15 to 20/200, two rows of spatial frequencies(6 and 12 cycles/degree) and a real-worlddrivers scene.$250.00 15. CSV-1000-S Used for in or out of office screening and forcataract evaluation The test is very useful for cataractdocumentation as it provides a standard acuityscore, a functional acuity score and a real-worldsimulation.$250.00 16. CSV-1000 LAN C Provided the same tests asstandard CSV-1000-Sexpect that acuity ispresented in landolt cformat Useful when patient cantread English alphabet 17. CSV-1OOORS The CSV-1000RS test face is usedwidely for screening refractive surgerypatients. The test presents ETDRS LogMARacuity from 20/10 to 20/100 and onerow of spatial frequency at 12cycles/degree. The patient can be easily screened inthe examination chair for ETDRS acuityand contrast sensitivity. If a contrast sensitivity deficit is found,retesting the patient with all fourspatial frequencies using the CSV-1000E is recommended. 18. CSV-1000 CVA Used to evaluate bothcontrast sensitivity andlow contrast acuity Contain 3 contrastlevels 19. CSV -1000 1.5 cpd It is special test designedspecifically for food anddrug administration clinicaltrials Recommended test distanceof 8 feet, The gratings test one spatialfrequency of 1.5cycles/degree.$250.00 20. Contrast sensitivity view intesters Sine-wave grating contrastsensitivity testing isavailable in view-in testers The advantages are thatthey eliminate the need tocontrol room light levelsand can be used in smalltest space 21. Pelli-robson letter contrastsensitivity It is simply of quickly measured and provides areliable measurement of low spatial frequencycontrast sensitivity ( 0.5 2 cycles)Method: Sit the patient 1m from the chart with his or hercorrection if needs Occlude one eye or with both eye With both eyes result high with 0.15 log units 22. The patient is asked to read the alphabets startingfrom left hand corner, when he fails to respond several seconds are givento him to retry and guess the alphabet. The score of the test is recorded by the faintesttriplet out of which at least 2 letters are correctlyidentified. The log CS value for this triplet is given by thenumber on the scoring pad nearest to the triplet,either on the left or the right side. 23. Record the contrast sensitivity score in log unitsRReessuullttss:: For patient 20-50 years old monocular contrastsensitivity should be 1.80 log unit Patient less than 20 years and older so yearsmonocular contrast sensitivity should be 1.65 logunits 24. Most common errors Not allowing patient at least 20 secondfor letters to become visible Not pushing patient to guess Illumination is poor 25. Mars Perceptrix Letter Contrast Test The Mars Perceptrix contrast test indicates thelowest contrasts your patients can perceive. With the Mars test, it is the contrast, and not theletter size, which diminishes from the beginning tothe end of the chart. The letters are large, insuring that most patients,even those with low vision, can see them. The Mars Perceptrix test comes with 3 low contrastcharts, instructions and storage pouch. 26. Mars Perceptrix Letter Contrast Test$395.00$150.00 each 27. Mars Perceptrix Numbers Contrast Chart$395.00$150.00 each 28. Adult Near Contrast Test This adult near vision low contrast test featuresboth ETDRS Format and Continuous Text in100%, 25%, 10%, 5%, and 2.5% contrast level. Continuous text letter sizes range from 6/30 to6/6 equivalent in each contrast level. ETDRS format letters sizes range from 6/120 to6/3 equivalent in 17 increments for each contrastlevel. The near vision contrast booklet contains 7 pagesmeasuring 15.8 cm x 15.8 cm. testing distance : 40 cm 29. $140.00 30. Sloan Letter Low Contrast FlipChar t Easily measure, record, and detect changes in thetransfer of visual information when the change affectsonly visual acuity at low contrast levels. Charts include the following contrast levels: black,25%, 10%, 5%, 2.5%, and 1.25%. Each chart includes recording forms and instructions.6 pages, 8.25 cm x 22.9 cm.$95.00 31. Pacific Acuity Test The Pacific Acuity Test is a vanishing optotype test It is designed with opposing figures to provide asimple forced-choice testing format. It is appropriate for nonverbal children andindividuals with developmental disabilities who areunable to respond to standard optotype recognitiontests. Each card has two figures, a simple face, and anopposing oval target of the same overall size butwith interior details that allow discrimination fromthe face at the threshold of acuity. 32. Pacific Acuity Test$680.00 33. Pacific Acuity Test The full test kit consists of 18 cards with two cardsat each level. The cards at each acuity level have a differentposition of the face target compared to the opposingoval figure. Each card can be presented at either 50 cm or 1meter But the 1 meter test distance is recommended forgreater accuracy and comparison to distance visualacuity tests. The test range from 20/400 down to 20/20 allowsfor testing a broad range of visual acuity 34. Cardiff Pediatric Low Contrast Charts Cardiff Low Contrast Charts are designed to measurecontrast sensitivity indeveloping toddlers and young children,as well as in older children and adults with intellectualimpairment. Test targets are pictures of the same size thatdecrease in contrast between light and dark bands. The contrast sensitivity is determined by the faintestbands for which the target is visible. The test covers 12 contrast levels using 3 cards ateach level (36 cards total) using the preferentiallooking technique. 35. Cardiff Pediatric Low Contrast Charts Contrast levels begin at 46% and decrease to 1%, whichequates to sensitivity levels of 2.17 to 100. Cardiff Low Contrast Chart test is conducted at distance of 50 cm, the targets represent 1.9 cpd (6/90) distance of 1 m the targets represent 3.8 cpd(6/45). distance of 25 cm the targets represent 1.0 cpd (6/180).$1,650.00 36. Hiding Heidi Low Contrast FaceTest Visual communication is the most importantcommunication method during the first year oflife. The ability to detect objects of low contrast is animportant component of the visual system. For example, facial expressions are mediated byfaint shadows and changes in the contours of themouth and eyes. 37. Hiding Heidi Low Contrast FaceTest Determining the levels of contrastthat an infant can detect helpsprovide

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