What is a Vistech chart?

What is a Vistech chart?

The Vistech CS chart was first introduced in 1984,27 and contains circular photographic plates of sine wave gratings arranged in five rows (spatial frequencies 1.5, 3, 6, 12 and 18 cycles per degree (cpd)) and nine columns (contrast levels).

What is normal contrast sensitivity?

Norms for different levels of contrast loss include profound loss at less than 0.48 log contrast, severe at 0.52-1.00, moderate 1.04-1.48, normal for individuals older than 60 years is 1.52-1.76 and normal for individuals age 60 and younger is 1.72-1.92 log contrast.

What is contrast sensitivity chart?

5. CONTRAST SENSITIVITY CURVE C . S is presented as curve which plots the lowest contrast level a patient can detect for specific size target.

Which one is affecting contrast sensitivity?

Contrast sensitivity is also influenced by pupil size. Changes in pupil size negatively affect contrast sensitivity at both ends of the spectrum. It has been suggested that contrast sensitivity is reduced by diffraction with a miotic pupil, and possibly by spheric aberrations with a dilated pupil.

What causes loss of contrast sensitivity?

Low contrast sensitivity can be a symptom of certain eye conditions or diseases such as cataracts, glaucoma or diabetic retinopathy. Changes in contrast sensitivity also can occur after LASIK, PRK and other types of refractive surgery.

What is poor contrast?

Poor contrast sensitivity also can increase your risk of a fall if you fail to see that you need to step down from a curb onto similarly colored pavement. Low contrast sensitivity can be a symptom of certain eye conditions or diseases such as cataracts, glaucoma or diabetic retinopathy.

How do you read a contrast sensitivity test?

The symbols of the visual acuity charts are close to the maximum contrast. If the lowest contrast perceived is 5%, contrast sensitivity is 100/5=20. If the lowest contrast perceived by a person is 0.6%, contrast sensitivity is 100/0.6=170.

What is high contrast sensitivity?

The higher the contrast sensitivity, the lower the contrast level at which the patient can detect a target. The contrast of the grating is calculated as shown in the image above and contrast sensitivity is the inverse of contrast threshold.

How does a Pelli-Robson chart measure contrast sensitivity?

Pelli-Robson test measures contrast sensitivity using a single large letter size (20/60 optotype), with contrast varying across groups of letters. Specifically, the chart uses letters (6 per line), arranged in groups whose contrast varies from high to low.

What is normal contrast sensitivity Pelli-Robson?

In a study of 10-year-old children, the normal mean for the Pelli-Robson test was 1.66. 10 It was 1.86 in a study of children aged 6 to 12 years. 23 Our results in the 6 to 19 year group were slightly better than those in the study of 10 year olds but worse than in the study of 6 to 12 year olds.

What kind of contrast sensitivity tests does vistech have?

Vistech VCTS 6000 and 6500 Contrast Sensitivity Tests. A new contrast sensitivity vision test chart. The Vistech contrast sensitivity chart s have been. BAILEY LOVIE CHART Low contrast acuity testing & acuity testing in presence of glare.

Are the vistech and fact CS charts suitable for cataract surgery research?

The Vistech and FACT CS charts are ill suited for refractive or cataract surgery outcomes research.

Are contrast sensitivity charts useful for cataract and Refractive Surgery?

The usefulness of Vistech and FACT contrast sensitivity charts for cataract and refractive surgery outcomes research The Vistech was confirmed as providing poorly repeatable data. The FACT chart, likely because of a smaller step size, showed slightly better retest agreement.

Is there a contrast sensitivity chart for the VCTS 6500?

ABSTRACT Two contrast sensitivity charts (Vistech and Pelli-Robson) have become available to the ey. Thirdly, we determined the contrast sensitivity function using the VCTS-6500 only under photopic conditions.