[One Day, One Knowledge #3] Understanding Ocular Age with Contrast Sensitivity Tests
- ooleycare
- Jul 2, 2024
- 2 min read
Updated: 2 days ago
When it comes to eye health, traditional acuity tests have long been the standard method for assessing vision quality. However, there's a way to measure your "ocular age" by changing just one aspect: the contrast of the word with the background. This is known as the contrast sensitivity test.
Contrast sensitivity refers to the ability to distinguish objects from their background based on differences in contrast, rather than just their size or shape. It's particularly useful for evaluating patients with conditions like macular degeneration, glaucoma, traumatic brain injury, amblyopia, and optic nerve disorders such as multiple sclerosis. It's also beneficial for people with high visual demands, such as firefighters or pilots.
How is Contrast Sensitivity Tested?
Contrast sensitivity can be easily tested using the Pelli-Robson contrast sensitivity chart. This test is similar to traditional acuity tests but assesses your ability to detect letters that become less contrasted with the white background as your eyes move down the chart.
Scoring: The tester is given a score based on the last group of letters where 2 or 3 letters were correctly read. The Pelli-Robson score is a logarithmic measure of the subject's contrast sensitivity. For instance, a score of 2.0 indicates normal contrast sensitivity of 100%, meaning the subject could read letters with a contrast of 1%.
Interpreting Scores: A score of less than 1.5 suggests visual impairment, while a score of less than 1.0 indicates visual disability
According to studies from the SEE project, there is a negative correlation between age and contrast sensitivity, meaning contrast sensitivity tends to decline with age.
Why is Contrast Sensitivity Important?
Comprehensive Eye Health: It provides a more complete picture of your eye health beyond just seeing clearly defined objects.
Functional Vision: It better reflects real-world visual challenges, such as driving at night or reading in low-light conditions.
Contrast sensitivity testing is a valuable tool for understanding your ocular age and overall eye health. It helps detect vision problems that might not be apparent with traditional acuity tests and offers a better understanding of how your eyes function in everyday situations.
Stay tuned for more insights and updates on keeping your eyes healthy!
Reference:
American academy of ophthalmology. (2024). 2020–2021 BCSC Basic and Clinical Science Course™. Retrieved from Chapter 03: Retinal Physiology and Psychophysics: https://www.aao.org/education/bcscsnippetdetail.aspx?id=9598aff8-1495-4365-9185-487b6ec7ee11
Heiting, G. (2019, February 27). All about vision . Retrieved from Contrast sensitivity testing: https://www.allaboutvision.com/eye-exam/contrast-sensitivity.htm
Vectorvision. (2024). vectorvision. Retrieved from Ability to Detect Subtle Shades of Gray in the Real-World: https://www.vectorvision.com/contrast-sensitivity-background/
Rubin GS, Bandeen-Roche K, Huang GH, Muñoz B, Schein OD, Fried LP, West SK. The association of multiple visual impairments with self-reported visual disability: SEE project. Invest Ophthalmol Vis Sci. 2001 Jan;42(1):64-72.
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