Why is 6/6 vision deemed 'perfect' vision? Does having 6/12 vision means it's not good? Our optometry team from Singapore National Eye Centre (SNEC) explains what these results mean.
Understanding visual acuity, test results, and when to seek help
Your eyes are your window to the world, and keeping them in check is crucial for overall well-being.
But what is visual acuity, how do you interpret the results, and when should you be concerned? Let's break it down in simple terms.
What is visual acuity (VA)?
Visual acuity measures how well you see details at a distance. It's like a scorecard for your eyesight, often compared to the Snellen chart test (shown below) used in clinics.
VA results are recorded in a fraction-like format, such as 6/6 (in meters) or 20/20 (in feet). In Singapore, we use the metric system, so you'll typically see it noted as 6/6.
6/6 vision: You can see clearly at 6 meters what a "perfect" eye can see at the same distance.
6/12 vision: You see at 6 meters what a perfect eye sees at 12 metres.
6/45 vision: You see at 6 meters what a perfect eye sees at 45 metres.
A 6/6 +1 or 6/6 -1 result means you're just above or below the perfect mark, like missing or identifying an extra letter on the chart.
What do the results mean?
Perfect vision (6/6): Congratulations! You have perfect eyesight! However, perfect vision doesn't always mean healthy eyes. Some conditions, like glaucoma, might not affect vision until later stages.
Functional vision (6/12 or Better): You might not have perfect vision, but this is still considered functional for most activities, including driving.
Below functional vision: If your results show something like 6/45, it means your vision is significantly reduced, and it's time to seek advice from an eye care professional.
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VA and driving requirements in Singapore
Good eyesight is essential for safe driving. In Singapore, here's the VA score you need to drive the following vehicles:
For personal vehicles (Class 1–3): VA of 6/12 or better in at least one eye.
For commercial vehicles (taxis, buses etc.): VA of 6/12 or better in both eyes. Additional checks, like color vision and night vision, may also be required.
What if my VA isn't 6/6? Should I be concerned?
Don't worry — it's more common than you think! A lower VA could be due to:
Uncorrected refractive errors: Maybe your glasses or contact lenses need an update.
Incorrect use of corrective eyewear: Like wearing the wrong prescription glasses.
Other eye conditions: Some might not be serious but still need attention.
What to do if your VA is poorer than 6/6
Visit an optician or optometrist: They can confirm the test results and determine if corrective lenses might help.
Check for underlying conditions: If glasses don't improve your vision, you might need further testing at a healthcare facility.
Monitor existing eye conditions: If you already have an eye condition, reduced VA could simply reflect your baseline vision.
Key takeaways
Regular checks are essential. Even if your VA is 6/6, certain eye diseases can develop silently.
If your vision isn't perfect, consult an eye care professional for guidance and potential correction.
Prevention is better than cure. Don't wait until symptoms worsen—early detection can save your sight.
Your eyes deserve care and attention, so take charge of your vision health today! For any concerns, book a visit with your optician or optometrist for a comprehensive eye exam.
Ref: H24
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