Vision Simulator

20/40 Vision Simulator (Driving Standard)

Interactive vision simulator — drag the slider to compare eyesight levels.

Drag the slider to compare 20/40 vision with 20/20 - road signs and faces look noticeably softer without correction.

Noticeable distance-blur simulation of 20/40 vision on street signs.

Status: 20/40

20/20 (Perfect) 20/200 (Blind)

Drag slider to compare

With 20/40 vision, you see at 20 feet what someone with 20/20 sees at 40 feet.

This simulator is for educational purposes only and does not replace a professional eye exam.

Estimated Prescription Converter

20/40 Vision ≈ -0.50 to -1.25 Diopters

This level of myopia is common and typically easy to correct with glasses.

A light prescription in this range often brings distance vision back to 20/20, but exact diopters vary by person.

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Daily Life Impact Check

Driving

Corrective lenses required by law.

Reading

May need large print or zooming.

Pilot License

Legally Blind?

Boundary is 20/200.

20/40 vision is a common mild-to-moderate reduction in distance clarity. You may pass some vision tests, but glasses are often needed for driving or sharper detail.

On a Snellen chart, 20/40 means you see at 20 feet what a person with 20/20 eyesight could see at 40 feet.

Meaning: mild distance blur compared with 20/20.
What you'll notice: signs and faces soften at range, especially in low light.
Next step: many people use light glasses for driving or sharper outdoor detail.

Road signs and street names look soft until you get closer.
Faces across a room lose fine detail (you may recognize people by shape, not features).
Watching a scoreboard or presentation from the back can feel slightly fuzzy.
Night driving often feels harder because blur and glare stack together.

20/40 is usually considered mild distance vision loss.

It is far from the legal-blindness level (20/200).
Many people function well day to day, but distance detail is softer.
A light prescription often restores near-20/20 sharpness.

Many regions use 20/40 as a common minimum for an unrestricted driver's license.

If your uncorrected vision is worse than 20/40, you may be required to wear glasses to drive.
Clearer correction improves safety in rain, at dusk, and at night.

Mild nearsightedness (myopia) or astigmatism (most common).
Dry eyes or screen-related eye strain.
Early lens changes like cataracts.

Only an eye exam can confirm the cause.

Typical estimate for simple myopia:

Range	Often feels like
-0.75 to -1.25D	mild distance blur, near vision usually OK

Astigmatism can shift this range.
Treat any number here as a rough estimate only.

Consider an eye exam if you notice:

you squint to read distance details
night driving feels stressful because of blur or glare
headaches or eye fatigue after distance tasks

20/40 often shows up most in:

reading highway signs early while driving
seeing faces or presentation text across a room

An exam confirms the cause and the right lenses.

Quick comparison:

Level	What to expect
20/30	slightly clearer than 20/40
20/40	current level on this page
20/50	more blur than 20/40

This simulator is for education only. Screen size, viewing distance, lighting, and eye health all affect what you see. If you are worried about your vision, please schedule a professional eye exam.

Last updated: December 12, 2025

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20/40 is mildly to moderately blurry for distance. Many people function well, but fine details and road signs can look soft without glasses.

Some regions allow driving at 20/40, but many require correction to meet the standard. Glasses can make driving safer and clearer.

20/40 vision often corresponds to a light myopia prescription, commonly around -0.50 to -1.25 diopters. Only an eye exam can confirm your exact numbers.

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