Eyesight numbers · 20/30 explained
What does 20/30 vision mean?
20/30 means that at 20 feet you read what a typical eye reads from 30 feet — two lines softer than the 20/20 row, and an approximate −0.50 glasses number. It is mild enough that most daily life works without lenses, and it still sits above the roughly 20/40 line US states use for an unrestricted licence.
Your chart result
20/30
20/30 is low in the mild band (−0.25 to −3.00), at an approximate −0.50 — a step past 20/25 and a step short of the 20/40 driving line. The moderate band does not begin until −3.25, roughly six times this magnitude.
What 20/30 actually means
At 20/30 the softness starts about two thirds of the way across a big room. A face at the far end of a hall is recognisable but not crisp, a motorway sign resolves later than it does for the driver beside you, and small text on a screen across a lecture theatre needs a moment. Close and mid-range work — a book, a phone, a monitor, a conversation across a table — is completely unaffected, which is the pattern nearsightedness always follows.
This is the last chart result that stays clear of the driving line. The 20/40 row is one step coarser, and most US states set the unrestricted standard there, so 20/30 passes. Plenty of people at this level keep a light pair of glasses for night driving, where a soft edge on headlights and signs shows up more, and go without the rest of the time.
The approximate −0.50 pairing is a ballpark rather than a conversion — the chart measures what you can resolve, the glasses number measures how much lens it takes to sharpen it, and two people reading 20/30 can end up a quarter-step apart. What the number is not is anything close to “legally blind”: that threshold is 20/200 or worse with the best lenses on, and 20/30 here is measured with none.
See where any number lands
20/30is one point on the scale. The free interactive explainer takes any 20/xx chart result or glasses number and shows the clear distance, the mild-to-high band, and what “legally blind” does and doesn't mean — with the diagrams above and a side-by-side chart-to-glasses table.
Open the eyesight-numbers explainer →
Not sure which line is yours? The free online eye test draws a real letter chart sized for your screen and your distance and reads a 20/xx line per eye. Test your own line →
Have the paper from the optician? The free eye prescription calculator explains every number on it.
Common questions
What does 20/30 vision mean?
At 20 feet you read what a typical eye reads from 30 feet — two lines softer than the 20/20 row. Distant faces and signs lose their edge about two thirds of the way across a large room, while close-up vision stays sharp. It matches an approximate −0.50 glasses number.
Is 20/30 vision bad?
It is mild. Only real distance softens, close work is untouched, and it still clears the roughly 20/40 line most US states use for an unrestricted licence. Glasses at 20/30 are commonly kept for night driving rather than worn all day.
Can you drive with 20/30 vision?
Yes in most US states, since the unrestricted line sits around 20/40 and 20/30 is one row sharper. Night driving is where people at this level most often reach for a light pair of glasses, because soft edges on signs and headlights show up more after dark.
What glasses number is 20/30 vision?
An approximate −0.50, give or take a quarter-step. The chart and the glasses number measure different things, so this is a ballpark rather than a conversion — two people who both read 20/30 can be written down slightly differently.
What to do with your number
The full method is a structured 90-day program — proper lenses, measured progress, the things only experience can tune.
EndMyopia members work on lowering their glasses numbers step by step. The whole thing — your numbers explained, lens recommendations, daily habits, weekly check-ins — lives inside BackTo20/20. Full Program $1,788 $149/mo × 12 · lifetime access · money-back guarantee.
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Or keep exploring with the free Eyeball Analyzer (20 minutes, your numbers, what they mean).
Limitations & disclaimer
EndMyopia treats myopia as a refractive state, not a medical condition. This is a free educational tool — not medical advice, diagnosis, or a substitute for a licensed optometrist. Measurements depend on camera quality and how carefully you mark the card edges; expect ±5–10 % on laptops, ±10–15 % on phones. For lens orders, eye health concerns, or any task requiring full 20/20 vision, see a licensed professional.
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