“Harry, your eyesight really is awful,” said Hermione, as she put on glasses (Deathly Hallows, Chapter Four - "The Seven Potters")

In-universe, do we know to what extent Harry Potter's eyesight was bad?

Obviously, we wouldn't have exact prescription dioptre numbers, but what I'm hoping for is some canon or WoG example of Harry not able (vs able) to see something specific when not wearing glasses.

  • 1
    Perfect example of a question that will never have any real-world usefulness - also known as a "who the hell cares" question ;-)
    – Rand al'Thor
    Dec 26, 2015 at 1:32
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    @randal'thor I think you forgot "(in my opinion)" ;-)
    – Insane
    Dec 26, 2015 at 2:55
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    @randal'thor: Isn't writing a piece of fanfic where the eyesight is a plot point enough usefulness for an in-universe-fact to matter? Dec 26, 2015 at 9:34
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    @O.R.Mapper - yay. This is my new go-to excuse when anyone accuses me of "why is that a real question?". I'm writing a fanfic. Cross between Conan, Star Wars, Harry Potter, Percy Jackson, GPF, Honor Harrington, Dune and Rama. Dec 26, 2015 at 13:25

2 Answers 2


After taking polyjuice potion, he sees with Goyle's (unaided) vision. His glasses "cloud" his eyes, suggesting that his vision (with glasses) must be at least 4-5 points off 20:20. Anything less and his vision would simply be distorted rather than actually blurry:

Then he realised that his glasses were clouding his eyes, because Goyle obviously didn’t need them - HP: CoS

He can't see well enough to distinguish that what he's looking at is a large dog, but he can see well enough to tell that it's an animal of some kind:

Harry set down his goblet and was about to turn back to his bed when something caught his eye. An animal of some kind was prowling across the silvery lawn. - HP: POA

He can distinguish his location and make out his friends easily from across the room. If he squints, he can bring his vision to something approaching normality:

Everything was slightly blurred. Somebody had removed his glasses. He was lying in the dark hospital wing. At the very end of the ward, he could make out Madam Pomfrey with her back to him, bending over a bed. Harry squinted. Ron’s red hair was visible beneath Madam Pomfrey’s arm - HP: PoA

Familiar people have "fuzzy outlines", again, suggestive of moderate myopia

He could see the fuzzy outlines of Mrs Weasley and Bill close by. Mrs Weasley was on her feet. ‘That’s Fudge’s voice,’ she whispered. ‘And that’s Minerva McGonagall’s, isn’t it? But what are they arguing about?’ - HP: GoF

Room is blurry

Harry emerged from behind his towel; the changing room was blurred because he was not wearing his glasses, but he could still tell that everyone’s face was turned towards him. - HP:OotP

He can't distinguish individual firework sparks

He got into bed, yawning. With his glasses off, the occasional firework passing the window had become blurred, looking like sparkling clouds, beautiful and mysterious against the black sky. - HP: OotP

  • I don't know what impresses me more, that you found all these quotes or that JKR managed to keep such a minor detail pretty consistent throughout the series.
    – Kevin
    Jul 25, 2016 at 9:16
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    @kevin - She's usually pretty consistent about anything not involving maths. That being said, I stand by my assertion that she didn't write the books. They were clearly ghost-written for her by a team working for the studio.
    – Valorum
    Jul 25, 2016 at 10:30

Which means Harry is near-sighted. Things far away are blurs. How near-sighted? Probably 20:100 That means what is normally seen clearly at 100 feet needs to be at 20 for him. It might be closer to 20:200 (legally blind) because if Mrs. Weasley is close enough to whisper to him, she should NOT be blurred less than ten feet away at 20:100

  • Do you have any evidence for any of this that you could edit in?
    – TheLethalCarrot
    Jun 5, 2020 at 19:43
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    @TheLethalCarrot - This doesn't really feel like an answer. It feels more like an attempt to comment on my answer.
    – Valorum
    Jun 5, 2020 at 20:00
  • @Valorum it certainly reads as a comment but it can be argued it’s an answer still.
    – TheLethalCarrot
    Jun 5, 2020 at 20:06
  • @TheLethalCarrot - Oh, sure. Which is why I've not flagged it.
    – Valorum
    Jun 5, 2020 at 20:11
  • "Which means Harry is near-sighted." This does not make sense as a response to anything in the question; it only makes sense in the context of a comment on Valorum's answer. "Things far away are blurs." Which things? How far away? Where are the quotes? In Valorum's answer; it's pretty clear this is a comment, not an answer.
    – DavidW
    Jun 5, 2020 at 20:46

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