eyeglasses grade

[curiousmarcus]

Your lenses are kind of thick. What is your grade?

Oh, it's very high. Five hundred and fifty.

Is the above conversation understandably clear that it's about eyeglasses? What are better ways to ask and answer?

 

[Rover_KE]

Q. Your glasses have thick lenses, haven't they?

A. Yes - my sight is very bad and I'd rather you pretended not to notice because I'm very sensitive about it.

 

[Barb_D]

I agree that it's not generally considered "casual conversation" to ask about this, but if you did have a reason to ask, I would not understand "grade" at all.

What is your prescription?
Even then, I wouldn't be able to reply with diopters or anything, but I'd say "I'm 20/400 - it's pretty bad!"

 

[curiousmarcus]

Okay, so the above conversation was a bad idea. How about this:

How did your visit to the optometrist go?

Pretty alright. I'll get my glasses tomorrow, because they run out of lenses. I'm afraid they're going to be thick.

What's your prescription?

Oh, it's pretty high. Five hundred and fifty.

1. So it should be it's pretty bad as opposed to it's pretty high?

2. How do you read that 20/400? Is it okay to just say four hundred, or five hundred and fifty as in the case of my example?

3. So the word to use is prescription, and not grade?

4. Do you normally say glasses as opposed to ​eyeglasses?

 

[GoesStation]

In AmE we usually say glasses. 20/400 is read "twenty four hundred"; it's a crude measure of vision, not the prescription, which is given in diopters. 20/400 means that when you see something twenty feet away, you resolve it the way a person with perfect vision would at a distance of four hundred feet.

I don't know what five hundred and fifty means in your quote. We don't use numbers like that in lens prescriptions.

The word grade isn't used in this context in AmE.

 

[Rover_KE]

We say glasses in BE, too, or more informally, specs.

My optician, Seymour Clearly, confirms that his prescriptions are incomprehensible to the layman.

I haven't a clue what all those numbers mean, and I don't need to know.

 

[curiousmarcus]

I don't know what five hundred and fifty means in your quote. We don't use numbers like that in lens prescriptions.

It's most probably 20/550. We likely just dropped the twenty since all prescription starts with that.

 

[curiousmarcus]

]it's a crude measure of vision, not the prescription, which is given in diopters.

So how do you ask the question?

What is your prescription?

What is your vision?

What is your vision in diopters?

 

[Rover_KE]

In my experience, nobody ever asks such questions. We neither know our own prescription nor care about anybody else's.

The nearest we get to asking about a friend's vision is 'Do you need glasses just for reading or distance?' 'Did it take you long to get used to those varifocals?' 'Have you thought about contact lenses?'

 

[GoesStation]

It's most probably 20/550. We likely just dropped the twenty since all prescription starts with that.

No. 20/550 is not a prescription. It's a measure of a person's vision.

 

[GoesStation]

We say glasses in BE, too, or more informally, specs.

My optician, Seymour Clearly, confirms that his prescriptions are incomprehensible to the layman.

I haven't a clue what all those numbers mean, and I don't need to know.

I get my glasses from Ken Tsiyu.

 

[curiousmarcus]

After scouring the internet, I think I'll go with What's your prescription, as Barb_D suggested.

http://boards.straightdope.com/sdmb/archive/index.php/t-256938.html

https://ph.answers.yahoo.com/question/index?qid=20111001085810AA9kIyr

 

[curiousmarcus]

It's most probably 20/550. We likely just dropped the twenty since all prescription starts with that.

My bad. Five hundred and fifty isn't 20/550. It's -5.50. Not sure if that's how it's read though.

 

[GoesStation]

The unit in that prescription is diopters ("dioptres" in BrE). Few people who wear glasses actually know their prescription though.

If someone who does know says theirs is 550, and means 5.50, that is not the same as -5.50. A 5.50 lens is convex and corrects farsightedness. A -5.50 lens is concave and corrects myopia or nearsightedness. You'd read that as "minus five fifty" or "minus five point five oh/zero".