Comment refers to the girl's eyeglass prescription, not a ranking of her attractiveness.

Based on the distortion visible in her glasses, her prescription is approximately -1.00 to -1.50 diopters. Severely nearsighted prescriptions would cause the wearer to appear to have much smaller eyes; farsighted prescription would cause the eyes to appear larger.

The doctor is saying what her likely rx is, the responder i think assumes hes talking about her attractiveness out of 10, or is just being a snarky dick.

Aw man I always miss the drama

I love rephrasing that as "Looking at an ass is a full mark"

That's also Dr. Glaucomflecken a semi-famous optometrist.

I assumed he'd estimated it based on how distorted the face appears behind the glasses. I do that all the time.

At this angle it's hard for me to do that, since I usually use the edges of the face to estimate it. negative glasses pull the line inwards, positive outwards. I can reliably tell when someone is wearing fake glasses (0 strength) for example, and probably estimate strength within 30% of the actual value.

If the image was higher res maybe I could estimate this case too. Or this professional optometrist is just a lot better at it than I am.

Strong negative glasses: (Note the faces contours in the glasses appearing well inside the faces contours around the glassed)

Fake glasses:

Positive glasses:

PS: Searching for generic terms yields 100% fake glasses, so I took a specific person I remember having strong glasses for myopia.

Diopter was my first reading too, and my account isn't even "Dr. Glaucomflecken".