When optometrists measure your prescription, they use a machine that switches between different diopters. Except, the lenses on this machine are essentially parallel to the walls and orthogonal to the ground. Whereas, my ears are lower than my eyes, so the 'arms' of my glasses tilt downwards from my eyes to my ears. This means the prescription is kind of bullcrap. Why don't optometrists account for this?
2 Answers
Although the tops of your ears maybe below the centre(s) of your eye(s) - you can have one ear lower than the other too - everyone is different. Some may find their ears are above the eye centres.
When receiving your prescription made spectacles you should have them fitted (adjusted) to fit your specific shape.
The link I provided shows adjustments and slight tweaks you can make yourself and some best done by the opticians.
As well as adjusting the temples for pinching and being too wide — although if given proper clear advice when choosing your frames, you should have been provided with frames which are the correct width for your face in the first place — they can be adjusted to accommodate the different ear height by putting a slight bend at the temples either upward or downward.

- 6,167
- 1
- 18
- 53
For measurements the best configuration to avoid errors introduced by slanted, oblique perspective, and misalignment of the axis of your eye lens and the trial lens is what they do.
Later the eyeglass technician has to adjust the angle of handles and the nose rest pads to maintain the correct line up of the lenses.
Contact lenses usually don't have these kinds of issues, unless your eyes corneas have surface bumps or other geometrical issues.

- 107
- 4
-
It's not possible. In order to have the lenses parallel like the machine, I have to lift the ears/handles up by 2-3 inches from my ears. – user3180 Jun 19 '19 at 04:45
-
I have had glasses for 65 years and I just don't understand what you mean. I appreciate if you could explain it. Or even better just draw a rough sketch. When I said they adjust my glasses frame, I meant bending of millimeters or just tightening the hinges. – kamran Jun 19 '19 at 06:06