Oh, since you’re apparently the creator of this community, I failed to mention the facts that I had to do my best to identify the exact center of the lens before grinding it down.
I did so by basically aligning an overhead light source against the reflection from both the front and back sides of the lens, then marked that spot with a sharpie marker, until I finished grinding anyways, then cleaned it off with rubbing alcohol.
Maybe I should have mentioned such details in my original post, I’m not even sure if I’m describing it properly, but I gather you totally understand.
Anyways, thank you for creating this community, and thank you for your skills and talents making frames and helping others with poor vision.
I know you only recently started this community, I hope to see it grow! 👓
One easier and more precise way to determine the optical center - and rotational alignment too, which is important if your correction has a cylinder, but you didn’t mention it so I assume yours doesn’t - is simply to go to an optician and ask them to pop your lens in their lensometer and measure it. The lensometer will spot 3 dots on the lens. The center dot is the optical center and the line formed by the 3 dots is the horizontal alignment.
A lot of opticians are located in malls or supermarkets, so it’s simply a matter of taking your lens with you when you next go for groceries. It takes seconds to measure a lens and the optician won’t charge you for it - and if they try, you’ll know which optician never to patronize 🙂
I actually do have a cylinder measurement, but have absolutely no way to know how to explain to others how to find or even approximate that at home, so I didn’t bring it up.
I went through a lot of trial and error runs with mine to find the sweet spot to best align the cylinder angle before I marked my alignment notch.
Look closely at my lens, right where the keyring opening is, the lens has a subtle notch carved into it to match. That notch is meant to align with the keyring opening, and that’s meant to point right when used in my right eye. That notch is no accident.
Indeed, I must have made it sound slightly simpler than it really is, I really did put in some extra homework and experimentation for my backup lens.
For you application, it¨s not too critical. But to make proper, dependable glasses you wear every day, I don’t even bother. I always go to an optician for anything to do with lenses. And I go to a proper eye doctor for prescriptions, even if it’s eye-wateringly expensive. I just don’t skimp on that.
I mean I’m a cheapskate and I make frames because I don’t like to be taken for a dandelion and being grossly overcharged for simple technology that’s been around for centuries. Not to mention, I don’t like wasting perfectly good lenses just because the frames are broken.
But lenses are generally out of my competencies and I don’t have the tools needed to work on them - nor do I want them, because I don’t need to rework my or other people’s lenses nearly often enough to justify the expense.
So I let opticians measure my lenses and I order them ready-made and properly edged. I would like nothing better than to not bring any of my business to the eyewear industry for a variety of reasons, but it’s simply not cost-effective - or even safe - to DIY optical lenses in any way that impacts optical properties.
Oh, since you’re apparently the creator of this community, I failed to mention the facts that I had to do my best to identify the exact center of the lens before grinding it down.
I did so by basically aligning an overhead light source against the reflection from both the front and back sides of the lens, then marked that spot with a sharpie marker, until I finished grinding anyways, then cleaned it off with rubbing alcohol.
Maybe I should have mentioned such details in my original post, I’m not even sure if I’m describing it properly, but I gather you totally understand.
Anyways, thank you for creating this community, and thank you for your skills and talents making frames and helping others with poor vision.
I know you only recently started this community, I hope to see it grow! 👓
Thanks!
One easier and more precise way to determine the optical center - and rotational alignment too, which is important if your correction has a cylinder, but you didn’t mention it so I assume yours doesn’t - is simply to go to an optician and ask them to pop your lens in their lensometer and measure it. The lensometer will spot 3 dots on the lens. The center dot is the optical center and the line formed by the 3 dots is the horizontal alignment.
A lot of opticians are located in malls or supermarkets, so it’s simply a matter of taking your lens with you when you next go for groceries. It takes seconds to measure a lens and the optician won’t charge you for it - and if they try, you’ll know which optician never to patronize 🙂
I actually do have a cylinder measurement, but have absolutely no way to know how to explain to others how to find or even approximate that at home, so I didn’t bring it up.
I went through a lot of trial and error runs with mine to find the sweet spot to best align the cylinder angle before I marked my alignment notch.
Look closely at my lens, right where the keyring opening is, the lens has a subtle notch carved into it to match. That notch is meant to align with the keyring opening, and that’s meant to point right when used in my right eye. That notch is no accident.
Indeed, I must have made it sound slightly simpler than it really is, I really did put in some extra homework and experimentation for my backup lens.
For you application, it¨s not too critical. But to make proper, dependable glasses you wear every day, I don’t even bother. I always go to an optician for anything to do with lenses. And I go to a proper eye doctor for prescriptions, even if it’s eye-wateringly expensive. I just don’t skimp on that.
I mean I’m a cheapskate and I make frames because I don’t like to be taken for a dandelion and being grossly overcharged for simple technology that’s been around for centuries. Not to mention, I don’t like wasting perfectly good lenses just because the frames are broken.
But lenses are generally out of my competencies and I don’t have the tools needed to work on them - nor do I want them, because I don’t need to rework my or other people’s lenses nearly often enough to justify the expense.
So I let opticians measure my lenses and I order them ready-made and properly edged. I would like nothing better than to not bring any of my business to the eyewear industry for a variety of reasons, but it’s simply not cost-effective - or even safe - to DIY optical lenses in any way that impacts optical properties.