Thanks, dear Tracy, realy helpful topic to learn how to check prism on lensometer, before watching this video I have some doubt but now no more doubt,,,
Very helpful! Thank you so much for this video. When measuring glasses with prism, do you find it easier to measure the prisms first or the prescription first?
Thanks! I'm glad it helped! The way I see it, you measure the prescription first. During the process of measuring the prescription, you will identify and measure any unwanted prism. You're kind of doing them at the same time. Prescribed prism works the same way. The only difference is that the illuminated power lines will be centered at the prescribed prism location and not the center of the target.
Correct me if Im wrong, but if we are going to look at prismEFFECT on spherical lensens, I have to consider if it is negative/positive sphere to decide the base direction, right?
Not when you're using the lensmeter. The illuminated target is the base of the prism and the center of the target is the wearer's "pupil". What you need to know to determine base direction - is the location of the wearer's nose (which eye we are working with). The base direction is what it is when it comes to the lensmeter. For a right lens (nose is on the right). If the illuminated target is right of center there is base IN prism. If the illuminated target is left of center there is base OUT prism. - What you're thinking of is the actual movement of the lens... this will be in opposite directions for plus and minus powers. When using diagrams to examine prism, you will need to know whether the power is plus or minus, but this is not needed when working with the lensmeter. The power of the lens (plus or minus) needs to be used when you're determining base direction using schematic drawings. For example, the OC is displaced 4mm out/temporally from the pupil, what base direction will the wearer experience? In this case, you'll need to know the whether we are dealing with a plus or minus lens power and whether it's the right or left lens.
Only when you are calculating and determining stuff on paper. In the lens meter you just move the lens in what ever direction you need to make the base direction correct. It will be opposite movements of the lens for plus and minus powers but the base direction in the lens meter is the same. Right lens base in is illuminated target to the right and out is to the left. It’s all about the location of the patient’s nose.
Thanks for your feedback. I'm not too proud of it myself, but I won't take it down until I've made one that covers the info. It was created for one student but I posted it at a request from other students who wanted access to it. It was also one of my first videos. Sorry you disliked it so much.
I have had a hard time figuring out compound prism. This was very helpful. Thanks!
Glad it helped!
Thanks, dear Tracy, realy helpful topic to learn how to check prism on lensometer, before watching this video I have some doubt but now no more doubt,,,
That's great to hear! It really isn't that difficult once you get the hang of it. Dare I say, it even becomes pretty easy.
Thank you. I finally have it🙂
Very helpful! Thank you so much for this video. When measuring glasses with prism, do you find it easier to measure the prisms first or the prescription first?
Thanks! I'm glad it helped! The way I see it, you measure the prescription first. During the process of measuring the prescription, you will identify and measure any unwanted prism. You're kind of doing them at the same time. Prescribed prism works the same way. The only difference is that the illuminated power lines will be centered at the prescribed prism location and not the center of the target.
Very helpful ❤
Correct me if Im wrong, but if we are going to look at prismEFFECT on spherical lensens, I have to consider if it is negative/positive sphere to decide the base direction, right?
Not when you're using the lensmeter. The illuminated target is the base of the prism and the center of the target is the wearer's "pupil". What you need to know to determine base direction - is the location of the wearer's nose (which eye we are working with). The base direction is what it is when it comes to the lensmeter. For a right lens (nose is on the right). If the illuminated target is right of center there is base IN prism. If the illuminated target is left of center there is base OUT prism. - What you're thinking of is the actual movement of the lens... this will be in opposite directions for plus and minus powers. When using diagrams to examine prism, you will need to know whether the power is plus or minus, but this is not needed when working with the lensmeter.
The power of the lens (plus or minus) needs to be used when you're determining base direction using schematic drawings. For example, the OC is displaced 4mm out/temporally from the pupil, what base direction will the wearer experience? In this case, you'll need to know the whether we are dealing with a plus or minus lens power and whether it's the right or left lens.
lens meter. Great help what about plus or minus does it make a difference?
Only when you are calculating and determining stuff on paper. In the lens meter you just move the lens in what ever direction you need to make the base direction correct. It will be opposite movements of the lens for plus and minus powers but the base direction in the lens meter is the same. Right lens base in is illuminated target to the right and out is to the left. It’s all about the location of the patient’s nose.
Informational, but this is the worst instructional video I’ve ever watched.
Thanks for your feedback. I'm not too proud of it myself, but I won't take it down until I've made one that covers the info. It was created for one student but I posted it at a request from other students who wanted access to it. It was also one of my first videos. Sorry you disliked it so much.