Difference between revisions of Severe myopia

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===Pick frames with a well-matching pupillary distance===

Lenses are cut to fit the frame such that their optical axis (the thinnest part of a minus lens) sits right in front of the pupil of each of your eyes. If the frame perfectly matches your pupillary distance, the optical axis of the lenses will be right in the middle between the rims of the frame. This minimizes the thickness of the edges, and hence weight.

===Pick round or oval frames===

With the optical axes of your eyes nicely centered in a frame, round frames result in a constant thickness of the lens edge since all of the edge is at the same distance from the optical axis. This means that round lenses minimize thickness and hence weight for a given field of view.

You probably want a bit more field of view horizontally than vertically, which makes oval frames a good compromise at the cost of thicker lens edges on the leftmost and rightmost sides. Avoid rectangular frames since the corners of the rectangles will be relatively far from the optical axis, making the lens edges there unnecessarily thick, ugly, and heavy.

==View compression==

==View compression and accounting for vertex distance==

Strong minus glasses significantly compress objects in your field of view such that they appear smaller. The closer the lenses are to your eyeballs, the less compression happens. Try it: move your minus glasses away from and back towards your eyeballs, and the view compression effect will be apparent.

When the lenses sit on your eyeballs, view compression is absent. This is the case when you wear contact lenses. But for glasses you can get some of this benefit by choosing frames with really small diameter lenses and having the nose pads and ear hooks adjusted to pull the frames closer to your eyeballs than you would be able to with larger diameter frames.

When the lenses sit on your eyeballs, view compression is absent. This is the case when you wear contact lenses. But for glasses you can get some of this benefit by choosing frames with really small diameter lenses and having the nose pads and ear hooks be adjusted to pull the frames closer to your eyeballs than you would be able to with larger diameter frames as these won't fit between your eyebrow ridge and cheek bones.

~~But hang on~~, moving a minus ~~lenses~~ closer to ~~the eyes also~~ increases ~~their effect~~ strength. Read the page on [[vertex distance]] to learn the details.

The practical limit of how deep you can place small-diameter lenses is reached when your eye lashes brush against the inside of the lenses.

As a severe myope, you probably learned that pushing your frames up your nose a bit will bring distant objects into better focus. This is because moving a minus lens closer to your eyeball increases its effective strength. Read the page on [[vertex distance]] to learn the details. For high-strength minus lenses, this results in a significant vertex distance correction that you have to take into account when doing the End Myopia program.

@@ Line 29: / Line 29: @@
 ===Pick frames with a well-matching pupillary distance===
 Lenses are cut to fit the frame such that their optical axis (the thinnest part of a minus lens) sits right in front of the pupil of each of your eyes. If the frame perfectly matches your pupillary distance, the optical axis of the lenses will be right in the middle between the rims of the frame. This minimizes the thickness of the edges, and hence weight.
 ===Pick round or oval frames===
 With the optical axes of your eyes nicely centered in a frame, round frames result in a constant thickness of the lens edge since all of the edge is at the same distance from the optical axis. This means that round lenses minimize thickness and hence weight for a given field of view.
 You probably want a bit more field of view horizontally than vertically, which makes oval frames a good compromise at the cost of thicker lens edges on the leftmost and rightmost sides. Avoid rectangular frames since the corners of the rectangles will be relatively far from the optical axis, making the lens edges there unnecessarily thick, ugly, and heavy.
-==View compression==
+==View compression and accounting for vertex distance==
 Strong minus glasses significantly compress objects in your field of view such that they appear smaller. The closer the lenses are to your eyeballs, the less compression happens. Try it: move your minus glasses away from and back towards your eyeballs, and the view compression effect will be apparent.
-When the lenses sit on your eyeballs, view compression is absent. This is the case when you wear contact lenses. But for glasses you can get some of this benefit by choosing frames with really small diameter lenses and having the nose pads and ear hooks adjusted to pull the frames closer to your eyeballs than you would be able to with larger diameter frames.
+When the lenses sit on your eyeballs, view compression is absent. This is the case when you wear contact lenses. But for glasses you can get some of this benefit by choosing frames with really small diameter lenses and having the nose pads and ear hooks be adjusted to pull the frames closer to your eyeballs than you would be able to with larger diameter frames as these won't fit between your eyebrow ridge and cheek bones.
-But hang on, moving a minus lenses closer to the eyes also increases their effect strength. Read the page on [[vertex distance]] to learn the details.
+The practical limit of how deep you can place small-diameter lenses is reached when your eye lashes brush against the inside of the lenses.
+As a severe myope, you probably learned that pushing your frames up your nose a bit will bring distant objects into better focus. This is because moving a minus lens closer to your eyeball increases its effective strength. Read the page on [[vertex distance]] to learn the details. For high-strength minus lenses, this results in a significant vertex distance correction that you have to take into account when doing the End Myopia program.