Difference between revisions of Severe myopia

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==Avoid heavy glasses==

The front of minus lenses is flatter than the back, which is curved more strongly. In the center, minus lenses are typically only about 1.5mm thick (thinner would make the lenses too fragile), but moving away from the center (optical axis) the glass becomes thicker. The more minus the diopters, the larger the difference in curvature between the front and back surface of the lens, and the thicker the edge.

The front of minus lenses is flatter than the back, which is curved more strongly. In the center, minus lenses are typically only about 1.5mm thick (thinner would make the lenses too fragile), but moving away from the center (optical axis) the glass becomes thicker. The more minus the diopters, the larger the difference in curvature between the front and back surface of the lens, and the thicker the edge. You can determine how thick the lenses will get if you know all the parameters using [https://opticampus.opti.vision/tools/thickness.php this handy thickness calculator].

When choosing a normal frame with regular diameter lenses, you will end up with very thick lens edges and hence uncomfortably heavy glasses that easily slide off your nose and look ugly from the side. What to do?

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 ==Avoid heavy glasses==
-The front of minus lenses is flatter than the back, which is curved more strongly. In the center, minus lenses are typically only about 1.5mm thick (thinner would make the lenses too fragile), but moving away from the center (optical axis) the glass becomes thicker. The more minus the diopters, the larger the difference in curvature between the front and back surface of the lens, and the thicker the edge.
+The front of minus lenses is flatter than the back, which is curved more strongly. In the center, minus lenses are typically only about 1.5mm thick (thinner would make the lenses too fragile), but moving away from the center (optical axis) the glass becomes thicker. The more minus the diopters, the larger the difference in curvature between the front and back surface of the lens, and the thicker the edge. You can determine how thick the lenses will get if you know all the parameters using [https://opticampus.opti.vision/tools/thickness.php this handy thickness calculator].
 When choosing a normal frame with regular diameter lenses, you will end up with very thick lens edges and hence uncomfortably heavy glasses that easily slide off your nose and look ugly from the side. What to do?