Prism ballast is almost always used on front surface toric lenses because the toricity of the lens does not rest on the cornea so the lens will be more inclined to move. Prism ballast and peri ballast designs are very common for all types of astigmatism lenses. A hyperflange is used on a high minus lens to minimize edge thickness and thin the edge of the lens. This decreases lens awareness and allows the lens to center properly.
Great info as usual! Thanks for explaining it thoroughly!
Thank YOU for watching! 😊
What if toric lens -3.00/-2.50 x170 has over refraction of +0.75/-1.00×75 in order to get clear VA from 6/6-3 to 6/5
What if the sphero cylinder over refraction had a different axis than the original?
You would use LARS. In relation to 180, Left rotation Add 90 degrees to the original Axis and Right rotation you would subtract 90.
Quick question. Totally unrelated, but Why would I need a prism ballast over a hyoflange? Taking the test in a week and can’t find the answer to that!
Prism ballast is almost always used on front surface toric lenses because the toricity of the lens does not rest on the cornea so the lens will be more inclined to move. Prism ballast and peri ballast designs are very common for all types of astigmatism lenses.
A hyperflange is used on a high minus lens to minimize edge thickness and thin the edge of the lens. This decreases lens awareness and allows the lens to center properly.
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Nice explanation
Thank you!! 👏👏👏
I really appreciate you watching!