Difference between revisions of Trial lens kit
Dlskidmore (talk | contribs) Created page with "A trial lens kit is a set of lenses of various powers and usually a frame shaped like a pair of glasses but with mounting points for the lenses. The number of lenses and powe..." |
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* https://www.youtube.com/watch?v=HjRcdlXmR1A | * https://www.youtube.com/watch?v=HjRcdlXmR1A | ||
= How to test Astigmatism = | |||
Testing for astigmatism is tricky, and you should master testing for myopia first. Errors such as being off by 90 degrees are common. | Testing for astigmatism is tricky, and you should master testing for myopia first. Errors such as being off by 90 degrees are common. | ||
== JCC Lens == | |||
The JCC Lens has two cylinders at opposite angles and powers. By holding the lens in different ways over a trial cylinder lens, you can determine if the angle or power of the cylinder lens should be changed. (This is the part of the refraction test where the doctor is happy if both options are equally blurry.) | The JCC Lens has two cylinders at opposite angles and powers. By holding the lens in different ways over a trial cylinder lens, you can determine if the angle or power of the cylinder lens should be changed. (This is the part of the refraction test where the doctor is happy if both options are equally blurry.) | ||
* https://youtu.be/ba4ck7oYauY | * https://youtu.be/ba4ck7oYauY | ||
== Stenopeaic Slit == | |||
A stenopeaic slit is just an opaque disk with a slit in it. By putting the slit at different angles and taking standard myopic refraction, one can calculate the angle and power cylinder needed. | A stenopeaic slit is just an opaque disk with a slit in it. By putting the slit at different angles and taking standard myopic refraction, one can calculate the angle and power cylinder needed. | ||
* http://www.journalrepository.org/media/journals/OR_23/2018/Feb/Chowdhury822018OR39503.pdf | * http://www.journalrepository.org/media/journals/OR_23/2018/Feb/Chowdhury822018OR39503.pdf | ||
== JCC vs Stenopeaic == | |||
The use of a Stenopeaic slit vs a JCC lens seems to be cultural. Most US doctors will use JCC lens, while middle eastern doctors prefer the stenopeaic slit. Both tests work and it's more about how your doctor was trained which he/she will use. For DIY types, the stenopeaic slit is easy to make at home and is compatible with the simpler cm [[measurement]] when a full trial lens kit is not available. | The use of a Stenopeaic slit vs a JCC lens seems to be cultural. Most US doctors will use JCC lens, while middle eastern doctors prefer the stenopeaic slit. Both tests work and it's more about how your doctor was trained which he/she will use. For DIY types, the stenopeaic slit is easy to make at home and is compatible with the simpler cm [[measurement]] when a full trial lens kit is not available. | ||
= Pinhole = | |||
The pinhole accessory in many trial lens sets may help distinguish between refractive issues and medical issues. If the vision does not improve or gets worse with use of the pinhole lens, this is an issue that should be addressed by an [[optometrist]]. | The pinhole accessory in many trial lens sets may help distinguish between refractive issues and medical issues. If the vision does not improve or gets worse with use of the pinhole lens, this is an issue that should be addressed by an [[optometrist]]. | ||