What is the best base curve?
The most basic rule is that you always want the base curve to be as close to +6.00 as you can get and still have the Rx work. In theory +6.00 should always give you the best possible combination of curves for weight, optics, etc.
How do I choose a base curve?
Figuring out the proper base curve based upon Rx is fairly simple: Plus Power – Use the Spherical Equivalent (Sphere power plus half the cylinder power) and add 4.00 diopter to that. Example – Rx of +2.50, the base curve will be approximately 6.50.
What is a steep base curve?
A person with a higher base curve number has a flatter cornea (the clear, front surface of the eye) compared to someone with a lower base curve number, which indicates a steeper cornea.
What is the average eye base curve?
Typical base curve values range between 8.0 and 10.0 mm, though it can be flatter (from 7.0mm) if you have a rigid gas-permeable lens. A person with a higher base curve number has a flatter cornea (the clear, front surface of the eye) compared to someone with a lower base curve number, which indicates a steeper cornea.
Can I change the base curve of my contacts?
Correcting a flat or steep fitting custom soft contact lens requires changing the sagittal depth of the lens by altering the base curve or diameter. As with any custom soft contact lens it is imperative to make sure the fit of the contact lens is correct and optimal before chasing vision.
How important is base curve in contacts?
When the base curve and contact lens diameter are appropriate, there is adequate tear exchange from under the lens surface, which helps clear out debris. All these factors contribute to your lenses being comfortable to wear and also to preventing eye damage and strain, thereby promoting overall eye health.
What is the best base curve for RX work?
The most basic rule is that you always want the base curve to be as close to +6.00 as you can get and still have the Rx work. In theory +6.00 should always give you the best possible combination of curves for weight, optics, etc.
How do you choose the right base curve chart?
You will find charts have overlapping ranges so you must be careful and be sure you are choosing the curve that is closest to that +6.00. A simple base curve chart might look like this: BUT it also falls between -1.50 and -5.75 and that BC is closer to our +6.00 so we choose +4.25 NOT +2.25.
Why is it important to use the recommended base curve?
It is particularly important with aspheric lens designs to use the recommended base curve, since their peripheral optical performance will be even more sensitive to base curve changes. 3. Do not match base curves unless absolutely necessary. Matching base curves is sometimes done to reduce adaption difficulties after prescription changes.
What is the best index to place on a lens base curve?
So Polycarbonate (1.59) and 1.67 Index should be placed on a steeper base curve in order to maintain best form fitting parameters. But that would result in less attractive cosmetics and thicker lenses. They best solution?