How do you convert to base curve?
Accurate Shortcut for Radius/Diopter Base Curve Conversion. Just divide 337.5 by either the radius value OR the diopter value and you will get the answer you are looking for.
Is 8.4 or 8.6 base curve?
Studies show that a single base curve of 8.4mm managed a “good or better” fit in approximately 90% of individuals,1 and base curves of 8.4mm and 8.6mm together encompassed 98% of individuals….
| LENS | BASE CURVES AVAILABLE (mm) | DIAMETERS AVAILABLE (mm) |
|---|---|---|
| 5 | 8.6 | 14.0 |
| 6 | 8.5, 9.0 | 14.2 |
| 7 | 8.4, 8.8 | 14.0 |
| 8 | 8.7 | 14.2 |
What is the base curve of contact lens?
The base curve of a contact lens is the curvature of the back surface of the lens. It determines the type of fit the lens must have to match the natural curvature of your eye. It is usually expressed in millimetres and may be further characterised as steep, median, or flat.
What base curve should I choose?
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. The more minus the power (less plus power to minus power) the lower plus the base curve will become. A high minus Rx may even have a base curve of +0.25 or even 0.00.
What happens if you wear contacts with the wrong base curve?
If your lenses have the wrong diameter or base curve, you’ll likely feel that something is always in your eye. If the lenses are too flat, your eyelids will tend to dislodge them when you blink. The wrong size lenses can even cause an abrasion of your cornea.
What is base curve in eyeglasses?
What is a base curve? Base curve is a description of the front surface curvature of a lens measured in diopters. Example: an 8 base lens shape will have the equivalent front surface curvature to an 8 power lens made out of crown glass. The higher the curvature gives the glasses more of a curvature.
What happens if you wear the wrong base curve?
Is there a difference between 8.6 and 8.8 base curve?
A base curve of 8.6 mm of radius is more curved, and therefore a tighter fit, compared to the 8.8 mm base curve. People who have steeper corneas require tighter fitting contacts.
Is there a big difference between 8.6 and 8.8 base curve?
A base curve of 8.6 mm of radius is more curved, and therefore a tighter fit, compared to the 8.8 mm base curve. People who have steeper corneas require tighter fitting contacts. If a contact is too loose, it may be uncomfortable, fold, or come right out.
What is the difference between 8.4 and 8.8 base curve?
The 8.4mm base curve is still the likely best fit for the majority of eyes. In instances when the 8.4mm lens is too steep, the 8.8mm lens allows a flatter option. This is more likely needed in smaller eyes, and possibly in some very flat corneas.
How do I figure out my contact lens base curve?
Base curve = 0.95 * 34.82 D = 33.07 D and then round up or down to the nearest whole diopter to arrive at the following final base curve to use for a contact lens over-refraction: Base curve = 33.00 D (actual measured base curve is 32.95 D)
How do you determine base curve?
Simple Rule for estimating lens base curve on a PLUS POWER lens
- For plus power use the spherical equivalent (SE) and add 4.00 diopters to that. For example, if you have an Rx of + 2.00 sphere, the base curve for the lens will be approximately 6.00.
- Rx +2.00Sph -> [+2.00 +4.00D] = 6.00BC.