What is a steep base curve?

The base curve is the radius of the sphere of the back of the lens that the prescription describes (the lower the number, the steeper the curve of the cornea and the lens, the higher the number, the flatter the curve of the cornea and the lens).

Is there a big difference between 8.4 and 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)
3 8.6 14.2
4 8.4, 8.6 13.8
5 8.6 14.0
6 8.5, 9.0 14.2

What is the base curve on glasses?

The base relates to the standard curvature of the frame, also known as wraparound effect. The higher your prescription number, the more wraparound the frame is. On average, eyeglasses should have no more than a base of 4-6. However, the base can go as high as 8, especially for non-prescription sunglasses.

Which base curve works well on steeper corneas?

Larger corneas may need the flatter 8.8 mm base curve, while smaller corneas may achieve a better fitting relationship with the steeper 8.5 mm base curve. Due to subtle differences in individual eyes, a two-base curve system is helpful in achieving the best fitting relationship possible.

What does higher base curve mean?

The base curve of a contact lens is the curvature of the back surface of the 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.

What base curve do I need?

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 know my 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.

Can I wear a different base curve?

Can I order contact lenses with a different base curve? You should never order contact lenses with a base curve that is different from your prescription. This can damage your eyes and cause problems with vision.

What happens if you wear 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.

Does BC and DIA matter for contacts?

Both the Base Curve (BC) and Diameter (DIA) of a contact lens ensures a proper fit on your cornea and total eye surface. Those features ensure comfort and encourage eye health, including allowing proper oxygen to the eye. You’ll also need this information if you want to order contact lenses online.

What does making the base curve steeper do to a contact lens?

“Steeper” base curves in today’s lenses provide the best centration, improve comfort and minimize eyelid interaction and tear film disruption.

How does base curve affect vision?

The base curve of a lens may affect certain aspects of vision, such as distortion and magnification, and wearers may notice perceptual differences between lenses with different base curves. Consequently, some practitioners may specify “match base curves” on a new prescription.

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. In theory +6.00 should always give you the best possible combination of curves for weight, optics, etc.

Can I wear a different base curve?

Can I order contact lenses with a different base curve? You should never order contact lenses with a base curve that is different from your prescription. This can damage your eyes and cause problems with vision.

How do I know what base curve my glasses are?

How To Measure The Base Curve? The base curve of any lens can be measured with a tool called a radius gauge, also known as a lens clock. A lens clock has three prongs that can measure the curvature of lenses (and other surfaces). When those 3 prongs are place against a flat surface, the gauge should read zero.

Can the base curve of your eye change?

Base curve can also change as you wear a contact lens based on environmental factors like the lens drying out, temperature changes, and exposure to makeup or soaps.

Is there a big difference between 8.4 and 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)
3 8.6 14.2
4 8.4, 8.6 13.8
5 8.6 14.0
6 8.5, 9.0 14.2

How important is base curve?

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.

Does BC and DIA matter for contacts?

Both the Base Curve (BC) and Diameter (DIA) of a contact lens ensures a proper fit on your cornea and total eye surface. Those features ensure comfort and encourage eye health, including allowing proper oxygen to the eye. You’ll also need this information if you want to order contact lenses online.

What’s 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.

What does BC and DIA mean for contacts?

BC – Base Curve (usually a number between 8 and 10) DIA – Diameter (usually a number between 13 and 15) Brand – The brand/type of contact lens that your doctor has fitted you for.

What is the difference between 14.0 and 14.2 diameter contacts?

14.0mm and 14.2mm contacts

In fact, there is not much difference between these two. Some manufacturers only make 14.2mm diameter contacts, and some others produce 14.0mm diameter contacts. However, there is no manufacturer that makes both 14.0mm and 14.2mm diameter contacts.

Does 0.00 power contacts mean?

On a glasses prescription, 0.00 (zero focusing power needed) represents good vision. Generally, the further away from zero you go (whether the number is positive or negative), the worse your eyesight and the greater the need for vision correction.

How do you tell contacts apart?

If you see slight double contours or shadow-like effects on the clock for example you should also switch the lenses and see if it is better. Depending on the types of contact lenses you wear if you take them out you might be able to see if the lens was actually for the right or the left eye.

What prescription is legally blind?

What Eye Prescription is Considered Legally Blind? Simply put, if your prescription is -2.5 or lower, this means that you are legally blind. Visual acuity of -2.5 is equivalent to 20/200 vision. Visual acuity of -3.0, for instance, means that you have 20/250 or 20/300 vision.

What does D mean on contacts?

diopters

Sphere (SPH): The amount of lens power, measured in diopters (D), which corrects nearsightedness or farsightedness. If the number under this heading features a minus sign (–), this means you’re nearsighted; if it has a plus sign (+), this means you’re farsighted.