How important is Dia in contact lenses?

The diameter of a contact lens is the width of the lens from edge to edge. … When you wear a contact lens with the appropriate diameter, the lens will remain stable in your eye, i.e. hold its position. If you wear a contact lens with the wrong diameter, it can cause discomfort and may even fall out.

Is there a big difference between 14.0 and 14.5 diameter 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. … Many 14.0mm contacts users use 14.5mm or 14.8mm contacts to demonstrate dolly effects on their eyes.

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.

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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

Does base curve have to be exact?

The base curve number would be a number between 8.0 and 10.0 millimeters and would be more precise because these lenses need to fit just right. Now that most contact lenses dispensed are soft lenses, this measurement doesn’t need to be quite as precise.

Is there a big difference between 8.5 and 8.6 base curve?

No there is not a big diff between the two base curves. However, it’s the relationship between diameter and base curve that is more important. Also, the material of the lens can also affect the fit. You can have 3 diff contact lenses with the same BC, Diameter and power and they will all fit differently.

Is there a difference between 14.2 and 14.3 diameter contacts?

Yes they do matter. The BC, or base curve, is measured based on your cornea’s curvature. If the base curve is too small, it’ll squeeze your eye, and if it is too big, it won’t stay on your cornea.

Is 14.2 mm contact lens big?

14.2-14.3 mm — natural enlarging effect; 14.5 mm — well noticeable and at the same time quite natural enlarging effect; 14.7–15.0 mm — very noticeable enlarging effect, “dolly eyes”.

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.

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Does diameter matter in contact lenses?

It is not recommended to wear contact lenses with a different diameter from your prescription. If the diameter is too wide, the lens will be loose in the eye and may slip out of place. If the diameter is too small, the lens will have a tight fit, causing discomfort.

What happens if base curve is too high?

The BC, or base curve, is measured based on your cornea’s curvature. If the base curve is too small, it’ll squeeze your eye, and if it is too big, it won’t stay on your cornea. These both may cause damage to your eye.

What is BC and DIA in contact lenses?

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.

How do I know my base curve?

Simple Rule for estimating lens base curve on a PLUS POWER lens

  1. 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.
  2. Rx +2.00Sph -> [+2.00 +4.00D] = 6.00BC.

How do I choose a 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.

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What happens if you wear the wrong size contacts?

It is not recommended to wear contact lenses with a different diameter from your prescription. If the diameter is too wide, the lens will be loose in the eye and may slip out of place. If the diameter is too small, the lens will have a tight fit, causing discomfort.

Does your eye base curve 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. As a doctor, selecting a contact lens for best fit is also challenging because the sagittal depth of any contact lens is not notated on the packaging.

What is the smallest contact lens diameter?

The smallest sclerals are approximately 14.5 mm in diameter, and the largest can be up to 24 mm. Lenses that are 18 mm or smaller are subcategorized as mini-sclerals.