# What is the normal eye diameter for contacts?

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The diameter of a contact lens is the width of the lens from edge to edge. It is also expressed in millimetres. This number is usually between 13 mm and 15 mm, though it can be as small as 9mm if a rigid gas-permeable lens, and it determines where the lens will sit in your eye.

## 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. … Many 14.0mm contacts users use 14.5mm or 14.8mm contacts to demonstrate dolly effects on their eyes.

## What is a normal base curve for contacts?

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.

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## 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.

## Does the diameter matter on 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.

## What is the average iris diameter?

The average horizontal visible iris diameter (HVID) is 11.6mm to 12.0mm, but only 50% of patients fall within this range. This means that the other half of the patient population is wearing contact lenses that do not fit well and are either too large or too small for a patient’s eye.

## Is there a big difference between 8.3 and 8.4 base curve?

Usually yes, that is a big difference. 8.3 are for corneas that are steeper than average , while 8.6 is for flatter curvatures. Someone who requires an 8.3 or 8.4 usually can’t wear an 8.6 because they just keep sliding all over the eye.

## 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.

## 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”.

## How do I know my eye diameter?

For accuracy and consistency, always measure from the white part of one side of the eye directly across to the white part of the other side of the eye. Reference the example image below; the corneal diameter or visible iris diameter measures 12.01mm.

## What diameter are circle lenses?

The diameter of regular contact lenses that are sold in the United States are on average 14mm–16mm. Similar to the diameter of regular contact lenses, circle lenses have no more than 15mm diameter since larger sizes would be harmful to the eyes at daily wear.

## How do you tell if your contacts are not the right size?

Top Signs of Contact Lens Discomfort

1. Stinging, burning and itchy eyes.
2. Abnormal feeling of something in your eye.
3. Excessive tearing.
4. Unusual eye secretions.
5. Eye redness.
6. Poor visual acuity.
7. Blurred vision or halos around objects.
8. Light sensitivity.

## 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 does 8.4 mean on contacts?

A BC of 8.4 mm of radius is more curved, and therefore a tighter fit, than 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.

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