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Will The Wrong Base Curve of Contact Lenses Cause Discomfort?

We do love to wear different sizes of lens or colored lens to have larger eyes visually, or to wear it as per the cosplay character’s colors or design. Somehow it can affect us for not following our right base curve and diameter size in order to achieve the look we wanted. Wearing the wrong size of contact lens may not worsen your vision but definitely will cause discomfort. Here we will go through with you what will be the wrong base curve and wrong diameter symptoms.

Estimated reading time: 6 minutes

Is A Fitted Contact Lens Important?

Maybe we did not realize it, but when buying any clothing or shoes we will require the sizes that fitted us, getting ourselves a pair of contact lenses doesn’t have the same reputation. Some did not aware that wearing poorly fitted contact lens can cause serious harm to your overall eye health.

If you wear lenses that don’t fit your eyes there’s a good chance you’ll develop contact lens intolerance. This condition can cause a person to be forced to wear eyeglasses or undergo laser vision correction. People with contact lens intolerance are not able to apply lenses to their eyes without pain, or wearing them for more than a few minutes.

How To Tell If Your Contacts Are Not The Right Size?

When your contact lens fits over the cornea perfectly, it means you’ve got the right pair! But if the lens is moving too much, it can be telling you that the contacts is too big for your cornea.

Having different materials of contact lenses can also make a difference in the way the lens fits. Compared with soft contact lenses, gas permeable contacts may move even a little more than that, which is two to three millimeters.

Base curve or diameter of contact lens is a major factor that adds to the patient’s annoyance. It is necessary to trace the reasons for the discomfort so that you could make an intelligent choice the next time, you are offered vision correction lenses.

No matter what is the sizes of the lens you are going for, the base curves & diameter of your eyes are the parameters that decide the lens sizes that sit in your eyes perfectly and crisp clear vision.

Contact lenses are available in varying strengths, base curves & diameter. The most important thing that decides the fit of contact lenses in a patient’s eye is the base curve. Diameter is yet another factor but patients have reported problems of symptoms more with wrong base curve than size.

Do you know contact lens cleanliness also plays an important role in ensuring eye comfortability?


What is Diameter Size (DIA)?

Diameter is the measurement of the size of the contact lenses. Circle lenses are available in different sizes from 14.00 mm to 20.00 mm being the biggest. An average fit contact lens should cover past your iris, which is 1-2 millimetres bigger. If on the other hand your contact lens sits exactly on the edge of the iris called limbus; you may risk leaving it scratched.

The size eyes of an average person for adults are usually from 26mm to 28mm. Iriz size varies between 12 to 14mm, with 13mm being the most common. Hence, 14.0mm diameter is the size that best sit in your eyes.

But knowing that the larger diameter lens can create enlarging eyes effect, sizes ranging from 14.5-16mm are the choices for certain groups of people who wanted to look better with larger eyes or being used in some cosplay character. When some will go for 14.0mm that tends to lean towards a more natural and non-enlarging style.

Wrong Diameter Symptoms

Contact lens diameter too big will cause your problem.

The wider of the lens the better enlarging effect you could have. But bear in mind if the diameter is too big, the lens will be loose in the eye and may slip out of place. Not only feeling discomfort all the time but also feeling that you are not wearing the lens properly.

Other than that some may even feel itchiness by wearing lenses that is too wide for their eyes.

What is Base Curve Size (BC)?

Base curve is the measurement of the curvature of contacts. It is important in order to allow the contact lens to fit well to your cornea for comfort, to facilitate tear exchange, and to allow oxygen transmission. An average base curve is 8.6mm.

Wrong Base Curve Symptoms

If your lenses are too loose and keep moving up with every blink of eye, your contacts are a larger base curve. On the other hand, steeper or smaller base curves make your eyes feel tighter. 

An ill-fitted base curve also obstructs oxygen flow & causes discomfort.

If this goes on for too long, the cornea can begin to swell or develop edema. The cornea can still handle a tiny bit of edema and hypoxia. But once the swelling and hypoxia become mild, not only hazy or blurry vision but it will develop cysts as well if it becomes worsen. These are the wrong base curve symptoms that you should be aware of.

Others Symptoms & Factors

Apart from the wrong base curve or diameter, some other symptoms and factors that lead to contact lens discomfort are digital eye strain, dirty contact lenses & contact lenses with either too high or too low water content. You know the wrong size of contact lenses is causing you discomfort if it keeps falling out or restricts swift floating on the cornea.

Here are some tips to help you find the right size of circle contacts. 


Even though contact lenses are supposed to be a flexible option to fit your lifestyle, we would still recommend wearing the proper size that fits you best in the long run to protect your eyes and your sight. Please follow the recommended prescriptions provided by your eye care specialists.

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