December 10, 2022 | Keratoconus

Is There A Corneal Cross Linking Age Limit?

By Barrett Eubanks, M.D.

Is There A Corneal Cross Linking Age Limit?

Keratoconus is a condition which affects almost all ages. Young to old.

But keratoconus also has a safe and effective treatment to halt the progression of the disease and limit vision loss. This treatment is called corneal cross linking.

Fortunately there are no real age limits or cut-offs to having the eyes treated with corneal cross linking. The procedure can be performed whenever it is needed: from the very young ages to the older crowd.

But not all age groups have the same need for corneal cross linking. In fact, the younger you are, the bigger the need for corneal cross linking. To see why, let’s first take a look at what changes in the eye with keratoconus.

Background on Keratoconus

Keratoconus causes the cornea to progressively weaken and change shape over time. At first this leads to an increase in prescription and astigmatism in the eye. Gradually, however, the change in shape of the cornea causes distortions, halos, starbursts and loss of vision.

Corneal cross linking is used to treat Keratoconus. By adding strong bonds within the cornea, the procedure can prevent keratoconus from getting worse. Corneal cross linking works quite well and is able to prevent any further progression of the keratoconus for the vast majority of individuals. Also check out How Good Is The Corneal Cross Linking Success Rate?

Effect of Age on Keratoconus

But cross linking is actually a natural phenomenon. The procedure just speeds up that natural process so that the cornea doesn’t get worse in the meantime.

But why is it important that cross linking naturally occurs? Because for some people, they will eventually reach an age where their keratoconus doesn’t get worse anymore.

Because of the change in the cornea with age, it is also less common to develop keratoconus the older you get. The vast majority of keratoconus starts before the age of 40.

The older you get, the less the cornea changes. The less likely it is that you need corneal cross linking.

So while there is no upper limit of age on corneal cross linking, there can be times when it is unnecessary. It becomes more important to follow the cornea and prescription over time to assess for change.

Note: corneal cross linking is also used to treat another condition when the cornea becomes weak because of prior vision correction surgeries such as lasik - called post-lasik ectasia. Because this condition isn’t naturally occurring (it first requires a lasik treatment), it can occur at older ages than with keratoconus. Patients who have had high prescription treatments and thinner corneas can be at a higher risk of developing this condition.

Younger Ages

If keratoconus becomes less severe with age, it seems logical to reason that the younger you are, the worse the keratoconus is. And that is absolutely the case.

Keratoconus most commonly develops in younger patients - typically in the early 20s.

In young patients (and especially children / pediatric patients), keratoconus can progress very aggressively and rapidly.

But thanks to corneal cross linking and its ability to prevent further change and progression of the keratoconus, we can prevent many of these individuals from losing vision.

No True Lower Age Limit To Cross Linking

Because of that, there is no real true lower age limit to treating keratoconus with corneal cross linking. As soon as keratoconus can be detected, corneal cross linking should be considered to stop the progression of it.

In the United States, the FDA approval for corneal cross linking included pediatric patients as young as 14 years of age. As it wasn’t fully studied for the procedure approval, the FDA just isn’t able to comment about the safety and effectiveness below that age (or above the age of 65).

But cross linking has been performed successfully at ages younger than 14.

A collection of studies have demonstrated that corneal cross linking can be safely and effectively performed in patients as young as 8 years of age. In fact, the youngest reported cross linking patient was only 4 years old!

In fact, the only thing really limiting how young keratoconus can be performed is the ability to diagnose the condition in the first place. Because keratoconus is diagnosed through special topography maps of the cornea, the child must be able to sit through an eye exam and be able to cooperate during those diagnostic tests. (if you can’t imagine your 4 year old sitting through something like that, don’t worry, keratoconus isn’t very common in 4 year olds).

But it is reassuring to know that cross linking can be performed as young as needed to treat keratoconus and slow down the progression.

Success Rate In Children

Corneal cross linking is more successful with less severe keratoconus. If the cornea isn’t quite as weak, corneal cross linking is more effectively able to stop the progression entirely forever.

But with severe keratoconus, cross linking isn’t 100% at preventing ALL future progression. There may be some continued progression in the future and a need to repeat the corneal cross linking. (But much less progression than if corneal cross linking wasn’t done).

Children fall into the category of severe keratoconus. Because of this, roughly 25% of those who get cornea cross linking may need to get it again in the future.

Thus, while corneal cross linking is important to prevent severe vision loss, it is still important to continue to have regular eye exams to make sure than any additional progression gets detected and treated.


Corneal cross linking can be performed whenever it is needed to treat keratoconus. There are no firm age limits. It can be done as young or as old as needed. However, when used to treat very severe keratoconus, corneal cross linking becomes less effective at stopping all change forever and there are times in which it may need to be repeated.

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