It’s estimated that about 35,000 people worldwide have LHON vision. However, thousands more carry a LHON genetic mutation, and could suddenly lose their vision at any time.

LHON vision loss can happen at any age, so if you carry a LHON mutation, you’re never “too young” or “too old” to be affected.

The most common situation is for LHON to affect men around the ages 15 to -25. Women tend to be affected at a broader range of ages, often around times of estrogen loss.

Source: https://www.lhon.org/lhon-101