For my experience, from children to adults, they all can wear contact lenses. However, there are some exceptional conditions when you can not or more precisly are not suggested to wear contact lenses.
*Severe dry eye syndrome presents a significant problem with wearing contact lenses. Severe dry eye syndrome can cause not only significantly uncomfortable contact lens wear, but it can put a person at risk of corneal scarring and potential infection because tears help keep contact lenses moist and lubricated.
*Blepharitis is another common condition that reduces chance of success with contact lens wear.
*Having severe eye allergies can create problems wearing contact lenses
* If you have odd prescription such as high amounts of astigmatism, the contact lenses may not best fr you. Contact lenses do provide a new type of freedom, but for some people they do not always provide the sharpness and clarity that a high quality pair of eyeglasses provides.