What is normal eyebrow hair loss ?

Thank you for the question.  You should not place Rogaine on the eyebrows because this will go into and irritate the eyes.  If you are concerned about thinning eyebrows and permanent makeup is not satisfactory, you can consider an eyebrow hair transplantation as a permanent solution.  An eyebrow hair transplantation would permanently replace the lost eyebrow hairs.  Eyebrow hair transplantation is a very delicate and specialized procedure so you should see a hair transplant physician that specializes in this procedure.   

It is always a good idea to see an experienced physician if you are concerned about hair loss. A doctor can help you determine if your condition is due to side effects from medications or other health related causes. Latisse has only been approved by the FDA to treat the upper eyelashes. It has not been proven to work on the eyebrows. Using Rogaine on the brows is another off-label usage for the product. Whether or not it can grow brow hair is inconclusive. And most doctors are reluctant to allow patients to use this topical drug so close to the eyes.  There are other methods for treating eyebrow hair loss. In some cases, an eyebrow hair transplant can be an option for those experiencing permanent hair loss on the brow, even those with cosmetic tattoos.
To learn more about eyebrow hair loss and possible treatments, visit the link below.

You need to see a doctor to understand why you are losing eyebrow hairs before considering treatment.  It can be ANYTHING from an infection to genetic hair loss.