Friends Aidrop is convenient because it can be used multiple times after opening.

Artificial tears have become a household item. When the eyes feel dry and gritty, people tend to rub them repeatedly, and as soon as the eyes are touched, they are considered contaminated. The more you touch, the more unbearable the itching becomes, so the best method is to avoid touching the eyes altogether. Therefore, if the eyes are very itchy and sticky, one drop of artificial tears is used. Overuse is harmful, so it is done very carefully.

I prefer Friends Drops. I mainly use Friends Drop Cool, which contains menthol for a refreshing cooling sensation. It's convenient because it can be used up to a month after opening.