That can be tough in some cases. If there is a question of whether the PI is open, it is best to say I don't know whether your PI is open. Let's do a new one or make the old one larger. The are not convincing to me. But I think they should not be ignored.
Theory is the enemy of good care.
If you are using Timolol and your glaucoma gets better, then keep taking it. If your are using Timolol and your glaucoma gets worse, then Timolol may not be the best drug for you. What's good for the goose is often bad for the gander. Some drugs are good for some, and bad for others. Timolol is a drug which has different effects in different people, as is true for all drugs.