I just started using the Clarins line of products a couple months ago, and boy have I been missing out! As I'm getting older my skin has become very sensitive, and I've had a difficult time finding products that don't irritate my skin and cause a rash. Clarins has truly been a life changer. I also have dark circles and tired looking eyes. Even when well rested I look tired. I decided to give the Instant Light Brush-On Perfector a try. It is now my can't live without product! It truly does what they say it does. It illuminates the eyes and gives them a healthy glow. It stays on all day and doesn't cake up. It is so light weight you can't feel that you have it on. It is expensive for such a small amount but it doesn't take much. I only use one "click" per eye, and rather than brushing it on, I click the product and rub it on my pinky finger to apply so I have more control of the application. I simply dot it on where I want it over my foundation, then finish it off with a gentle brush of powder. I love this product!! It is worth every penny!!