This is an excellent question. What you have experienced is not unusual. There is a great deal of evidence that suggests cataract surgery can lower intraocular pressure, and that some glaucoma patients may be able to reduce or stop their glaucoma medications for some time. The reason for the decrease in eye pressure after cataract surgery is not yet known, but there are several studies trying to find the answer. Some people have proposed that the cataract, which is the natural lens in the eye that has gotten cloudy may be at fault. Over our lifetime, the natural lens in the eye continues to grow similar to an onion adding layers. As the lens gets bigger, it may crowd the drainage system in the eye causing the pressure to increase (like a sink backing up when the drain gets clogged).

Removing the lens may allow the drainage system to expand again and begin to flow better. Other people have proposed that the inflammation caused after the surgery may in fact be of benefit and cause the drainage system to start working better. Finally, some people feel that some of the techniques that we currently use to remove the cataract (i.e. phacoemulsification) may have steps that cause the drainage system to be cleaned and begin flowing better. The true answer is that we don't know; however, we do know it is a real phenomenon.

There are some lucky patients (like my grandmother) who used glaucoma drops for years prior to cataract surgery and have never had to restart them again. However, on average, we tend to see the eye pressure staying lower for about 1-2 years, and then it often increases again over time. It is important that you continue to see your eye doctor for routine exams to check the intraocular pressure, vision, visual fields and optic nerves because we cannot predict who will need to restart their medications or when this need will occur. Best of luck, and I hope you are one of the lucky patients that get to stay off of your drops.