First of all, the doctor attending to your eye will make an assessment on how severe the glaucoma is.
So let's say it is not severe at all, and eye pressure is very well controlled with one eye drop, then usually one can safely go ahead and do the cataract surgery. That's it, we just continue with treatment.
But let's say patients have severe glaucoma and have a very severe cataract, one can consider both surgeries in the same sitting. Of course, the assessment of the severity is important.
