There are two reasons to perform this part of the exam prior to refractive surgery.
Most people understand that a dilating drop makes the pupil big.
The reason this is important is that it allows us to look inside your eye with our lights to make sure the retina and internal eye are healthy prior to proceeding. The second reason is a bit more complicated but let us make sense of this for you since it is so important. To understand why it is important you must first understand the process of accommodation. Accommodation is the process our eyes use to read. When we read, the lens inside your eye that sits right behind your pupil gets more fat or curved.