Two. A vacuum ring is put across the cornea, which serves to stabilize the eyeball and also functions for a System to the microkeratome. When vacuum is activated, the vision results in being hazy and pressure on the eye is felt. The probability of issues happening are scarce but from https://wekurehealth.com/blog/lasik-eye-surgery-in-mumbai-advanced-vision-correction-for-a-clear-and-active-life/