Star Trek: 10 Things You Didn't Know About Geordi's VISOR
7. Why Geordi Declined Treatment
Geordi's VISOR actually caused him a lot of discomfort. He would often get headaches and become overwhelmed by all of the information his brain was receiving. The data from the sensors was transmitted into the brain through short pulses, rather than all at once, which made it a bit easier to process, but he still experienced constant pain in his day to day life.
In Encounter At Farpoint, Doctor Crusher offered to either give him painkillers or a surgery to numb the affected parts of his brain, but he declined both options because he believed that they would cause the VISOR to be less effective.
Keeping the VISOR at peak performance was really important to Geordi. He used his advanced sight in his engineering work constantly. Hopefully Geordi will have found an effective way to treat these symptoms when we see him in the third season of Star Trek: Picard.