LASIK, or any other laser refractive surgery such as PRK/SMILE etc, makes the cornea thinner in certain areas. This can potentially cause an underestimation in the real eye pressure whenever this is measured after the surgery.
As such, there is theoretical concern that people who develop glaucoma (which is usually associated with high eye pressures), may be diagnosed late because their eye pressures seem normal after LASIK when they actually are high. In other words, an eye with an actual high eye pressure may be measured to be at normal levels after laser refractive surgery is done.
Having said that, the underestimation caused by laser refractive surgery is usually on the order of a few mmHg. In reality, if a doctor is careful and looks at factors beyond pressure such as optic disc appearance, retinal nerve fiber layer thickness and visual fields, he or she will not miss a glaucoma condition regardless of whether LASIK had been done or not.
Whether a person with high eye pressure can have LASIK depends on several things. First, is it really high? Some instruments may not be very accurate in measuring this, such as the airpuff tonometer, so the 'high' pressure may need to be rechecked with a different instrument. Second, how high is high? eg 22mmHg vs 30mmHg or 40mmHg? A 'borderline' high pressure with a thick cornea may be considered 'normal' and LASIK may be possible as long as all other parameters are normal. On the other hand, an established case of glaucoma with high pressure and visual field changes is not considered a good candidate for LASIK because of various reasons, such as possible effects on vision from both glaucoma and LASIK adding up, or the possibility of needing glaucoma surgery in the future (which may affect the refractive state of the eye), or the effects of high pressure on refractive measurements, etc.
So to sum up, each case needs to be considered on its own merits. Ultimately, the suitability or otherwise for refractive surgery can only be determined after a full check up and taking into consideration the results of the various tests as mentioned above.
