Laser refractive surgery, such as PRK and LASIK, using excimer laser to ablate and flatten the cornea and let people to be free from corrective eyewear. Although laser refractive surgery does not cause glaucoma but can interfere with detection of the condition. It is well known that intraocular pressure (IOP) measurements using conventional methods, such as Goldmann tonometry and non-contact pneumotonometry, are falsely low after laser refractive surgery. Falsely low IOP readings may result in delay in diagnosis of future glaucoma, inability to detect steroid responders after laser refractive surgery, and delay recognition of ocular hypertension patients.
Not only IOP, peripapillary retinal nerve fibers layer (P-RNFL) thickness measurement by scanning laser polarimetry (SLO) with fixed corneal compensation will also be influenced due to changes in the polarization features of the cornea caused by laser refractive surgery. Fortunately, there are no significant differences in P-RNFL thickness measurement by SLO with variable corneal compensation (VCC) and optical coherence tomography (OCT) before and after laser refractive surgery. Therefore, we still can rely on SLO with VCC and OCT to measure P-RNFL thickness for diagnosing glaucoma.
Although IOP is an important factor for diagnosis and management of glaucoma, we should keep in mind that glaucoma is a diagnosis made on careful optic nerve exam, nerve fiber exam and visual field and imaging studies. In the refractive era, ophthalmologists should monitor their patients more carefully and look at other parameters besides IOP.