We report a case of ischemic optic neuropathy arising from elevated intraocular pressure (IOP) masked by interface fluid in a post-laser in situ keratomileusis (LASIK) eye. A 51-year-old man, who had had LASIK 6 years prior to presentation, sustained blunt trauma to the left eye that resulted in a hyphema and ocular hypertension. Elevated IOP resulted in accumulation of fluid in the stromal bed–LASIK flap interface, leading to underestimation of IOP when measured centrally over the flap. After days of unrecognized ocular hypertension, ischemic optic neuropathy developed. To our knowledge, this is the first reported case of ischemic optic neuropathy resulting from underestimated IOP measurements in a post-LASIK patient. It highlights the inaccuracy of IOP measurements in post-LASIK eyes and a vision-threatening potential complication.No author has a financial or proprietary interest in any material or method mentioned.