OBJECTIVE To compare intraocular pressure (IOP) between patients with myotonic dystrophy (DM1) and normal subjects, taking into account corneal characteristics. To determine whether lower IOP measurements in patients with DM1 are due to thinner corneas. METHODS Comparative case series. METHODS Fifty-three eyes of patients with DM1 and 53 eyes of normal age- and sex-matched subjects. METHODS Corneal biomechanical properties and corneal compensated intraocular pressure (IOPcc) measured with the Ocular Response Analyzer (Reichert Inc., Depew, NY), central corneal thickness measured with the Oculus Pentacam (Oculus, Wetzlar, Germany), and IOP were evaluated in patients with DM1 and compared with age- and sex-matched healthy subjects. METHODS Goldmann applanation tonometry, central corneal thickness, corneal hysteresis (CH), corneal resistance factor (CRF), and IOPcc. RESULTS Compared with the healthy subjects, patients with DM1 showed lower IOP (12.4+/-3.6 mm Hg vs. 14.9+/-3.4 mmHg) (P<0.01) and IOPcc (12.7+/-4.5 vs. 15.9+/-3.5) (P<0.01), and thicker cornea (575.9+/-35.02 mum vs. 556.3+/-33.2 microm) (P<0.01), but no significant changes in CH (P = 0.03) and CRF (P = 0.37). CONCLUSIONS Lower IOP in patients with DM1 is not related to differences in central corneal thickness or corneal biomechanical properties. BACKGROUND The author(s) have no proprietary or commercial interest in any materials discussed in this article.