Intraocular pressure and corneal biomechanical properties in patients with Myotonic Dystrophy

PURPOSE: 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. DESIGN: Comparative case series. PARTICIPANTS: 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. MAIN OUTCOME MEASUREMENTS: 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.