title: Corvis ST Tonometer for Measuring Postoperative IOP in LASIK Patients.
abstract: OBJECTIVE
  To compare the postoperative measurements of intraocular pressure (IOP) using the Corvis ST Tonometer (CST), ocular response analyzer (ORA), and Goldmann applanation tonometry (GAT) in eyes undergoing laser in situ keratomileusis (LASIK), as well as to analyze the relationship between the corneal biomechanical parameters of the CST and the ORA.
  
  
  METHODS
  Fifty participants who had undergone LASIK to treat myopia in the previous 3 months were enrolled. Postoperative IOP measurements of these participants were obtained using the CST, ORA (corneal-compensated IOP [IOPcc], Goldmann-correlated IOP [IOPg]), and GAT. Device agreement was calculated by Bland-Altman analysis. The metrics of corneal biomechanical properties were recorded using the ORA and the CST. Corneal biomechanical parameters were compared.
  
  
  RESULTS
  The Bland-Altman analysis revealed a significant bias between CST and GAT, between CST and IOPcc, and between CST and IOPg of 3.4, 1.0, and 3.8, mm Hg, respectively, with 95% limits of agreement of -0.7 to 7.5 mm Hg, -2.1 to 4.2 mm Hg, and -0.4 to 8.0 mm Hg. The ORA-derived IOP measurements, CST-derived IOP, and GAT IOP values showed good correlation with each other. The CST IOP and IOPcc were higher than the GAT IOP (all p < 0.05), whereas IOPg did not differ from the GAT IOP readings. Ocular response analyzer-derived corneal biomechanical parameters (corneal hysteresis and the corneal resistance factor) showed significant correlations with CST-derived parameters, including the maximum deformation amplitude at the corneal apex and the time from start until the first applanation.
  
  
  CONCLUSIONS
  The CST offers an alternative method for measuring postoperative IOP in LASIK patients, and it appears to obtain higher IOP values than other tonometry techniques. The technique may facilitate the investigation of corneal biomechanical property changes in LASIK-treated eyes.
authors: *MPA, MD, PhD †MD ‡MD, PhD School of Life Sciences, Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Xiamen, China (JH, ZL); Department of Ophthalmology, Eye, Ear, Nose, and Throat Hospital, School of Shanghai Medicine, Fudan University, Shanghai, China (JH, ZY, CJ, XZ, XS, JX); State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai, China (XS); Key Laboratory of Myopia, National Health and Family Planning Commission, Shanghai, China (XS); and Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts (JH).
authors: Jiaxu
authors: J
authors: Hong
authors: Zhiqiang
authors: Z
authors: Yu
authors: Chunhui
authors: C
authors: Jiang
authors: Xingtao
authors: X
authors: Zhou
authors: Zuguo
authors: Z
authors: Liu
authors: Xinghuai
authors: X
authors: Sun
authors: Jianjiang
authors: J
authors: Xu
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003315:Cornea / Q000502:physiology*; D003319:Corneal Stroma / Q000601:surgery; D004548:Elasticity / Q000502:physiology; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000601:surgery*; D011184:Postoperative Period; D013524:Surgical Flaps; D014065:Tonometry, Ocular / Q000295:instrumentation* / Q000379:methods; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult