title: Factors influencing corneal biomechanical changes after microincision cataract surgery and standard coaxial phacoemulsification.
abstract: OBJECTIVE
  To determine the factors affecting corneal biomechanics using biomechanical waveform analysis after microincision cataract surgery (MICS) and standard coaxial phacoemulsification with different incision sizes.
  
  
  METHODS
  Vissum-Instituto Oftalmologico de Alicante, Alicante, Spain.
  
  
  METHODS
  This prospective nonrandomized study comprised eyes with significant cataract that had MICS (sub-1.8 mm incision) or coaxial phacoemulsification (2.75 mm incision). Corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured by biomechanical waveform analysis (Ocular Response Analyzer) preoperatively, immediately postoperatively, and at 1 month. Results were analyzed and compared between groups.
  
  
  RESULTS
  In the MICS group (n = 30), there was a significant increase in Goldmann-correlated intraocular pressure (IOP) and corneal-compensated IOP, although CH decreased in the immediate postoperative period (P<.05). At 1 month, all parameters in the MICS group returned to normal. The coaxial group (n = 30) had an increase in Goldmann-correlated IOP and corneal-compensated IOP, both of which were higher than normal at 1 month. Backward multiple regression analysis showed significant correlations between CH and preoperative Goldmann-correlated IOP and preoperative CRF (r(2) = 0.631, P<.05); between age, axial length (AL), and preoperative CRF (r(2) = 0.418, P<.05); and between the change in CH and AL, total incision length, and preoperative CH (r(2) = 0.429, P<.05).
  
  
  CONCLUSIONS
  Cataract surgery with MICS and coaxial phacoemulsification significantly altered corneal biomechanics. Corneal hysteresis was inversely correlated with Goldmann-correlated IOP; CRF was inversely correlated with age and AL. The MICS technique provided more stable corneal biomechanical properties than standard coaxial phacoemulsification 1 month postoperatively.
authors.affiliation: Vissum Corporation-Instituto Oftalmologico de Alicante, Division of Ophthalmology, Miguel Hernández University, Departamento de Optica (Piñero), Farmacologia y Anatomia, Universidad de Alicante, Spain. jlalio@vissum.com
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Alió
authors.forename: Ma Cecilia C
authors.initials: MC
authors.lastname: Agdeppa
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Rodríguez-Prats
authors.forename: Francisco
authors.initials: F
authors.lastname: Amparo
authors.forename: David P
authors.initials: DP
authors.lastname: Piñero
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena / Q000502:physiology; D003315:Cornea / Q000502:physiology*; D004548:Elasticity / Q000502:physiology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D018918:Phacoemulsification / Q000379:methods*; D011446:Prospective Studies; D012307:Risk Factors