title: [Long-term changes of corneal endothelial cells with radial keratotomy].
abstract: OBJECTIVE
  To investigate the long-term loss and variation of corneal endothelial cells after radial keratotomy.
  
  
  METHODS
  By the way of case-control study, 51 myopia (101 eyes) patients who underwent RK in Beijing Friendship hospital, from January 1989 to December 1996 is the RK group. 51 myopia (102 eyes) outpatients who have no other eye diseases is the control group. The volunteers are the outpatients of Department of Ophthalmology in Beijing Friendship Hospital from November 2006 to March 2007. Corneal endothelial cells are examined by Topcon SP2000 non-contact corneal endothelial microscope. To survey corneal endothelium of center, superior, inferior, temple side and nasal side, to study endothelial cell density, average areas, coefficient of cell variation in size and hexagonality.
  
  
  RESULTS
  The differences of endothelial cell density, average areas, hexagonality are no significant between the RK group and the control group with the same age stage (P > 0.05). The differences of coefficient of cell variation are significant. In the 30 year old stage, the result of center is t = 3.742, P = 0.000, the result of superior is t = 3.627, P = 0.000, the result of inferior is t = 3.180, P = 0.002, the result of nasal side is t = 2.448, P = 0.016, the result of temple side is t = 3.149, P = 0.002. In the 40 year old stage, the result of center is t = 4.446, P = 0.000, the result of superior is t = 2.444, P = 0.017, the result of inferior is t = 2.113, P = 0.038, the result of nasal side is t = 3.214, P = 0.002, the result of temple side is t = 2.680, P = 0.009. In the 50 year old stage, the result of center is t = 2.360, P = 0.024, the result of superior is t = 2.600, P = 0.013, the result of inferior is t = 2.787, P = 0.008, the result of nasal side is t = 2.144, P = 0.038, the result of temple side is t = 2.177, P = 0.036. But the differences of coefficient of cell variation have no relationship with the time of RK (P > 0.05). The differences of endothelial cell density, average areas, coefficient of cell variation in size and hexagonality are no significant among different incision group (P > 0.05). There are impalpable changes in the morphology of endothelial cells, coefficient of cell variation in size is greater than the control with the same age stage.
  
  
  CONCLUSIONS
  If proforming other eye operations to RK patients, it is necessary to evaluate the corneal endothelial cells before operations.
authors.affiliation: Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhao
authors.forename: Yan-ling
authors.initials: YL
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002452:Cell Count; D048429:Cell Size; D004728:Endothelium, Corneal / Q000166:cytology*; D004847:Epithelial Cells / Q000166:cytology*; D005260:Female; D006801:Humans; D007646:Keratotomy, Radial; D008297:Male; D011184:Postoperative Period