title: Myopic shift after combined phacoemulsification and vitrectomy with gas tamponade.
abstract: BACKGROUND
  Combination surgery of vitrectomy and phacoemulsification is a common procedure. The present study was undertaken to determine whether gas tamponade plays a role in the myopic shift that has been found previously after this type of surgery.
  
  
  METHODS
  The study compared 26 subjects undergoing combined procedures without gas tamponade and 28 subjects undergoing the same combined procedures with gas tamponade. The preoperative anticipated refraction was compared with the postoperative measured refraction.
  
  
  RESULTS
  The difference (Delta) between the predicted preoperative refraction and the resulting refractive status 2 months postoperatively was significantly different (t = 2.66, df = 48, p < 0.01) in eyes undergoing the combined procedure with gas tamponade (mean Delta = -0.30 D, SD = 0.66) compared with those eyes not receiving gas tamponade (mean Delta = 0.16 D, SD = 0.55). A difference in final refraction between the 2 groups of -0.46 D was found.
  
  
  CONCLUSIONS
  Patients undergoing combined procedures with gas tamponade show a statistically significant myopic shift compared with those patients not receiving gas tamponade. Ophthalmologists performing combined procedures with gas tamponade should be aware of this shift in order to select the appropriate intraocular lens and to secure the best visual outcome postoperatively.
authors.affiliation: The Opthamology Department, Queens's University, Kingston, Ontario, Canada.
authors.forename: Kelly D
authors.initials: KD
authors.lastname: Schweitzer
authors.forename: Raúl
authors.initials: R
authors.lastname: García
mesh_terms: D000368:Aged; D002386:Cataract / Q000150:complications / Q000628:therapy; D005260:Female; D005466:Fluorocarbons / Q000009:adverse effects*; D006801:Humans; D019654:Lens Implantation, Intraocular; D008297:Male; D009216:Myopia / Q000209:etiology*; D018918:Phacoemulsification / Q000009:adverse effects*; D012029:Refraction, Ocular / Q000502:physiology; D012164:Retinal Diseases / Q000150:complications / Q000601:surgery; D014792:Visual Acuity / Q000502:physiology; D014821:Vitrectomy / Q000009:adverse effects*
chemical_list: D005466:Fluorocarbons; C042852:perflutren