title: Influence of severity of nuclear cataract on optical biometry.
abstract: OBJECTIVE
  To compare preoperative and postoperative measurements of the axial length (AL) performed with the IOLMaster (Carl Zeiss Meditec) to evaluate the effect of nuclear cataract on the optical biometry.
  
  
  METHODS
  Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
  
  
  METHODS
  In 245 consecutive eyes of 162 patients scheduled for cataract surgery, type and severity of cataract was evaluated using the Lens Opacities Classification System III. Preoperative and postoperative axial length measurements were performed with the IOLMaster. The postoperative readings of AL were corrected for the IOL optic material implanted.
  
  
  RESULTS
  The preoperative AL measurements were 0.07 mm +/- 0.05 (SD) (range -0.18 to 0.11 mm) longer than the postoperative measurements (P<.001). These differences in AL were only weakly correlated (r = -0.28, P = .01) with the nuclear cataract grade, mean 3.5 +/- 0.9.
  
  
  CONCLUSIONS
  In this study, AL measurements with optical biometry using the IOLMaster were not influenced by the severity of nuclear cataract to a clinically relevant degree. Furthermore, it was found that AL in the phakic eye was overestimated by about 0.07 mm because of a slightly too low value of the group refractive index used for the crystalline lens.
authors.affiliation: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors.forename: Ana
authors.initials: A
authors.lastname: Prinz
authors.forename: Thomas
authors.initials: T
authors.lastname: Neumayer
authors.forename: Wolf
authors.initials: W
authors.lastname: Buehl
authors.forename: Barbara
authors.initials: B
authors.lastname: Kiss
authors.forename: Stefan
authors.initials: S
authors.lastname: Sacu
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Drexler
authors.forename: Oliver
authors.initials: O
authors.lastname: Findl
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001699:Biometry; D002386:Cataract / Q000145:classification / Q000175:diagnosis*; D005123:Eye / Q000473:pathology*; D006801:Humans; D007368:Interferometry; D007834:Lasers; D019654:Lens Implantation, Intraocular; D007907:Lens Nucleus, Crystalline / Q000473:pathology*; D008875:Middle Aged; D018918:Phacoemulsification; D011182:Postoperative Care; D011300:Preoperative Care; D011446:Prospective Studies; D019591:Pseudophakia / Q000175:diagnosis*; D012720:Severity of Illness Index