title: The comparison of central and mean true-net power (Pentacam) in calculating IOL-power after refractive surgery.
abstract: OBJECTIVE
  To compare the accuracy of central true net corneal power (cTNP) and mean true net corneal power (mTNP) of the Pentacam system to give a keratometry (K) reading for calculating IOL (intraocular lens) power in eyes following refractive surgery.
  
  
  METHODS
  Refraction, an automated K-reading (Km), cTNP and mTNP were measured for 15 eyes that required cataract surgery and had previously undergone refractive surgery. The difference between postoperative manifest refraction values and target refraction values calculated with the SRK/T formula using cTNP were compared with the one using mTNP.
  
  
  RESULTS
  The mean deviation from the desired post-cataract refractive outcome was 0.60 diopter (D)+/-0.47 (standard deviation) using cTNP; 0.75+/-0.54 using mTNP (p=0.386). The actual refraction was within +/-0.50D of the intended refraction for 60% (cTNP) and 33.3% (mTNP) of eyes, and within +/-1.00D for 93% (cTNP) and 66.7% (mTNP) of eyes.
  
  
  CONCLUSIONS
  Although not statistically significant, the cTNP showed better accuracy than mTNP to give a keratometry (K) reading for post-refractive surgery eyes requiring cataract surgery.
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Siloam Eye Hospital, Seoul, Korea.
authors.forename: Jeong-Ho
authors.initials: JH
authors.lastname: Yi
authors.forename: Joo Youn
authors.initials: JY
authors.lastname: Shin
authors.forename: Byoung Jin
authors.initials: BJ
authors.lastname: Ha
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Beom Jin
authors.initials: BJ
authors.lastname: Cho
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
authors.forename: Tae-im
authors.initials: TI
authors.lastname: Kim