Optical and ultrasound measurement of axial length and anterior chamber depth for intraocular lens power calculation

J Cataract Refract Surg. 2003 Jan;29(1):85-8. doi: 10.1016/s0886-3350(02)01500-6.


Purpose: To evaluate the precision, reproducibility, and applicability of an optical method based on partial coherence interferometry for intraocular lens (IOL) power calculation.

Setting: Ultrasound laboratory of a university eye hospital.

Methods: A prospective comparison of measurements made by the IOLMaster optical instrument (Carl Zeiss) and Ultrascan Digital 2000 contact ultrasound A-scan (Alcon) for IOL calculations was performed. Examined were 255 eyes of 134 persons (204 phakic, 47 pseudophakic, and 4 aphakic). The mean age of the patients was 67.9 years (range 7 to 94 years).

Results: The IOLMaster measurements were successful in more than 80% of cases: in 82%, 99%, and 99% for axial length (AL), anterior chamber depth (ACD), and keratometry measurements, respectively. The reproducibility of the AL and ACD measurements was very high (coefficient of variation 0.13% and 2.20%, respectively). The AL and ACD values were significantly larger with the IOLMaster (P <.001) than with the Ultrascan Digital 2000. The correlation between ultrasound and optical AL measurements was high (r = 0.985; P <.001); however, there was no correlation between ACD measurements (r = 0.079; P =.397). The corneal refractive power measurements of a Javal-type keratometer and the IOLMaster were highly correlated (r = 0.955; P <.001), with a mean difference of 0.2 diopter.

Conclusions: The results show that measurements for IOL calculation are easy and precise with the optical method. It is a noncontact method, so no anesthesia is needed and there is no risk of infection.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anterior Chamber / diagnostic imaging*
  • Anterior Chamber / pathology*
  • Aphakia / diagnostic imaging
  • Aphakia / pathology
  • Aphakia / physiopathology
  • Child
  • Cornea / physiopathology
  • Female
  • Humans
  • Interferometry*
  • Lenses, Intraocular*
  • Male
  • Middle Aged
  • Optics and Photonics*
  • Prospective Studies
  • Pseudophakia / diagnostic imaging*
  • Pseudophakia / pathology
  • Pseudophakia / physiopathology
  • Refraction, Ocular
  • Reproducibility of Results
  • Ultrasonography