title: Correlation Between Axial Length and Anterior Chamber Depth in Normal Eyes, Long Eyes, and Extremely Long Eyes.
abstract: OBJECTIVE
  The objective of this study was to investigate the correlation between axial length (AL) and anterior chamber depth (ACD) in normal to long eyes and in extremely long eyes.
  
  
  METHODS
  This was an observational cross-sectional study in a single-center, private hospital.
  
  
  METHODS
  Axial length and ACD data were retrieved from the intraocular lens (IOL) Master database of patients who presented for IOL or phakic lens implantation. Only left eyes were included. The correlation between AL and ACD was tested with Pearson correlation coefficient in all eyes, normal to long eyes (AL < 27.5 mm), and extremely long eyes (AL ≥ 27.5 mm). P < 0.01 was statistically significant.
  
  
  RESULTS
  The cohort was composed of 1184 eyes of 1184 Chinese patients. The mean age was 65.8 ± 13.3 years (range, 19-98 years). The mean AL and ACD were 24.73 ± 2.48 mm (range, 20.51-36.20 mm) and 3.09 ± 0.44 mm (range, 1.95-4.68 mm), respectively. Pearson correlation coefficients in all eyes, normal to long eyes (1026 eyes, 87%), and extremely long eyes (158 eyes, 13%) were 0.56 (P < 0.001), 0.59 (P < 0.001), and -0.15 (P = 0.67), respectively.
  
  
  CONCLUSIONS
  There was a statistically significant positive correlation between AL and ACD in normal and long eyes but not in extremely long eyes. No correlation between AL and ACD in extremely long eyes requires newer-generation IOL formulas (ACD included) to increase the accuracy of IOL implantation.
authors.affiliation: From the Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong, China.
authors.forename: John S M
authors.initials: JS
authors.lastname: Chang
authors.forename: Silvania Y F
authors.initials: SY
authors.lastname: Lau