Influence of corneal asymmetry on the phakometric measurement of ocular surface alignment

A. Cervino, H. Uppal, Mark C.M. Dunne*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Phakometric measurements of corneal and crystalline lens surface alignment are influenced by corneal asymmetry in which the corneal apex does not coincide with the limbal centre. The purpose of this study was to determine the horizontal separation (e) between these corneal landmarks. Measurements were made in 60 normal eyes (30 subjects) using the Orbscan Ilz corneal analysis workstation. Our results show that both corneal landmarks typically coincide, so that e = 0, but that inter-subject variations of about ±1 mm can be expected (so that the corneal apex may fall nasal or temporal to the visual axis). This suggests that no correction for corneal asymmetry is required when estimating average amounts of ocular alignment from samples of eyes but that the measurement of e is strongly recommended for measurements in individual eyes. © 2004 The College of Optometrists.

Original languageEnglish
Pages (from-to)411-418
Number of pages8
JournalOphthalmic and Physiological Optics
Issue number5
Publication statusPublished - Sept 2004


  • corneal apex
  • corneal topography
  • ocular alignment
  • visual axis


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