May 2003
Volume 44, Issue 13
ARVO Annual Meeting Abstract  |   May 2003
Quantification of Enantiomorphism of Astigmatism
Author Affiliations & Notes
  • O. Touzeau
    Hosp Des Quinze-Vingts, Paris, France
  • S.E. Scheer
    Hosp Des Quinze-Vingts, Paris, France
  • C. Allouch
    Hosp Des Quinze-Vingts, Paris, France
  • R. Kopito
    Hosp Des Quinze-Vingts, Paris, France
  • V.M. Borderie
    Hosp Des Quinze-Vingts, Paris, France
  • L. Laroche
    Hosp Des Quinze-Vingts, Paris, France
  • Footnotes
    Commercial Relationships  O. Touzeau, None; S.E. Scheer, None; C. Allouch, None; R. Kopito, None; V.M. Borderie, None; L. Laroche, None.
Investigative Ophthalmology & Visual Science May 2003, Vol.44, 2544. doi:
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      O. Touzeau, S.E. Scheer, C. Allouch, R. Kopito, V.M. Borderie, L. Laroche; Quantification of Enantiomorphism of Astigmatism . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2544.

      Download citation file:

      © ARVO (1962-2015); The Authors (2016-present)

  • Supplements

Abstract: : Purpose: To quantify enantiomorphism (mirror-image symmetry) of astigmatism Methods: Polar values (cylinder, axis) of regular astigmatism were transformed in rectangular coordinates (x,y). Left eye astigmatism and right eye perfect enantiomorphism astigmatism were expressed as points in a "dioptric plane". The distance between the two points was measured to quantify the enantiomorphism. The validity of the index was graphically verified using Holladay's graph. The index was tested in various clinical situations. Results: The value of the index is null only when both eyes present a perfect enantiomorphism: equal cylinders and mirror symmetry for both axes (sum of both axes equal 180°). Values of index differ significantly according to the etiologic group (idiopathic astigmatism: 0.72D, phacoemulsification: 1.41D, extracapsular cataract extraction: 2.88D, keratoconus: 4.56D, penetrating keratoplasties: 8.09D; p<0.001). Enantiomorphism decrease significantly with aging (0.62D in young patients versus 0.93D in older patients; p<0.001). Corneal astigmatism shows higher enantiomorphism than subjective astigmatism (0.70D versus 0.91D; p=0.02). Conclusions: Enantiomorphism of astigmatism can easily be quantified by an index calculated using cylinders and axes. Aging, anterior segment surgery and keratoconus decrease enantiomorphism of astigmatism.

Keywords: astigmatism • cornea: clinical science • optical properties 

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.