March 2012
Volume 53, Issue 14
ARVO Annual Meeting Abstract  |   March 2012
Vector Analysis of Induced Astigmatism after 2.2 mm and 2.6 mm Scleral Incisions
Author Affiliations & Notes
  • Peter Jeppesen
    Ophthalmology, Aarhus Univ Hospital, Aarhus, Denmark
  • Thomas K. Olsen
    Ophthalmology, Aarhus Univ Hospital, Aarhus, Denmark
  • Footnotes
    Commercial Relationships  Peter Jeppesen, None; Thomas K. Olsen, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 6721. doi:
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      Peter Jeppesen, Thomas K. Olsen; Vector Analysis of Induced Astigmatism after 2.2 mm and 2.6 mm Scleral Incisions. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6721.

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

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To compare the induced corneal astigmatism after 2.2 mm and 2.6 mm superior scleral incision phacoemulsification cataract surgery.


Two groups of seventy-eight patients had pre- and postoperative keratometry measurements using an automated keratometer (Nidek Tonoref II). The K-readings were transformed to corneal power and preoperative astigmatism (Cpre) and postoperative astigmatism (Cpost). The induced astigmatism was calculated by simple subtraction (Csubtraction). The induced astigmatism was also calculated by vector analysis (Cdelta). The percentage of with-the-rule induced astigmatism (WTR) and against-the-rule (ATR) was calculated


The results are given in table 1 A significant difference was found between the vector calculated induced cylinder showing a lesser vector of astigmatism in 2.2 mm surgery No significant differences were found between the pre-, post-, or the subtraction calculated cylinder.


A detailed analysis using vector decomposition showed a significant difference between 2.2 and 2.6 mm incision in phacoemulasification cataract surgery. This indicates that a smaller incision size induces less astigmatism.  

Keywords: astigmatism • refractive surgery • cataract 

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