Evaluation of intraocular lens power calculation formulas in the triple procedure

C. W. Flowers, S. D. McLeod, Peter J McDonnell, J. A. Irvine, R. E. Smith

Research output: Contribution to journalArticle

Abstract

Purpose: To determine whether the choice of intraocular lens (IOL) power formula improves IOL power predictions and whether personalized constants within the IOL power formula are critical factors in improving refractive predictions after combined penetrating keratoplasty, cataract extraction, and IOL implantation. Methods: Records of 46 patients who had the triple procedure between January 1988 and December 1992 were evaluated using the SRK II, SRK/T, Holladay, and Hoffer Q formulas to predict the postoperative spherical equivalent refractions for implanted lens power. Calculations were carried out with and without the use of personalized constants. The predictive accuracy of each formula was assessed by comparing the actual postoperative spherical equivalent refractive error with that predicted by the formulas. The predictive error and the distribution of predictive errors were used to assess predictive accuracy. Results: There was no difference in the mean absolute predictive errors and the distribution of predictive errors for the four formulas evaluated (P > .05). The use of personalized formula constants significantly reduced the mean absolute predictive error for the SRK II, SRK/T, and Holladay formulas (P <.05) and approached significance for the Hoffer Q formula. Conclusion: The findings suggest that the choice of IOL power formula does not affect IOL power predictions in the corneal triple procedure; however, personalized constants within a formula appears to be a critical factor in improving postoperative refractive predictions.

Original languageEnglish (US)
Pages (from-to)116-122
Number of pages7
JournalJournal of Cataract and Refractive Surgery
Volume22
Issue number1
StatePublished - 1996
Externally publishedYes

Fingerprint

Intraocular Lenses
Penetrating Keratoplasty
Intraocular Lens Implantation
Refractive Errors
Cataract Extraction
Lenses

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Evaluation of intraocular lens power calculation formulas in the triple procedure. / Flowers, C. W.; McLeod, S. D.; McDonnell, Peter J; Irvine, J. A.; Smith, R. E.

In: Journal of Cataract and Refractive Surgery, Vol. 22, No. 1, 1996, p. 116-122.

Research output: Contribution to journalArticle

Flowers, C. W. ; McLeod, S. D. ; McDonnell, Peter J ; Irvine, J. A. ; Smith, R. E. / Evaluation of intraocular lens power calculation formulas in the triple procedure. In: Journal of Cataract and Refractive Surgery. 1996 ; Vol. 22, No. 1. pp. 116-122.
@article{95680d566b454f428c8ce50ba1f97cc6,
title = "Evaluation of intraocular lens power calculation formulas in the triple procedure",
abstract = "Purpose: To determine whether the choice of intraocular lens (IOL) power formula improves IOL power predictions and whether personalized constants within the IOL power formula are critical factors in improving refractive predictions after combined penetrating keratoplasty, cataract extraction, and IOL implantation. Methods: Records of 46 patients who had the triple procedure between January 1988 and December 1992 were evaluated using the SRK II, SRK/T, Holladay, and Hoffer Q formulas to predict the postoperative spherical equivalent refractions for implanted lens power. Calculations were carried out with and without the use of personalized constants. The predictive accuracy of each formula was assessed by comparing the actual postoperative spherical equivalent refractive error with that predicted by the formulas. The predictive error and the distribution of predictive errors were used to assess predictive accuracy. Results: There was no difference in the mean absolute predictive errors and the distribution of predictive errors for the four formulas evaluated (P > .05). The use of personalized formula constants significantly reduced the mean absolute predictive error for the SRK II, SRK/T, and Holladay formulas (P <.05) and approached significance for the Hoffer Q formula. Conclusion: The findings suggest that the choice of IOL power formula does not affect IOL power predictions in the corneal triple procedure; however, personalized constants within a formula appears to be a critical factor in improving postoperative refractive predictions.",
author = "Flowers, {C. W.} and McLeod, {S. D.} and McDonnell, {Peter J} and Irvine, {J. A.} and Smith, {R. E.}",
year = "1996",
language = "English (US)",
volume = "22",
pages = "116--122",
journal = "Journal of Cataract and Refractive Surgery",
issn = "0886-3350",
publisher = "Elsevier Inc.",
number = "1",

}

TY - JOUR

T1 - Evaluation of intraocular lens power calculation formulas in the triple procedure

AU - Flowers, C. W.

AU - McLeod, S. D.

AU - McDonnell, Peter J

AU - Irvine, J. A.

AU - Smith, R. E.

PY - 1996

Y1 - 1996

N2 - Purpose: To determine whether the choice of intraocular lens (IOL) power formula improves IOL power predictions and whether personalized constants within the IOL power formula are critical factors in improving refractive predictions after combined penetrating keratoplasty, cataract extraction, and IOL implantation. Methods: Records of 46 patients who had the triple procedure between January 1988 and December 1992 were evaluated using the SRK II, SRK/T, Holladay, and Hoffer Q formulas to predict the postoperative spherical equivalent refractions for implanted lens power. Calculations were carried out with and without the use of personalized constants. The predictive accuracy of each formula was assessed by comparing the actual postoperative spherical equivalent refractive error with that predicted by the formulas. The predictive error and the distribution of predictive errors were used to assess predictive accuracy. Results: There was no difference in the mean absolute predictive errors and the distribution of predictive errors for the four formulas evaluated (P > .05). The use of personalized formula constants significantly reduced the mean absolute predictive error for the SRK II, SRK/T, and Holladay formulas (P <.05) and approached significance for the Hoffer Q formula. Conclusion: The findings suggest that the choice of IOL power formula does not affect IOL power predictions in the corneal triple procedure; however, personalized constants within a formula appears to be a critical factor in improving postoperative refractive predictions.

AB - Purpose: To determine whether the choice of intraocular lens (IOL) power formula improves IOL power predictions and whether personalized constants within the IOL power formula are critical factors in improving refractive predictions after combined penetrating keratoplasty, cataract extraction, and IOL implantation. Methods: Records of 46 patients who had the triple procedure between January 1988 and December 1992 were evaluated using the SRK II, SRK/T, Holladay, and Hoffer Q formulas to predict the postoperative spherical equivalent refractions for implanted lens power. Calculations were carried out with and without the use of personalized constants. The predictive accuracy of each formula was assessed by comparing the actual postoperative spherical equivalent refractive error with that predicted by the formulas. The predictive error and the distribution of predictive errors were used to assess predictive accuracy. Results: There was no difference in the mean absolute predictive errors and the distribution of predictive errors for the four formulas evaluated (P > .05). The use of personalized formula constants significantly reduced the mean absolute predictive error for the SRK II, SRK/T, and Holladay formulas (P <.05) and approached significance for the Hoffer Q formula. Conclusion: The findings suggest that the choice of IOL power formula does not affect IOL power predictions in the corneal triple procedure; however, personalized constants within a formula appears to be a critical factor in improving postoperative refractive predictions.

UR - http://www.scopus.com/inward/record.url?scp=0030021230&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030021230&partnerID=8YFLogxK

M3 - Article

C2 - 8656348

AN - SCOPUS:0030021230

VL - 22

SP - 116

EP - 122

JO - Journal of Cataract and Refractive Surgery

JF - Journal of Cataract and Refractive Surgery

SN - 0886-3350

IS - 1

ER -