Intraocular lens power calculations after laser in situ keratomileusis.
OBJECTIVE
To compare the accuracy of several techniques for calculating intraocular lens (IOL) power after laser in situ keratomileusis (LASIK).


METHODS
Retrospective review of 10 eyes from nine patients undergoing phacoemulsification after LASIK. Corneal power (K) was measured by manual keratometry (MK), refractive history (RH), contact lens overrefraction (CTL), videokeratography (VK), and an average of the refractive history and contact lens methods (AVG 2). Results were compared with the back-calculated K value generated by the Holladay IOL Consultant program. Age-matched patients undergoing phacoemulsification without previous refractive surgery served as controls.


RESULTS
Mean spherical equivalent postoperative refraction was +0.21 diopter (D) (SD, 1.54; range, -2.25 to +2.25 D) for patients undergoing cataract extraction after LASIK versus -0.56 D (SD, 0.66; range, -2.375 to +0.5 D; p= 0.16) for controls. Thirty percent of cases versus 90% of controls were within 1 D ( p= 0.002) of emmetropia. Forty percent of cases versus no controls were more than 1 D hyperopic ( p= 0.08). The mean differences for each method compared with the back-calculated K values were MK, +0.82 D; VK, +1.24 D; RH, -0.76 D; CTL, +0.91 D; AVG 2, +0.08 D. The mean absolute deviations from the back-calculated K values were MK, 1.91 D; VK, 2.01 D; RH, 1.68 D; CTL, 1.62 D; AVG 2, 1.42 D.


CONCLUSIONS
Significant refractive errors occurred with each of the methods investigated for determining IOL power after LASIK. RH, CL, or AVG 2 provided the most accurate results.
Randleman
J Bradley
JB
Department of Ophthalmology, Emory University, Atlanta, Georgia, USA.
Loupe
Donna N
DN
Song
C Diane
CD
Waring
George O
GO
Stulting
R Doyle
RD
D000328:Adult; D000368:Aged; D002387:Cataract Extraction; D003315:Cornea / Q000601:surgery; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D055095:Optics and Photonics; D011182:Postoperative Care; D012029:Refraction, Ocular / Q000502:physiology*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014792:Visual Acuity