Influence of pupil dilation on predicted postoperative refraction and recommended IOL to obtain target postoperative refraction calculated by using third- and fourth-generation calculation formulas
Received 3 May 2018
Accepted for publication 4 August 2018
Published 2 October 2018 Volume 2018:12 Pages 1913—1919
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr Scott Fraser
Takeshi Teshigawara,1–3 Akira Meguro,3 Nobuhisa Mizuki3
1Yokosuka Chuoh Eye Clinic, Yokosuka, Kanagawa, Japan; 2Tsurumi Chuoh Eye Clinic, Yokohama, Kanagawa, Japan; 3Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan
Purpose: To evaluate the influence of pupil dilation on predicted postoperative refraction (PPR) and recommended intraocular lens (IOL) power to obtain target postoperative refraction calculated by using the third- and fourth-generation IOL power calculation formulas with a new optical biometer.
Methods: This retrospective study included 162 eyes with cataract that underwent uneventful phacoemulsification with IOL implantation. PPR, recommended IOL power, anterior chamber depth (ACD), and lens thickness (LT) were measured pre- and post-pupil dilation. The change in PPR detected by using third-generation (Hoffer Q and SRK/T) and fourth-generation formulas (Haigis and Holladay 2) and the changes in ACD and LT were evaluated pre- and postdilation. The influence of dilation on the recommended IOL power calculated by each formula was analyzed.
Result: ACD and LT significantly changed from pre- to postdilation. The mean absolute change in PPR between pre- and postdilation was significantly higher for fourth-generation formulas compared with third-generation formulas. The change in PPR between pre- and postdilation showed a significantly positive correlation with change in ACD and a significantly negative correlation with change in LT with fourth-generation formulas, but not with third-generation formulas. The discrepancy rate of recommended IOL power between pre- and postdilation calculated by fourth-generation formulas was significantly higher than that calculated by third-generation formulas.
Conclusion: ACD and LT significantly changed by dilation. PPR and recommended IOL power significantly changed more by dilation when using fourth-generation formulas compared with third-generation formulas. Given the significant correlations of the change in PPR (between the pre- and postdilation) in the fourth-generation formulas and the changes in ACD and LT, the latter changes may be key in influencing dilation in the fourth-generation power calculation. Knowledge of the influence of dilation on fourth-generation formulas could help improve IOL calculation.
Keywords: pupil dilation, IOL power calculation, predicted postoperative refraction
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