Meta-analysis of accuracy of intraocular lens power calculation formulas in short eyes

ImportanceIntraocular lens (IOL) power selection is a critical factor affecting visual outcome after IOL implantation in short eyes. Many formulas have been developed to achieve a precise prediction of the IOL power. However, controversy regarding the accuracy remains. BackgroundTo investigate the accuracy of different IOL power calculation formulas in short eyes. DesignMeta-analysis. ParticipantsPatients with the axial length of eyes less than 22mm from previously reported studies. MethodsA comprehensive search in Pubmed, EMBASE, Cochrane Data Base of Systematic Reviews and the Cochrane Central Register of Controlled Trials was conducted by October 2016. We assessed the methodological quality using a modified QUADAS-2 tool and performed analysis on weighted mean differences of mean absolute errors (MAE) among different formulas. Main Outcomes MeasuresThe between-group difference of MAE was evaluated with weighted mean difference and 95% confidence intervals. ResultsTen observational studies, involving 1161 eyes, were enrolled to compare six formulas: Haigis, Holladay 2, Hoffer Q, Holladay 1, SRK/T and SRK II. Among them, the Holladay 2 introduced the smallest overall MAE (0.496D) without statistical significance. The difference of MAE is statistically significant between Haigis and Hoffer Q (mean difference=-0.07D, P=0.003), Haigis and SRK/T (mean difference=-0.07D, P=0.009), Haigis and SRK II (mean difference=-0.41D, P=0.01). For publication bias and small-study effect, neither funnel plot nor egger's test detected statistical finding. Conclusion and RelevanceThe overall evidence from the studies confirmed the superiority of Haigis over Hoffer Q, SRK/T and SRK II in prediction IOL power in short eyes.