Reducing hyperopia

Eyes with axial lengths of greater than 25.0mm often end up with postoperative hyperopia owing in part to problems with current IOL power calculation formulas. An international study group looked at the accuracy of refractive prediction of four popular IOL power calculation formulas in eyes with axial length greater than 25.0mm in an attempt to improve outcomes. They evaluated refractive prediction errors associated with the Holladay 1, Haigis, SRK/T, and Hoffer Q formulas in consecutive cases. The optimised axial length values were highly correlated with the IOLMaster AL (R2 from 0.960 to 0.976). In the validating group, the method of optimising axial length significantly reduced the mean numerical errors for IOLs greater than 5.00 D, from +0.27 to +0.68 D to -0.10 to -0.02 D. Errors in IOLs of 5.00 D or less improved from +1.13 to +1.87 D to -0.21 to +0.01 D. In two additional validation data sets, this method significantly reduced the percentage of eyes that would be left hyperopic. The researchers recommend caution when using the optimised axial length formulas as slightly myopic results may occur. They noted that as data are accumulated, the manufacturer’s lens constants should be optimised and the accuracy could be improved further.

L Wang et al., JCRS,  'Optimizing intraocular lens power calculations in eyes with axial lengths above 25.0 mmâ€, Volume 37, No. 11, 2018-2027.'