Purpose
Wang et al proposed a method of optimizing axial length (AL) in eyes longer than 25.0 mm to reduce the proportion of eyes with hyperopic outcomes. The objective of this study is to compare the accuracy of predicting postoperative refractive error in eyes with AL >25.0 mm undergoing cataract surgery at a large academic center using the IOLMaster AL, 1-center and 2-center optimized ALs.
Methods
Retrospective consecutive case series including 50 eyes with an AL >25.0 mm that underwent cataract extraction with intraocular lens (IOL) implantation at Penn State Hershey Eye Center between 12/2013 and 10/2014. Inclusion criteria were (1) biometric measurements by partial coherence interferometry (IOLMaster, Carl Zeiss Meditec, Inc.), (2) no previous ocular surgery or intraoperative or postoperative complications, and (3) postoperative corrected distance visual acuity of 20/30 of better. For each case, an optimized AL was calculated using equations published previously by Wang et al. These optimized ALs were then used to predict the residual refractive error using the Holliday1, SRK/T, Haigis and HofferQ formulas. The refractive prediction error was calculated as the difference between the actual postoperative spherical equivalent and the predicted postoperative spherical equivalent. Mean numerical error (MNE) was calculated for the four formulas using the IOLMaster AL, the 1-center optimized AL, and the 2-center optimized ALs.
Results
Table 1 shows the mean numerical errors (MNE), ranges, and proportions of eyes with a hyperopic outcome using the IOLMaster AL, 1-center optimized AL, and 2-center optimized AL. The MNEs using optimized ALs were significantly reduced when compared to MNEs using IOLMaster ALs (all p <0.05). The proportion of eyes with hyperopic outcomes was reduced for all formulas using both the 1-center and 2-center optimized ALs compared to the IOLMaster ALs (all p values <0.05).
Conclusions
The accuracy of predicting postoperative spherical equivalent refractive error in axial myopes was significantly improved using optimized AL equations recently proposed by Wang et al. Based on our results, the Holladay1 2-center optimized AL should be used for eyes with an AL >25.0 mm undergoing cataract extraction with IOL implantation since its use was associated with the highest accuracy of postoperative refraction and lower proportion of eyes with hyperopic outcomes.