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To compare accuracy of current intraocular lens (IOL) power calculation formulas with intraoperative wavefront aberrometry (ORA) in eyes with previous hyperopic and myopic advanced surface ablation surgery (LASIK/PRK)
Retrospective review of eyes with history of hyperopic or myopic ablation who underwent phacoemulsification between April 2015 and September 2019. All eyes underwent pre-operative optical biometry using the IOLMaster® and intraoperative biometry using ORA. IOL power was calculated using the Barrett-True K formula for post-hyperopic and post-myopic ablation. Comparison between ORA-recommended, Barrett-True K recommended, and IOL implanted was conducted. The error in the predicted refraction was calculated as the difference between the actual postoperative refractive outcome and the predicted refraction for each formula or method. A group of nonrefractive eyes was used as control.
48 eyes with previous hyperopic ablation, 50 eyes with history of myopic ablation and 62 controls were included in this study. In the hyperopic group, the lowest mean prediction error (PE) was observed with the ORA-recommended IOL (0.03±0.57), compared to IOL implanted (0.108±0.65), and Barrett-True K (0.396±0.63; p=0.03). In the myopic group, the highest mean PE was observed with Barrett-True-K formula (0.46±0.79), followed by ORA-recommended (0.061±0.48) and IOL implanted (0.06±0.48; p=0.001). In the control group, no statistically significant difference was seen in IOL calculations using Barrett Universal II (-0.01±0.66) and ORA (-0.06±0.77; p=0.69).
Intraoperative biometry may be an important tool to improve postoperative refractive outcomes in patients post-hyperopic or post-myopic advanced laser ablation, whereas in normal eyes, standard IOL calculation using Barrett Universal II yields good refractive outcomes.