ABSTRACT
Purpose: Barrett toric calculator (BTC) is known for its accuracy in toric IOL (tIOL) calculation over standard calculators; however, there is no study in literature to compare it with real?time intraoperative aberrometry (IA). The aim was to compare the accuracy of BTC and IA in predicting refractive outcomes in tIOL implantation. Methods: This was an institution?based prospective, observational study. Patients undergoing routine phacoemulsification with tIOL implantation were enrolled. Biometry was obtained from Lenstar?LS 900 and IOL power calculated using online BTC; however, IOL was implanted as per IA (Optiwave Refractive Analysis, ORA, Alcon) recommendation. Postoperative refractive astigmatism (RA) and spherical equivalent (SE) were recorded at one month, and respective prediction errors (PEs) were calculated using predicted refractive outcomes for both methods. The primary outcome measure was a comparison between mean PE with IA and BTC, and secondary outcome measures were uncorrected distance visual acuity (UCDVA), postoperative RA, and SE at one month. SPSS Version?21 was used; P < 0.05 considered significant. Results: Thirty eyes of 29 patients were included. Mean arithmetic and mean absolute PEs for RA were comparable between BTC (?0.70 ± 0.35D; 0.70 ± 0.34D) and IA (0.77 ± 0.32D; 0.80 ± 0.39D) (P = 0.09 and 0.09, respectively). Mean arithmetic PE for residual SE was significantly lower for BTC (?0.14 ± 0.32D) than IA (0.001 ± 0.33D) (?0.14 ± 0.32D; P = 0.002); however, there was no difference between respective mean absolute PEs (0.27 ± 0.21 D; 0.27 ± 0.18; P = 0.80). At one?month, mean UCDVA, RA, and SE were 0.09 ± 0.10D, ?0.57 ± 0.26D, and ?0.18 ± 0.27D, respectively. Conclusion: Both IA and BTC give reliable and comparable refractive results for tIOL implantation.
ABSTRACT
Purpose: This study was conducted to evaluate the accuracy of intraoperative aberrometry (IA) in intraocular lens (IOL) power calculation and compare it with conventional IOL formulas. Methods: This was a prospective case series. Eyes with visually significant cataract and axial hyperopia (AL <22.0 mm) underwent IA?assisted phacoemulsification with posterior chamber IOL (Alcon AcrySof IQ). Postoperative spherical equivalent (SE) was compared with predicted SE to calculate the outcomes with different formulas (SRK/T, Hoffer Q, Haigis, Holladay 2, Barrett Universal ? and Hill?RBF). Accuracy of intraoperative aberrometer was compared with other formulas in terms of mean absolute prediction error (MAE), percentage of patients within 0.5 D and 1 D of their target, and percentage of patients going into hyperopic shift. Results: Sixty?five eyes (57 patients) were included. In terms of MAE, both Hoffer Q (MAE = 0.30) and IA (MAE = 0.32) were significantly better than Haigis, SRK/T, and Barrett Universal ? (P < 0.05). Outcomes within ±0.5 D of the target were maximum with Hoffer Q (80%), superior to IA (Hoffer Q > IA > Holladay 2 > Hill?RBF > Haigis > SRK/T > Barrett Universal ?). Hoffer Q resulted in minimum hyperopic shift (30.76%) followed by Hill?RBF (38.46%), Holladay 2 (38.46%), Haigis (43.07%), and then IA (46.15%), SRK/T (50.76%) and Barrett Universal ? (53.84%). Conclusion: IA was more effective (statistically significant) in predicting IOL power than Haigis, SRK/T, and Barrett Universal ? although it was equivalent to Hoffer Q. Hoffer Q was superior to all formulas in terms of percentage of patients within 0.5 D of their target refractions and percentage of patients going into hyperopic shift