Immediate Sequential Bilateral Implantable Collamer Lens Surgery Is Safe and Effective.

PURPOSE: To assess the clinical outcomes and safety profiles of patients who underwent immediate sequential bilateral phakic lens surgery. METHODS: This retrospective multicenter study included 254 consecutive patients (508 eyes) who underwent bilateral same-day Implantable Collamer Lens (ICL) (STAAR Surgical) surgery. The authors focused on 1-year postoperative clinical outcomes and adverse events. RESULTS: In the initial cohort, 176 patients (352 eyes) met inclusion criteria. Of these, 335 eyes underwent myopic ICL placement, and 17 eyes received a hyperopic ICL. Notably, 87% of eyes achieved ±0.50 diopters (D) and 95% achieved ±1.00 D of the intended refraction. One year postoperatively, 78% of eyes demonstrated optimal vaulting (250 to 750 µm), with a significant 19% reduction in vaulting observed over the 12 months (P < .001). Only minor adverse events, including early cataract formation (1 case), secondary toric ICL rotation (3 cases), and ICL exchange due to inappropriate vaulting (6 cases), were noted. CONCLUSIONS: The findings corroborate the safety and efficacy of immediate sequential bilateral phakic lens surgery and indicate its potential as a treatment option. The low incidence of minor adverse events further reinforces its favorable safety profile. [J Refract Surg. 2024;40(5):e313-e320.].

An analysis of the factors involved in IOL decentration after phacoemulsification using CASIA 2 anterior segment optical coherence tomography.

PURPOSE: To evaluate the magnitude of IOL transversal shift (ITS) after phacoemulsification and to analyse the factors contributing to IOL decentration and ITS. METHODS: 94 consecutive patients who underwent cataract surgery and IOL implantation was enrolled. Each patient underwent anterior segment optical coherence tomography with CASIA 2 (Tomey, Nagoya, Japan) to assess crystalline lens decentration, thickness and diameter seven days preoperatively and at one and sixty days postoperatively. Univariate and multivariate linear regression analysis were performed to evaluate the determinants of ITS and final decentration. RESULTS: The preoperative crystalline lens diameter was associated with the ITS and with the IOL final decentration. A positive association between the final IOL decentration and the first post-surgical day decentration was found (p < 0.0001). CONCLUSION: Greater crystalline lens diameter was associated with greater decentration and with greater ITS. Day-one IOL decentration seems to be the main determinant of final IOL decentration.

Meridional analysis for calculation of the toric power of phakic IOLs.

PURPOSE: To present a reproducible method to calculate the toricity needed at the intraocular lens (IOL) plane with toric phakic IOLs (ICL, Staar Surgical) and compare its results with those obtained with the online calculator provided by the manufacturer. DESIGN: Retrospective case series. SETTING: Private practice, Buenos Aires, Argentina. METHODS: The formula originally described by Holladay to calculate the IOL power in phakic eyes was used to calculate the required spherical power along the less refractive meridian and along the more refractive meridian. Meridional analysis was applied to calculate the required toricity at the IOL plane and the surgically induced corneal astigmatism was incorporated into the calculations. The refractive cylinder predicted by this method and by the online calculator of the manufacturer were compared to the postoperative refractive cylinder by means of vector analysis. The possible changes in the ratio of toricity in patients with different amounts of astigmatism and anterior chamber depth are assessed in a theoretical section. RESULTS: In 35 eyes, the measured mean postoperative refractive cylinder was 0.09 D @ 99°, the mean predicted postoperative refractive astigmatism was 0.04 D @ 102° according to the manufacturer's online calculator and 0.09 D @100° according to our method. With both methods, 91.43% of eyes had an absolute cylinder prediction error within ±0.50 diopters. CONCLUSIONS: The method described in this article to calculate the toricity of phakic IOLs has a refractive accuracy similar to that of the original calculator developed by the manufacturer.

Evaluation of the Agreement Between a New Pyramid Wavefront Sensor Aberrometer and Scheiner-Smirnov Aberrometers.

PURPOSE: To assess agreement between a new aberrometer (Osiris-T; CSO) employing pyramid wavefront sensor technique and Scheiner-Smirnov aberrometer (OPD-Scan III; Nidek) on measuring ocular, corneal, and internal aberrations in healthy participants. METHODS: The measurements were conducted three times consecutively by an experienced examiner. The total root mean square (RMS) aberrations, higher order aberration RMS, coma Z3±1, trefoil Z3±3, spherical aberration Z40, and astigmatism II Z4±2 up to 7th order were exported in both 4-and 6-mm pupil zones. The parameters between the two devices were statistically compared using the paired t-test, and the differences assessed with Bland-Altman plots and 95% limits of agreement. RESULTS: This prospective study included 70 right eyes of 70 healthy participants with an average age of 25.94 ± 6.59 years (range: 18 to 47 years). The mean difference in the two devices ranged from 0.01 µm for astigmatism II Z4±2 to 0.63 µm for total RMS in 4 mm and from 0.01 to 1.41 µm in 6-mm pupil size. The Bland-Altman analysis of ocular, corneal, and internal aberrations indicated high agreement between the two devices and the maximum absolute values for 95% limits of agreement ranged from 0.03 to 1.06 µm for 4-mm pupil diameters and 0.12 to 1.13 µm for 6-mm pupil diameters. CONCLUSIONS: The newly developed pyramid wavefront sensor technique aberrometer demonstrated a high agreement with a Scheiner-Smirnov aberrometer when measuring ocular, corneal, and internal aberrations in healthy participants. Thus, the two aberrometers may be considered interchangeable for clinical applications. [J Refract Surg. 2024;40(4):e218-e228.].

Differences Between Simulated Keratometry and Total Corneal Power in Eyes With Keratoconus and a Formula to Improve IOL Power Calculation Results.

PURPOSE: To compare simulated keratometry (SimK) and total corneal power (TCP) in keratoconic eyes, to determine whether the differences are systematic and predictable and to evaluate an adjusted TCP-based formula for intraocular lens (IOL) power calculation. METHODS: In a consecutive series of keratoconic eyes, measurements of SimK, TCP, posterior keratometry, and anterior and posterior corneal asphericities (Q-values) were retrospectively collected. The difference between SimK and TCP was linearly correlated to the biometric parameters. In a separate sample of keratoconic eyes that had undergone cataract surgery, IOL power was calculated with the Barrett Universal II, Hoffer QST, Holladay 1, Kane, and SRK/T formulas using the SimK and an adjusted TCP power. The respective prediction errors were calculated. RESULTS: A total of 382 keratoconic eyes (271 patients) were enrolled. An increasing overestimation of SimK by TCP was detected from stage I to III, with a significant correlation between the SimK and TCP difference and SimK in the whole sample (P < .0001, r2 = 0.1322). Approximately 7% of cases presented an underestimation of SimK by TCP. IOL power calculation with the adjusted TCP improved outcomes, achieving a maximum of 80% of eyes with a prediction error within ±0.50 diopters with the Hoffer QST, Holladay 1, and Kane formulas. CONCLUSIONS: Overall, SimK overestimated TCP. Such a difference could not be predicted by any variable. The proposed TCP-adjustment formula (TCPadj = TCP + 0.56 diopters) in keratoconic eyes for IOL power calculation might be valuable for improving refractive outcomes. [J Refract Surg. 2024;40(4):e253-e259.].

Evaluation of a New All-in-One Optical Biometer and Comparison With a Validated Swept-source OCT Biometer.

PURPOSE: To assess agreement between a new all-in-one non-contact optical biometer based on optical low coherence reflectometry (SW-9000 µm Plus; Suoer) and a swept-source optical coherence tomography biometer (OA-2000; Tomey). METHODS: Each eye was scanned three times in a row by each device at random. The measured ocular parameters included central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), axial length (AL), flat keratometry (Kf), steep keratometry (Ks), mean keratometry (Km), astigmatism, corneal diameter (CD), and pupil diameter (PD). The paired t test was used to show the differences between the SW-9000 and OA-2000. Bland-Altman plots and the 95% limits of agreement (LoA) were applied to assess the consistency of the measurements. RESULTS: Sixty eyes from 60 healthy participants were examined, with a mean spherical equivalent refraction of -5.58 ± 2.31 diopters and a mean age of 30.40 ± 6.07 years. The Bland-Altman plots showed high agreement for AL, ACD, LT, Kf, Ks, Km, astigmatism, and CD measurements (95% LoA: -0.06 to 0.04 mm, -0.10 to 0.06 mm, -0.12 to 0.11 mm, -0.30 to 0.29 D, -0.35 to 0.38 D, -0.29 to 0.30 D, -0.30 to 0.34 D, and -0.50 to 0.06 mm, respectively), whereas the agreement for CCT and PD were moderate (95% LoA: 7.12 to 20.43 µm, -0.75 to 1.19 mm, respectively). CONCLUSIONS: The new all-in-one non-contact biometer had high agreement with the OA-2000 biometer on the AL, ACD, LT, Kf, Ks, Km, astigmatism, and CD measurements. For most of the ocular parameters assessed, they were clinically interchangeable. [J Refract Surg. 2023;39(12):825-830.].

The Current Burden and Future Solutions for Preoperative Cataract-Refractive Evaluation Diagnostic Devices: A Modified Delphi Study.

Purpose: To obtain consensus on the key areas of burden associated with existing devices and to understand the requirements for a comprehensive next-generation diagnostic device to be able to solve current challenges and provide more accurate prediction of intraocular lens (IOL) power and presbyopia correction IOL success. Patients and Methods: Thirteen expert refractive cataract surgeons including three steering committee (SC) members constituted the voting panel. Three rounds of voting included a Round 1 structured electronic questionnaire, Round 2 virtual face-to-face meeting, and Round 3 electronic questionnaire to obtain consensus on topics related to current limitations and future solutions for preoperative cataract-refractive diagnostic devices. Results: Forty statements reached consensus including current limitations (n = 17) and potential solutions (n = 23) associated with preoperative diagnostic devices. Consistent with existing evidence, the panel reported unmet needs in measurement accuracy and validation, IOL power prediction, workflow, training, and surgical planning. A device that facilitates more accurate corneal measurement, effective IOL power prediction formulas for atypical eyes, simplified staff training, and improved decision-making process for surgeons regarding IOL selection is expected to help alleviate current burdens. Conclusion: Using a modified Delphi process, consensus was achieved on key unmet needs of existing preoperative diagnostic devices and requirements for a comprehensive next-generation device to provide better objective and subjective outcomes for surgeons, technicians, and patients.

Precision of Corneal Aberrations Measured by a New SD-OCT/Placido Topographer and Its Agreement With a Scheimpflug/Placido Topographer.

PURPOSE: To evaluate the precision of corneal aberrations measured by a new SD-OCT/Placido topographer, the MS-39 (CSO), and to compare them with those provided by a Scheimpflug/Placido device, the Sirius (CSO), in normal eyes. METHODS: This study enrolled 90 normal eyes of 90 patients. Total root mean square (RMS), higher order RMS, coma, trefoil, spherical aberration, and astigmatism II were analyzed. The within-subject standard deviation (Sw), test-retest repeatability, and intraclass correlation coefficient (ICC) were calculated to assess the precision. Bland-Altman plots and 95% limits of agreement (LoAs) were calculated to assess the agreement. RESULTS: For intraobserver repeatability of anterior and total corneal aberrations, most of the ICCs were greater than 0.869, except for trefoil and astigmatism II. Regarding the posterior corneal surface, the ICCs of total RMS, coma, and spherical aberration were higher than 0.878, whereas the ICCs of higher order RMS, trefoil, and astigmatism II were lower than 0.626. All test-retest repeatability values were 0.17 µm or less. In terms of interobserver reproducibility, the Sw values were 0.04 µm or less, Test-retest repeatability values were less than 0.11 µm, and all ICCs ranged from 0.532 to 0.996. Regarding agreement, 95% LoAs were small for all Zernike coefficients, and the mean difference was close to zero. CONCLUSIONS: The new SD-OCT/Placido device exhibited excellent repeatability and reproducibility for anterior and total surface, whereas total RMS, coma, and spherical aberrations showed high precision on the posterior surface. High agreement was confirmed between the SD-OCT/Placido and Scheimpflug/Placido devices. [J Refract Surg. 2023;39(6):405-412.].

Rotational Stability of a New Progressive Toric Hydrophobic Intraocular Lens With Gradually Decreasing Cylinder Power.

PURPOSE: To investigate the rotational stability of a new hydrophobic C-loop one-piece toric intraocular lens (IOL). METHODS: In this retrospective multicenter case series, the Avansee Preload1P Toric Clear (Kowa Co Ltd) was implanted using a digital marking system. Its orientation was assessed with retroillumination photographs at 1 hour, 1 day, 1 week, 1 month, 3 months, and 6 months. The mean rotation at each follow-up examination and percentage of eyes with a rotation within 5° and 10° were recorded. RESULTS: Seventy-two eyes were enrolled and completed the 3-month follow-up examination; data for the 6-month follow-up examination were obtained in 56 eyes. From the first postoperative to the 3-month examination, the mean arithmetic and absolute rotations were 0.58° ± 2.97° and 1.44° ± 2.65°, respectively. During this period, the rotation was 10° or less in 71 of 72 eyes (98.6%) and 5° or less in 67 of 72 eyes (93.1%). In the subgroup of 56 eyes with a 6-month follow-up, the mean arithmetic and absolute rotations were 0.95° ± 2.86° and 2.27° ± 1.96°, respectively, from the first to the last examination. During this period, the rotation was 10° or less in 100% of eyes and 5° or less in 53 of 56 eyes (94.6%). CONCLUSIONS: The new toric IOL has high rotational stability. The measured values were better than the corresponding values previously reported for other toric IOLs at all times considered up to 3 months and similar to them at 6 months. It satisfies the International Organization of Standardization and American National Standards Institute requirements. [J Refract Surg. 2023;39(6):374-380.].

Double-flanged knotless technique for iris prosthesis and IOL implantation associated with keratoplasty.

INTRODUCTION: Anterior segment reconstruction and penetrating keratoplasty combined with iris prosthesis (IP) and intraocular lens (IOL) scleral fixation require prolonged open-sky surgery and complex suturing. Herein we present a novel double-flanged knotless surgical technique that minimizes the open sky duration and facilitates the fixation of the IP and IOL complex to the sclera. METHODS: After corneal trephination and removal, a temporary keratoprosthesis is fixated. Three 5.0 polypropylene suture segments are introduced in the anterior chamber transconjunctivally and then externalized through keratoprosthesis. Each suture is threaded through the eyelets of the IP and then flanged. The temporary keratoprosthesis is removed, and the IP and IOL complex is positioned in the sulcus. A donor cornea button is sutured in place and the IP is centred on the optical axis by adjusting the polypropylene sutures. Finally, the suture ends are shortened, flanged, and buried under the conjunctiva. RESULTS: Surgery was performed on three eyes of three patients. No intraoperative complications occurred, while cystoid macular edema and ocular hypertension occurred in two patients during the follow-up period. The best corrected visual acuity was 6/20, 8/20, and 13/20. So far the IPs remained stable in the three eyes with a maximum follow-up of 18 months. CONCLUSION: This novel technique of penetrating keratoplasty combined with an intraocular lens (IOL) and iris prosthesis implantation makes it possible to reduce open sky surgery time, avoid complex suturing, and ensure optimal IOL visual axis alignment by adjusting suture tension.

Recommendation for Presbyopia-Correcting Intraocular Lenses: A Delphi Consensus Statement by the ESASO Study Group.

PURPOSE: To establish consensus among experts in lens and refractive surgery to guide general ophthalmologists on issues related to presbyopia-correcting intraocular lenses (IOLs). DESIGN: A modified Delphi method to reach a consensus among experts. METHODS: A steering committee formulated 105 relevant items grouped into four sections (preoperative considerations, IOL selection, intraoperative considerations, and postoperative considerations). The consensus was defined as ≥ 70% of experts agreeing with the evaluation of a statement. RESULTS: Ten experts participated and completed all rounds of questionnaires (100% response rate). Of 68 items considered in the preoperative considerations, consensus was achieved in 48 (70.6%). There was a lack of consensus over IOL selection, the experts only agreed on the importance of the patient's habits for the optical IOL design selection. Of the 14 considerations related to intraoperative issues, the experts reached a consensus on 10 (71.4%). The postoperative considerations section reached the highest consensus in 10 items of 13 (76.9%). CONCLUSIONS: Key recommendations for a diffractive multifocal IOL were a potential postoperative visual acuity > 0.5, a keratometry between 40-45 diopters, a pupil >2.8 mm under photopic conditions and <6.0 mm under scotopic conditions, a root mean square of higher order corneal aberrations <0.5 µm for 6-mm pupil size, while monofocal or non-diffractive IOLs should be considered for patients with coexisting eye disorders. A lack of agreement was found in the issues related to the IOL selection.

Refractive surgery and dry eye.

Refractive surgery is one of the most common elective surgeries performed worldwide. The incidence of dry eye disease (DED) after corneal refractive surgery varies among different studies. Pre-existing untreated DED has been identified as a risk factor for postsurgical dry eye symptoms. On the basis of both evidence and clinical experience, some recommendations for ocular surface and DED management pre- and post-refractive surgery are described. In aqueous deficiency Dry Eye Disease, preservative-free lubricating drops should be preferred, in addition to ointment and gel forms. Topical anti-inflammatory agents (Cyclosporine 0.1%, hydrocortisone phosphate, fluorometholone) should be used for 3-6 months in cases of ocular surface damage. The therapy of evaporative DED includes lifestyle modifications, lid hygiene (either performed by the patient or offered as professional lid hygiene by the physician), use of lubricating eye drops with lipid components, topical and/or systemic antibiotic treatment with anti-inflammatory properties and Intense Pulsed Light (IPL-) Treatment for meibomian gland dysfunction.

Accuracy of 24 IOL Power Calculation Methods.

PURPOSE: To scrutinize the accuracy of 24 intraocular lens (IOL) power calculation formulas in unoperated eyes. METHODS: In a series of consecutive patients undergoing phacoemulsification and implantation of the Tecnis 1 ZCB00 IOL (Johnson & Johnson Vision), the following formulas were evaluated: Barrett Universal II, Castrop, EVO 2.0, Haigis, Hoffer Q, Hoffer QST, Holladay 1, Holladay 2, Holladay 2 (AL Adjusted), K6 (Cooke), Kane, Karmona, LSF AI, Naeser 2, OKULIX, Olsen (OLCR), Olsen (standalone), Panacea, PEARL-DGS, RBF 3.0, SRK/T, T2, VRF, and VRF-G. The IOLMaster 700 (Carl Zeiss Meditec AG) was used for biometric measurements. With optimized lens constants, the mean prediction error (PE) and its standard deviation (SD), the median absolute error (MedAE), the mean absolute error (MAE), and the percentage of eyes with prediction erros within ±0.25, ±0.50, ±0.75, ±1.00, and ±2.00 D were analyzed. RESULTS: Three hundred eyes of 300 patients were enrolled. The heteroscedastic method revealed statistically significant differences (P < .05) among formulas. Newly developed methods such as the VRF-G (standard deviation [SD] ±0.387 D), Kane (SD ±0.395 D), Hoffer QST (SD ±0.404 D), and Barrett Universal II (SD ±0.405) were more accurate than older formulas (P < .05). These formulas also yielded the highest percentage of eyes with a PE within ±0.50 D (84.33%, 82.33%, 83.33%, and 81.33%, respectively). CONCLUSIONS: Newer formulas (Barrett Universal II, Hoffer QST, K6, Kane, Karmona, RBF 3.0, PEARL-DGS, and VRF-G) were the most accurate predictors of postoperative refractions. [J Refract Surg. 2023;39(4):249-256.].

Efficacy and safety of UT-DSAEK combined with Carlevale's sutureless scleral fixation IOL.

PURPOSE: To evaluate a novel surgical combination of ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) and sutureless scleral fixation for Carlevale intraocular lens (SSF-Carlevale IOL) implantation to manage corneal endothelial decompensation when there is a concomitant need for secondary IOL fixation. METHODS: Clinical data collected from 10 eyes of 9 patients with bullous keratopathy (BK) who underwent combined UT-DSAEK and SSF-Carlevale IOL implantation in a single procedure were retrospectively analyzed. Anterior chamber IOL (4 cases), aphakia (4 cases, 1 of which associated with PEX), and previous trauma (2 cases) were the conditions responsible for BK. Corrected distance visual acuity (CDVA), intraocular pressure (IOP), endothelial cell density (ECD), central corneal thickness (CCT), graft thickness (GT) and complications were recorded over a 12-month follow-up period. RESULTS: In 90% (9/10) of eyes graft clarity was maintained during follow-up. The mean CDVA improved significantly (p < 0.0001) from 1.78 ± 0.76 logMAR preoperatively to 0.53 ± 0.3 logMAR at 12 months. ECD on average decreased from 2575 ± 125.3 cells/mm2 (donor tissue) to 1697 ± 133.3 cells/mm2 in 12 months. The mean CCT decreased from 870 ± 200 µm to 650 µm ± 9 at 12 months (ANOVA, p = 0.0005). CONCLUSIONS: Combined UT-DSAEK and SSF-Carlevale IOL implantation was associated with good corneal graft survival and IOP control, with few complications. These findings suggest that this surgical approach is a practical option for patients requiring both treatment for corneal endothelial dysfunction and secondary IOL implantation.

Predictability of the vault after implantable collamer lens implantation using OCT and artificial intelligence in White patient eyes.

PURPOSE: To compare the predicted vault using machine learning with the achieved vault using the online manufacturer's nomogram in patients undergoing posterior chamber implantation with an implantable collamer lens (ICL). SETTING: Centro Oculistico Bresciano, Brescia, Italy, and I.R.C.C.S.-Bietti Foundation, Rome, Italy. DESIGN: Retrospective multicenter comparison study. METHODS: 561 eyes from 300 consecutive patients who underwent ICL placement surgery were included in this study. All preoperative and postoperative measurements were obtained by anterior segment optical coherence tomography (AS-OCT; MS-39). The actual vault was quantitatively measured and compared with the predicted vault using machine learning of AS-OCT metrics. RESULTS: A strong correlation between model predictions and achieved vaulting was detected by random forest regression (RF; R2 = 0.36), extra tree regression (ET; R2 = 0.50), and extreme gradient boosting regression ( R2 = 0.39). Conversely, a high residual difference was observed between achieved vaulting values and those predicted by the multilinear regression ( R2 = 0.33) and ridge regression ( R2 = 0.33). ET and RF regressions showed significantly lower mean absolute errors and higher percentages of eyes within ±250 µm of the intended ICL vault compared with the conventional nomogram (94%, 90%, and 72%, respectively; P < .001). ET classifiers achieved an accuracy (percentage of vault in the range of 250 to 750 µm) of up to 98%. CONCLUSIONS: Machine learning of preoperative AS-OCT metrics achieved excellent predictability of ICL vault and size, which was significantly higher than the accuracy of the online manufacturer's nomogram, providing the surgeon with a valuable aid for predicting the ICL vault.

Accuracy of Nine Formulas to Calculate the Powers of an Extended Depth-of-Focus IOL Using Two SS-OCT Biometers.

PURPOSE: To evaluate the accuracy of nine formulas to calculate the power of a new extended depth-of-focus intraocular lens (EDOF IOL), the AcrySof IQ Vivity (Alcon Laboratories, Inc), using measurements from two optical biometers, the IOLMaster 700 (Carl Zeiss Meditec AG) and Anterion (Heidelberg Engineering GmbH). METHODS: After constant optimization, the accuracy of these formulas was analyzed in 101 eyes: Barrett Universal II, EVO 2.0, Haigis, Hoffer Q, Holladay 1, Kane, Olsen, RBF 3.0, and SRK/T. Both standard and total keratometry from the IOLMaster 700 and standard keratometry from the Anterion were used for each formula. RESULTS: Constant optimization provided slightly different values for the A-constant, which ranged between 118.99 and 119.16, depending on the formula and the optical biometer. According to the heteroscedastic test, within each keratometry modality the standard deviation of the SRK/T was significantly higher compared to that of the Holladay 1, Kane, Olsen, and RBF 3.0 formulas. The SRK/T formula provided less accurate results also when the absolute prediction errors were compared by Friedman test. According to McNemar's test with Holm corrections, statistically significant differences were found within each keratometry modality between the percentage of eyes with a prediction error within ±0.25 diopters obtained with the Olsen formula compared to the Holladay 1 and Hoffer Q formulas. CONCLUSIONS: Constant optimization remains a mandatory step to achieve the best outcomes with the new EDOF IOL: the same constant should not be used for all formulas and for both optical biometers. Different statistical tests revealed that older IOL formulas have lower accuracy compared to newer formulas. [J Refract Surg. 2023;39(3):158-164.].

Comparison of the new Hoffer QST with 4 modern accurate formulas.

PURPOSE: To investigate the new Hoffer QST (Savini/Taroni) formula (HQST) and compare it with the original Hoffer Q (HQ) and 4 latest generation formulas. SETTING: I.R.C.C.S.-G.B. Bietti Foundation, Rome, Italy. DESIGN: Retrospective case series. METHODS: Refractive outcomes of the HQST, Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) 2.0, HQ, Kane, and Radial Basis Function (RBF) 3.0 formulas were compared. Subgroup analysis was performed in short (<22 mm) and long (>25 mm) axial length eyes. The SD of the prediction error (PE) was investigated using the heteroscedastic method. RESULTS: 1259 eyes of 1259 patients divided in a White group (n=696), implanted with the AcriSof SN60AT (Alcon Labs), and an Asian group (n=563), implanted with the SN60WF (Alcon Labs), were investigated. In the Asian group, the heteroscedastic method did not disclose any significant difference among the SD of the 4 modern formulas (range from 0.333 to 0.346 D), whereas the SD of the HQ formula (0.384 D) was significantly higher. Compared with the original HQ formula, in both White and Asian groups, the HQST formula avoided the mean myopic PE in short eyes and the mean hyperopic PE in long eyes. CONCLUSIONS: The new HQST formula was superior to the original HQ formula and reached statistical and clinical results comparable with those achieved by the BUII, EVO, Kane, and RBF formulas.