SPS-203 Intraoperative Aberrometry, Toric Marking & Alignment | ASCRS
2020 ASCRS Virtual Annual Meeting

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Papers in this Session
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Comparison of Intraoperative Aberrometry and Modern Biometry for IOL Selection in Cataract Surgery with Capsular Tension Rings
Christopher P. Long
Allison J. Chen, MD
Tianlun Lu, MS
Kevin Garff, MD
Chris W. Heichel, MD

Retrospective chart review of 138 eyes undergoing cataract surgery with IWA from 05/2017 to 05/2019. Fifty-six torics, 36 multifocals (MFs), 27 multifocal torics (MFTs), and 19 standard lenses were included. A capsular tension ring (CTR) was placed in all eyes. Accuracy of ORA and the above formulas was assessed via mean numerical error (MNE), mean absolute error (MAE), and percentages of prediction error within ±0.25D, ±0.50D, ±0.75D, and ±1.00D. Sub-analysis by axial length (AL>25.0, 22.0-25.0, and <22.0), toric and multifocal status were also performed. Patients with prior refractive or corneal surgery were excluded.

MAE with ORA was 0.422. MAE for Hill-RBF, Barrett II, SRK/T, and Holladay 1 were 0.470, 0.454, 0.478, and 0.457 (F=0.26, p=0.90). MNE for ORA and the above formulas were 0.043, 0.110, 0.039, -0.038, and 0.006 (F=0.59, p=0.66). Percent of patients with ORA MAE within 0.25D, 0.50D, 0.75D and 1.00D were 42%, 70%, 86%, and 93%. There was no difference in this percent distribution between ORA and the above formulas (p=0.9). MAE for various AL eyes in ORA/Hill-RBF/Barrett II were long AL (N=37): 0.481/0.494/0.574 (F=0.04, p=0.96); normal AL (N=100): 0.400/0.461/0.410 (F=0.66, p=0.52); short AL (N=1): 0.505/0.460/0.240. Sub-analysis by toric status and MF IOLs will be presented in the final paper.

Our study suggests that the accuracy of ORA and modern biometric formulas are comparable in patients undergoing cataract surgery with CTRs. Our findings suggest that the accuracy of ORA does not vary significantly by long versus normal AL eyes, though further studies with larger sample sizes and evaluating outcomes in shorter AL eyes are necessary.
Clinical Evaluation of Toric Intraocular Lens Implantation Based on Itrace Wavefront Keratometric Astigmatism
Zhe Zhang, MD, PhD
Suhua Zhang, MD

The prospective study included 85 eyes of 63 patients undergoing phacoemulsification and toric IOL implantation. The patients all had cataracts with preexisting regular corneal astigmatism and wanted a toric IOL implantation, with their cylindric values between 0.75 diopters (D) and 5.00 D. The IOL power and cylinders were chosen with the help of the itrace toric planning program using wavefront keratometric astigmatism (WaveFront K’s). Over a 3-month follow-up period, rotational stability and astigmatic changes were evaluated using the Alpins vector method.

Postoperatively mean refractive astigmatism decreased significantly from 1.91D ± 0.69 (SD) to 0.48D ± 0.34 (SD). Surgical induced astigmatism (SIA) was 1.73D ± 0.77 (SD), the correction index (CI) was 0.89±0.22, showing slight undercorrection. The proportion of astigmatism less than or equal to 0.50D increased from 0 to 71.8% postoperatively.

This is the first study on evaluation of the clinical outcomes of using iTrace WaveFront K readings to plan toric IOL implantation. It shows that the iTrace built-in toric calculator with wavefront keratometric astigmatism is safe and effective.
Comparative Evaluation of Intra-Operative Aberrometry and Barrett’s Toric Calculator in Toric Intraocular Lens Implantation
Ritika Mukhija, MD
Murugesan Vanathi, MD
Meena Verma, BScOptom
Noopur Gupta, MS, DNB, PhD
Radhika Tandon, MD, DNB, FRCOphth, FRCSEd

Study Design: Prospective, observational, non-randomized Inclusion Criteria: Age > 18 years; Visually significant cataract with significant corneal astigmatism; Written informed consent Exclusion Criteria: Any co-existent ocular co-morbidity, previous intra-ocular surgery Methods: All patients fulfilling the selection criteria would undergo MICS phaco-emulsification with toric IOL implantation with IOL power and axis placement aided by intra-operative aberrometry. Outcome Measures: 1. Uncorrected distance visual acuity & post-operative residual astigmatism at 1 month 2. Correlation between residual clinical refractive error, residual error prediction by ORA, and Barrett’s toric calculator.

A total of 30 patients with mean age of 59.13+11.64 were included; mean pre-op UDVA, axial length, average keratometry and keratometric astigmatism were logMAR 1.120.58, 23.480.79mm, 44.011.85D & 1.720.66D respectively. At one month post-op, mean UDVA, mean residual astigmatism and mean residual spherical equivalent was logMAR 0.090.10, 0.600.34 D and -0.190.26 D respectively. The mean residual astigmatism was calculated as 0.170.02D on ORA and as 0.200.03D using Barretts toric calculator (P=0.35). The mean difference between residual astigmatism at one month and that calculated by Barretts was 0.390.07D (P<0.05) and 0.350.05D (P<0.05) when compared to calculations by ORA.

Both intra-operative aberrometry & Barrett’s toric calculator give reliable & comparable results in prediction of post-operative residual astigmatism for toric IOL implantation. Although the difference compared to clinical residual astigmatism using both techniques was statistically significant, it may not be clinically significant.
Comparing Refractive Outcomes Following Cataract Surgery When Using the Barrett II Universal Formula Versus Intraoperative Amberrometry
Michael D. Greenwood, MD

Patients underwent cataract extraction and intraocular lens (IOL) implantation. The predicted residual refractive error was calculated preoperatively using Barrett Universal II and Hill-RBF formulas and intraoperatively using IA. The postoperative spherical equivalent (SE) was compared with the predicted SE to evaluate the accuracy of each aforementioned method.

We evaluate cases of monofocal, toric monofocal, multifocal, and toric multifocal where the surgeon IOL and ORA suggested IOL were different. When the surgeon ignored ORA and placed the pre-op IOL (n=33), the Barrett formula was within 0.5 D 65.79%, Hill-RBF 69.23%, and ORA suggested 78.57%. Although this difference in accuracy did not reach statistical significance, there is a definite trend towards ORA suggested IOL being more accurate. Given the same scenario, but the surgeon placed the ORA suggested IOL (n=22), the Barrett formula was within 0.5 D 77.78%, Hill-RBF 83.33%, and ORA suggested 81.82%. The difference between the formulas was not significant.

Surgeon selection of an IOL pre-operatively is influenced by many factors. When faced with a scenario where the pre-op IOL and ORA suggested IOL disagree, the results suggest that following the ORA suggested IOL will produce more outcomes that are within 0.5 D of target. More data is being collected to review cases with previous refractive surgery
Economic Analysis Comparing Intraoperative Aberrometry with Conventional Preoperative Planning in the United States
Bonnie An Henderson, MD, ABO
Margaret H. Ainslie-Garcia, MSc
Nicole C. Ferko, MSc
Carine C.W. Hsiao, MS

A literature review of MEDLINE and Google Scholar was conducted to identify peer-reviewed published studies on the clinical performance of IA versus conventional preoperative biometry and planning (PBP). Outcomes of interest included proportions of patients with emmetropia (within ±0.5 diopters of target) or ametropia. Published and grey literature was used to parameterize the model for a United States (US) region, including average annual patient volumes, reduction in enhancement surgeries (ie, refractive surgery, lens rotation, or exchange), with literature values or Medicare payments used as a proxy for procedural costs to the surgeon. The economic analysis was completed in Excel.

A large retrospective US database assessing 32,189 eyes showed a 6% reduction in the proportion of patients with refractive error >0.5 diopters when IA was used, versus PBP alone (18.1% and 24.1% respectively, P<0.0001). Assuming an annual surgical volume of 400 cases for a typical US surgeon, the analysis predicted that IA could help realize up to $30,380 in cost-savings to the surgeon per year due to avoided enhancement procedures. This translates into an estimated savings of $76 per patient.

The use of IA is predicted to contribute to cost-savings through follow-up procedural event avoidance. As recent trends in the area of cataract surgery indicate increasing patient expectations of visual outcomes, with declining reimbursement, IA may be an important asset moving forward, both financially, and as a tool for patient satisfaction.
Prediction Accuracy of Intraoperative Aberrometry Compared to Pre-Operative Biometry Formulas for Intraocular Lens Power Selection
Jingyi Ma
Sherif El-Defrawy, FRCSC, PhD
John C. Lloyd, MD, ABO
Amandeep S. Rai, MD

Consecutive, retrospective case series of 209 cataract extractions with monofocal, trifocal or toric IOL implantation from November 1, 2017 to September 30, 2019. Exclusion criteria included previous corneal refractive surgery and other ocular diseases. All patients received pre-operative biometry measurements from the IOLMaster500. The spherical equivalent was predicted pre-operatively with Barrett Universal II, SRKT, Holladay I and II, Haigis, HofferQ, and Hill-RBF and intraoperatively with wavefront aberrometry. The primary outcomes were the mean prediction error and proportion of eyes with a spherical equivalent within 0.5D of the refractive target at the one month post-operative visit.

The analysis included 126 eyes. Formulas with the lowest mean prediction error were Barrett Universal II (0.31D), Hill-RBF (0.32D), SRKT (0.32D), IWA (0.32D), Holladay I (0.36D), Holladay II (0.38D), Haigis (0.38D), and HofferQ (0.43D). Formulas with the highest proportion of eyes within 0.5D of the refractive target were IWA (82%), Hill-RBF (80%), Barrett Universal II (80%), SRKT (80%), Holladay II (74%), Holladay I (73%), Haigis (70%), and HofferQ (67%). In 63% of eyes, IWA recommended a different IOL spherical or toric power than the surgeon previously chose. In 34% of eyes, the IOL implanted differed from the pre-operative choice.

Based on preliminary results, Barrett Universal II, IWA, Hill-RBF, and SRKT all had similar mean prediction errors. Intraoperative aberrometry was slightly more effective than pre-operative biometry formulas at achieving the refractive target. Data collection is ongoing and will be complete prior to the meeting.
Refractive Outcomes of Intraoperative Wavefront Aberrometry Vs Optical Biometry for IOL Power Calculation in Post Radial Keratotomy
Laura Capitian, MD
Ricardo M. Nosé, MD
Claudia M. Francesconi, PhD
Ana Cristina Carvalho, MD
Vanessa Vizzotto, MD
Adriana S. Forseto, MD, PhD
Junia C. Marques, MD
Walton Nosé, MD

A retrospective chart-review study of 50 eyes from 36 patients (21 F/ 15M) with history of radial keratotomy (RK) submitted to phacoemulsification and intraocular lens (IOL - monofocal toric and non-toric). IOL power was calculated in the preoperative period using the Haigis suite and Barrett from the IOL Master 700, ASCRS calculator, Aramberri double k and intraoperative using ORA. ORA and others calculator were compared to the ideal IOL and the discrepancies were analyzed. Inclusion criteria: Cataract patients previously undergone RK (4 or 8 incisions) Minimum postoperative data : 30 days Exclusion criteria: Retinal diseases

Eyes operated using of biometry (n=10) had, on average, the mean differences between pre-op predicted refraction and target refraction of -0.470 (SD=0.75181) and those with ORA (N=22) a mean of -0.238 (SD = 0.777). The medians difference between both groups was not statistically significant (Mann-Whitney U=90, z=-0.792, p-value = 0.4295). We observed lack of evidences regarding RK (4 vs. equal or greater than 8) on delta (i.e., difference) between post-operation spherical equivalent and target refraction (Mann-Whitney U = 217.5, z=-1.118, p-value = 0.264). The CCC for power between ORA and Biometry was 0.9648 and for the pre-op predicted refraction was 0.9498.

There was lack of evidence regarding the between groups in terms of the delta between post-operation spherical equivalent and ORA suggested predicted refraction compared with pre-operation predicted refraction with biometry, respectively. So, we have lack of evidences that biometry or ORA has higher median when compared each other.

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