Intraoperative aberrometry vs modern preoperative formulas in predicting intraocular lens power

Visual Function After Implantation of Trifocal and Trifocal Toric Intraocular Lenses Using Intraoperative Aberrometry

Purpose

To evaluate patient outcomes and visual function following trifocal and trifocal toric intraocular lens (IOL) implantation using intraoperative aberrometry at a single site in the US.

Methods

This prospective, single arm study included 21 subjects that completed 3 month follow-up. Inclusion criteria were visually significant cataract and potential post-operative visual acuity of 20/25 or better. Endpoints included postoperative prediction error, refractive outcomes, uncorrected visual acuities at distance (UDVA), intermediate (UIVA), and near (UNVA), contrast sensitivity, and subject responses on the modified Visual Function Quality of Life Questionnaire (VF-14 QOL).

Results

Binocular UDVA, UIVA, and UNVA were 20/25 or better in 100% (21/21), 100% (21/21), 90% (19/21) of subjects. The absolute prediction error was 0.50 D or less in 79% (33/42) of eyes, and 81% (34/42) and 86% (36/42) of eyes achieved ≤0.5 D of residual astigmatism and manifest refraction spherical equivalent, respectively. On the modified VF-14 QOL, driving at night, reading small print, and reading a newspaper or book were the tasks that had the lowest percentages of subjects reporting no difficulty or a little difficulty.

Conclusion

Implantation with trifocal and trifocal toric IOLs using intraoperative aberrometry can provide high refractive precision, leading to excellent visual performance and low visual task difficulty at all ranges (distance, intermediate, and near).

Accuracy of the Majority Voting Method with Multiple IOL Power Formulae

Purpose

This study aimed to evaluate the efficacy of a majority decision algorithm that integrates intraoperative aberrometry (IA) and two intraocular lens (IOL) frequency formulas. The primary objective was to compare the accuracy of three formulas (IA; Sanders, Retzlaff, and Kraff/Theoretical (SRK/T); and Barrett Universal II (BUII)), in achieving emmetropia in eyes implanted with TFNT lenses (Alcon).

Patients and Methods

A total of 145 eyes of 145 patients were included in the evaluation. Preoperative data were obtained from IOLMaster 700, while intraoperative data were collected from ORA SYSTEMTM. Visual acuity ≥0.8 at the 3-month post-surgery mark was confirmed. We assessed refractive prediction error (RPE), which is the difference between predicted refraction (PR) and postoperative subjective refraction. This evaluation aimed to identify the optimal IOL power with the implemented algorithm.

Results

Among the 145 eyes evaluated, 55.9%, 78.7%, and 97.2% achieved postoperative subjective refraction within ±0.13 Diopters (D), ±0.25 D, and ±0.50 D, respectively. The percentages of eyes within ±0.25 D of PR varied by formula type, with values of 57%, 57%, and 54% for IA, BUII, and SRK/T, respectively. For eyes with short to medium axial length (AL<26.00 mm), the percentages within ±0.25 D of RPE were 52%, 58%, and 58% for IA, SRK/T, and BUII, respectively. In contrast, for eyes with long axial length (≥26.00 mm) the percentages were 68%, 52%, and 45% for IA, BUII, and SRK/T, respectively.

Conclusion

The proposed majority decision algorithm incorporating IA and two IOL frequency formulas was effective in reducing postoperative refractive error. IA was particularly beneficial for eyes with long axial length. These findings suggest the algorithm has potential to optimize IOL power selection to improve quality of life of patients and clinical practice outcomes.

Evaluating the Predictability of Postoperative Target Refraction Using the Prototype of a New Intraoperative Aberrometer

Despite all the progress in cataract and refractive lens surgery, refractive surprise is common in clinical practice. A significant postoperative refractive error is particularly annoying - and contributes to the patient's dissatisfaction with the procedure and the surgeon - when a multifocal IOL, an EDOF-IOL or a toric IOL has been implanted. The relatively new technology of intraoperative aberrometry offers the surgeon the option to intraoperatively measure the eye and its refraction, either directly after lens extraction and/or following IOL implantation. Currently, three different systems are available. In a number of studies, the technology has shown a better refractive predictability than preoperative biometry. Besides giving an evaluation of the prototype of a new intraoperative aberrometer, the I-O-W-A system, we also present our results on the influence of the kind of anaesthesia chosen and of two different IOL designs on the predictability of intraoperative aberrometry.

Prospective evaluation of the ESCRS online calculator for calculation of a multifocal intraocular lens

PURPOSE

To evaluate a recently introduced ESCRS online calculator for intraocular lens (IOL) calculation of a multifocal IOL in refractive lens exchange and cataract surgery in a prospective setting.

SETTING

Department of Ophthalmology, Goethe University Frankfurt, Germany.

DESIGN

Prospective, consecutive case series.

METHODS

Eyes that received lens extraction and multifocal IOL implantation were included. The mean prediction error, mean absolute error, and median absolute prediction error (MedAE) provided by the ESCRS online calculator were compared, as were the number of eyes within ±0.5 diopters (D), ±1.0 D, ±2.0 D of target refraction. The SRK/T formula was also included for comparison. Postoperative spherical equivalent was measured at 3 months. 1 eye per patient was included.

RESULTS

88 eyes from 88 patients with a mean age of 62 ± 9.5 years were included. The MedAE was low for all formulas and ranged from 0.26 D (Kane), Hill-RBF (0.27 D), Hoffer Q Savini/Taroni (Hoffer QST) (0.27 D), Barrett Universal II (BUII) (0.28 D), Emmetropia Verifying Optical (EVO) (0.29 D), Cooke K6 (0.27 D), 0.30 D (Postoperative spherical Equivalent prediction using Artificial intelligence and Linear algorithms, by Debellemaniére, Gatinel, and Saad [Pearl DGS]) to 0.31 D (SRK/T). No statistically significant difference was found ( P = .627). Considering the number of eyes within ±0.5 D of the calculated refraction the best performing was again the Hill-RBF (84%, 74 eyes), again followed by Kane (71, 81%), EVO, Pearl DGS, Hoffer QST, BUII (each 80%, 70 eyes), Cooke K6 (78%, 69 eyes), and SRK/T (74%). Again, no statistically significant difference was found ( P = .39).

CONCLUSIONS

Using a recently introduced ESCRS online IOL calculator in multifocal IOLs leds to a high number of eyes reaching target refraction and low prediction errors. All formulas performed similarly well. Hill-RBF showed the highest number of eyes within ±0.5 D, but no significance was found.

Rotational stability and refractive outcomes of the DFT/DATx15 toric, extended depth of focus intraocular lens

PURPOSE

To quantitatively assess postoperative rotational stability and visual acuity with the DFT/DATx15 extended depth of focus (EDOF) toric intraocular lens (IOL).

METHODS

In this prospective case series, thirty-five patients with a calculated IOL power between + 15.0 D and + 25.0 D, corneal astigmatism between 0.75 D and 2.25 D, and no significant ocular pathology underwent cataract surgery. Primary outcome was rotational stability of the IOL at 1 month post-operatively. Secondary outcomes included residual refractive astigmatism, absolute residual astigmatism prediction error, and monocular distance and intermediate visual acuities.

RESULTS

Mean absolute postoperative IOL rotation was 1.1 ± 0.2 degrees, with no rotation of more than 3 degrees at the final visit. Monocular mean best spectacle-corrected distance visual acuity (BSCDVA) improved from logMAR 0.27 ± 0.030 to 0.078 ± 0.017 (P < .001). Monocular uncorrected distance visual acuity (UCDVA) improved from 0.93 ± 0.096 to 0.18 ± 0.022 (P < .001). Best spectacle-corrected intermediate visual acuity (DSCIVA) was 0.17 ± 0.025, and uncorrected intermediate visual acuity (UCIVA) was 0.27 ± 0.040. Residual regular astigmatic refractive error was 0.21 ± 0.047 D.

CONCLUSIONS

The toric DFT/DATx15 EDOF lens showed excellent rotational stability and effective and predictable correction of astigmatism. Its refractive outcomes and safety profile were similar to those identified in prior studies of the non-toric DFT/DAT015 EDOF IOL. A small difference in monocular BSCDVA, of uncertain clinical significance, was found when comparing these outcomes with prior DFT/DAT015 data. The trial was retrospectively registered on November 5, 2021 (TRN ​​NCT05119127).

Prediction accuracy of intraoperative aberrometry compared with preoperative biometry formulae for intraocular lens power selection

OBJECTIVE

To compare the accuracy of intraoperative wavefront aberrometry to preoperative biometry formulae for predicting intraocular lens power.

DESIGN

Retrospective, consecutive case series.

PARTICIPANTS

Eyes undergoing cataract extraction with at least 1 month of follow-up after surgery at an ambulatory surgical centre in Toronto.

METHODS

Consecutive sample of 228 cataract extractions with monofocal, trifocal, or toric intraocular lens implantation from November 1, 2017, to December 31, 2019. The spherical equivalent was predicted preoperatively with Barrett Universal II, Hill-Radial Basis Function (RBF), SRK/T, Holladay I, Holladay II, Haigis, and HofferQ using biometry measurements and intraoperatively with wavefront aberrometry. The primary outcomes were mean prediction error and proportion of eyes with a spherical equivalent within 0.5 D of the refractive target at postoperative month 1.

RESULTS

The analysis included 159 eyes with 52% females and a mean age of 69.4 years. Formulae with the lowest mean prediction error were Hill-RBF (0.32 D ± 0.02 D), Barrett Universal II (0.32 D ± 0.02 D), intraoperative aberrometry (0.32 D ± 0.02 D), SRK/T (0.33 D ± 0.02 D), Holladay II (0.34 D ± 0.03 D), Holladay I (0.35 D ± 0.02 D), Haigis (0.37 D ± 0.02 D), and HofferQ (0.42 D ± 0.02 D). There were no statistically significant differences between intraoperative aberrometry and the preoperative formulae. Formulae with the highest proportion of eyes within 0.5 D of the refractive target were intraoperative aberrometry (82%), Barrett Universal II (81%), Hill-RBF (80%), SRK/T (77%), Holladay II (76%), Holladay I (75%), Haigis (71%), and HofferQ (70%).

CONCLUSIONS

Intraoperative aberrometry and modern preoperative biometry formulae are equally effective at reaching the refractive target. In normal eyes, intraoperative aberrometry does not appear to provide any additional benefit to modern prediction formulae.

Intraoperative aberrometry: an update on applications and outcomes

PURPOSE OF REVIEW

There is now a large body of experience with intraoperative aberrometry. This review aims to synthesize available data regarding intraoperative aberrometry applications and outcomes.

RECENT FINDINGS

The Optiwave Refractive Analysis (ORA) System utilizes Talbot-moiré interferometry and is the only commercially available intraoperative aberrometry device. There are few studies that include all-comers undergoing intraoperative aberrometry-assisted cataract surgery, as most studies examine routine patients only or atypical eyes only. In non-post-refractive cases, studies have consistently shown a small but statistically significant benefit in spherical equivalent refractive outcome for intraoperative aberrometry versus preoperative calculations. In studies examining axial length extremes, most studies have shown intraoperative aberrometry to perform similarly to preoperative calculations. Amongst post-refractive cases, post-myopic ablation cases appear to benefit the most from intraoperative aberrometry. For toric intraocular lenses (IOLs), intraoperative aberrometry may be used for refining IOL power (toricity and spherical equivalent) and alignment, and most studies show intraoperative aberrometry to achieve low postoperative residual astigmatism.

SUMMARY

Intraoperative aberrometry can be utilized as an adjunct to preoperative planning and surgeon's judgment to optimize cataract surgery refractive outcomes. Non-post-refractive cases, post-myopic ablation eyes, and toric intraocular lenses may have the greatest demonstrated benefit in intraoperative aberrometry studies to date, but other eyes may also benefit from intraoperative aberrometry use.

Intraoperative aberrometry versus preoperative biometry for intraocular lens power selection in patients with axial hyperopia

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 Ⅱ 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 Ⅱ (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 Ⅱ). 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 Ⅱ (53.84%).

Conclusion

IA was more effective (statistically significant) in predicting IOL power than Haigis, SRK/T, and Barrett Universal Ⅱ 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.

Refractive Outcomes Following Trifocal Intraocular Lens Implantation in Post-Myopic LASIK and PRK Eyes

Purpose

To assess refractive outcomes of a trifocal intraocular lens (IOL) in post-myopic laser refractive surgery eyes.

Methods

This was a retrospective chart review of 35 eyes (21 patients), with history of laser refractive surgery, who were implanted with a trifocal IOL. Surgeon’s standard procedure included femtosecond laser (FLACS), digital registration, and intraoperative aberrometry (IA). The primary outcome measure was absolute prediction error. Secondary measures were refractive outcomes, postoperative residual astigmatism (PRA), monocular uncorrected visual acuity at distance (UDVA; 4m), intermediate (UIVA; 60cm), and near (UNVA; 40cm), and monocular best-corrected visual acuity at distance (BCVA; 4m).

Results

At 3 months postoperatively, 71% and 68% of eyes had absolute prediction error 0.5 D or less with IA and preoperative planning respectively, which was not statistically significant (p > 0.05). The PRA was 0.5 D or less in 91% of eyes with IA and 56% of eyes with preoperative planning. The PRA differences between IA and preoperative planning were statistically significant (p < 0.002). The percentage of eyes 20/20 or better for monocular UCVA, BCVA, UIVA, and UNVA was 29%, 77%, 78%, and 66%, respectively. Absolute prediction error 0.5 D or less was significantly higher in post-LASIK eyes versus post-PRK eyes (p < 0.003), at 85% and 56% of eyes, respectively.

Conclusion

Implantation with a trifocal IOL can provide acceptable refractive and visual outcomes with minimal residual astigmatism in post-myopic LASIK and PRK eyes.

The Use of Intraoperative Aberrometry in Normal Eyes: An Analysis of Intraocular Lens Selection in Scenarios of Disagreement

PURPOSE

To compare prediction error outcomes between the Optiwave Refractive Analysis System (ORA) (Alcon Laboratories, Inc) and two modern intraocular lens (IOL) formulas (Hill-RBF2.0 [HRBF] and Barrett Universal II [BUII]), and further analyze IOL selection in scenarios of disagreement between methods.

METHODS

Patients with no previous history of corneal refractive surgery who underwent cataract extraction and had intraoperative aberrometry measurements between October 2016 and December 2019 were analyzed. The prediction error for the ORA, HRBF, and BUII were calculated based on the postoperative manifest refraction. Further analysis was performed evaluating prediction error for scenarios of disagreement between the three methods.

RESULTS

After exclusions, 281 eyes were included. The mean absolute prediction errors were 0.28 diopters (D) (ORA), 0.31 D (HRBF), and 0.33 D (BUII) (P < .05). In instances when the IOL recommended by the ORA was in disagreement with what was selected preoperatively, there was no benefit when the lens recommended by the ORA was selected based on anecdotal experience. When further analyzing these instances of disagreement, selecting the ORA-recommended lens when it is higher in power results in improved refractive outcomes: the ORA resulted in more eyes within ±0.25 diopters (D) of predicted spherical error (65% ORA, 37% HRBF, 32% BUII; P = .004) and fewer hyperopic surprises (5% ORA, 15% HRBF, 24% BUII; P = .009).

CONCLUSIONS

In normal eyes without previous corneal refractive surgery, intraoperative aberrometry is not different from to two modern preoperative IOL formulas. Placing the ORA-recommended lens when it is higher in power than that selected preoperatively results in better refractive outcomes. [J Refract Surg. 2022;38(5):304-309.].

Intraoperative aberrometry compared to preoperative Barrett True-K formula for intraocular lens power selection in eyes with prior refractive surgery

To compare the predictive refractive accuracy of intraoperative aberrometry (ORA) to the preoperative Barrett True-K formula in the calculation of intraocular lens (IOL) power in eyes with prior refractive surgery undergoing cataract surgery at the Loma Linda University Eye Institute, Loma Linda, California, USA. We conducted a retrospective chart review of patients with a history of post-myopic or hyperopic LASIK/PRK who underwent uncomplicated cataract surgery between October 2016 and March 2020. Pre-operative measurements were performed utilizing the Barrett True-K formula. Intraoperative aberrometry (ORA) was used for aphakic refraction and IOL power calculation during surgery. Predictive refractive accuracy of the two methods was compared based on the difference between achieved and intended target spherical equivalent. A total of 97 eyes (69 patients) were included in the study. Of these, 81 eyes (83.5%) had previous myopic LASIK/PRK and 16 eyes (16.5%) had previous hyperopic LASIK/PRK. Median (MedAE)/mean (MAE) absolute prediction errors for preoperative as compared to intraoperative methods were 0.49 D/0.58 D compared to 0.42 D/0.51 D, respectively (P = 0.001/0.002). Over all, ORA led to a statistically significant lower median and mean absolute error compared to the Barrett True-K formula in post-refractive eyes. Percentage of eyes within ± 1.00 D of intended target refraction as predicted by the preoperative versus the intraoperative method was 82.3% and 89.6%, respectively (P = 0.04). Although ORA led to a statistically significant lower median absolute error compared to the Barrett True-K formula, the two methods are clinically comparable in predictive refractive accuracy in patients with prior refractive surgery.

Predictive accuracy of an intraoperative aberrometry device for a new monofocal intraocular lens

PURPOSE

To evaluate refractive outcomes for the Clareon monofocal intraocular lens (IOL) in terms of achieved target refraction for the ORA (ALCON) intraoperative wavefront aberrometry device and preoperative noncontact biometry.

SETTING

University Eye Clinic Maastricht, Maastricht University Medical Center+, the Netherlands.

DESIGN

Prospective observational clinical trial.

METHODS

Patients with bilateral age-related cataracts undergoing phacoemulsification, either by delayed sequential surgery or on the same day, were included in the study. Exclusion criteria were an increased risk for refractive surprise or complicated surgery. Implanted IOL power was based on noncontact optical biometry data using the Barrett Universal II (BU-II) formula, optimized for the Clareon IOL. Postoperative subjective refraction was measured 4 to 6 weeks after surgery. Catquest-9SF questionnaires were completed preoperatively and 3 months after surgery.

RESULTS

100 eyes (51 patients) were included. The percentages of eyes within 1.0 diopters (D), 0.75 D, 0.50 D, and 0.25 D of target for ORA vs BU-II were 84% (84 eyes), 72% (72 eyes), 57% (57 eyes), and 21% (21 eyes) vs 97% (97 eyes), 88% (88 eyes), 77% (77 eyes), and 53% (53 eyes), respectively. Mean absolute prediction error was significantly higher for ORA vs preoperative biometry (P < .001). After global optimization, the prediction accuracy of ORA improved significantly (P < .001). Catquest-9SF questionnaires showed improved levels of ability at 3 months after surgery (P < .001).

CONCLUSIONS

This study showed lower percentages of eyes within target refraction for ORA (prior to lens constant optimization) compared with the BU-II formula when implanting the Clareon IOL. However, prediction accuracy of ORA improved significantly after global optimization. Therefore, further intraoperative measurements, postoperative measurements, and optimization are needed to improve the ORA prediction for this IOL.

Influence of Posterior Corneal Asphericity on Refractive Error of SRK-T and Barrett Formulas for Lucidis IOL

PURPOSE

To evaluate the influence of posterior corneal asphericity on the refractive error using SRK-T and Barrett formulas for the intraocular lens (IOL) power calculation for Lucidis Extended Depth of Focus (EDOF) IOL.

SETTING

This study was carried out at a tertiary ophthalmology center in Geneva, Switzerland.

DESIGN

A retrospective study. Medical records from all enrolled patients were analyzed and the following information was extracted retrospectively, over 1 month following surgery.

METHODS

We retrospectively reviewed 75 eyes that underwent cataract surgery and were implanted with a Lucidis EDOF IOL. We measured the posterior corneal asphericity (Q value), axial length (AL), and anterior chamber depth (ACD) and then calculated the IOL power using SRK-T and Barrett formulas.

RESULTS

Seventy-five eyes were included, all of which had 1-month postoperative data. In the cohort, 32 eyes were from females (43%) and 43 from males (57%). The mean age of the study population was 73 ± 8.8 years. The mean AL was 23.5 ± 0.98 and the mean ACD was 3.13 ± 0.3. The mean posterior Q value was - 0.35 ± 0.2. In a regression analysis, we found a statistically significant relationship between the error in refraction prediction and the posterior Q value, irrespective of the formula used. The relationship between posterior corneal asphericity and the refraction prediction error was stronger for the Barrett II Universal formula than for the SRK-T formula.

CONCLUSIONS

Posterior corneal asphericity was correlated with the refractive error of calculation of both SRK-T and Barrett formulas, with a stronger correlation to the latter formula.

Clinical Outcomes of Monofocal Toric IOLs Using Digital Tracking and Intraoperative Aberrometry

Purpose

To evaluate clinical outcomes of a toric IOL using digital tracking (DT) and intraoperative aberrometry (IA).

Methods

This was a retrospective, single surgeon study examining 151 eyes of 106 patients. Inclusion criteria were subjects who presented with visually significant cataracts (or as a candidate for clear lens extraction) and were implanted with a toric intraocular lens. Spherical equivalent prediction errors for IA and preoperative planning were calculated and compared. Preoperative and postoperative refractive data and monocular uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were also collected at 3 months postoperatively.

Results

Postoperative actual residual refractive astigmatism with IA was 0.50 D or less in 140 eyes (92.8%) and was 0.50 D or less in 88 eyes (58.3%) with back-calculations based on preoperative planning. The absolute spherical equivalent prediction error was 0.50 D or less in 135 eyes (89.4%) for IA compared to 123 eyes (85.4%) for preoperative planning. Postoperative monocular UDVA was 0.10 logMAR or better in 124 eyes (82.1%) and 0.00 logMAR or better in 90 eyes (59.6%). Postoperative CDVA was 0.10 logMAR or better in 147 eyes (97.4%) and 134 eyes (88.7%) were 0.00 logMAR or better.

Conclusion

The results demonstrate that toric implantation with DT and IA can provide excellent refractive and visual outcomes.

Repeatability of intraoperative Hartmann-Shack wavefront sensing in cataract surgery

PURPOSE

To evaluate the repeatability of aphakic intraoperative wavefront aberrometry and compare it with preoperative and postoperative aberrometry.

SETTING

Department of Ophthalmology, Hanusch Hospital, Vienna, Austria.

DESIGN

Prospective case series.

METHODS

Patients scheduled for cataract surgery were each measured 3 consecutive times using Hartmann-Shack wavefront sensing (HS-WFS) preoperatively, intraoperatively in aphakia, and 2 months postoperatively after intraocular lens implantation by a single examiner. Intraclass correlation coefficients (ICCs) of spherical equivalent (SE) values were evaluated for each timepoint. Intrasubject standard deviation (Sw) as repeatability (Sr) with corresponding repeatability limit () and mean SE differences with corresponding limits of agreement (LoA) were calculated for comparison.

RESULTS

A high consistency of repeated measurements was found with ICCs above 0.9 for each of the 3 timepoints. Intraobserver repeatability (Sr) and repeatability limit (r) of intraoperative aberrometry SE measurements (30 eyes of 30 patients) were 0.34 diopters (D) and 0.95 D, respectively. The LoA for intraoperative aphakic SE across 3 consecutive measurements were -0.71 to +0.85 D. For comparison, Sr and r for phakic preoperative measurements in the cataractous state (30 eyes of 30 patients) and postoperative measurements in the pseudophakic state (24 eyes of 24 patients) were 0.33 D and 0.93 D and 0.23 D and 0.64 D, respectively. Similarly, the LoA for preoperative and postoperative SE measurements were -0.66 to +0.60 D and -0.27 to +0.45 D, respectively.

CONCLUSIONS

HS-WFS test-retest reliability was high for all 3 timepoints, but the intraoperative setting resulted in a lower repeatability and broadened the agreement range.

Clinical outcomes of a diffractive trifocal intraocular lens with femtosecond laser, digital tracking, and intraoperative aberrometry

OBJECTIVE

To evaluate clinical outcomes of a trifocal intraocular lens using femtosecond laser-assisted cataract surgery (FLACS), digital tracking (DT), and intraoperative aberrometry (IA).

SETTING

One site (Abbotsford, B.C., Canada) DESIGN: Retrospective, single-surgeon study.

METHODS

This was a retrospective, single-surgeon study examining 200 eyes of 100 bilaterally implanted patients. Eligible participants were those presenting with visually significant cataracts or as a candidate for clear lens extraction who were interested in implantation of a diffractive toric or non-toric intraocular lens. Preoperative and postoperative data were collected for manifest refraction spherical equivalent (MRSE), refractive astigmatism (RA), and monocular uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), and uncorrected near visual acuity (UNVA).

RESULTS

Mean postoperative MRSE was 0.006 ± 0.27 D. The absolute prediction error was 0.50 D or less in 88.0% (176/200) of eyes. Postoperative RA was 0.50 D or less in 98.5% (197/200) of eyes. Postoperative UDVA was 0.10 logMAR or better in 86% (172/200) of eyes, and 66.0% (132/200) of eyes were 0.00 logMAR or better. Postoperative UIVA was 0.10 logMAR or better in 99.5% (199/200) of eyes, and 95.0% (190/200) of eyes were 0.00 logMAR or better. Postoperative UNVA was 0.10 logMAR or better in 91.5% (183/200) of eyes, and 73.5% (147/200) of eyes were 0.00 logMAR or better.

CONCLUSION

The results demonstrate that trifocal implantation with FLACS, DT, and IA can provide excellent refractive and visual outcomes.

Endothelial Keratoplasty Update 2020

ABSTRACT

Endothelial keratoplasty has revolutionized the treatment of corneal endothelial dysfunction and lowered the threshold for treatment by providing rapid visual rehabilitation and setting a high standard for safety and efficacy. Over time, endothelial keratoplasty techniques have evolved toward the use of thinner tissue to optimize visual outcomes; refinements have facilitated donor tissue preparation, handling, and attachment; and adaptations have expanded utilization in eyes with challenging ocular anatomy. Despite early concerns about graft longevity, emerging 10-year endothelial cell loss and graft survival data have been encouraging. A shortage of human donor corneas restricts utilization in many areas of the world and is driving a search for keratoplasty alternatives. Further work is needed to expand the donor supply, minimize impediments to adoption, optimize graft survival, and improve refractive predictability.

Five Pearls for Long Eyes

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Recent developments in intraocular lens power calculation methods-update 2020

For many decades only a few formulas have been available to calculate the intraocular lens (IOL) power for patients undergoing cataract surgery: the Haigis, Hoffer Q, Holladay 1 and 2 and SRK/T. In recent years, several new formulas for IOL power calculation have been introduced with the aim of improving the accuracy of refraction prediction in eyes undergoing cataract surgery. These include the Barrett Universal II, the Emmetropia Verifying Optical (EVO), the Kane, the Næser 2, the Olsen, the Panacea, the Pearl DGS, the Radial Basis Function (RBF), the T2 and the VRF formulas. Although most of them are unpublished so that their structure is unknown, we give an overview of each formula and report the results of the studies that have compared them. Their performance in short and long eyes is provided and a special focus is given on the issue of segmented axial length, which is a promising method to obtain more accurate outcomes in short and long eyes. Here, the group refractive index originally developed for the IOLMaster may not represent the best method to convert the optical path length into a physical distance. The issue of posterior and total corneal astigmatism (TCA) is discussed in relation to toric IOLs; the latest formulas for toric IOLs and their results are also reported.

Intraocular Lens Power Formulas, Biometry, and Intraoperative Aberrometry: A Review

The refractive outcome of cataract surgery is influenced by the choice of intraocular lens (IOL) power formula and the accuracy of the various devices used to measure the eye (including intraoperative aberrometry [IA]). This review aimed to cover the breadth of literature over the previous 10 years, focusing on 3 main questions: (1) What IOL power formulas currently are available and which is the most accurate? (2) What biometry devices are available, do the measurements they obtain differ from one another, and will this cause a clinically significant change in IOL power selection? and (3) Does IA improve refractive outcomes? A literature review was performed by searching the PubMed database for articles on each of these topics that identified 1313 articles, of which 166 were included in the review. For IOL power formulas, the Kane formula was the most accurate formula over the entire axial length (AL) spectrum and in both the short eye (AL, ≤22.0 mm) and long eye (AL, ≥26.0 mm) subgroups. Other formulas that performed well in the short-eye subgroup were the Olsen (4-factor), Haigis, and Hill-radial basis function (RBF) 1.0. In the long-eye group, the other formulas that performed well included the Barrett Universal II (BUII), Olsen (4-factor), or Holladay 1 with Wang-Koch adjustment. All biometry devices delivered highly reproducible measurements, and most comparative studies showed little difference in the average measures for all the biometric variables between devices. The differences seen resulted in minimal clinically significant effects on IOL power selection. The main difference found between devices was the ability to measure successfully through dense cataracts, with swept-source OCT-based machines performing better than partial coherence interferometry and optical low-coherence reflectometry devices. Intraoperative aberrometry generally improved outcomes for spherical and toric IOLs in eyes both with and without prior refractive surgery when the BUII and Hill-RBF, Barrett toric calculator, or Barrett True-K formulas were not used. When they were used, IA did not result in better outcomes.