Toric intraocular lenses: historical overview, patient selection, IOL calculation, surgical techniques, clinical outcomes, and complications

The comparison of white-to-white via triple person-times caliper measuring and machine-measuring in V4c implantable collamer lens implantation

This study aimed to compare the differences and characteristics of white-to-white (WTW) values obtained before V4c implantation using triple person-times caliper, IOL-Master 700, Pentacam HR, and UBM, and to assess their correlation with vaulting. A total of 930 myopia patients (1842 eyes) who were interested in undergoing ICL surgery were assessed before the procedure using various instruments. The WTW measurements were obtained using a triple person-times caliper, Pentacam HR, and IOL-Master 700, whereas the angle-to-angle (ATA) measurements were obtained using UBM. The size of the ICL was subsequently calculated using triple person-times caliper measurements. The vault of the ICL was assessed using Pentacam HR three months after the surgery. The WTW was determined to be 11.30 ± 0.29 mm, 11.43 ± 0.29 mm, and11.86 ± 0.38 mm, respectively, using the triple person-times caliper, Pentacam HR, and IOL-Master 700. The measurement of ATA was 11.57 ± 0.51 mm, as done by UBM. The ICL vault was measured to be 400.97 ± 198.46 µm when examined with Pentacam HR three monthsafter the procedure. The linear regression analyses of ICL size and WTW of triple person-times caliper, ICL vault and WTW were (R = 0.703, p < 0.001; R = 0.0969, p < 0.001) respectively. The highest correlation was found between IOL-Master and Pentacam HR (r = 0.766, p = 0.000). The lowest correlation was found between UBM and Pentacam HR (r = 0.358, p = 0.002). Bland-Altman analysis showed that the 95% limits of agreement (LoA) were the triple person-times caliper and Pentacam HR (- 0.573, 0.298) and the triple person-times caliper and UBM (- 1.15, - 0.605). This indicated a strong agreement between the triple person-times caliper and Pentacam HR and a lack of agreement between the triple person-times caliper and UBM. Triple person-times caliper measurements offer excellent maneuverability, practicality, and reliable outcomes for determining ICL vaults. Measurements obtained using the triple-person caliper were less differece than those obtained using the Pentacam HR.

Criteria for premium intraocular lens patient selection

PURPOSE OF REVIEW

To discuss available premium intraocular lenses (IOLs), patient selection, and important considerations for each premium IOL.

RECENT FINDINGS

We review important topics and considerations for premium IOL selection: specifically, toric, extended depth of focus (EDOF), multifocal/trifocal, light adjustable lenses (LALs), and small aperture IOLs. Toric lenses are an excellent option for patients with astigmatism. However, to achieve optimal patient satisfaction, it is critical to account for the ATR astigmatism contribution from the posterior cornea and high angle alphas. Additionally, examining the ocular surface prior to placement of EDOF/multifocal IOLs is important, yet the significance of HOAs on outcomes after implantation still must be elucidated more. Finally, recent studies reveal that the small aperture lens is a good alternative for those with corneal irregularities, and second generation LALs are a great option to achieve target refractions in those with less predictable refractive outcomes, such as in Fuchs' dystrophy or in eyes with previous refractive surgery.

Evaluation of the Efficiency of a Digital Workflow for Cataract Planning in Patients with Astigmatism

Purpose

To evaluate the efficiency and associated costs of a digital cataract workflow system and manual cataract workflow system for patients, with astigmatism presenting for cataract surgery in Brisbane, Australia.

Patients and Methods

Sixty patients with bilateral cataract requiring toric intraocular lenses (IOL) were sequentially assigned to a manual cataract workflow (n = 30) or digital workflow (n = 30) using EQ Workplace (SW v1.7.0) running on FORUM (SW v.4.2.1.66) (Carl Zeiss Meditec, Jena, Germany). Each step of preoperative data acquisition and analysis was timed. Steps in each workflow were divided into presurgical planning time and total workflow time, the latter including the time required to input toric data into CALLISTO eye (Carl Zeiss Meditec). Secondary outcomes included staff costs within each workflow.

Results

Median presurgical planning time using a digital workflow process was 6.51 ± 0.65 minutes, and using a manual workflow process, 12.32 ± 0.56 minutes (p < 0.001). Similarly, median total workflow time using a digital workflow process was 6.93 ± 0.57 minutes and using a manual workflow process, 13.49 ± 0.47 minutes (p < 0.001). Evaluating the staff remuneration during presurgical planning and the operating costs associated with running EQ Workplace, there was a cost-reduction of 35% per patient when using the digital cataract workflow process.

Conclusion

Using a digital cataract workflow process is more efficient and provides staff cost-savings compared to a manual workflow process when planning for toric IOL implantation.

Comparison of corneal topography maps obtained using the IOLMaster 700® and the Anterion® in candidates for toric IOL implantation

OBJECTIVES

To compare central corneal topography (CT) obtained using the IOLMaster 700® biometer to corneal topography obtained using a Swept-Source OCT-based predicated topographer (PT), in candidates for toric intraocular lens (IOL) implantation.

METHODS

A retrospective comparative study was conducted in consecutive patients undergoing a routine cataract surgery assessment with significant astigmatism on keratometry. Each patient was examined using both the IOLMaster 700® (Carl Zeiss Meditec, Jena, Germany) and the Anterion® (Heidelberg Engineering, Heidelberg, Germany) for routine preoperative measurements. The corneal axial anterior power map obtained with each device was then anonymized and analysed independently by two ophthalmologists using a reading grid. The reading grid assessed the usual parameters describing astigmatism and evaluated if a toric IOL was indicated or a second topography examination was needed to confirm the indication.

RESULTS

In total, 169 eyes of 120 patients were included. The inter-examination agreement for the astigmatism description ranged from 56 to 85% depending on the reader and parameter. The decision to implant a toric IOL based on the axial map was the same in 59-60% of cases depending on the examiner. A second examination was needed in 18-25% and 8-14% of cases after CT and PT, respectively. The IOLMaster 700® central anterior axial map allowed toric IOL implantation in 58-70% of cases with no need for second corneal examination.

CONCLUSION

The agreement between the anterior axial maps obtained using both devices was good. However, in about a quarter of the cases, dedicated topography had to be performed to confirm the surgical indication.

Accuracy of toric intraocular lens power calculation depending on different keratometry values using a novel network based software platform

Purpose

To compare different corneal keratometry readings (swept-source-OCT-assisted biometry and Scheimpflug imaging) with a novel software platform for calculation of toric intraocular lenses.

Setting

Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.

Design

Retrospective, non-randomized, clinical trial.

Methods

Twenty-three eyes undergoing toric intraocular lens implantation were included. Inclusion criteria were preoperative regular corneal astigmatism of at least 1.00 D, no previous refractive surgery, no ocular surface diseases and no maculopathies. Lens exchange was performed with CALLISTO eye (Zeiss). For each patient, the expected postoperative residual refraction was calculated depending on three different corneal parameters of two different devices: standard K-front (K) and total keratometry (TK) obtained by a swept-source-OCT-assisted biometry system (IOL Master 700, Zeiss) as well as total corneal refractive power (TCRP) obtained by a Scheimpflug device (Pentacam AXL, Oculus). Barrett's formula for toric intraocular lenses was used for all calculations within a novel software platform (EQ workplace, Zeiss FORUM®). Results were statistically compared with postoperative refraction calculated according to the Harris dioptric power matrix.

Results

The standard K values (mean PE 0.02 D ± 0.45 D) and TK values (mean PE 0.09 D ± 0.43 D) of the IOL Master 700 reached similar results (p = 0.96). 78% of eyes in both K and TK groups achieved SE within ±0.5 D of attempted correction and all eyes (100%) were within ±1.0 D of attempted correction in both groups. By contrast, the prediction error in the IOL calculation using the TCRP of the Scheimpflug device was significantly greater (mean PE -0.56 D ± 0.49 D; p = 0.00 vs. standard K and p = 0.00 vs. TK) with adjusted refractive indices. Thirty-nine and Ninety-one percentage of eyes in the TCRP group achieved SE within ±0.5 D (p = 0.008 K vs. TCRP and p = 0.005 TK vs. TCRP) and ± 1.0 D (p = 0.14 vs. TCRP) of attempted correction, respectively.

Conclusion

All three corneal parameters (standard K, TK, TCRP) performed well in calculating toric IOLs. The most accurate refractive outcomes in toric IOL implantation were achieved by IOL calculations based on swept-source-OCT-assisted biometry. The SS-OCT-based K-front and TK values achieve comparable results in the calculation of toric IOLs.

Comparison of the effect of capsular bend on the rotational stability between 2 toric intraocular lenses

PURPOSE

To compare the effect of capsular bend on the rotational stability between 2 toric intraocular lenses (IOLs).

SETTING

Eye Hospital of Wenzhou Medical University, Hangzhou, Zhejiang Province, China.

DESIGN

Prospective study.

METHODS

Patients with preexisting astigmatism received AcrySof IQ (SN6AT) or TECNIS (ZCT/ZMT) toric IOL during cataract surgery. CASIA2 was used to record the toric IOL axial orientation and capsular bend index (CBI) at the 1-day, 1-week, 1-month, and 3-month interval postoperatively. The postoperative rotational stability and CBI of both models were compared.

RESULTS

A total of 58 eyes from 58 patients were enrolled in this study. The total misalignment of the TECNIS (ZCT/ZMT) group (6.96 ± 5.10 degrees, 7.41 ± 5.19 degrees, 6.93 ± 5.29 degrees, and 6.86 ± 5. 27 degrees) was significantly higher than that of the AcrySof IQ (SN6AT) group (3.55 ± 2.21 degrees, 4.00 ± 2.74 degrees, 3.72 ± 2.72 degrees, and 3.52 ± 2.50 degrees) at all follow-up intervals ( P < .05). The mean rotation of the TECNIS (ZCT/ZMT) group (2.66 ± 2.18 degrees) was significantly greater than that of the AcrySof IQ (SN6AT) group (1.65 ± 1.47 degrees) from 1 day to 1 week postoperatively ( P < .05). The capsular bend formation in the TECNIS (ZCT/ZMT) group was delayed compared with the AcrySof IQ (SN6AT) group ( P < .05, at the 1-week, 1-month, and 3-month interval). The TECNIS (ZCT/ZMT) group showed fibrosis in the peripheral anterior capsule, leading to its stretching away from the IOL surface, while the AcrySof IQ (SN6AT) group exhibited gentle adherence of the anterior capsule to the IOL surface.

CONCLUSIONS

The AcrySof IQ toric IOL (SN6AT) exhibited greater rotational stability than the TECNIS toric IOL (ZCT/ZMT), which may partially result from the delay in capsular bend formation of TECNIS at the 1-day to 1-week follow-up postoperatively.

Rotational stability of a new hydrophobic acrylic intraocular lens platform

PURPOSE

To evaluate rotational stability for ease of rotation of a new intraocular lens (IOL) platform with 4 haptics in an ex vivo model and compare it with a control single-piece lens with 2 open loops.

SETTING

Intermountain Ocular Research Center, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah.

DESIGN

Experimental study.

METHODS

10 human cadaver eyes were prepared as per the Miyake-Apple technique. After injection of the test or control lens, clockwise and counterclockwise rotations were attempted with a hook, with and without an ophthalmic viscosurgical device in place. Ease of rotation was scored as (1) very easy, (2) easy, (3) difficult, and (4) very difficult. Rotation of the entire eye containing test or control IOL was also performed with a multipurpose rotator (2 minutes; 220 revolutions per minute) to evaluate its effect on IOL alignment.

RESULTS

There were statistically significant differences regarding ease of rotation between test and control lenses in all 4 scenarios, with rotation being more difficult with the test lens ( P < .05, Wilcoxon signed-rank test). No change in the alignment of test or control lenses was observed after eye rotation with the multipurpose rotator.

CONCLUSIONS

The new IOL platform showed greater rotational stability than the control lens in this model, owing to design features such as 4 small arcs of contact between the haptics and the bag equator, a bulge at the distal end of each haptic, and arcuate haptics with curvatures oriented toward each other.

Comparison of toric intraocular lens alignment between femtosecond laser-assisted capsular marking and digital marking

PURPOSE

To compare the accuracy of toric intraocular lens (IOL) alignment between femtosecond laser-assisted capsular marking and digital marking.

SETTING

Ruhr University Eye Clinic, Bochum, Germany.

DESIGN

Prospective clinical trial.

METHODS

In this study, 28 eyes of 23 patients, who underwent femtosecond laser-assisted cataract surgery with implantation of a toric IOL, were included. Intraoperatively, both femtosecond laser-assisted capsular marking and digital marking were applied simultaneously and compared in every case. The toric IOL was aligned to the capsular markings. Postoperatively, the axis of the capsular markings and toric IOL alignment was examined. Visual acuity and refractive outcomes were evaluated.

RESULTS

Both alignment methods were performed without intraoperative complications in all cases. 25 eyes were included in the final analysis. Misalignment was significantly lower with femtosecond laser-assisted capsular marking than with digital marking (1.71 ± 1.25 degrees vs 2.64 ± 1.70 degrees, P = .016). Deviation from the target axis of the toric IOL was 1.62 ± 1.24 degrees 4 to 6 weeks postoperatively. Postoperative uncorrected distance visual acuity was 0.14 ± 0.13 logMAR, and residual astigmatism was 0.3 ± 0.23 diopter (D) with an astigmatism ≤0.5 D in 93% of eyes.

CONCLUSIONS

Both methods showed excellent results for the alignment of toric IOLs. However, femtosecond laser-assisted capsular marking was significantly more precise than digital marking and showed good refractive results. In addition, capsular marking offers the possibility to avoid parallax error and evaluating postoperative IOL rotation.

Rotational stability and capsular bag performance of a hydrophobic acrylic open-loop single-piece intraocular lens

PURPOSE

To evaluate the rotational stability and capsular bag performance of a blue light-absorbing hydrophobic acrylic open-loop single-piece intraocular lens (IOL) with a blast-finished anchor wing haptic design during the first 6 postoperative months.

METHODS

In this prospective clinical study, patients with age-related cataract and potential postoperative corrected distance visual acuity (CDVA) of 0.2 logMAR or better were included. The patients received a non-toric hydrophobic acrylic single-piece IOL with an axis mark (YST0.00; Nidek Co. Ltd, Japan). Surgeries were video-taped. Retroillumination images were acquired 1 h, 1 week and 6 months postoperatively. Rotational stability was assessed by precise image overlay. At 6 months, Purkinje meter measurements were performed to evaluate tilt and decentration.

RESULTS

In total, 100 eyes of 77 patients were included in the analysis. Mean absolute rotation was 2.1 ± 1.7° (median 1.7, range: 0-7.9) at 6 months (1 h - 6 months postoperatively). IOL rotation was ≤3° and ≤6° in 74 (74%) and 98 (98%) eyes, respectively. Mean absolute IOL rotation from the end of surgery to 6 months was 2.5 ± 2.2° (median 2.3, range: 0-15.6; n = 78). Mean tilt (pupillary axis) and decentration were 4.1 ± 1.9° (median 4.0, range: 0.5-8.2) and 0.35 ± 0.17 mm (median 0.32, range: 0.06-0.91) respectively (n = 84). Postoperatively, 98 (98%) eyes achieved a CDVA of 0.2 logMAR or better, 95 (95%) of ≤0.1 and 81 (81%) of ≤0.0.

CONCLUSIONS

This hydrophobic acrylic single-piece IOL showed an excellent rotational stability and capsular bag position with low tilt and decentration values.

Rotational stability of monofocal and diffractive multifocal toric intraocular lens with identical design and material: a propensity score based prospective comparative study

PURPOSE

To compare the rotational stability of a monofocal and a diffractive multifocal toric intraocular lens(IOLs) with identical design and material.

METHODS

This prospective study enrolled patients who underwent plate-haptic toric IOL (AT TORBI 709 M and AT LISA 909 M) implantation. Propensity score matching (PSM) was performed to balance baseline factors. Follow-up examinations were conducted at 1 h, 1 day, 3 days, 1 week, 2 weeks, 1 month, and 3 months postoperatively. A linear mixed model of repeated measures was used to investigate the changes in IOL rotation over time. A 2-week timeframe was utilized to assess differences in IOL rotation between the two groups.

RESULT

After PSM, a total of 126 eyes were selected from each group for further analysis. Postoperatively, the time course of IOL rotation change in the two groups remained consistent, with the greatest rotation occurring between 1 h and 1 day postoperatively. At the 2-week postoperative mark, the monofocal toric IOL exhibited a higher degree of rotation compared to the multifocal toric IOL (5.40 ± 7.77° vs. 3.53 ± 3.54°, P = 0.015). In lens thickness(LT) ≥ 4.5 mm and white-to-white distance(WTW) ≥ 11.6 mm subgroups, the monofocal toric IOL rotated greater than the multifocal toric IOL (P = 0.026 and P = 0.011, respectively).

CONCLUSION

The diffractive multifocal toric IOL exhibits superior rotational stability compared to the monofocal toric IOL, especially in subgroups LT ≥ 4.5 mm and WTW ≥ 11.6 mm. Moreover, the time course of IOL rotation change is consistent for both, with the maximum rotation occurring between 1 h and 1 day postoperatively.

Determination of the toric axis by using internal astigmatism axis in non-dilated eyes

PURPOSE

To determine the toric intraocular lens (IOL) axis by using internal astigmatism axis obtained from Optical Path Difference (OPD) Scan III (Nidek Co.) in non-dilate eyes.

METHODS

The eyes of patients who underwent toric IOL implantation for astigmatic correction were investigated. Patients who have ocular surface disorder, keratoconus, posterior capsule opacification were excluded. The IOL axis measured in non-dilated eyes in mesopic conditions by OPD scan III device and the IOL axis measured by using classical slit lamp biomicroscopy method in dilated eyes were detected at postoperative 1st and 6th months. Results were compared with correlation and linear regression analysis.

RESULTS

Totally, 26 eyes of 18 patients were included. The difference between biomicroscopic IOL axis and OPD internal astigmatism axis was 4.96 ± 4.41 degrees at the 1st month and 3.62 ± 3.5 degrees at the 6th month. There was a significant and high correlation between biomicroscopic IOL axis and OPD internal astigmatism axis at both 1st month (r = 0.992 p < 0.001) and 6th month (r = 0.995 p < 0.001). According to regression analysis, the results of two measurement methods were significantly compatible with each other at 1st month (R Sq = 0.984 p < 0.001) and 6th month (R Sq = 0.990 p < 0.001) and there was a close to ideal linear (R Sq = 1) relationship between two methods.

CONCLUSIONS

In eyes with toric IOL implantation, the IOL axis and IOL rotation according to target IOL axis can be detected easily and effectively in a short time by OPD scan internal astigmatism axis without the need to dilate the pupil.

The predictive accuracy of Barrett toric calculator using measured posterior corneal astigmatism derived from swept source-OCT and Scheimpflug camera

PURPOSE

To compare the performance of Barrett toric calculator incorporated with measured posterior corneal astigmatism (PCA) derived from IOL Master 700 and Pentacam HR versus predicted PCA.

METHODS

The predicted residual astigmatism using Barrett toric IOL calculator with predicted PCA, measured PCA from IOL Master 700 and measured PCA from Pentacam were calculated with the preoperative keratometry and intended IOL axis with modification. The vector analysis was performed to calculate the mean absolute prediction error (MAE), the centroid of the prediction error and the percentage of eyes with a prediction error within ±0.50 D, ±0.75 D, and ±1.00 D.

RESULTS

In 57 eyes of 57 patients with mean age of 70.42 ± 10.75 years, the MAE among the three calculation methods were 0.59 ± 0.38 D (Predicted PCA), 0.60 ± 0.38 D (Measured PCA from IOL Master 700) and 0.60 ± 0.36 D (Measured PCA from Pentacam) with no significant difference, either in the whole sample, the WTR eyes and the ATR eyes (F = 0.078, 0.306 and 0.083, p = 0.925, 0.739 and 0.920, respectively). Measured PCA obtained from IOL Master 700 resulted in one level reduction (from Tn to Tn-1) in 49.12% eyes in cylindrical model selection, while measured PCA obtained from Pentacam resulted in one level reduction of toric model selection in 18.18% eyes.

CONCLUSION

The present study suggested that the incorporation of measured PCA values derived from IOL Master 700 and Pentacam produce comparable clinical outcome with the predicted PCA mode in Barrett toric calculator.

Toric Intraocular Lens versus Peripheral Corneal Relaxing Incisions for Astigmatism between 0.75 and 2.5 Diopters: 5-Years Outcomes

PURPOSE

To compare 5-year outcomes of toric intraocular lens (tIOL) or peripheral corneal relaxing incision (PCRI) for correction of keratometric astigmatism (KA) between 0.75 and 2.5 diopters (D).

METHODS

Setting: University Hospital. Design: Randomized clinical trial. Eighty eyes (80 participants) received either tIOL or PCRI. Patients were assessed preoperatively, 1-month, 1, and 5 years. Primary outcomes were uncorrected (UDVA) and best-corrected distance logMAR visual acuity (CDVA). Secondary outcomes were a manifest refractive sphere, refractive astigmatism (Ra), spherical equivalent (SEQ), KA & mean keratometry (KM), and Quality-of-Life Impact of Refractive Correction (QIRC) scores.

RESULTS

There was no difference between the two groups in UDVA, CDVA, refractive sphere, KM, RA, and SEQ. KA reduced after 1 month in the PCRI group and remained stable until 5 years. From 1 to 5 years, the number of eyes with distance emmetropia (within ±0.13D) changed from 59% (20/34 eyes) to 32% (6/19 eyes) for tIOLs and from 43% (15/36 eyes) to 20% (4/21 eyes) for PCRIs with 32% (6/19 eyes) and 20% (4/21 eyes) showing >0.5D change in SEQ at 5-years respectively. Compared to 1-year, Ra significantly increased at 5 years in both groups with no difference between the groups. Mean overall QIRC scores were not different between the groups (tIOL: 49.88 ± 7.47; PCRI: 52.09 ± 7.02; p = .18).

CONCLUSIONS

Although there was no difference between the overall visual and vision-related quality of life outcomes between tIOLs and PCRIs, an increase in refractive astigmatism and reduction in distance emmetropia with time was noted in both groups.

Comparison between IOL MASTER 500 and MYAH with vector analysis in low and mild anterior corneal astigmatism

PURPOSE

Evaluate the agreement between IOL Master 500 (Carl Zeiss Meditec AG, Germany) and MYAH (Topcon EU, Visia Imaging, Japan) in measuring axial length, keratometry, and anterior corneal astigmatism.

SETTING

Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Ophthalmology Clinic, University of Messina, Messina, Italy.

METHODS

In this prospective study, 40 eyes (right eye 25, left eye 15) of 40 patients were included. Axial length (AL), keratometry (K1, K2), and anterior corneal astigmatism (ACA) were measured. AL, mean K (Kavg) and magnitude of ACA were compared using Bland - Altman plot analysis, parametric and nonparametric statistical analysis. The difference vector and angle of error of the ACA measured by the two devices were evaluated by vector analysis using polar diagrams.

RESULTS

Mean and standard deviation with IOL Master and with MYAH device was for AL 24.25 ± 1.22 mm and 24.25 ± 1.22 mm (p = .99), for Kavg 42.75 ± 1.53 D and 42.85 ± 1.52 D (p = .78), for Magnitude of ACA 1.00 ± 0.58 D and 0.89 ± 0.56 D (p = .38) respectively. High correlations were found for AL (R² = 0.999), Kavg (R² = 0.996), and ACA Magnitude (R² = 0.889). Bland-Altman analysis of the two devices found high agreement and absence of proportional bias (MYAH-IOL MASTER) were found between the two assessments for AL (bias = -0.0005 mm, p = .93), Kavg (bias = 0.0955 D, p = .76) and ACA (bias = 0.11 D, p = .41). Limit of agreement (upper/lower LoA, 95%CI) were respectively +0.057/-0.058 mm for AL, + 0.29/-0.09 D for Kavg and +0.49/-0.27 D for ACA. No statistical difference was found between the x-component and y-component of the ACA vector (p > .01), the difference vector (IOL MASTER-MYAH) was +0.14 D axis 159 with an absolute mean angle of error of 7.2 ± 7.5 degree.

CONCLUSIONS

The instruments appear to be interchangeable for measurements of AL, keratometry, and magnitude of ACA with high agreement between the two devices. Also, in the presence of low astigmatism, the two instruments give the same results in terms of ACA.

Analysis of higher-order aberrations in relation to the clinical outcome of an enhanced monofocal IOL

PURPOSE

To analyse higher-order aberrations of an enhanced monofocal aspheric intraocular lens (IOL) in relation to the clinical outcome compared to a monofocal aspheric IOL.

SETTING

Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Germany.

DESIGN

Prospective, monocentric, controlled, non-randomized, two-armed study.

METHODS

After phacoemulsification, a total of 30 patients (60 eyes) were bilaterally implanted with either TECNIS Eyhance IOL model ICB00 (Johnson & Johnson Surgical Vision, Inc.) or TECNIS Monofocal 1-Piece IOL model ZCB00 (Johnson & Johnson Surgical Vision, Inc.) in 30 eyes each. Assessments were performed 1 and 3 months after surgery including refraction, uncorrected and best-corrected distance, intermediate and near visual acuity, defocus curves, contrast sensitivities under photopic, mesopic and mesopic conditions with glare, higher-order aberrations (HOAs) at pupil sizes of 5, 4, 3 and 2 mm and patient satisfaction.

RESULTS

At 3-month follow-up, measurements of HOAs revealed significant higher negative internal and ocular primary spherical aberrations in the ICB00 group at pupil sizes of 5, 4, 3 and 2 mm. The ICB00 showed significant better results in intermediate and near visual acuity, but no difference in distance visual acuity. No significant difference was found in contrast sensitivities at any condition or spatial frequency. Spectacle independence was significant better without significant higher rates of dysphotopsia in the ICB00 group.

CONCLUSIONS

Higher negative spherical aberrations in the ICB00 group at all measured pupil sizes appear to lead to a superior clinical outcome in intermediate and near vision compared to the ZCB00 group without compromising contrast sensitivity or distance visual acuity.

Premium Intraocular Lenses in Glaucoma-A Systematic Review

The incidence of both cataract and glaucoma is increasing globally. With increasing patient expectation and improved technology, premium intraocular lenses (IOLs), including presbyopia-correcting and toric IOLs, are being increasingly implanted today. However, concerns remain regarding the use of premium IOLs, particularly presbyopia-correcting IOLs, in eyes with glaucoma. This systematic review evaluates the use of premium IOLs in glaucoma. A comprehensive search of the MEDLINE database was performed from inception until 1 June 2023. Initial search yielded 1404 records, of which 12 were included in the final review of post-operative outcomes. Studies demonstrated high spectacle independence for distance and good patient satisfaction in glaucomatous eyes, with positive outcomes also in post-operative visual acuity, residual astigmatism, and contrast sensitivity. Considerations in patient selection include anatomical and functional factors, such as the type and severity of glaucomatous visual field defects, glaucoma subtype, presence of ocular surface disease, ocular changes after glaucoma surgery, and the reliability of disease monitoring, all of which may be affected by, or influence, the outcomes of premium IOL implantation in glaucoma patients. Regular reviews on this topic are needed in order to keep up with the rapid advancements in IOL technology and glaucoma surgical treatments.

Comparison of corneal aberrations from anterior segment swept source OCT versus Placido-topography combined spectral domain OCT in cataract patients

BACKGROUND

To comprehensively evaluate the agreement of component corneal aberrations from the newly updated wavefront analysis software of a swept-source optical coherence tomographer (SS-OCT) and a referential Placido-topography combined OCT device in elderly cataract patients.

METHODS

Retrospective study including 103 eyes from 103 elderly patients scheduled for cataract surgery that were measured on the same day with a SS-OCT (Heidelberg Engineering, Germany) device and a Placido-topography combined OCT device (CSO, Italy). Anterior, total, and posterior corneal wavefront aberrations were evaluated for their mean differences and limits of agreement (LoA) via Bland-Altman plots. Vector analysis was additionally employed to compare corneal astigmatism measurements in dioptric vector space.

RESULTS

Mean differences of all corneal aberrometric parameters did not exceed 0.05 μm. Total corneal aberrations were not significantly different from 0 except for vertical coma (- 0.04 μm; P = 0.003), spherical aberration (- 0.01 μm, P < 0.001), and root mean square (RMS) higher-order aberration (HOA) (0.03 μm, P = 0.04). The 95% LoA for total corneal aberration parameters between both devices were - 0.46 to 0.42 μm for horizontal astigmatism, - 0.37 to 0.41 μm for oblique astigmatism, - 0.19 to 0.17 μm for oblique trefoil, - 0.33 to 0.25 μm for vertical coma, - 0.20 to 0.22 μm for horizontal coma, - 0.22 to 0.20 μm for horizontal trefoil, - 0.11 to 0.08 μm for spherical aberration, and - 0.22 to 0.28 μm for RMS HOA. Vector analysis revealed no statistically significant mean differences for anterior, total, and posterior corneal astigmatism in dioptric vector space.

CONCLUSION

In eyes undergoing cataract surgery with a regular elderly cornea, corneal wavefront analysis from the SS-OCT device showed functional equivalency to the reference device. Nevertheless, clinically relevant higher order aberration parameters should be interpreted with caution for surgical decision-making.

Rotational stability of a new toric intraocular lens with an advanced optical profile

PURPOSE

To examine the rotational stability of a new toric intraocular lens (IOL), the TECNIS Eyhance Toric II, over a course of 3 months.

SETTING

Vienna Institute for Research in Ocular Surgery, Hanusch Hospital, Vienna, Austria.

DESIGN

Prospective unmasked single-center study.

METHODS

50 eyes of 50 patients with cataract and regular corneal astigmatism ≥0.75 diopters (D) were included. The TECNIS Eyhance Toric II IOL was implanted in 1 eye of each study patient. Images of the alignment axis of the IOL were taken intraoperatively, as well as at 1 hour, 1 week, and 3 months postoperatively. For the measurement of toric IOL rotation, images were superimposed on the basis of ocular landmarks. Uncorrected and corrected distance (4 m) and intermediate (66 cm) visual acuities were assessed at the 3-month visit.

RESULTS

There was no significant difference in the rotational position between the intraoperative and 3 month timepoints, with a mean rotation of 1.34 ± 1.46 degrees, in 27 examined eyes. ( P = 0.313). No patients had to undergo repositioning of the toric IOL. A significant reduction of refractive cylinder occurred from preoperatively 1.8 ± 1.1 to 0.40 ± 0.42 D at the 3-month visit ( P = .001; n = 43). The corrected distance visual acuity improved significantly from 0.28 ± 0.16 logMAR preoperatively to -0.01 ± 0.13 logMAR at 3 months postoperatively ( P = .001; n = 43).

CONCLUSIONS

The TECNIS Eyhance Toric II showed a good visual performance with no significant rotation over a course of 3 months and, therefore, an excellent rotational stability. The intraocular lens showed a good safety profile with no adverse events.

Implanting toric implantable collamer lens displays better astigmatism correction than implantable collamer lens combined with manually limbal relaxing incision

BACKGROUND

This retrospective study aimed to compare the outcomes of toric implantable collamer lens (TICL) surgery with those of implantable collamer lens (ICL) implantation combined with limbal relaxing incision (LRI) in patients with low myopia and astigmatism.

METHODS

A total of 40 eyes of 28 patients who underwent TICL implantation and 40 eyes of 27 patients who underwent ICL implantation combined with manually LRI between 2021 and 2022 were included. Primary outcomes were manifest sphere and cylinder, intraocular pressure, visual acuity, and astigmatism parameters at 1 day, 1 week, and 1, 3, and 6 months postoperatively.

RESULTS

The two surgeries showed comparable effects on manifest sphere and cylinder, intraocular pressure, and visual acuity (all p > 0.1). Surgery-induced astigmatism (SIA) was maintained as stable in the TICL group (1.73 to 1.68, p = 0.420), but was significantly reduced in the ICL/LRI group (1.74 to 1.17, p = 0.001) from preoperative to postoperative 6 months. The TICL group displayed significantly higher SIA and correction index at postoperative 1, 3, and 6 months than the ICL/LRI group (at 6 months: SIA, 1.68 (1.26, 1.96) vs., 1.17 (1.00, 1.64), p = 0.010; CI: 0.98 (0.78, 1.25) vs. 0.80 (0.61, 1.04), p = 0.018). No complications occurred during follow-up.

CONCLUSIONS

The effects of ICL/LRI are comparable to those of TICL in correcting myopia. TICL implantation displays better astigmatism correction than ICL/LRI.

Ray tracing optimization: a new method for intraocular lens power calculation in regular and irregular corneas

To develop a novel algorithm based on ray tracing, simulated visual performance and through-focus optimization for an accurate intraocular lens (IOL) power calculation. Custom-developed algorithms for ray tracing optimization (RTO) were used to combine the natural corneal higher-order aberrations (HOAs) with multiple sphero-cylindrical corrections in 210 higher order statistical eye models for developing keratoconus. The magnitude of defocus and astigmatism producing the maximum Visual Strehl was considered as the optimal sphero-cylindrical target for IOL power calculation. Corneal astigmatism and the RMS HOAs ranged from - 0.64 ± 0.35D and 0.10 ± 0.04 μm (0-months) to - 3.15 ± 1.38D and 0.82 ± 0.47 μm (120-months). Defocus and astigmatism target was close to neutral for eyes with low amount of HOAs (0 and 12-months), where 91.66% of eyes agreed within ± 0.50D in IOL power calculation (RTO vs. SRK/T). However, corneas with higher amounts of HOAs presented greater visual improvement with an optimized target. In these eyes (24- to 120-months), only 18.05% of eyes agreed within ± 0.50D (RTO vs. SRK/T). The power difference exceeded 3D in 42.2% while the cylinder required adjustments larger than 3D in 18.4% of the cases. Certain amounts of lower and HOAs may interact favourably to improve visual performance, shifting therefore the refractive target for IOL power calculation.

Correction of Asymmetric Bowtie Corneal Astigmatism with a Toric Intraocular Lens: Outcomes and Accuracy of Measurement Modes

The outcomes of toric intraocular lens (IOL) implantation in correcting asymmetric bowtie corneal astigmatism remain uncertain. The accurate measurement of corneal astigmatism is essential for surgical planning. In this prospective cohort study, patients with asymmetric or symmetric bowtie corneal astigmatism who underwent toric IOL implantation were recruited. Preoperative corneal astigmatism was measured with an IOLMaster and Pentacam (including the simulated keratometry (SimK), total corneal refractive power (TCRP), and wavefront aberration (WFA) modes). At 3 months after surgery, the refractive outcomes and residual astigmatic refractive errors were compared with patients with symmetric bowtie astigmatism. The prediction errors (the differences between the calculated actual corneal astigmatism and the measured corneal astigmatism) were compared among the different measurement modes in the asymmetric group. There were no differences in residual astigmatism between the asymmetric and symmetric groups. However, the mean absolute residual astigmatic refractive error was greater in the asymmetric group than in the symmetric group (0.72 ± 0.42 D vs. 0.53 ± 0.24 D, p = 0.043). In the asymmetric group, the mean absolute prediction errors for the IOLMaster, SimK, TCRP and WFA modes were 0.53 ± 0.40, 0.56 ± 0.47, 0.68 ± 0.52, and 0.43 ± 0.40 D, respectively. The Pentacam WFA mode was the most accurate mode (p < 0.05). The absolute prediction error of the WFA mode was positively correlated with the total corneal irregular astigmatism higher-order aberrations and coma (r = 0.416 and r = 0.473, respectively; both p < 0.05). Our study suggests toric IOL implantation effectively corrected asymmetric bowtie corneal astigmatism. The Pentacam WFA mode may be the most accurate measurement mode, although its accuracy decreased as asymmetry increased.

Development Pattern of Medical Device Technology and Regulatory Evolution of Cataract Treatment

To prevent regulation from becoming an obstacle to healthcare technological innovation, regulation should evolve as new healthcare technologies are developed. Although regulation is closely related to healthcare technology development, there are few studies that view healthcare technological advances from the multi-layered perspective of papers, patents, and clinical research and link this with regulatory evolution. Therefore, this study tried to develop a new method from a multi-layer perspective and draw regulatory implications based on it. This study applied this method to intraocular lens (IOLs) for cataract treatment and detected four major healthcare technologies and two recent healthcare technologies. Moreover, it discussed how current regulations evaluate these technologies. The findings provide implications for healthcare technological advances and the evolutionary direction of regulation through the example of IOLs for cataract treatment. This study contributes to the development of theoretical methods for co-evolution with regulations based on healthcare technology innovation.

Optimal Timing of Repositioning Surgery for a Plate-Haptic Toric Intraocular Lens: A Multicenter Retrospective Study

PURPOSE

To evaluate risk factors for significant rotation and determine optimal timing for repositioning surgery following a plate-haptic toric intraocular lens (IOL) implantation.

METHODS

This retrospective study enrolled patients who underwent the plate-haptic toric IOL implantation at seven hospitals in Shanghai. IOL rotation and residual astigmatism were compared before and after repositioning surgery. Risk factors for significant IOL rotation after cataract surgery were identified by stepwise multiple linear regression analysis. Spearman's and linear regression analyses were performed to identify factors associated with IOL rotation after repositioning. The receiver operator characteristic (ROC) curve was used to analyze the optimal timing for repositioning surgery.

RESULTS

Among 2,745 eyes implanted with the toric IOL, 46 eyes (1.68%) of 45 patients underwent repositioning surgery. Axial length and lens thickness were significantly associated with IOL rotation before repositioning. After repositioning surgery, IOL rotation and residual astigmatism were significantly reduced (all P < .001). IOL rotation after repositioning was negatively associated with the timing of repositioning surgery (all P < .001). The ROC curve showed that the optimal cut-off for the timing of repositioning surgery was 15 days or greater.

CONCLUSIONS

The prevalence of repositioning surgery after the plate-haptic toric IOL implantation was 1.68%, and the optimal timing for repositioning surgery was recommended to be 2 to 3 weeks after cataract surgery. [J Refract Surg. 2023;39(2):120-126.].

The impact of posterior corneal astigmatism on the surgical planning of toric multifocal intraocular lens implantation

Purpose

To investigate the influence of posterior corneal astigmatism on the prediction accuracy of toric multifocal intraocular lens (IOL) calculation.

Methods

The keratometric astigmatism measured by Lenstar LS 900 (KCAL), keratometric astigmatism (KCAP) and total corneal astigmatism (TCA) measured by Scheimpflug camera (Pentacam HR) were documented and analyzed accordingly. Three deduction models using different parameters were compared. Model 1: KCAL ​+ ​keratometric corneal surgically induced astigmatism (KCSIA, 0.30 D @ 50°); Model 2: KCAP ​+ ​KCSIA); Model 3: TCA ​+ ​total CSIA (TCSIA, 0.23 D @ 50°). The prediction errors of each model as the difference vector between the actual and the intended residual astigmatism were compared.

Results

Seventy-six eyes implanted with toric multifocal IOLs were included in this study. The vector differences of the actual KCSIA and TCSIA were statistically significant in the total sample and against-the-rule (ATR) subgroup (both P ​< ​0.05). Model 1 deduced the smallest mean values of prediction error, while that of Model 3 were smaller than that of Model 2, both in the total sample and the ATR subgroups (all P ​< ​0.05). Meanwhile, in the total sample and ATR subgroups, the centroid vector magnitudes of Model 3 were smaller than that of Model 1 (0.31 ​± ​0.76 D and 0.39 ​± ​0.76 D).

Conclusions

The calculation of toric multifocal IOL should be individualized especially in the ATR eyes for the impact of PCA on the estimation of the preoperative corneal astigmatism and the CSIA.

Effect of capsular bend on the rotational stability of toric intraocular lens

PURPOSE

To assess the effect of capsular bend and axial length on the rotational stability of toric IOL.

METHODS

The prospective study included patients with preexisting astigmatism that were implanted with Acrysof IQ Toric IOL. According to the pre‑operative axial length, all patients were divided into 2 groups: high myopia (AL ≥ 26 mm) group, and emmetropia or low to moderate myopia group (AL <26 mm). High-speed Swept-source Optical Coherence Tomography (SS-OCT) radial scanning was performed after pupil dilation to obtain the toric IOL axial orientation and capsular bending index (CBI) at 1-day, 1-week, 1-month and 3-month intervals postoperatively. The correlation between the rotation of toric intraocular lens and the axial length or CBI was subsequently analyzed.

RESULTS

68 eyes of 57 patients were included in the research. The rotation of toric IOL within the high myopia group was greater than the control group (P = 0.001, 1month postoperative). Capsular contact with the IOL was delayed in highly myopic eyes, although the results were not statistically significant (P = 0.094, 1-month postoperatively). There was a positive correlation between the degree of rotation and axial length at the interval found between 1-week and 1-month after the operation (r = 0.333, P = 0.005). There was a significant negative correlation between the IOL rotational speed and CBI (P < 0.001). The regression equation was Y = -0.441*X + 1.712 (R2 = 0.323, P < 0.001).

CONCLUSION

There was a significant negative correlation between the IOL rotation speed and the CBI, while the influence of the axial length and capsular bending mainly occurred between one week and one month after the operation.

The Impact of Posterior Corneal Astigmatism on Surgically Induced Astigmatism in Cataract Surgery

PURPOSE

This study aimed to evaluate the changes in posterior corneal astigmatism after cataract surgery and provide a theoretical basis to accurately evaluate the total corneal astigmatism (TA) to be corrected before toric intraocular lens (IOL) implantation.

PATIENTS AND METHODS

Sixty-two patients (89 eyes) who underwent phacoemulsification combined with toric IOL implantation (AcrySof IQ Toric SN6AT2-T9) at Shanxi Eye Hospital between January 2017 and September 2018 were enrolled. Surgically induced astigmatism of the posterior cornea (SIAPA) was analysed using vector analysis during pentacam examination.

RESULTS

The vector variances of keratometric astigmatism (KA), TA, and posterior corneal astigmatism (PA) preoperatively and postoperatively in the "with-the-rule (WTR) astigmatism" group and "overall patient" group were statistically significant (P < 0.05). A statistically significant difference was observed between surgically induced KA (SIAKA) and surgically induced astigmatism of the total cornea (SIATA) for all patients, including those with WTR astigmatism. For all patients, SIAKA was less than SIATA by 0.05 ± 0.21 D, and for patients with WTR astigmatism, SIAKA was less than SIATA by 0.09 ± 0.22 D. For patients in the "against-the-rule (ATR) astigmatism" group, there were no statistically significant differences between SIAKA and SIATA, although SIAKA was greater than SIATA by 0.03 ± 0.18 D. When PA ≤0.4 D or KA ≤2.0 D, SIAPA can be ignored. However, when PA >0.4 D or KA >2.0 D, ignoring SIAPA caused by cataract surgery incision will cause SIAKA in patients with WTR astigmatism to underestimate SIATA, while SIAKA in patients with ATR astigmatism will cause an overestimation of SIATA.

CONCLUSION

SIA on the posterior corneal astigmatism may have a significant role on more precise planning of toric IOL implantation, especially in cases with higher preoperative anterior or posterior corneal astigmatism.

One-dioptre toric IOL versus spherical IOL in eyes with low preoperative corneal astigmatism

Purpose

To investigate the advantages/disadvantages of a 1.0 D toric IOL vs spherical IOL after regular phacoemulsification in eyes with preoperative astigmatism ≤ 1 D.

Methods

Retrospective comparative series involving pseudophakic eyes with preoperative topographic astigmatism ≤ 1.0 D implanted either with monofocal 1.0 D Toric IOL (T-group), or with spherical IOL (S-group). The postoperative refractive astigmatism (PRA, i.e. surgically induced + corneal) was the main outcome; also considered in the analyses were the uncorrected and best-corrected distance visual acuity (VA). The data were referred to the last postoperative follow-up visit, 2 to 4 months after surgery.

Results

A total of 60 eyes were included: 30 in the T-group and 30 in the S-group, matched for patient’s age, laterality, and axial length. Before surgery, the mean corneal astigmatism was 0.62 ± 0.39 D in the T-group and 0.54 ± 0.33 D in the S-group (p = 0.4). In the S-group, PRA was 0.73 ± 0.37 D, higher than the corresponding preoperative corneal astigmatism (p = 0.040). In the T-group, PRA was 0.58 ± 0.31 D; the variation was not statistically significant. Uncorrected VA was significantly better in the T-group vs the S-group (p = 0.007), and the best-corrected VA was comparable in the two groups.

Conclusion

The present study indicated that in eyes with very low preoperative astigmatism, 1.0 D toric IOLs were able to limit the increase of the PRA instead of those observed with the spherical IOLs. This could support the better uncorrected VA recorded in the T-group.

Incidence and Risk Factors of Repositioning Surgery to Correct Misalignment of Toric Intraocular Lenses after Cataract Surgery: A Single-Center Retrospective Observational Study

PURPOSE

The aim of this study was to analyze the incidence and outcomes of repositioning surgery to correct misalignment of several toric intraocular lenses (IOLs) after cataract surgery.

METHODS

In this retrospective study, patients who underwent repositioning surgery to correct misalignment of toric IOLs following cataract surgery between January 2019 and December 2021 were enrolled. The medical data on patients' age, gender, preoperative axial length, corneal astigmatism, the axis of astigmatism, IOL models, IOL axis, uncorrected distance visual acuity, residual refraction, and postoperative outcomes were analyzed.

RESULTS

Among the 1,135 eyes implanted with toric IOLs at Qingdao Eye Hospital, 23 (2.026%, 23/1,135) underwent repositioning surgery. Univariate analysis revealed that the incidence of repositioning surgery was significantly lower with AcrySof (0.636%, 5/786) than with ZEISS (2.959%, 5/169) and TECNIS (7.222%, 13/180) IOL platforms; the incidence of repositioning surgery with monofocal toric IOLs (1.169%, 11/941) was significantly lower than multifocal toric IOLs (6.186%, 12/194) (p < 0.001); additionally, a significant difference in age was also observed (p = 0.002). Multivariate logistic regression analysis showed that the IOL platform (p = 0.004) and younger age (p = 0.006) were independent risk factors for repositioning surgery.

CONCLUSION

The incidence of repositioning surgery of toric IOLs after cataract surgery was 2.026%. It was linked to the IOL platform, multifocal toric IOLs, and younger age.

Reproducibility of the Magnitude of Lens Rotation Following Implantation of a Toric Intraocular Lens with Modified Haptics

Purpose

To evaluate the reproducibility of magnitude of postoperative IOL rotation following implantation of a toric intraocular lens (IOL) with modified haptics, in comparison with a Proof-of-Concept (POC) study of prototype IOLs featuring the same haptic design.

Patients and Methods

A post-market, prospective, multicenter, single-arm, open-label clinical study was conducted. TECNIS Toric II IOL (Johnson & Johnson Vision, Irvine, CA, USA, Models ZCU150 to 600) were implanted in 125 subjects and evaluated at 1-day and 1-week postoperatively. An objective photographic method was used to determine postoperative IOL rotation. Uncorrected distance visual acuity (UCDVA), postoperative astigmatism, and surgeon satisfaction were also assessed. Rotation data were compared to the POC study in which two prototype non-toric monofocal IOLs, one with the same haptic design as Model ZCU, were studied.

Results

Mean absolute rotation was 0.82° ± 1.0° and 0.84° ± 0.92°at 1-day and 1-week visits, respectively. The percentage of eyes with ≤5° of absolute rotation was 98.9% and 99.5% at the 1-day and 1-week visits, respectively. The magnitude of rotation was similar to the POC study prototype IOLs. At 1-week, mean monocular UCDVA was 0.026 ± 0.135 (~20/21) logMAR and mean residual manifest refractive cylinder was 0.30 D ± 0.35 D. The mean signed axis difference (postoperative minus operative) of the TECNIS Toric II IOL was 0.23° ± 1.27° at 1-day and −0.07° ± 1.25° at 1-week, indicating a clockwise drift. At 1-week, surgeons were very satisfied or satisfied with overall clinical outcomes and rotational stability in 98% of implanted eyes.

Conclusion

The TECNIS Toric II IOL, with frosted, squared haptics, demonstrated low magnitude of postoperative IOL rotation, excellent uncorrected distance vision, and minimal residual astigmatism. The POC study design was supported, demonstrating that prototype non-toric monofocal IOLs can predict clinical performance of toric IOLs with the same haptic design.

Efficacy of the Image-Guided Alignment System for a Four-Haptic Hydrophobic Monofocal Toric Intraocular Lens

OBJECTIVE

To compare the difference in performance between the image-guided alignment system and the manual-marking method in the four-haptic hydrophobic monofocal toric intraocular lens (IOL).

METHODS

Medical records of patients who underwent cataract surgery with a four-haptic hydrophobic monofocal toric IOL implantation between May 2020 and April 2021 and with 3-month visit data available were investigated. Toric IOL misalignment, residual astigmatism, and mean prediction errors between the two groups were compared.

RESULTS

This study included 49 eyes of 44 patients (women: 68%; mean age: 67.2±7.0 [range: 47-82] years). Twenty-nine eyes of 26 patients were treated with toric IOL implantation using the image-guided system and 20 eyes of 18 patients were treated using the manual-marking method. No statistical differences were observed regarding the baseline characteristics of the two groups. Three months after the surgery, the misalignment of the toric IOL was significantly lower in the image-guided group (2.18°±0.65°, range: 1.26°-3.95°) than in the manual; marking group (4.72°±0.74°, range: 3.44°-6.21°; P<0.001).

CONCLUSION

In comparison to the manual-marking method, the image-guided system reduced the misalignment of a four-haptic hydrophobic monofocal toric IOL.

Visual and refractive outcomes of monofocal toric intraocular lens implantation in amblyopic eyes

PURPOSE

To evaluate the visual and refractive outcomes of monofocal toric intraocular lens (IOL) implantation after cataract surgery in amblyopic eyes.

METHODS

Our center's database was used to identify patients who had undergone bilateral cataract surgery between 2016 and 2020 with the implantation of a toric IOL in their amblyopic eye. Exclusion criteria were the presence of strabismus, ocular pathologies other than cataract or intra-surgical complications. The outcomes analysed were uncorrected distance visual acuity (UDVA), subjective refraction and corrected distance visual acuity (CDVA) one month after surgery.

RESULTS

Ninety patients were included, with a mean age of 68.96 ± 7.81years. CDVA was lower for the amblyopic eye, both before and after surgery. There was a mean improvement in CDVA of 0.23 ± 0.21 LogMAR for the dominant eye and of 0.39 ± 0.33 for the amblyopic eye, p < 0.001 in both cases. Postoperative subjective refractive cylinder was higher in the amblyopic eye (-0.24 ± 0.39 D versus -0.10 ± 0.25 D, p < 0.01), as well as mean cylinder prediction error (-0.30 ± 0.47 D versus 0.02 ± 0.42 D, p < 0.01), compared to the dominant eye. There was a statistically significant correlation between preoperative and postoperative CDVA in amblyopic eyes (Spearmańs Rho = 260, p = 0.013). Mean postoperative UCVA was 0.15 ± 0.25 for amblyopic and 0.03 ± 0.12 for dominant eyes. Only one patient required distance spectacle correction due to residual astigmatism.

CONCLUSIONS

Cataract surgery with toric IOL implantation in amblyopic eyes leads to an improvement in visual acuity and to spectacle independence in almost all cases, even in the presence of a higher cylinder prediction error.

Accuracy of OCT-derived net corneal astigmatism measurement

PURPOSE

To assess the repeatability and accuracy of corneal astigmatism measurement with a spectral-domain optical coherence tomography (OCT) system (Avanti, Optovue) and compare them with Scheimpflug imaging (Pentacam HR, Oculus) and swept-source optical biometry (IOLMaster 700, Carl Zeiss Meditec AG).

SETTING

Casey Eye Institute, Oregon Health & Science University, Portland, Oregon.

DESIGN

Prospective cross-sectional observational study.

METHODS

60 pseudophakic eyes with monofocal nontoric intraocular lens that previously had refractive surgery were analyzed. To assess accuracy, simulated keratometry (SimK) and net corneal astigmatism, obtained from each device, were compared with subjective manifest refraction astigmatism. Repeatability for corneal astigmatism was assessed for OCT and Pentacam HR by the coefficient of repeatability from 3 repeated measures.

RESULTS

Compared with manifest refraction, SimK readings produced with-the-rule astigmatic bias that was reduced for net astigmatism for the 3 devices. Except for OCT net astigmatism, all instruments significantly overestimated the magnitude of the astigmatism (linear mixed-effects model [LMM], P < .05). OCT net astigmatism showed the highest accuracy for manifest astigmatism prediction with the smaller 95% confidence ellipse for the mean difference vector. OCT net mean absolute difference was 0.57 diopters (D), significantly smaller than that of the other modalities (LMM, P < .05). Net corneal astigmatism measured with OCT showed the best repeatability (coefficient of repeatability = 0.29 D).

CONCLUSIONS

OCT has the capability to measure net corneal astigmatism with higher precision and accuracy than Pentacam HR Scheimpflug imaging and IOLMaster 700 swept-source optical biometry in postrefractive subjects.

Real-world incidence of monofocal toric intraocular lens repositioning: analysis of the American Academy of Ophthalmology IRIS Registry

PURPOSE

To determine the 12-month incidence of reoperation to realign 2 commercially available types of implanted monofocal toric acrylic intraocular lenses (IOLs).

SETTING

American Academy of Ophthalmology IRIS (Intelligent Research in Sight) Registry.

DESIGN

Registry retrospective study.

METHODS

Eyes that underwent cataract extraction and were implanted with a TECNIS or AcrySof monofocal toric IOL in 2016 and 2017 were identified. The rate of reoperation for IOL realignment (Current Procedural Terminology code 66825) within 365 days of implantation was determined for each IOL group. Risk factors for repositioning were evaluated using logistic regression modeling.

RESULTS

A total of 6482 eyes were implanted with a monofocal toric IOL, including 2013 (31.06%) with a TECNIS and 4469 (68.94%) with an AcrySof IOL. During the first postoperative year, 87 (1.3%) eyes underwent surgical IOL repositioning. The incidence of repositioning was significantly higher (P < .0001) for TECNIS-implanted (3.1%, 62/2013) than for AcrySof-implanted (0.6%, 25/4469) eyes (odds ratio [OR] 5.6; 95% CI, 3.5-8.9). Younger age (OR 0.76; 95% CI, 0.67-0.86 per 5-year increase) was associated with a higher risk for IOL repositioning.

CONCLUSIONS

Real-world analysis of U.S. patients in the IRIS Registry revealed that the rate of surgical IOL repositioning was 5 times higher in eyes implanted with TECNIS than with AcrySof monofocal toric IOLs for astigmatic correction at the time of cataract surgery. These findings should be considered when selecting a toric IOL for correction of astigmatism in cataract patients, particularly in younger patients with a higher risk for misalignment requiring repositioning.

Modified Harada-Ito Procedure with Intraoperative Adjustable Sutures Using a Mendez Ring for Excyclotorsion

Purpose: We report a case of using a modified Harada-Ito procedure with intraoperative adjustment via a Mendez ring in a patient with bilateral superior oblique palsy, resulting in satisfactory postoperative outcomes.Case summary: A 47-year-old male patient presented with bilateral diplopia after cerebral hemorrhage. Bilateral superior oblique palsy was diagnosed, and double Maddox rod tests confirmed 20° of excyclotorsion in both eyes. After 6 months of observation, surgical correction was attempted. To check the amount of cyclodeviation, a modified Harada–Ito procedure was performed on the superior oblique muscle after marking at the 6 and 12 o'clock positions of the corneal limbus. Following the procedure, a Mendez ring was placed on the limbus to check for the amount of incyclotorsion. Thirty degrees of incyclotorsion was aimed at both eyes, and a 5-mm resection of the right superior oblique tendon was performed for additional correction. There was no complaint of diplopia at 6 months postoperatively, and no deviation was observed.Conclusions: A modified Harada-Ito procedure with intraoperative adjustment using a Mendez ring effectively corrected excyclotorsion with torsional diplopia.

Impact of Material and Lens Design on Repositioning Surgery of Toric Intraocular Lenses: A Single-Arm Meta-Analysis

Aim

To analyze the pooled incidence rate in repositioning surgery by considering different materials and designs.

Methods

All published studies investigating the repositioning surgery of toric intraocular lenses (IOLs) before September 1, 2020, were searched and evaluated. The R3.5.2 software was used to extract the data, and a single arm meta-analysis was performed.

Results

19 cases from 18 published studies articles were included in the meta-analysis. The pooled incidence rate in repositioning surgery was 2% (I² = 53%, P_{heterogeneity}<0.01). Plate and silicone IOLs had significantly higher incidence rates (6% for each) than loop (2%) and hydrophobic acrylate (2%). Incidence rates of Acrysof, Staar, TECNIS, PhysIOL SA, T-flex 623T, and Microsil 6116TU groups were 1% (95% CI [1%–2%]), 6% (95% CI [4%–9%]), 3% (95% CI [2%–4%]), 1.40% (1/71), 3.03% (1/33), and 4.76% (1/21), respectively.

Conclusions

The pooled incidence rate of repositioning surgery in IOLs was 2%. Materials and designs would be risk factors for the rotational stability of the toric IOLs. Pooled incidence rates of the hydrophobic acrylate and loop group were lower than those of the silicone and plate group. Product identity is the main driver of heterogeneity.

Type of residual astigmatism and uncorrected visual acuity in pseudophakic eyes

It is difficult to assess the pure impact of the type of residual astigmatism (with-the-rule; WTR, against-the-rule; ATR, and oblique astigmatism) on uncorrected distance visual acuity (UDVA) in pseudophakic eyes due to different age distribution of patients between those subgroups. We conducted the current study to investigate the association between astigmatism type and UDVA in eyes after cataract surgery with consideration for various confounding factors such as age. Data were retrospectively collected from 1535 pseudophakic eyes with corrected distance visual acuity (CDVA) of 20/20 or better, and spherical equivalent between − 0.125 D and 0.0 D. They were classified based on the pattern of residual refractive astigmatism into four groups; minimum astigmatism (< 0.5 D), WTR, ATR, and oblique astigmatism groups. The stepwise multivariate regression analysis showed that the magnitude of residual refractive astigmatism (standardized partial regression coefficient β = 0.559, p < 0.001), CDVA (β = 0.381, p < 0.001), minimum astigmatism group (β = − 0.188, p < 0.001), and WTR astigmatism group (β = − 0.058, p < 0.001) were significantly associated with UDVA (r² = 0.795). Variables excluded from the multivariate regression model include age, preoperative corneal astigmatism, axial length, anterior chamber depth, intraocular lens power, and postoperative spherical equivalent. These results indicate that UDVA is significantly better in eyes with minimum and WTR astigmatism than in those with ATR and oblique astigmatism, after adjustment for confounding parameters. In pseudophakic eyes, oblique and ATR astigmatism exerts a greater impact on UDVA than WTR astigmatism does, even after controlling for age.

[The impact of the position of toric intraocular lenses on the functional outcomes of phaco surgery]

The article reviews data on the impact of the position (orientation) of toric intraocular lenses on the functional outcomes of cataract phacoemulsification surgery, discusses the algorithm of astigmatism correction with intraocular lenses including preoperative determination of the size and position of main meridians, calculation of lens parameters, marking of corneal meridians, intraoperative positioning, as well as rotation and/or repositioning of the lens when necessary.

Toric Intraocular Lenses for the Management of Corneal Astigmatism at the Time of Cataract Surgery

Methods

This audit was conducted in a UK ophthalmology department and included 48 eyes of 42 patients. Surgery was performed during 2019 in patients with 2.50 diopters (D) or more corneal astigmatism. Anterior keratometry readings were used to determine the toric IOL power. Vector analysis using the Alpins method was used to assess changes in astigmatism pre to postoperatively.

Results

There were 18 right and 26 left eyes included. In terms of gender, 61% of patients were female and 39% were male. The mean (±standard deviation (SD)) age was 70 (±11) years. The mean (±SD) axial length, K1, K2, and delta K was 23.55 (±1.4) mm, 42.71 (±1.39) D, 45.78 (±1.60) D, and 3.01 (±0.89) D, respectively. Postoperatively, the median spherical, cylinder, and spherical equivalent refraction was 0.00 D, −1.00 D, and 0.00 D, respectively. Postoperatively, 41% of the eyes had ≤0.50 D of spectacle astigmatism and 80% had ≤1.00 D. No patient required a secondary procedure to reposition the IOL from rotation. In vector analysis with the use of polar diagrams, there was a tendency for overcorrection of with-the-rule astigmatism and undercorrection of against-the-rule astigmatism.

Conclusions

Significant reductions in astigmatism can be achieved with the use of toric IOLs in patients undergoing cataract surgery. Further improvements may be possible with surgeon-specific determination of their surgically induced astigmatism and flattening effect from the main corneal incision. Furthermore, the use of an optical biometer that directly measures the posterior corneal curvature and permits automatic toric IOL power determination with modern formulas avoiding the need for manual data entry may reduce the risk of human error and improve visual and refractive outcomes.

The Effect of Toric Intraocular Lens Implantation in Irregular Corneal Steep and Flat Meridian

Purpose

To evaluate the effect of toric intraocular lens implantation in cataract patients with irregular corneal steep and flat meridian.

Methods

Data of 112 eyes of 78 patients who underwent toric intraocular lens implantation were analyzed retrospectively. Steep meridian deviations (not 180°) and steep and flat meridian deviations (not 90°) were classified as 0, 1–9, 10–19, 20–29, 30–39, and over 30°. Meridian deviation was measured with a sagittal map of a rotating Scheimpflug camera (Pentacam®: Oculus, Wetzlar, Germany) using PicPickTools (NGWIN, Seoul, Korea).

Results

Residual astigmatism (D) of 0 (0.51 ± 0.13, 0.55 ± 0.15) and 1–9 (0.61 ± 0.16, 0.66 ± 0.19) groups were significantly lower than that of 10–19 (0.92 ± 0.24, 0.90 ± 0.28), 20–29 (0.10 ± 0.32, 1.01 ± 0.35), and over 30° groups (1.12 ± 0.37, 1.14 ± 0.40) both in steep meridian deviations and horizontal and vertical meridian deviations at 6 months (P < 0.05). Postoperative mean UCVA (logMAR) of 0 (0.09 ± 0.04, 0.09 ± 0.05) (logMAR) and 1–9 (0.10 ± 0.04, 0.11 ± 0.08) groups was significantly improved compared to that of 10–19 (0.14 ± 0.05, 0.17 ± 0.10), 20–29 (0.18 ± 0.08, 0.21 ± 0.10), and over 30° groups (0.20 ± 0.09, 0.22 ± 0.11) both in steep meridian deviations and horizontal and vertical meridian deviations at 6 months (P < 0.05).

Conclusions

Correction of astigmatism with toric intraocular lens implantation is not accurate in corneas with steep meridian deviations and steep and flat meridian deviations of more than 10°. Therefore, care should be taken when we perform toric intraocular lens implantation in patients with irregular corneal meridian.

The Influence of Analysis Mode Selection on Prediction Accuracy of Corneal Astigmatism Using Pentacam

Purpose: To evaluate the influence of analysis mode selection on prediction accuracy of corneal astigmatism using Pentacam.

Methods: Fifty-nine eyes of 59 patients implanted with toric intraocular lenses (IOLs) were included in the retrospective study. Preoperative corneal astigmatism (total refractive power) measured with Pentacam was analyzed based on 2-, 3-, 4-, or 5-mm ring or zone mode either centered on corneal apex or pupil center. Actual corneal astigmatism was calculated based on residual astigmatism on the corneal plane, surgical-induced astigmatism, and effective toric power on the corneal plane. Prediction error, the difference between actual corneal astigmatism and measured astigmatism, was compared among different analysis modes. Influences of local topography on prediction error were also evaluated.

Results: Based on the zone mode, prediction error was lower when centered on corneal apex than on pupil center at different diameters, whereas based on the ring mode, this difference was only seen at 2-mm cornea (all P < 0.05). When centered on the corneal apex, the zone mode showed lower prediction error than the ring mode at 4- and 5-mm corneas (both P < 0.001), regardless of asymmetric or symmetric astigmatism. In symmetric bowtie, the zone mode showed lower prediction error than the ring mode at 2-mm cornea of the small bowtie, and 4- and 5-mm corneas of the large bowtie (all P < 0.05).

Conclusions: For toric IOL planning, the corneal apex may be a better reference center. At a cornea diameter ≥4 mm, the zone mode is more accurate than the ring mode. Local topography affects prediction accuracy in the symmetric bowtie.

Cataract: Advances in surgery and whether surgery remains the only treatment in future

Background

Cataract is the world's leading eye disease that causes blindness. The prevalence of cataract aged 40 years and older is approximately 11.8%-18.8%. Currently, surgery is the only way to treat cataracts.

Main Text

From early intracapsular cataract extraction to extracapsular cataract extraction, to current phacoemulsification cataract surgery, the incision ranges from 12 to 3 ​mm, and sometimes to even 1.8 ​mm or less, and the revolution in cataract surgery is ongoing. Cataract surgery has transformed from vision recovery to refractive surgery, leading to the era of refractive cataract surgery, and premium intraocular lenses (IOLs) such as toric IOLs, multifocal IOLs, and extended depth-of-focus IOLs are being increasingly used to meet the individual needs of patients. With its advantages of providing better visual acuity and causing fewer complications, phacoemulsification is currently the mainstream cataract surgery technique worldwide. However, patient expectations for the safety and accuracy of the operation are continually increasing. Femtosecond laser-assisted cataract surgery (FLACS) has entered the public's field of vision. FLACS is a combination of new laser technology and artificial intelligence to replace fine manual clear corneal incision, capsulorhexis, and nuclear pre-fragmentation, providing new alternative technologies for patients and ophthalmologists. As FLACS matures, it is being increasingly applied in complex cases; however, some think it is not cost-effective. Although more than 26 million cataract surgeries are performed each year, there is still a gap in the prevalence of cataracts, especially in developing countries. Although cataract surgery is a nearly ideal procedure and complications are manageable, both patients and doctors dream of using drugs to cure cataracts. Is surgery really the only way to treat cataracts in the future? It has been verified by animal experiments that lanosterol therapy in rabbits and dogs could make cataract severity alleviated and lens transparency partially recovered. Although there is still much to learn about cataract reversal, this groundbreaking work provided a new strategy for the prevention and treatment of cataracts.

Conclusions

Although cataract surgery is nearly ideal, it is still insufficient, we expect the prospects for cataract drugs to be bright.

Transitional conic toric intraocular lens evaluation after femtosecond laser-assisted cataract surgery using intraoperative aberrometry

PURPOSE

To assess refractive and visual outcomes following phacoemulsification with femtosecond laser-assisted cataract surgery (FLACS) using intraoperative aberrometry and implantation of a toric intraocular lens (IOL) in eyes with different degrees of astigmatism.

METHODS

One hundred two eyes of 70 patients who underwent implantation of the transitional toric 565 Precizon IOL (Ophtec BV) were enrolled. FLACS, capsular tension ring insertion, and intraoperative aberrometry were performed. Main outcome measures were refractive error, uncorrected- and corrected distance snellen decimal visual acuity values (UDVA and CDVA, respectively), and IOL rotation. Specifically, a vector analysis was carried out with J0 and J45 evaluation. Eyes were evaluated 1-year after surgery.

RESULTS

Overall, 94.12% (96 eyes) and 100% (102 eyes) of the eyes showed a spherical equivalent (SE) within ± 0.50D and ± 1.00D, respectively. The mean SE and refractive cylinder were - 0.06 ± 0.29D and - 0.23 ± 0.37D, respectively. Vector analysis revealed that 100% of the eyes were within ± 0.50D for the J0 and J45 cylindrical components. The mean toric axis rotation was 1.10 ± 1.71° (from 0° to 5°), 77% (79 eyes), and 100% (102 eyes) of the eyes showed UDVA and CDVA of 20/25, respectively. The postoperative mean values of monocular UDVA and CDVA were 0.88 ± 0.17 and 0.96 ± 0.07 (about 20/20), respectively. No patient required IOL realignment during the postoperative follow-up.

CONCLUSIONS

The present study suggests that the use of the Precizon IOL after FLACS, using intraoperative aberrometry in patients with different amounts of astigmatism, provides good visual acuity, accurate refractive outcomes, and excellent rotational stability.

Sources of Error in Toric Intraocular Lens Power Calculation

PURPOSE

To evaluate the influencing factors on remaining astigmatism after implanting a toric intraocular lens (IOL) during cataract surgery.

METHODS

This retrospective study included parameters that were considered to have an influence on toric IOL power calculation. Therefore, data from the literature and the authors' own data were used. This included axial eye length, anterior chamber depth, central corneal thickness, corneal radii (anterior and posterior), diurnal changes of the cornea, inter-device differences, rotational misalignment of the IOL, tilt and decentration of the IOL, pupil size, angle kappa, and surgically induced astigmatism. Ray-tracing and Gaussian error propagation analysis was performed to quantify the sources of error.

RESULTS

In total, 4,949 eyes (4,365 eyes of 42 studies and 584 eyes of retrospectively analyzed study data) were included in the study and the difference vector between aimed and calculated remaining astigmatism was 0.81 diopters (D). The main source of error was the preoperative measurement of the cornea (27%), followed by IOL misalignment (14.4%) and IOL tilt (11.3%). Other factors, such as angle kappa (10.9%), pupil size (8.1%), surgically induced astigmatism (7.8%), anterior chamber depth (7.5%), axial eye length (7.5%), and decentration (5.6%), also contributed to the refractive astigmatic error.

CONCLUSIONS

The main source of error in toric IOL power calculation is the preoperative corneal measurement followed by IOL misalignment and tilt. [J Refract Surg. 2020;36(10):646-652.].

Astigmatism Management with Astigmatism-Correcting Intraocular Lens Using Two Toric Calculators - A Comparative Case Series

Background

To compare refractive outcomes after phacoemulsification and toric IOL implantation using two different toric calculators for initial astigmatism assessment in a real-world setting.

Methods

This was a retrospective, comparative, interventional case series. Patients over 30-year-old who underwent phacoemulsification and toric IOL implantation (AcrySof^® Toric IOL) by the same surgeon between 2017 and 2018 were included. Eyes with irregular astigmatism, previous corneal refractive surgery, intraocular surgery, corneal pathology, macular pathology and pupil abnormalities were excluded. IOL toricity was determined by using a calculator provided by the AcrySof Toric calculator before 2018 and Barrett Toric Calculator after 2018. Patient demographics, corneal topography, vector and preoperative and postoperative refraction were collected and analyzed at three months postoperative.

Results

Thirty-two eyes of 32 patients were included in the final analysis. 0.1D for surgically induced astigmatism was used. Group 1 included 14 eyes assessed with the original (AcrySof) toric IOL calculator, and group 2 included 18 eyes assessed with the Barrett toric IOL calculator. In group 1, postoperative astigmatism less than −1.00D, −0.75 D, and −0.5D was achieved in 88.2%, 76.1% and 53.7% of eyes, respectively, while, in group 2, 89% eyes achieved postoperative residual astigmatism less than 0.5D and all eyes achieved postoperative residual astigmatism less than 0.75D. The proportion of patients with lower postoperative astigmatism was significantly higher in Group 2 (p< 0.05 by chi-square test), a pattern that still held when we divided patients into multiple groups. Vector analysis with the Alpins methods also supported better outcomes in the Barrett group (0.71 D vs 0.35 D).

Conclusion

The Barrett Toric calculator resulted in better results in the prediction of residual astigmatism than original (AcrySof) toric calculators.

Rotational stability of toric intraocular lenses with a newly modified capsular tension ring

PURPOSE

To determine whether a newly modified capsular tension ring (CTR) is effective at preventing toric intraocular lens (TIOL) rotation and misalignment.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental study.

METHODS

Ten human cadaver eyes were used to test the ease or difficulty of TIOL rotation in the capsular bag under 3 experimental conditions: a TIOL alone, a TIOL with a standard CTR, or a TIOL with a newly modified CTR with indentations in a sinusoidal pattern. Scores for the ease of IOL rotation were compared by using the nonparametric Friedman analysis of variance test. In addition, both anterior and posterior Miyake-Apple views were filmed to observe the rotational stability of TIOLs in the capsular bag under the 3 test conditions.

RESULTS

In the ten eyes of five patients, the rotational stability improved with a standard CTR, but further improvement was statistically observed (P < .05) with the newly modified CTR under all test conditions. This was true for both IOLs used (AcrySof and TECNIS toric IOLs), with or without ophthalmic viscosurgical device, and for either clockwise or counterclockwise rotations.

CONCLUSIONS

A newly designed CTR prototype represents a new technology for improving the rotational stability of a TIOL in the capsular bag. Under all test conditions, the prototype performed significantly better than a standard CTR. The results support the use of this new CTR design to improve the accuracy and refractive success of TIOLs.

Comparison of Preoperative Measurements with Intraoperative Aberrometry in Predicting Need for Correction in Eyes with Low Astigmatism Undergoing Cataract Surgery

Purpose

To determine whether intraoperative aberrometry during cataract surgery measures higher levels of absolute astigmatism than preoperative biometry readings and which method yields a lower, final level of astigmatism if the two do not agree.

Patients and Methods

Retrospective record review of all patients who underwent uncomplicated cataract surgery from February 2015 to May 2019 with planned intraoperative aberrometry. Data analysis included preoperative keratometry, total astigmatism as measured by intraoperative aberrometry, intraocular lens model and power used, and postoperative manifest refraction ≥1 month after surgery. The primary outcome measure was the proportion of patients requiring astigmatism correction (≥0.5 D) when measured by preoperative keratometry vs intraoperative aberrometry. Secondary outcomes included postoperative residual astigmatism, where adjusted preoperative astigmatism fell below the 0.5 D threshold for treatment but the intraoperative measurement was ≥0.5 D or ≥1.0 D.

Results

A total of 451 patient records were evaluated. Intraoperative aberrometry measured statistically higher levels of mean astigmatism than keratometry (0.86 D vs 0.79 D, respectively; P < 0.0001) and significantly greater astigmatism among patients with 0.5–1.5 D of adjusted preoperative astigmatism (P < 0.0001). Significantly more patients qualified for with-the-rule astigmatism correction when measured by intraoperative aberrometry (n=339; 75%) than by preoperative keratometry alone (n=314; 70%); P < 0.03. This difference did not hold for against-the-rule or oblique astigmatism. For patients whose preoperative biometry astigmatism differed from intraoperative biometry, final postoperative astigmatism was lower when corrected if the adjusted preoperative and intraoperative measurements had a vector difference of <0.5 D, but there was no additional benefit in final astigmatism reduction when the vector difference was ≥0.5 D.

Conclusion

Using intraoperative biometry readings can produce lower postoperative astigmatism than using preoperative biometry readings, but caution should be used when interpreting intraoperative readings that disagree with preoperative measurements with a vector magnitude of >0.5 D.