Comparative meta-analysis of toric intraocular lens alignment accuracy in cataract patients: Image-guided system versus manual marking

Comparison of Postoperative Axial Rotation of the Toric Intraocular Lens in Cataract Surgery Combined with Vitrectomy versus Cataract Surgery Alone

INTRODUCTION

This study compared the postoperative axial rotation of the toric intraocular lens (T-IOL) after cataract surgery combined with vitrectomy versus cataract surgery alone.

METHODS

This retrospective, non-randomized, observational study enrolled patients who underwent cataract surgery combined with vitrectomy in one eye and cataract surgery alone in the contralateral eye. AcrySof Toric IOLs (Alcon Laboratories) were implanted in both eyes of the same patient. The axial rotation of the T-IOL was analyzed 3 months postoperatively using photographs obtained during and after surgery. In the combined group, T-IOL axial alignment was performed before vitrectomy. Preoperative corneal astigmatism and postoperative residual astigmatism were also compared in both groups.

RESULTS

This study examined 36 eyes of 18 patients (74.7 ± 6.8 years). The axial rotation was 2.94 ± 1.70° in the cataract group versus 3.06 ± 2.34° in the combined group 3 months postoperatively, and the difference lacked significance (p = 0.98). In the combined group, the mean axial rotation during surgery was 2.17 ± 1.80°. Axial rotation within 5° was observed in 17 of 18 eyes (94.4%) in the cataract group and 16 of 18 eyes (88.9%) in the combined group, with no significant difference (p = 0.54). The comparison of postoperative residual astigmatism with preoperative corneal astigmatism revealed a significant improvement from 1.49 ± 0.40 D to 0.39 ± 0.47 D in the cataract group (p < 0.0001) and from 1.61 ± 0.40 D to 0.42 ± 0.43 D in the combined group (p < 0.0001).

CONCLUSIONS

The postoperative axial rotation of the T-IOL in eyes that underwent cataract surgery combined with vitrectomy was stable and comparable to that of eyes that underwent cataract surgery alone.

Image-Guided Marking versus Manual Marking in Phacoemulsification with Toric Intraocular Lens (IOL) Implantation: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

PURPOSES

The purpose of this meta-analysis is to systematically compare the alignment accuracy and post uncorrected distance visual acuity (UDVA) between image-guided marking and manual marking for toric intraocular lens (IOL) in cataract surgery.

METHODS

This work was done through the data searched from the PubMed, EMBASE and the Cochrane Library. The Cochrane Handbook was also used to evaluate the quality of the included studies. In addition, this meta-analysis was performed using Revman 5.4 software.

RESULTS

A total of 6 randomized controlled trials (RCTs) were included. Compared with manual marking group, image-guided marking group had less toric IOL axis misalignment (MD, -1.98; 95%CI, -3.27 to -0.68; p = .003), less postoperative astigmatism (MD, -0.13; 95%CI, -0.21 to -0.05; p = .001), better postoperative UDVA (MD, -0.02; 95%CI, -0.04 to -0.01; p = .0003) and smaller difference vector (MD, -0.10; 95%CI, -0.14 to -0.06; p(0.00001). For the proportion of patients with residual refractive cylinder within 0.5 D, there was no difference between two groups (p = .07).

CONCLUSION

Image-guided marking is prior to manual marking. As it can bring less toric IOL axis misalignment, less postoperative astigmatism, better postoperative UDVA and smaller difference vector for the patients with toric IOL implantation.

[Refractive Results after Implantation of Toric Intraocular Lenses Using the Zeiss Callisto System]

BACKGROUND

For cataract patients with astigmatism, the insertion of a toric intraocular lens is a safe and effective method to achieve emmetropia. The exact alignment of the lens along the calculated axis is essential for effective correction of astigmatism. The purpose of this study is to evaluate our own data using descriptive statistics. The primary focus is on the refractive outcome and thus the verification of the alignment accuracy of toric IOLs with the Zeiss Callisto system.

PATIENTS AND METHODS

The study evaluated a total of 106 eyes of 72 patients who underwent cataract surgery with implantation of a toric intraocular lens at our hospital between January 2019 and December 2020. Preoperative biometry and intraoperative marking of the implantation axis was performed using the Zeiss Callisto system. Postoperative controls were performed after one day, one week and 4 weeks, either at our hospital or by the referring ophthalmologist. For the analysis, only the data of the 4-week control were used.

RESULTS

In 64 eyes (60%), a Zeiss AT Torbi 709 M or MP and in 42 eyes (40%) a PhysIOL Ankoris toric yellow IOL were implanted. In 46 eyes, postoperative uncorrected visual acuity was not recorded. Of the remaining 60 eyes, the mean postoperative uncorrected visual acuity was 0.07 ± 0.12 logMAR. Postoperative uncorrected visual acuity ≥ 1.0 (decimal) was achieved in 48% of the eyes and visual acuity ≥ 0.6 (decimal) in 92%. The postoperative cylinder averaged - 0.65 ± 0.53 D. The cylinder of the target refraction was - 0.45 ± 0.39 D on average. The mean of the absolute value of the postoperative cylinder minus the cylinder of the target refraction was 0.42 ± 0.32 D.

CONCLUSIONS

The Zeiss Callisto system is an effective tool to align toric intraocular lenses.

Comparison of Visual and Refractive Outcome between Two Methods of Corneal Marking for Toric Implantable Collamer Lenses (TICL) in Phakic Eyes

PURPOSE

To compare the efficacy of digital-assisted reference marking for toric implantable collamer lenses (Callisto Eye System) with manual marking technique using a slit lamp markeur.

METHODS

This study included patients that underwent implantation of a toric implantable collamer lens (EVO Visian toric ICL, Staar Surgical). Patients were included if they had a myopia above -3 diopters (D) and regular corneal astigmatism of 0.75 diopters or higher. Between both groups a 1:2 matching regarding similar preoperative level of myopia and astigmatism was performed. Visual and refractive outcomes were evaluated. Vector analysis was performed to evaluate total astigmatic changes.

RESULTS

This study comprised 57 eyes of 57 patients with 19 eyes in the digital group and 38 eyes in the manual marking group. Postoperatively there were no statistically significant differences between both groups in UDVA (p = 0.467), spherical equivalent (SE) (p = 0.864), sphere (p = 0.761) and cylinder (p = 0.878). Vector analysis showed a slightly more accurate postoperative refractive astigmatism in the manual group (0.26 D at 107° ± 0.50 D) compared to the digital marking group (0.31 D at 107° ± 0.45 D), nevertheless with no statistically significant differences between both groups.

CONCLUSIONS

A digital tracking approach for toric ICL alignment was an efficient and safe method for toric marking with similar results regarding visual and refractive outcomes compared to a conventional corneal marking method. Nevertheless, image-guided surgery helped to streamline the workflow in refractive ICL surgery.

Comparison of INTEGRA and the Manual Method to Determine the Axis for Intraocular Lens Implantation-A Case Series of 60 Eyes

(1) Background: To compare the results of a new intraoperative contactless device (INTEGRA Optomed, Poland) with the result of a manual method for determining the axis for toric intraocular lens implantation. (2) Material and Methods: This retrospective observational study included 60 eyes of 40 patients (17 men, 23 women) who had toric intraocular lenses implanted. A video recording of each surgery that used the INTEGRA system was made for the analysis. Two researchers then independently assessed the location of the implant axes determined with both digital and manual slit-lamp methods, and compared the results between methods. (3) Results: The implantation axes suggested through the manual and INTEGRA methods were similar. The median axis disparities were 0.0 degrees for both groups. The standard deviation was 0.63 and 0.75 for researcher 1 and 2, respectively. The dominant value was 0.0 in both groups. The INTEGRA axis designation was statistically significantly different from the manual method for researcher 1 (p < 0.05), but it was statistically insignificant for researcher 2 (p = 0.79). (4) Conclusions: The INTEGRA system is a digital ink-free device for image tracking scleral vessels. It was helpful for determining the implantation axis in a precise manner, and the measurements were comparable with those obtained through a manual technique.

Digital versus slit-beam marking for toric intraocular lenses in cataract surgery

Purpose

To compare the visual outcomes of digital and slit-beam manual marking for toric intraocular lenses (IOL) in cataract surgery.

Setting

Single-center, Beijing Tongren Hospital, China.

Design

Retrospective study.

Methods

All patients with cataracts and regular corneal astigmatism greater than 0.75 diopters (D) underwent cataract surgery and astigmatism correction between June 2019 and June 2020. To mark the target axis of the toric IOL and the location of the incision, intraoperative digital marking was used by Callisto eye image-guided system in one group, while preoperative manual slit-beam marking was used in the other group. Uncorrected and best-corrected spectacle visual acuity, refraction, toric IOL axis, total higher order aberrations, coma, spherical aberration, and trefoil were evaluated at 1, 4, and 12 weeks postoperatively.

Results

Seventy-two eyes of 58 patients were included. At 3 months after surgery, the mean residual refractive cylinder was 0.42 ± 0.45D in the digital group and 0.39 ± 0.40D in the manual group (P = 0.844). There were no significant differences between groups in spherical equivalent refraction, uncorrected and best-corrected spectacle visual acuity, or the parameters of vector analysis. All toric IOL alignment errors were within 10° of the intended axis, and among them, about 42% of eyes in the digital group and 61% of eyes in the manual group had a rotation of 0–2° (P = 0.038). Trefoil in the manual group decreased postoperatively compared with the digital group (P = 0.012). Other aberration analyses did not reveal any statistical differences between groups.

Conclusions

Accurate slit-beam manual marking and digital image-guided marking are equally effective for toric IOL alignment.

Long-term outcomes of cataract surgery with toric intraocular lens implantation by the type of preoperative astigmatism

Surgical outcomes of toric intraocular lens (IOL) implantation for 8 years after surgery were analyzed. Data were retrospectively collected in 176 eyes of 176 patients before and 1 month, 1, 3, 5, and 8 years after phacoemulsification and implantation of a toric IOL. Preoperative corneal and postoperative manifest astigmatism was analyzed by converting to power vector notations; horizontal/vertical (J₀) and oblique (J₄₅) astigmatism components. Toric IOL implantation significantly reduced pre-existing astigmatism by decreasing J₀ in eyes with preoperative with-the-rule (WTR) astigmatism, increasing J₀ in eyes with against-the-rule (ATR) astigmatism, and correcting J₄₅ in eyes with oblique astigmatism. After surgery, the eyes with preoperative ATR astigmatism showed a significant ATR astigmatic shift, and J₀ at 5 and 8 years was significantly smaller than that at 1 month postoperatively. Uncorrected distance visual acuity was also significantly worse at 5 and 8 years than at 1 month postoperatively. In eyes with WTR and oblique astigmatism, the effects of toric IOLs on astigmatism and visual acuity were sustained for 8 years. The long-term astigmatism-correcting effects did not differ among the models of toric IOL used in this study, SN6AT3–8 (Alcon Laboratories). In eyes with preoperative ATR astigmatism, astigmatism-correcting effects of toric IOLs decreased at 5 years and later postoperatively, indicating that overcorrection may be considered at the time of cataract surgery. In eyes with WTR and oblique astigmatism, the effects of toric IOLs were maintained throughout the 8-year follow-up period.

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.

Comparison of Visual Outcomes Between Toric Intraocular Lenses and Clear Corneal Incisions to Correct Astigmatism in Image–Guided Cataract Surgery

Purpose

To compare the astigmatism correction effects of toric intraocular lenses (IOL) and clear corneal incisions during image-guided cataract surgery.

Methods

All patients with regular corneal astigmatism of 0.75–1.5 D underwent cataract surgery and astigmatism correction using the Callisto eye image-guided system. One group had implantation of an AcrySof toric IOL. Another group had implantation of aspheric IOL with 3.0 mm single clear corneal incision (SCCI) on the steep axis. Uncorrected and best-corrected spectacle visual acuity, refraction, and toric IOL axis were evaluated at 1, 4, and 12 weeks postoperatively.

Results

Sixty-eight eyes of 68 patients were included. The mean residual refractive cylinder was 0.34 ± 0.40 D in the toric group and 0.64 ± 0.57 D in the SCCI group. There were no significant differences in residual refractive cylinder, spherical equivalent, uncorrected distance visual acuity (UDVA), and best-corrected spectacle visual acuity (BCSVA) between groups. The percentage of the residual cylinder within ± 0.50 D was 75 and 56% for toric and SCCI cases, respectively (p &gt; 0.1). The mean surgical induced astigmatism vector was 0.61 ± 0.29 D in the SCCI group and 1.04 ± 0.38 D in the toric group. The mean magnitude of error was negative (−0.54 ± 0.48 D) and the correction index was &lt;1.0 (p &lt; 0.05) in SCCI group. At 3 months, all toric IOL alignment errors were within 5 degrees from the intended axis.

Conclusions

Both toric IOL and SCCI can correct low and medium astigmatism effectively with the help of a precise image-guided system.

A Review of Smartphone Apps Used for Toric Intraocular Lens Calculation and Alignment

Smartphone apps are becoming increasingly popular in ophthalmology, one specific area of their application being toric intraocular lens (IOL) surgery for astigmatism correction. Our objective was to identify, review and objectively score smartphone apps applicable to toric IOL calculation and/or axis alignment. This review was divided into three phases. A review was conducted on four major app databases (phase I): National Health Service (NHS) Apps Library, Google Play Store, Apple App Store and Amazon Appstore. A systematic literature review (phase II) was conducted to identify studies for included apps in phase I of our study. Keywords used in both searches included: “toric lens”, “toric IOL”, “refraction”, “astigmatism”, “ophthalmology”, “eye calculator”, “ophthalmology calculator” and “refractive calculator”. Included apps were objectively scored (phase III) by three independent reviewers using the mobile app rating scale (MARS), a validated tool that ranks the quality of mobile health apps using a calculated mean app quality (MAQ) score. Phase I of our study screened 2428 smartphone apps, of which six apps for toric IOL calculation and four apps for axis marking were eligible and were selected for quantitative analysis. Phase II of our study screened 477 studies from PubMed, Medline and Google Scholar. Three studies validating two apps (toriCAM, iToric Patwardhan) in a clinical setting as adjunct tools for preoperative axis marking were identified. Phase III ranked Toric Calculator for iPhone (Apple iOS, MAQ 4.13; average MAQ 3.34 ± 0.54) as the highest-scoring toric IOL calculator, and iToric Patwardhan (Android OS, MAQ 4.13; average MAQ 3.41 ± 0.44) was the highest-scoring axis marker in our study. Our review identified and objectively scored ten smartphone apps available for toric IOL surgery adjuncts. Toric Calculator for iPhone and iToric Patwardhan were the highest-scoring toric IOL calculator and axis marker, respectively. Current literature, though limited, suggests that axis marking smartphone apps can achieve similar levels of misalignment reduction when compared to digital systems.

Comparing IOLM700 TK, Berdahl and Hardten astigmatism fix calculator and Barrett Rx formula in managing residual astigmatism due to toric intraocular lens misalignment

Purpose:

To compare the accuracy in astigmatism reduction by using IOLM 700 steep total keratometry (TK) axis, Berdahl and Hardten astigmatism fix, and Barrett Rx formula following misaligned toric intraocular lens (IOL).

Methods:

Ten patients with residual refractive astigmatism due to misalignment following toric IOL implantation were included in this retrospective study. They were analyzed at days 4, 7/8, and 10/11 following primary cataract surgery on the platform of Berdahl and Hardten astigmatism fix, Barrett Rx formula, and IOLM 700 to determine the optimum axis of repositioning, and underwent IOL realignment on the steep TK axis of IOLM 700 assisted by the Callisto eye. The final outcome parameters were subjective refraction and orientation of toric IOL assessed 22 ± 1 days following repositioning surgery. These parameters were fed in the Barrett Rx formula and its vector analysis graph was utilized to determine the predicted ideal axis with the least residual astigmatism and the estimated residual astigmatism if the toric IOL was realigned according to the axis suggested by Berdahl and Hardten astigmatism fix and Barrett Rx formula.

Results:

Realigning the toric IOL on IOLM 700 steep TK axis along with the Callisto eye reduces the residual refractive astigmatism significantly (P = 0.003) from 2.00 ± 0.78 D to 0.18 ± 0.12 D (90.5 ± 7.6%) in comparison to the estimated 0.57 ± 0.31 D (68.4 ± 21.9%) by Berdahl and Hardten astigmatism fix and 0.61 ± 0.33 D (66.4 ± 23.5%) by Barrett Rx formula.

Conclusion:

Realigning the misaligned toric IOL on the IOLM 700 steep TK axis gives a better reduction in the residual refractive astigmatism in comparison to Berdahl and Hardten astigmatism fix and Barrett Rx formula.

[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.

Long-term changes in the refractive effect of a toric intraocular lens on astigmatism correction

Purpose

To examine the long-term changes in the astigmatism-correcting effect of a toric intraocular lens (IOL) after stabilization of surgically induced astigmatic changes due to cataract surgery.

Methods

Unilateral eyes of 120 patients that received a toric IOL for against-the-rule (ATR) or with-the-rule (WTR) astigmatism were enrolled. Manifest refractive and anterior corneal astigmatism, and ocular residual astigmatism which is mainly derived from internal optics were examined preoperatively, at approximately 2 months postoperatively (baseline) and at 5 ~ 10 years postbaseline. The astigmatism was decomposed to vertical/horizontal (Rx) and oblique components (Ry), which was compared between baseline and 5 ~ 10 years postbaseline.

Results

In the eyes having ATR astigmatism, the mean Rx and Ry of the manifest refractive and corneal astigmatism significantly changed toward ATR astigmatism between the baseline and 5 ~ 10 years postbaseline (p ≤ 0.0304), but those of ocular residual astigmatism did not change significantly between the 2 time points. In the eyes having WTR astigmatism, the Rx and Ry of refractive, corneal, and ocular residual astigmatism did not change significantly between the 2 time points. Double-angle plots revealed an ATR shift in refractive and corneal astigmatism and no marked change in the ocular residual astigmatism in the eyes with ATR astigmatism, and there is no change in this astigmatism in the eyes with WTR astigmatism.

Conclusion

The long-term changes with age in the effect of a toric IOL significantly deteriorated due to an ATR shift of corneal astigmatism in the eyes having ATR astigmatism, while it was maintained in eyes having WTR astigmatism, suggesting that ATR astigmatism should be overcorrected.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05406-7.

Comparison of rotational stability and repositioning rates of 2 presbyopia-correcting and 2 monofocal toric intraocular lenses

PURPOSE

To compare the rotational stability of 2 commonly used toric presbyopia-correcting (PC) intraocular lenses (IOLs) and their monofocal toric counterparts.

SETTING

Single 2-surgeon private practice.

DESIGN

Retrospective study.

METHODS

This study included 2 cohorts: (1) all eyes receiving a toric ReSTOR (n = 61 eyes, 49 patients) or toric Symfony (n = 779 eyes, 520 patients) IOL from September 2016 to January 2019; and (2) all eyes receiving an AcrySof (n = 2 393) or TECNIS (n = 731) monofocal toric IOL (TIOL) from April 2015 to January 2019. Eyes were only excluded if digital marking could not be used. All patients had image-guided digital marking to verify TIOL position at the conclusion of surgery. Postoperative rotation was determined by dilated examination performed later on the day of surgery or the following morning.

RESULTS

The toric ReSTOR IOL was more likely to rotate 5 degrees or less than the toric Symfony IOL, 91.8% vs 79.0% (P = .01). This remained true for rotation of 10 degrees or less (100% vs 89.5%, P < 0.003). The mean rotation was 2.3 degrees for toric ReSTOR IOL compared with 4.5 for toric Symfony IOL (P = .01). Statistically significantly more eyes with toric Symfony IOL required a return to the operating room for repositioning (6.9% vs 0%, P < .03). More TECNIS monofocal TIOL eyes required surgical repositioning than AcrySof monofocal TIOL eyes (3.5% vs 1.2%, P < .001).

CONCLUSIONS

Between these PC-TIOLs, the Symfony IOL was more likely to rotate and to require surgical repositioning than the ReSTOR IOL. The TECNIS TIOL built on the same platform as the Symfony IOL was more likely to require surgical repositioning than that by the AcrySof TIOL. Despite comparable rotational stability between the Symfony and TECNIS monofocal TIOLs, the Symfony was twice as likely to require surgical repositioning.

Outcomes of toric IOL implantation guided by iris-registered femtosecond laser capsulotomy markings

PURPOSE

To assess the accuracy and stability of iris-registered femtosecond laser-assisted anterior capsule axis markings (compensating cyclotorsion) along with refractive and visual outcomes after toric IOL implantation.

METHODS

This prospective case series included eyes with visually significant cataracts and regular corneal astigmatism ranging from 1.25D to 4.0D, which received FLACS and toric IOL implantation, at The Eye Institute of West Florida, Largo, Florida, USA. Preoperative iris registration was used in conjunction with a femtosecond laser platform to create cyclotorsion corrected axis marks at the capsulotomy edge to facilitate toric IOL axial alignment. Patients were examined one, seven and thirty days after surgery to assess capsulotomy marks axis, toric IOL axis along with visual and refractive outcomes.

RESULTS

Eighteen eyes of 13 patients aged 74.35 ± 8.65 years were included. Mean pre-op CDVA was 0.24 ± 0.16 LogMAR, while mean post-op UDVA was 0.09 ± 0.09 LogMAR. Mean pre-op corneal astigmatism was 1.85 ± 0.41 D, decreasing to 0.24 ± 0.41 D of refractive astigmatism postoperatively (p < 0.001). The capsular toric axis markings were visible in 100% of eyes throughout the follow-up; the mean difference between intended capsulotomy mark axis and measured capsulotomy mark axis was 1.6°, 1.7° and 1.3 ^o at the 1, 7 and 30 day intervals (p > 0.05), respectively. No capsule-related or any other type of complications was noted.

CONCLUSIONS

Iris-registered femtosecond laser-assisted anterior capsule axis markings are safe and may be considered as an alternative option to the known axis marking techniques for toric IOL axial alignment at the time of cataract surgery.

Rotational stability of modified toric intraocular lens

We evaluated the rotational stability of a new toric intraocular lens (IOL), HOYA XY-1 toric IOL that is an improved version of HOYA 355 toric IOL, with longer overall length (13.0 mm vs. 12.5 mm), shortened unfolding time, and texture processing of the surface of haptics. Data from 193 eyes of 165 patients (76.4 ± 8.3 years old) with preoperative corneal astigmatism exceeding 0.75 diopters who had undergone phacoemulsification and toric IOL implantation were collected and analyzed. Corneal astigmatism, refractive astigmatism, and uncorrected (UDVA) and corrected distance visual acuity (CDVA) were evaluated before and 1 day, 1 week, and 1 month after surgery. The degree of IOL decentration, IOL tilt, and toric axis misalignment was assessed at 1 day and 1 month postoperatively. Fifty eyes received AcrySof toric IOL, 51 eyes TECNIS toric IOL, 46 eyes HOYA 355 toric IOL, and 46 eyes HOYA XY-1 toric IOL. The amount of axis misalignment from the intended axis was significantly different among IOLs (p = 0.004, one-way ANOVA), and HOYA XY-1 showed significantly less amount of axis misalignment than TECNIS (p = 0.020, Tukey’s multiple comparison) and HOYA 355 (p = 0.010). The proportion of eyes that showed axis misalignment <10° at 1 month postoperatively was significantly higher with HOYA XY-1 toric IOL than with other toric IOLs (χ² test, p = 0.020). HOYA XY-1 toric IOL, the modified version of HOYA 355 toric IOL, showed excellent rotational stability in comparison with other models of toric IOLs.

Iris Registration Capsulotomy Marking Versus Manual Marking for Toric Intraocular Lens Alignment in Cataract Surgery

PURPOSE

To compare the accuracy of toric intraocular lens (IOL) alignment and visual outcomes using femtosecond laser-assisted capsulotomy marking (CM) versus conventional slit lamp-assisted manual marking (MM).

DESIGN

Prospective cohort study.

METHODS

A total of 57 patients who required cataract surgery and toric IOL implantation (Acrysof SN6AT3-T8) were assigned to the CM group (26 eyes) or the MM group (31 eyes). Uncorrected distant visual acuity (UCDVA), best-corrected distant visual acuity (BCDVA), residual astigmatism (RA), IOL misalignment, and modulation transfer function (area ratio [AR] value) were measured 1 and 3 months after surgery.

RESULTS

Postoperative UCDVA (logarithm of minimal angle of resolution [logMAR]) was significantly lower in the CM group than that in the MM group (P < .05). Postoperative RA and IOL misalignment were significantly lower in the CM group than that in the MM group (both P < .05). No significant difference between the groups was observed for BCDVA or AR value (both P > .05). UCDVA (logMAR) was positively correlated with RA (r = 0.339; P < .05) and IOL misalignment (r = 0.317; P < .05) and negatively correlated with the the AR value (r = -0.272; P < .05); RA was positively correlated with IOL misalignment (r = 0.405; P < .05).

CONCLUSIONS

The accuracy of the axis alignment was significantly higher in the CM group, which resulted in lower residual astigmatism and better visual outcomes.

Handling regular and irregular astigmatism during cataract surgery

PURPOSE OF REVIEW

There are several different approaches to handling regular and irregular astigmatism during cataract surgery, but still much debate on which solutions are most effective given unique patient circumstances. In this review, we examine recent literature and studies to highlight some of the most effective ways to plan preoperatively, manage regular and irregular astigmatism during cataract surgery, as well as managing postoperative complications.

RECENT FINDINGS

Recent developments in technology have provided increased courses of action for astigmatism management during cataract surgery. Additional options of toric IOLs with presbyopic platforms, light adjustable lenses, intraocular pinhole lenses, online technological tools and platforms, wavefront or topographic laser technology, and phototherapeutic keratectomy are all effective solutions to managing regular and irregular astigmatism. In this review, we will explore optimal approaches for unique situations.

SUMMARY

With increased technology, research, and methods, correcting regular and irregular astigmatism during cataract surgery is achievable in most patients. With in-depth preoperative planning, analysis of patient-specific factors, and a tailored approach, surgeons can obtain excellent uncorrected vision for patients.

Comparison of the Orientation of the Corneal Steep Meridian Determined by Image-Guided System and Manual Method in the Same Eye

Purpose

To evaluate the difference between the preoperative marking methods for toric intraocular lens (IOL) implantations using an image-guided system (IGS) and the manual marking method in the same eye.

Patients and Methods

In this retrospective case series, 82 patients (101 eyes) who underwent cataract surgery using both manual and IGS (VERION, Alcon  Laboratories) marking were enrolled. First, preoperative reference marks were placed at 6 o’clock and 3 or 9 o’clock position under slit-lamp biomicroscope in the outpatient department using the manual method. Using the reference unit of IGS, the ocular surface data were captured and overlaid. The difference was then measured (preoperative axis misalignment). In the operating room, the orientation of the steep meridian of the manual method was determined based on this reference mark under the surgical microscope. Just before surgery, the digital degree gauge of IGS was overlaid on the ocular surface, and the difference was then measured (total axis misalignment). We calculated the intraoperative axis misalignment by subtracting preoperative axis misalignment from the total axis misalignment.

Results

Mean absolute preoperative, intraoperative, and total axis misalignment values were 3.87±3.95 degrees, 5.46±4.42 degrees, and 4.98±4.49 degrees, respectively. In preoperative, intraoperative, and total misalignment, the ratios of 10 degrees or greater were 10 (14.7%), 12 (17.6%), and 20 (19.8%) eyes, respectively.

Conclusion

The manual method that determines the fixed position of the toric intraocular lens (IOL) may cause large misalignment compared with the IGS, suggesting that using manual method could sometimes result in a large misalignment of toric IOL implantation.

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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.

Clinical outcomes of Ankoris toric intraocular lens implantation using a computer-assisted marker system

PURPOSE

To report the clinical outcomes of patients who underwent cataract surgery with implantation of Ankoris monofocal toric intraocular lens (IOL) (PhysIOL SA, Liège, Belgium) using the Zeiss Callisto Eye (Carl Zeiss AG, Dublin, CA).

METHODS

We conducted a retrospective case series of patients who underwent routine cataract extraction and implantation of Ankoris toric IOL using the Zeiss Callisto eye between January 2018 and December 2018 by four senior surgeons. Patients' medical records were reviewed, and clinical outcomes including postoperative refraction, visual acuity outcomes, IOL position and deviation from planned axis were collected.

RESULTS

Fifty-six eyes of 56 patients were included, 48% were female, and the mean age was 70 ± 8 years. Patients with pseudoexfoliation syndrome, glaucoma or keratoconus were excluded from the study. Pre-operative mean corneal astigmatism was 2.38 ± 0.78 diopters (D), and mean implanted IOL cylindrical power was 3.06 ± 1.07 D. IOL rotation 30 days postoperatively was within 5° in 82% of eyes and between 6° and 10° in 10.8% of eyes. Mean postoperative refractive astigmatism 30 days postoperatively was 0.22 ± 0.36 D; in 84% of eyes the postoperative refractive astigmatism was ≤ 0.50 D. IOL rotation significantly increased between day 1 to day 7 postoperatively (1.91 ± 3.15° to 3.18 ± 3.3°, P = 0.001). However, no significant rotation had occurred between day 7 and day 30 postoperatively (P = 0.093).

CONCLUSION

Cataract surgery with implantation of Ankoris monofocal toric IOL using the Zeiss Callisto Eye marking system is predictable and effective in reducing refractive astigmatism.

Rotational slit-beam marking: an advanced manual corneal astigmatic marking method for toric intraocular lens implantation

PURPOSE

To evaluate the accuracy of an advanced manual corneal astigmatic marking method for toric intraocular lens (IOL) implantation.

METHODS

From 52 patients, 52 eyes with cataracts and corneal astigmatism were included. The target axis of the toric IOL was marked with the new manual marking method preoperatively and with the Zeiss CALLISTO Eye image-guided system intraoperatively. For the manual method, a slit-lamp with a minimum rotation angle of 5 degrees was used and rotated to the meridian of the toric IOL and incision axes. The relative rotational and vertical deviation of the IOL and incision axes were measured using the digital marker as a reference.

RESULTS

There was no significant difference between the manually marked IOL axis (100.9° ± 65.62°) and the digital mark (100.8° ± 65.76°; P = 0.771). The absolute values of the relative rotational and vertical deviations of the manually marked IOL axis were small, at 2.03° ± 1.44° and 0.46 ± 0.43 mm, respectively. There was no significant difference between the manually marked corneal incision and the digital meridian (P = 0.179). Then, patients were classified into three groups based on the type of astigmatism they had. There was no significant difference in mean absolute deviation among the groups (P = 0.112). The manual incision mark had a relative rotational deviation of 1.65° ± 1.44°. The vertical misalignment of the manually marked incision axis was 0.27 ± 0.30 mm.

CONCLUSION

Rotational slit-beam marking could be an effective and convenient marking method for toric IOL implantation. This method could be a potential alternative in underdeveloped areas where digital image-guided systems are not available.

Optical tolerance to rotation of trifocal toric intraocular lenses as a function of the cylinder power

BACKGROUND

The aim was to assess the impact of 5- and 10-degree rotations in the optical quality of a trifocal toric intraocular lens with different amounts of cylinder.

METHODS

Two Physiol Toric intraocular lenses with 1.5 and 3.0 D of cylinder were analysed in three different positions: centred, 5 and 10 degrees rotated. The optical quality of the intraocular lenses was evaluated with the PMTF optical bench through specific perpendicular targets. The analysis was performed by the through-focus modulation transfer function curves and the modulation transfer function corresponding to distance vision (0 D of vergence).

RESULTS

For a centred situation, the through-focus modulation transfer function curves of both intraocular lenses showed the classical three peaks corresponding to the powers of the two principal meridians of the intraocular lenses. When 5 and 10 degrees of rotation were induced, the three peaks were attenuated in both cases. The case with the intraocular lens with 3.0 D of cylinder and 10 degrees of rotation showed the worst optical quality and a significant loss of trifocality. The modulation transfer function values obtained for distance vision also showed the worst optical quality for the intraocular lens with 3.0 D of cylinder and 10 degrees of rotation.

CONCLUSION

Rotations over 5 degrees decreased the optical quality of trifocal toric intraocular lenses, being this reduction moderate from 5 to 10 degrees for low levels of cylinder (≤1.5 D). For mid-high levels of cylinder (≥3.0 D), rotations over 5 degrees cause a significant loss of optical quality at all object distances.