Higher order aberrations according to spherical, and astigmatic refractive errors in children

CLINICAL RELEVANCE

The results of this study present novel insights into the impact of spherical and astigmatic refractive errors on overall, corneal and internal aberrations and may provide a clear understanding of the emmetropisation process and the development of visual function.

BACKGROUND

This study aimed to assess the association between overall, corneal and internal higher-order aberrations and the spherical and astigmatic components (magnitude and angle) of refractive error in a large sample of children.

METHODS

A total of 311 children aged 7 - 8 years old were classified based on spherical equivalent refraction (myopic, emmetropic and hyperopic); magnitude of astigmatism (none, low and moderate); and angle of astigmatism (with-the-rule, against-the-rule and oblique). Refractive error and overall, corneal and internal higher-order aberrations were measured using the OPD-Scan III workstation.

RESULTS

Regarding spherical equivalent refraction, myopic eyes had greater root mean square (RMS) overall higher-order values, total spherical, tetrafoil and secondary astigmatism aberrations, and internal higher-order, total spherical and tetrafoil aberrations in comparison to emmetropic eyes. The magnitude of astigmatism was positively associated with all overall RMS aberrations and with internal higher order, coma, total coma, total spherical and tetrafoil aberrations. Eyes with with-the-rule astigmatism showed higher RMS values of coma and total coma compared to eyes with against-the-rule and oblique astigmatism.

CONCLUSIONS

Higher-order aberrations are dependent on the spherical as well as astigmatic components of refractive error. These findings enhance the current understanding of the emmetropisation process and visual function development.

Incidence and analysis of intraoperative complications in femtosecond laser-assisted cataract surgery: a large-scale cohort study to establish the learning curve

AIMS

To assess the safety of femtosecond laser-assisted cataract surgery (FLACS) based on surgical parameters and intraoperative complications analysis and to determine the length of the learning curve for FLACS.

METHODS

A prospective consecutive cohort study was conducted on Chinese patients who underwent either FLACS (3289 cases) or contemporaneous conventional phacoemulsification cataract surgery (2130 cases). The laser group was divided into four subgroups in chronological order. We recorded intraoperative complication incidences and compared with surgical parameters between groups. Subgroup analysis was conducted to explore the learning curve of FLACS.

RESULTS

The laser group had a 4.93% incidence of incomplete capsulotomies and a 1.22% incidence of anterior capsule tears. Subgroup analysis showed significant differences in 8 aspects between the first 250 cases (50 cases per surgeon) and the last 2539 cases, but only 2 aspects differed between the second 250 cases (50 cases per surgeon) and the last 2539 cases. There were no significant differences between the third 250 cases (50 cases per surgeon) and the last 2539 cases.

CONCLUSIONS

The intraoperative complications of FLACS were reported, and the learning curve is associated with a significant reduction in the incidence of intraoperative complications. The length of the basic learning curve of FLACS is 100 cases, and the length of the advanced learning curve was 150 cases. This study demonstrated that FLACS is characterised by a relatively straightforward and secure operative technique.

Assessment of intraocular lens tilt and decentration after femtosecond laser-assisted and conventional cataract surgery at 12 months and beyond

PURPOSE

To compare long-term intraocular lens (IOL) decentration and tilt following femtosecond laser-assisted cataract surgery (FLACS) and conventional surgery using swept-source anterior segment ocular coherence tomography (SS-ASOCT).

METHODS

In this retrospective cross-sectional study, all patients underwent FLACS or conventional cataract surgery. Those with a minimum of 12-months follow-up since surgery were included. Patients with surgical complications were excluded. Demographics, preoperative ocular measurements (axial length, anterior chamber depth), and postoperative measurements [corrected distance visual acuity (CDVA), autorefraction, keratometry, IOL type] were collected. Postoperative IOL tilt and decentration were compared using SS-ASOCT between patients with FLACS and conventional cataract surgery. Subgroup analysis was conducted to analyze tilt and decentration by haptic type (single-piece vs. three-piece).

RESULTS

A total of 188 eyes were included [110 (58.5%) in the FLACS group and 78 (41.5%) in the conventional group]. No differences were observed between the FLACS and conventional groups regarding preoperative parameters. FLACS resulted in less IOL decentration compared to conventional cataract surgery (170 μm vs. 240 μm, p = 0.002). No statistically significant differences were observed between the FLACS and conventional groups in the magnitude and axis of IOL tilt. Both groups had a trend of IOL tilt toward the inferotemporal aspects. Moreover, no difference regarding postoperative CDVA, spherical equivalent, and keratometric astigmatism was observed.

CONCLUSIONS

FLACS resulted in significantly better long-term IOL centration than conventional surgery with manual capsulotomy. No significant difference in IOL tilt or postoperative CDVA was observed between FLACS and conventional cataract surgery.

Comparative analysis of changes in retinal layer thickness following femtosecond laser-assisted cataract surgery and conventional cataract surgery

BACKGROUND

To investigate the influence of femtosecond laser-assisted cataract surgery (FLACS) on macula by examining changes in retinal layers after FLACS and to compare these changes with those after conventional cataract surgery (CCS).

METHODS

This study included 113 unrelated Korean patients with age-related cataract who underwent CCS or FLACS in Severance Hospital between September 2019 and July 2021. Optical coherence tomography was performed before and 1 month after surgery. The total retinal layer (TRL) was separated into the inner retinal layer (IRL) and outer retinal layer (ORL); moreover, the IRL was subdivided into the retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer (INL), outer plexiform layer, and outer nuclear layer. We performed between-group comparisons of the postoperative thickness in each retinal layer and the postoperative differences in retinal thickness. The average retinal thickness of the four inner macular ring quadrants was used for comparative analysis.

RESULTS

Compared with the CCS group, the FLACS group exhibited a thicker ORL (P = 0.004) and a thinner INL (P = 0.007) after surgery. All retinal layer thickness values showed significant postoperative changes regardless of the type of surgery (P < 0.05). The postoperative increase in TRL and IRL thickness was significantly smaller in the FLACS group than in the CCS group (P = 0.027, P = 0.012).

CONCLUSIONS

The 1-month postoperative retinal changes were less pronounced in the FLACS group than in the CCS group.

Comparison of short-term clinical outcomes of a diffractive trifocal intraocular lens with phacoemulsification and femtosecond laser assisted cataract surgery

PURPOSE

To evaluate short-term visual and refractive outcomes after implantation of a diffractive trifocal intraocular lens (IOL) in cataract patients with phacoemulsification (PHACO) and femtosecond laser assisted cataract surgery (FLACS).

SETTING

Department of Ophthalmology, Shanghai Aier Eye Hospital, China.

DESIGN

A retrospective, observational study.

METHODS

Patients who underwent cataract surgery combined with Acrysoft IQ PanOptix trifocal IOL implantation were enrolled and divided into three groups: PHACO group, LAstig-FLACS group (astigmatism less then 1D) and HAstig-FLACS group (astigmatism more than 1D). Logarithm of the minimum angle of resolution (logMAR) visual acuity of uncorrected distance (UDVA), intermediate (UIVA), near visual (UNVA), defocus curve, surgically induced astigmatism (SIA) were evaluated in 1 months postoperatively and wavefront aberrations were evaluated in 6 months.

RESULTS

101 eyes of 60 patients were included with 31 eyes in PHACO group, 45 eyes in LAstig-FLACS group and 25 eyes in HAstig-FLACS group. Significant difference was found of internal Strehl Ratio (SR) between PHACO and LAstig-FLACS group (P = 0.026). In PHACO group, 79.31%, 86.21%, 72.41% of eyes gain visual acuity LogMAR 0.1 or more in UDVA, UIVA and UNVA, while 83.72%, 93.02%, 93.02% of those in LAstig-FLACS group and 92.00%, 84.00%, 76.00% in HAstig-FLACS group.

CONCLUSIONS

Panoptix diffractive trifocal IOL provides satisfied visual outcome in no matter FLACS or PHACO. Besides, trifocal IOL implantation via FLACS can provide a better accumulative visual acuity outcome at all distance than PHACO in 1 month. Femtosecond laser assisted limbal relaxing incisions (FLLRIs) is an excellent way to reduce a patient's corneal astigmatism.

Intraocular pressure changes before and after a femtosecond laser procedure for cataract surgery

This study aimed to evaluate the changes in intraocular pressure (IOP) before and after femtosecond laser capsulorhexis and lens fragmentation for cataract surgery. We measured the IOP before, immediately, 30 min, and 1 h after the laser procedure in 47 eyes of 47 patients who underwent the femtosecond laser procedure. The mean IOP was 17.51 ± 3.28 mmHg, 30.23 ± 6.70 mmHg, 17.96 ± 3.75 mmHg, and 21.77 ± 5.88 mmHg before, immediately after, 30 min after, and 1 h after the laser procedure, respectively. The mean IOP significantly increased immediately (adjusted P < 0.001) and 1 h (adjusted P = 0.001) after the laser procedure compared with the pre-laser IOP. The mean IOP at 30 min after the laser procedure was significantly lower than that immediately after the procedure (adjusted P < 0.001). However, the IOP 1 h after the laser procedure became higher than that 30 min after the laser procedure. Additionally, the IOP 1 h after the laser procedure was positively correlated with the baseline IOP and negatively correlated with the axial length. In conclusion, this study demonstrated that cataract surgery should be commenced within 30 min after the femtosecond laser procedure to ensure a safe cataract surgery that reduces the risk of increased intraocular pressure.

Application of Femtosecond Laser in Challenging Cataract Cases

Femtosecond laser can provide precise and customized incision of ocular tissue with excellent accuracy and predictability. Thus, femtosecond laser-assisted cataract surgery (FLACS) can theoretically enhance the safety and efficacy of cataract surgery by providing reproducible and reliable clear corneal incision, limbal relaxing incision, anterior capsulotomy, and lens fragmentation. However, thus far, the superiority of the anatomical and visual outcomes of FLACS over those of conventional cataract surgery have been unclear. Nevertheless, studies have indicated that FLACS can potentially be helpful in improving the safety of cataract surgery in challenging situations, such as zonular weakness, preexisting capsular tear, white cataract, shallow anterior chamber, and pediatric cataracts, which may contribute to enhanced visual and anatomical outcomes. In this review, we provide a summary of the application of femtosecond laser in general cataract cases. In addition, we introduce the application of FLACS in the abovementioned challenging situations and discuss the results of studies regarding the safety and outcome of FLACS in these challenging cases.

Laser-assisted cataract surgery versus standard ultrasound phacoemulsification cataract surgery

BACKGROUND

Cataract is the leading cause of blindness in the world and, as such, cataract surgery is one of the most commonly performed operations globally. Surgical techniques have changed dramatically over the past half century with associated improvements in outcomes and safety. Femtosecond lasers can be used to perform the key steps in cataract surgery, such as corneal incisions, lens capsulotomy and fragmentation. The potential advantage of femtosecond laser-assisted cataract surgery (FLACS) is greater precision and reproducibility of these steps compared to manual techniques. The disadvantages are the costs associated with FLACS technology.

OBJECTIVES

To compare the effectiveness and safety of FLACS with standard ultrasound phacoemulsification cataract surgery (PCS) by gathering evidence from randomised controlled trials (RCTs).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 5); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov; the WHO ICTRP and the US Food and Drug Administration (FDA) website. We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 May 2022.

SELECTION CRITERIA

We included RCTs where FLACS was compared to PCS.

DATA COLLECTION AND ANALYSIS

Three review authors independently screened the search results, assessed risk of bias and extracted data using the standard methodological procedures expected by Cochrane. The primary outcome for this review was intraoperative complications in the operated eye, namely anterior capsule, and posterior capsule tears. The secondary outcomes included corrected distance visual acuity (CDVA), quality of vision (as measured by any validated patient-reported outcome measure (PROM)), postoperative cystoid macular oedema complications, endothelial cell loss and cost-effectiveness. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 42 RCTs conducted in Europe, North America, South America and Asia, which enrolled a total of 7298 eyes of 5831 adult participants. Overall, the studies were at unclear or high risk of bias. In 16 studies the authors reported financial links with the manufacturer of the laser platform evaluated in their studies. Thirteen of the studies were within-person (paired-eye) studies with one eye allocated to one procedure and the other eye allocated to the other procedure. These studies were reported ignoring the paired nature of the data. There was low-certainty evidence of little or no difference in the odds of developing anterior capsular tears when comparing FLACS and PCS (Peto odds ratio (OR) 0.83, 95% confidence interval (CI) 0.40 to 1.72; 5835 eyes, 27 studies) There was one fewer anterior capsule tear per 1000 operations in the FLACS group compared with the PCS group (95% CI 4 fewer to 3 more).  There was low-certainty evidence of lower odds of developing posterior capsular tears with FLACS compared to PCS (Peto OR 0.50, 95% CI 0.25 to 1.00; 5767 eyes, 26 studies). There were four fewer posterior capsule tears per 1000 operations in the FLACS group compared with the PCS group (95% CI 6 fewer to same).  There was moderate-certainty evidence of a very small advantage for the FLACS arm with regard to CDVA at six months or more follow-up, (mean difference (MD) -0.01 logMAR, 95% CI -0.02 to 0.00; 1323 eyes, 7 studies). This difference is equivalent to 1 logMAR letter between groups and is not thought to be clinically important. From the three studies (1205 participants) reporting a variety of PROMs (Cat-PROMS, EQ-5D, EQ-SD-3L, Catquest9-SF and patient survey) up to three months following surgery, there was moderate-certainty evidence of little or no difference in the various parameters between the two treatment arms. There was low-certainty evidence of little or no difference in the odds of developing cystoid macular oedema when comparing FLACS and PCS (Peto OR 0.84, 95% CI 0.56 to 1.28; 4441 eyes, 18 studies). There were three fewer cystoid macular oedema cases per 1000 operations in the FLACS group compared with the PCS group (95% CI 10 fewer to 6 more).  In one study the incremental cost-effectiveness ratio (ICER) (cost difference divided by quality-adjusted life year (QALY) difference) was GBP £167,620 when comparing FLACS to PCS. In another study, the ICER was EUR €10,703 saved per additional patient who had treatment success with PCS compared to FLACS. Duration ranged from three minutes in favour of FLACS to eight minutes in favour of PCS (I2 = 100%, 11 studies) (low-certainty evidence).  There was low-certainty evidence of little or no important difference in endothelial cell loss when comparing FLACS with PCS (MD 12 cells per mm2 in favour of FLACS, 95% CI -40 to 64; 1512 eyes, 10 studies).  AUTHORS' CONCLUSIONS: This review of 42 studies provides evidence that there is probably little or no difference between FLACS and PCS in terms of intraoperative and postoperative complications, postoperative visual acuity and quality of life. Evidence from two studies suggests that FLACS may be the less cost-effective option. Many of the included studies only investigated very specific outcome measures such as effective phacoemulsification time, endothelial cell count change or aqueous flare, rather than those directly related to patient outcomes. Standardised reporting of complications and visual and refractive outcomes for cataract surgery would facilitate future synthesis, and guidance on this has been recently published.

Femtosecond Laser-Assisted Cataract Surgery versus Conventional Phacoemulsification Surgery: Clinical Outcomes with EDOF IOLs

In this study, we evaluate and compare the outcomes of conventional phacoemulsification cataract surgery (CPS) and femtosecond laser-assisted cataract surgery (FLACS) with the implantation of an extended depth of field (EDOF) intraocular lens (IOL). A prospective, consecutive cohort study was conducted. Patients were given the option to choose FLACS or CPS and were implanted with an EDOF IOL. Refractive data, visual acuity data, ocular aberration measured with a wavefront aberrometer, and optical quality measured with an optical quality analysis system II were collected at one month postoperatively. A total of 92 eyes of 64 patients were enrolled in this study; 35 eyes of 26 patients were treated with FLACS, whereas 57 eyes of 38 patients were treated with CPS. Uncorrected visual acuity at far, intermediate, and near distance and best-spectacle-corrected visual acuity were not statistically significantly different between the groups (all p > 0.05), nor were the mean cylinder and mean spherical equivalent refraction (both p > 0.05). The FLACS group had a lower ocular trefoil than the CPS group (p = 0.033), and there was no significant difference between the two groups considering other aberration parameters, whether ocular or internal (all p > 0.05). Optical-quality-related parameters showed also no significant difference between the two groups (all p > 0.05). In conclusion, there was no significant difference between FLACS and CPS with implantation of EDOF IOLs in postoperative ocular parameters, refractive outcomes, ocular aberration, optical quality, and aberration parameters, except a lower ocular trefoil in the FLACS group. In terms of these indicators, FLACS does not provide an additional clinical benefit for patients over CPS.

FLACS vs conventional phacoemulsification by junior cataract surgeons: randomized trial

PURPOSE

To report intraoperative performance and postoperative outcomes of femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification (PE) in the hands of junior surgeons.

SETTING

Iladevi Cataract & IOL Research Centre, Ahmedabad, Gujarat, India.

DESIGN

Prospective single-masked randomized controlled trial.

METHODS

320 eyes (320 patients) undergoing cataract surgery for uneventful cataracts in the hands of junior surgeons were randomized to Group 1-FLACS or Group 2-PE. Intraoperatively, cumulative dissipated energy (CDE) and fluid used were compared. Postoperatively, the following were compared: central corneal thickness (CCT) on day 1, 1 week, and 1 month; corneal clarity (day 1 and 1 week); anterior chamber inflammation (day 1 and 1 week); change in endothelial cell density (ECD) at 6 months postoperatively; and corrected distance visual acuity (CDVA) at 1 week and 1 month postoperatively.

RESULTS

157 and 158 patients in groups 1 and 2 analysed. Intraoperatively, CDE (5.41 ± 2.73 vs 8.83 ± 4.28 in Groups 1 and 2, P = .0001) and fluid used (79.33 ± 33.46 vs 101.82 ± 32.23 mL in Groups 1 and 2, P < .0001) were significantly lesser in Group 1. CCT was significantly higher in Group 2 on day 1 (550.96 ± 33.64 vs 587.70 ± 55.76 μm in Groups 1 and 2, P < .0001) and at 1 week postoperatively (527.94 ± 30.78 vs 545.11 ± 35.17 μm in Groups 1 and 2, P = .001). 72% of eyes had clear corneas on day 1 in Group 1 compared with 39% in Group 2 ( P = .01). Anterior chamber inflammation and CDVA were comparable. Change in ECD was significantly lower (9.3%) in Group 1 vs 12.7% in Group 2, P < .0001.

CONCLUSIONS

FLACS showed lower intraoperative CDE, fluid usage, lesser increase in CCT, better early postoperative corneal clarity, and lesser change in ECD at 6 months postoperatively in the hands of junior surgeons during standard cataract surgery.

Comparative visual outcomes of EDOF intraocular lens with FLACS vs conventional phacoemulsification

PURPOSE

To investigate the visual quality after femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification surgery (CPS) with the implantation of an extended depth-of-focus (EDOF) intraocular lens (IOL) TECNIS Symfony.

SETTING

Eye Center, the Second Affiliated Hospital of Zhejiang University, Zhejiang, China.

DESIGN

Prospective cohort study.

METHODS

Patients were given the option to choose FLACS or CPS and were implanted with a TECNIS Symfony. Main outcome measures were postoperative examinations that included defocus curves, contrast sensitivity (CS), optic path difference aberrometry scan, anterior segment photography, and questionnaires.

RESULTS

261 patients (261 eyes) were enrolled. The circularity index of FLACS was more precise than that of CPS ( P = .001). FLACS demonstrated a significantly lower IOL decentration ( P = .011) and IOL tilt ( P = .009). FLACS presented a significantly lower total aberration ( P < .001), higher-order aberrations (HOAs) ( P = .001), coma ( P = .001), and spherical aberration ( P < .001). With IOL decentration of more than 0.40 mm, total internal aberration ( P = .023) and HOAs ( P = .045) were significantly deteriorated. As for defocus curve, FLACS was better at -1.00 diopter ( P < .01). The FLACS group achieved higher CS at 6 to 18 cycles per degree under glare condition ( P < .05). With regard to photic phenomena, the FLACS group received better outcomes ( P < .05).

CONCLUSIONS

With the implantation of an EDOF IOL, FLACS could precisely control the shape and size of the capsulotomy and induce a significantly better-centered IOL, leading to higher visual performance compared with CPS.

Femtosecond laser-assisted cataract surgery after corneal refractive surgery

Cataract is the leading cause of blindness worldwide, and advanced cataract techniques such as femtosecond laser-assisted cataract surgery (FLACS) have been commercially available. Corneal refractive surgery (CRS) is one of the most popular surgeries for the correction of refractive errors. CRS changes the cornea not only anatomically but also pathophysiologically. However, there has been no clinical research analyzing the refractive and safety outcomes of FLACS after CRS. The aim of this retrospective chart review and comparative study is to evaluate the effect and safety of FLACS after CRS comparing with conventional PCS. Participants with a previous CRS history who underwent FLACS or conventional PCS were included in this study. The visual outcomes and the refractive outcomes including refractive, corneal, and ocular residual astigmatism were compared. The safety outcomes were then studied intraoperatively and postoperatively. A total of 102 patients with age-related cataract were enrolled. At 3 months postoperatively, UCVA, BCVA, and predictive error were not significantly different between the FLACS and conventional PCS groups. Reduction of refractive astigmatism was higher in FLACS. Postoperative ORA was significant lower in FLACS. Reduction of ORA was higher in FLACS. The intraoperative and postoperative complications were also not significantly different between the two groups. FLACS could effectively change refractive astigmatism and ORA; without more complications than conventional PCS. FLACS’ competitive edge in postoperative ORA may provide better visual quality than conventional PCS in patients with a previous history of CRS.

[Femtolaser-assisted phacoemulsification of intumescent cataract]

PURPOSE

To optimize the technique of intumescent cataract phacoemulsification by involving the use of femtosecond lasers.

MATERIAL AND METHODS

Group 1 included 29 patients (30 eyes) with mature intumescent cataract, who underwent femtolaser-assisted phacoemulsification using a new, optimized technique. Group 2 included 20 patients (20 eyes), in whom the femtolaser stage was performed using the standard technique. Patients of groups 1 and 2 were almost identical in all preoperative parameters. The optimized femto-capsulorhexis technique included: preoperative assessment of intralenticular pressure, staining of the anterior capsule of the swelling lens with trypan blue, introduction of a viscoelastic with high molecular weight into the anterior chamber to balance intraocular and intralenticular pressures, increasing the laser energy when performing anterior capsulorhexis up to 10 mJ.

RESULTS

In group 1, there was a non-penetration of the anterior capsule in 2 eyes, in one of them in the 30° sector, in the second - in the 45° sector. Leakage of lens material into the anterior chamber and the floating anterior capsule were not observed in patients of group 1. In group 2, non-penetration of the anterior capsule was observed in 6 eyes, in the 45-60° sector - in 2 eyes, in the 90° sector - in 3 eyes, in the 180° sector - in 1 eye. Floating anterior capsule was observed in 5 cases. Leakage of lens material into the anterior chamber was observed in 9 eyes.

CONCLUSION

The optimized technique of femtolaser-assisted intumescent cataract phacoemulsification eliminates leakage of lens material into the anterior chamber and allows performing anterior capsulorhexis of given size and shape.

Measurement of tear resistance after manual capsulorhexis and femtosecond laser-assisted capsulotomy of crystalline lenses

Background

In this study, the tear resistance of porcine lens capsules after continuous curvilinear capsulorhexis (CCC) and femtosecond (fs)-laser-assisted capsulotomy for cataract surgery (FLC) with different laser parameters is measured with a custom-made testing setup.

Methods

Forty-five fresh porcine lenses were randomly chosen for CCC (n = 15) or FLC 1 (n = 15) and FLC 2 (n = 15). The FLC 1-group was treated with smaller spot distances than the FLC 2-group. The force necessary to break the opening of the anterior capsule and the maximum displacement were measured.

Results

The mean tear resistance of the CCC-group (150 ± 70 mN) was higher than that of the FLC 1-group (60 ± 20 mN) and the FLC 2-group (30 ± 20 mN).

Conclusion

It could be shown that CCC leads to a significantly higher tear resistance of the opening than FLC in porcine lenses. The femtosecond laser group demonstrated that smaller spot distances lead to a higher tear resistance.

Femtosecond laser-assisted cataract surgery versus conventional phacoemulsification: comparison of internal aberrations and visual quality

PURPOSE

To compare the internal aberrations and optical quality after femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification cataract surgery (CPCS).

METHODS

This study included patients who received FLACS or CPCS from January 2016 to July 2019. Postoperative examinations included wavefront measurements under pupil diameters of 3.0 mm and 5.0 mm, intraocular lens (IOL) decentration, visual acuity (VA), and refractive outcomes. Visual quality was measured with Strehl ratio and modulation transfer function (MTF). Subgroup analyses were conducted based on monofocal or multifocal-extended depth of focus (EDOF) IOL.

RESULTS

The study consisted of 221 eyes (105 eyes in FLACS and 116 eyes in CPCS). With a pupil diameter of 5.0 mm, FLACS demonstrated a significantly lower root mean square of total internal aberration (P = 0.004), higher order aberrations (HOAs) (P = 0.034), tilt (P = 0.049), coma (P = 0.004), and spherical aberration (P = 0.014). IOL tilt was found to be positively correlated with total internal aberration (P < 0.001), HOAs (P < 0.001), and coma (P < 0.001). The FLACS group presented significantly smaller IOL decentration than the CPCS group (P < 0.001), but there were no significant differences in terms of VA and refractive outcomes between groups. In the multifocal-EDOF subgroup, Strehl ratio and MTF values were significantly higher in the femtosecond group with a 3.0-mm pupil.

CONCLUSION

FLACS induced significantly lower values of IOL tilt, decentration, and internal aberrations compared with the CPCS group with a pupil diameter of 5.0 mm, while no significant differences were found in the VA or optical quality over long-term observation.

TRIAL REGISTRATION

This trial was registered at www.chictr.org.cn (registration number ChiCTR2000038965).

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.

Prospective comparison of apex-centered vs standard pupil-centered femtosecond laser-assisted capsulotomy in cataract surgery

PURPOSE

To compare the lens tilt after apex-centered capsulotomy with standard pupil-centered capsulotomy.

SETTING

Clinical practice.

DESIGN

Prospective, randomized, investigator-masked trial.

METHODS

This prospective, randomized, investigator masked study included 40 patients with age-related cataract scheduled for femtosecond laser-assisted cataract surgery (FLACS) in both eyes. The main outcome was the tilt of the intraocular lens (IOL), measured with the IOLMaster 700.

RESULTS

The study enrolled 80 eyes of 40 patients. The mean distance from the center of the apex-centered capsulotomy to the pupil-centered capsulotomy was 175.8 ± 97.2 μm. The amount of IOL tilt was not significantly reduced with the new technique (P > .05). Tilt orientation was more stable in eyes treated with apex-centered capsulotomy.

CONCLUSIONS

Centration of the capsulotomy on the lens apex in FLACS does not influence the amount of IOL tilt but the orientation stability. The clinical importance of this finding has to be further elucidated.

Femtosecond laser-assisted cataract surgery compared with phacoemulsification cataract surgery: randomized noninferiority trial with 1-year outcomes

PURPOSE

To report the 1-year outcomes of a randomized trial comparing femtosecond laser-assisted cataract surgery (FLACS) and phacoemulsification cataract surgery (PCS).

SETTING

Moorfields Eye Hospital, New Cross Hospital, and Sussex Eye Hospital, United Kingdom.

DESIGN

Multicenter, randomized controlled noninferiority trial.

METHODS

Patients undergoing cataract surgery were randomized to FLACS or PCS. Postoperative assessments were masked. Outcomes included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), complications, corneal endothelial cell count, and patient-reported outcomes measures.

RESULTS

The study enrolled 785 participants. A total of 311 of 392 (79%) participants were allocated to FLACS and 292 of 393 (74%) participants were allocated to PCS attended follow-up at 1 year. Mean UDVA was 0.14 (SD = 0.22) for FLACS and 0.17 (0.25) for PCS with difference of -0.03 logarithm of the minimum angle of resolution (logMAR) (95%, -0.06 to 0.01, P = .17). Mean CDVA was 0.003 (0.18) for FLACS and 0.03 (0.23) for PCS with difference of -0.03 logMAR (95% CI, -0.06 to 0.01, P = .11); 75% of both FLACS (230/307) and PCS (218/290) cases were within ±0.5 diopters (D) refractive target, and 292 (95%) of 307 eyes of FLACS and 279 (96%) of 290 eyes of PCS groups were within ±1.0 D. There were no significant differences between arms for all other outcomes with the exception of binocular CDVA mean difference -0.02 (-0.05 to 0.002) logMAR (P = .036) favoring FLACS. Mean cost difference was £167.62 per patient greater for FLACS (95% iterations between -£14.12 and £341.67).

CONCLUSIONS

PCS is not inferior to FLACS regarding vision, patient-reported health, and safety outcomes after 1-year follow-up. A difference was found for binocular CDVA, which, although statistically significant, was not clinically important. FLACS was not cost-effective.

Femtosecond laser-assisted cataract surgery compared with phacoemulsification: the FACT non-inferiority RCT

BACKGROUND

Cataract surgery is one of the most common operations. Femtosecond laser-assisted cataract surgery (FLACS) is a technique that automates a number of operative steps.

OBJECTIVES

To compare FLACS with phacoemulsification cataract surgery (PCS).

DESIGN

Multicentre, outcome-masked, randomised controlled non-inferiority trial.

SETTING

Three collaborating NHS hospitals.

PARTICIPANTS

A total of 785 patients with age-related cataract in one or both eyes were randomised between May 2015 and September 2017.

INTERVENTION

FLACS (n = 392 participants) or PCS (n = 393 participants).

MAIN OUTCOME MEASURES

The primary outcome was uncorrected distance visual acuity in the study eye after 3 months, expressed as the logarithm of the minimum angle of resolution (logMAR): 0.00 logMAR (or 6/6 if expressed in Snellen) is normal (good visual acuity). Secondary outcomes included corrected distance visual acuity, refractive outcomes (within 0.5 dioptre and 1.0 dioptre of target), safety and patient-reported outcome measures at 3 and 12 months, and resource use. All trial follow-ups were performed by optometrists who were masked to the trial intervention.

RESULTS

A total of 353 (90%) participants allocated to the FLACS arm and 317 (81%) participants allocated to the PCS arm attended follow-up at 3 months. The mean uncorrected distance visual acuity was similar in both treatment arms [0.13 logMAR, standard deviation 0.23 logMAR, for FLACS, vs. 0.14 logMAR, standard deviation 0.27 logMAR, for PCS, with a difference of -0.01 logMAR (95% confidence interval -0.05 to 0.03 logMAR; p = 0.63)]. The mean corrected distance visual acuity values were again similar in both treatment arms (-0.01 logMAR, standard deviation 0.19 logMAR FLACS vs. 0.01 logMAR, standard deviation 0.21 logMAR PCS; p = 0.34). There were two posterior capsule tears in the PCS arm. There were no significant differences between the treatment arms for any secondary outcome at 3 months. At 12 months, the mean uncorrected distance visual acuity was 0.14 logMAR (standard deviation 0.22 logMAR) for FLACS and 0.17 logMAR (standard deviation 0.25 logMAR) for PCS, with a difference between the treatment arms of -0.03 logMAR (95% confidence interval -0.06 to 0.01 logMAR; p = 0.17). The mean corrected distance visual acuity was 0.003 logMAR (standard deviation 0.18 logMAR) for FLACS and 0.03 logMAR (standard deviation 0.23 logMAR) for PCS, with a difference of -0.03 logMAR (95% confidence interval -0.06 to 0.01 logMAR; p = 0.11). There were no significant differences between the arms for any other outcomes, with the exception of the mean binocular corrected distance visual acuity with a difference of -0.02 logMAR (95% confidence interval -0.05 to 0.00 logMAR) (p = 0.036), which favoured FLACS. There were no significant differences between the arms for any health, social care or societal costs. For the economic evaluation, the mean cost difference was £167.62 per patient higher for FLACS (95% of iterations between -£14.12 and £341.67) than for PCS. The mean QALY difference (FLACS minus PCS) was 0.001 (95% of iterations between -0.011 and 0.015), which equates to an incremental cost-effectiveness ratio (cost difference divided by QALY difference) of £167,620.

LIMITATIONS

Although the measurement of outcomes was carried out by optometrists who were masked to the treatment arm, the participants were not masked.

CONCLUSIONS

The evidence suggests that FLACS is not inferior to PCS in terms of vision after 3 months' follow-up, and there were no significant differences in patient-reported health and safety outcomes after 12 months' follow-up. In addition, the statistically significant difference in binocular corrected distance visual acuity was not clinically significant. FLACS is not cost-effective.

FUTURE WORK

To explore the possible differences in vision in patients without ocular co-pathology.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN77602616.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 6. See the NIHR Journals Library website for further project information. Moorfields Eye Charity (grant references GR000233 and GR000449 for the endothelial cell counter and femtosecond laser used).

Comparison of Femtosecond Laser-Assisted Cataract Surgery and Conventional Phacoemulsification in Shallow Anterior Chambers and Glaucoma

Purpose

To compare femtosecond laser-assisted cataract surgery (FLACS) versus conventional phacoemulsification in shallow anterior chamber cataract patients with glaucoma or zonulysis.

Methods

This was a single-center retrospective review of cataract surgeries in shallow anterior chamber and glaucoma patients between January 2016 and December 2018 in which a LenSx femtosecond laser was used. The outcome measures included pre- and postoperative uncorrected and corrected distance visual acuity (UDVA and CDVA), intraocular pressure (IOP), endothelial cell density (ECD), endothelial cell loss (ECL), and object scatter index (OSI).

Results

One hundred and six eyes of 106 patients with a mean anterior chamber depth of 1.54 ± 0.51 mm were included in this study. Among them, 26 (23.2%) had zonulysis and 18 eyes had capsular tension ring implantation in general. The percentage of capsular tension ring implantation was statistically significantly lower in the FLACS group (P = 0.027). The UDVA, CDVA, ECD, and IOP were not statistically significant between the two groups at all time points. The postoperative ECL and OSI of the FLACS group was better than those of the conventional group (P < 0.01).

Conclusions

FLACS can reduce ECL and improve visual quality compared to the conventional phacoemulsification in shallow anterior chamber patients. Also, it has the trend of reducing the use of capsular tension rings in subluxated cataracts. It is an ideal choice for patients with complicated cataract such as with shallow anterior chambers, glaucoma, and zonulysis.

Femtosecond laser-assisted cataract surgery in shallow anterior chamber cases

PURPOSE

To assess the effectiveness, safety and predictability of femtosecond laser-assisted cataract surgery (FLACS) in eyes with shallow anterior chamber (AC).

METHODS

This is a prospective consecutive clinical study. All eyes presented an anterior chamber depth (ACD) ≤ 2.1 mm and were submitted to FLACS with monofocal intraocular lens (mIOL) or trifocal intraocular lens (tIOL) implantation. Uncorrected distance visual acuity (VA) and corrected distance VA values were used to assess efficacy and safety of the surgery. Refraction, intraocular pressure (IOP), endothelial cell density (ECD) and ACD were evaluated before and 6 months post-surgery.

RESULTS

Phacoemulsification was carried out successfully in all eyes, without intra- or postoperative complications. Efficacy and safety indexes were 0.96 and 1.26 for the mIOL group, and 0.87 and 1.01 for the tIOL group, respectively. The mean postoperative spherical equivalent was - 0.06 ± 0.28D and - 0.14 ± 0.38D for the mIOL and tIOL groups, respectively. The ECD varied from 2470 ± 483 to 2009 ± 538 cells/mm² (p < 0.05) and from 2443 ± 319 to 2245 ± 628 cells/mm² (p = 0.06) for the mIOL and tIOL groups, respectively. IOP significantly decreased (p < 0.05) after the surgery from 14.34 to 12.85 mmHg for the mIOL group and from 14.37 to 11.91 mmHg for the tIOL group, with a general reduction of medical hypotensive treatment in both groups (85% of cases required ≤ number of medications). ACD changed significantly (p < 0.05) from 1.96 ± 0.15 mm to 3.75 ± 0.30 mm after the surgery in the mIOL group and from 1.94 ± 0.15 mm to 3.23 ± 0.21 mm for the tIOL group.

CONCLUSION

FLACS with implantation of either mIOL or tIOL may provide good efficacy, safety and predictability in eyes with shallow AC.

[Correction of corneal astigmatism in femtosecond laser-assisted cataract extraction surgery]

PURPOSE

To perform a comparative analysis of clinical and functional results and efficiency of corneal astigmatism correction after femtosecond laser-assisted cataract surgery (FLACS) with implantation of toric intraocular lens (TIOL) and in combination with arcuate keratotomy (FL-AC).

MATERIAL AND METHODS

The examination included 60 patients (60 eyes). The first group consisted of 30 patients (30 eyes) who underwent FLACS with implantation of TIOL (Acrysof IQ Toric, Alcon, U.S.A.); the second group consisted of 30 patients (30 eyes) who underwent FLACS in combination with FL-AC. The examination was carried out before the operation, on the 3^rd day and 3 months after surgery. Corneal astigmatism correction efficiency was analyzed using the Alpins method and graphical vector analysis.

RESULTS

Uncorrected visual acuity (UCVA) indices increased to 0.70±0.24 and 0.66±0.31 in the FLACS with TIOL and FLACS with FL-AC groups, respectively, without statistically significant differences between the groups (p=0.03). The value of the residual cylinder was significantly lower in the FLACS with TIOL group (-0.77±0.58 and -0.80±0.39) compared with FLACS with FL-AC (-1.08±0.81 and -1.18±0.63) both on day 3 (p=0.02), and 3 months after surgery (p=0.02). In the FLACS with TIOL group, a higher correction index (0.99±0.18) and a smaller difference vector (0.77±0.64) were achieved compared to the FLACS with FL-AC group (0.78±0.35 and 1.05±0.76, respectively). Corneal higher-order aberrations (HOA) significantly differed on the 3^rd day after surgery in the 3.0 mm (p=0.04) and 5.0 mm (p=0.04) zones between the groups. Endothelial cells density was 2460.50±328.40 and 2526.125±196.74 cl/mm² after 3 months of observation in the FLACS with TIOL and FLACS with FL-AC groups, respectively (p=0.61).

CONCLUSION

Both methods had comparable visual acuity results (p=0.03). FLACS with TIOL provided more effective correction of the cylindrical component of refraction to 3.0 D.

Application of Femtosecond Laser in Anterior Segment Surgery

Femtosecond laser (FSL) is a near-infrared laser that can create reliable and reproducible tissue cutting with minimal damage to adjacent tissue. As the laser can also create incisions with various orientations, depths, and shapes, it is expected to be a useful tool for anterior segment surgery, such as cornea, refractive, and cataract surgery. In this review, the authors will introduce the application of FSL in various anterior segment surgeries and discuss the results of studies regarding the efficacy and safety of FSL in cornea, refractive, and cataract surgery. Experimental studies regarding the potential use of FSL will also be introduced. The studies discussed in this review suggest that FSL may be a useful tool for improving the prognosis and safety of surgeries of the anterior segment.

Femtosecond Laser-Assisted Cataract Surgery Versus Phacoemulsification Cataract Surgery (FACT): A Randomized Noninferiority Trial

Purpose

To report the 3-month results of a randomized trial (Femtosecond Laser-Assisted Cataract Trial [FACT]) comparing femtosecond laser-assisted cataract surgery (FLACS) with standard phacoemulsification cataract surgery (PCS).

Design

Multicenter, randomized controlled trial funded by the UK National Institute of Health Research (HTA 13/04/46/).

Participants

Seven hundred eighty-five patients with age-related cataract.

Methods

This trial took place in 3 hospitals in the UK National Health Service (NHS). Randomization (1:1) was stratified by site, surgeon, and 1 or both eyes eligible using a secure web-based system. Postoperative assessments were masked to the allocated intervention. The primary outcome was unaided distance visual acuity (UDVA) in the study eye at 3 months. Secondary outcomes included corrected distance visual acuity, complications, and patient-reported outcomes measures. The noninferiority margin was 0.1 logarithm of the minimum angle of resolution (logMAR). ISRCTN.com registry, number ISRCTN77602616.

Main Outcome Measures

We enrolled 785 participants between May 2015 and September 2017 and randomly assigned 392 to FLACS and 393 to PCS. At 3 months postoperatively, mean UDVA difference between treatment arms was −0.01 logMAR (−0.05 to 0.03), and mean corrected distance visual acuity difference was −0.01 logMAR (95% confidence interval [CI], −0.05 to 0.02). Seventy-one percent of both FLACS and PCS cases were within ±0.5 diopters (D) of the refractive target, and 93% of FLACS and 92% of PCS cases were within ±1.0 D. There were 2 posterior capsule tears in the PCS arm and none in the FLACS arm. There were no significant differences between arms for any secondary outcome.

Conclusions

Femtosecond laser-assisted cataract surgery is not inferior to conventional PCS surgery 3 months after surgery. Both methods are as good in terms of vision, patient-reported health, and safety outcomes at 3 months. Longer-term outcomes of the clinical effectiveness and cost-effectiveness are awaited.

Comparison between refractive outcomes of femtosecond laser-assisted cataract surgery and standard phacoemulsification

BACKGROUND

To compare the visual and refractive outcomes of femtosecond laser assisted cataract surgery (FLACS) using Victus platform (Technolas Bausch and Lomb (B&L), Munich, Germany) and conventional phacoemulsification cataract surgery (CPCS).

METHODS

A retrospective study of 100 eyes operated for cataract. FLACS was performed in 50 eyes and CPCS was done in another 50 eyes. Preoperative and 6 months postoperative visual and refractive evaluation (efficacy, safety, predictability, and surgically induced astigmatism) as well as higher-order aberrations were analyzed. Efficacy index which equals post-operative mean of uncorrected distance visual acuity (UDVA) divided by preoperative mean corrected distance visual acuity (CDVA) was calculated in both groups. Safety index equals post-operative mean of corrected distance visual acuity (CDVA) divided by preoperative mean CDVA.

RESULTS

Logarithm of the Minimum Angle of Resolution (LogMAR), UDVA improved in both groups after surgery (p < 0.05). It was 0.23 ± 0.20 and 0.291 ± 0.311 log MAR in FLACS and CPCS groups respectively. Safety index was 1.777 in FLACS group and 1.744 in CPCS groups showing high degree of safety of both measures. Mean surgically induced astigmatism (SIA) was 0.35 ± 0.67 D and 0.901 ± 0.882 D in FLACS and CPCS groups respectively (p = 0.015). The post-operative comparison between both groups was in favor of CPCS group vs. FLACS group regarding total aberrations (0.563 ± 0.386 vs. 0.91 ± 1.20) (p = 0.03), while low order aberrations were significantly less in FLACS group vs. CPCS group (0.64 + 0.63 vs. 2.07 + 3.15) (p = 0.027). RMS high order aberration was higher in FLACS group vs. CPCS group but of no statistical significance 0.54 ± 0.96 vs. 0.328 ± 0.360 (p = 0.082).

CONCLUSION

Femtosecond laser -assisted cataract surgery was a safe and precise procedure but enhanced visual outcomes only minimally when compared to conventional cataract surgery in experienced hands. Both FLACS and manual surgeries can achieve a high efficacy, predictability and safety with slight superior outcomes in FLACS.

TRIAL REGISTRATION NUMBER

PACTR201804003256258 (date: 27 Mar 2018) Available at: https://pactr.samrc.ac.za/.

Effect of manual capsulorhexis size and position on intraocular lens tilt, centration, and axial position

PURPOSE

To evaluate the influence of a manual capsulorhexis size, shape, and position on postoperative axial position, tilt, and centration of intraocular lenses (IOLs).

SETTING

Hanusch Hospital, Vienna, Austria.

DESIGN

Prospective cases series.

METHODS

Patients had cataract surgery and had follow-ups 1 hour and 3 months after surgery. Postoperatively, patients were divided into 3 groups according to the capsulorhexis shape and size as follows: control, symmetrical capsulorhexis between 4.5 mm and 5.5 mm; small group, capsulorhexis smaller than 4.5 mm; and eccentric, all other capsulorhexes. At both follow-ups, a retroillumination image, partial coherence interferometry measurements, and Purkinje meter measurements were performed.

RESULTS

This study comprised 255 eyes. The mean postoperative absolute anterior chamber depth shift in the control, eccentric capsulorhexis, and small capsulorhexis groups was 0.31 mm ± 0.27 (SD), 0.36 ± 0.24 mm, and 0.26 ± 0.24 mm, respectively (P = .419). The mean tilt in the control, eccentric capsulorhexis, and small capsulorhexis groups was 4.08 ± 2.13 degrees, 3.66 ± 2.04 degrees, and 2.82 ± 1.67 degrees, respectively (P = .370), and the mean decentration was 0.38 ± 0.23 mm, 0.40 ± 0.21 mm, and 0.17 ± 0.08 mm, respectively (P = .027).

CONCLUSIONS

Capsulorhexis size and shape had little effect on the capsular bag performance of modern IOLs. Only eyes with a severely malformed capsulorhexis had a slightly decentered IOL.

Morphologic features and surgically induced astigmatism of femtosecond laser versus manual clear corneal incisions

PURPOSE

To compare the morphologic features and surgically induced astigmatism (SIA) between laser and manual clear corneal incisions (CCIs) after femtosecond laser-assisted cataract surgery.

SETTING

Eye Center, 2nd Affiliated Hospital, Medical College of Zhejiang University, Hangzhou, China.

DESIGN

Prospective case series.

METHODS

Patients had femtosecond laser-assisted cataract surgery with a CCI created with the laser or manually after random allocation. The corrected distance visual acuity, corneal topography, and anterior segment optical coherence tomography were assessed at the 1-day, 1-week, 1-month, and 3-month follow-ups.

RESULTS

The laser CCI group comprised 45 eyes and the manual CCI group, 48 eyes. The SIA was significantly lower in the manual CCI group than the laser CCI group at all visits (P < .05). At the 1-day and 1-week follow-ups, the mean CCI thickness was significantly smaller in the manual CCI group (P < .05). In the laser CCI group, the perpendicular linear distance between the external wound opening and the corneal vertex central line was statistically shorter than in the manual CCI group (P < .05). At 3 months, the SIA was correlated with the perpendicular linear distance with a Pearson correlation coefficient of -0.341 (P = .001).

CONCLUSIONS

Femtosecond laser-created CCIs for cataract surgery caused more SIA than manually created CCIs, which could have resulted from inaccurate or uncertain corneal incision positioning of the femtosecond machine. Manual creation of CCIs is recommended in femtosecond laser-assisted cataract surgery until the locating system for the femtosecond laser incision is updated.

Influence of Angle κ and Higher-Order Aberrations on Visual Quality Employing Two Diffractive Trifocal IOLs

Prospective, randomized, comparative, and controlled study to estimate the association between angle κ distance and higher-order aberrations (HOAs) with postoperative visual acuity after presbyopia-correcting IOL implantation. Forty-three eyes from 43 patients were included and randomly assigned in two groups for either AT LISA tri 839MP or Acrysof IQ PanOptix IOL implantation. The OPD-Scan III analyzer was utilized to assess the angle κ distance and higher-order aberration (HOAs). Twenty-three eyes were in the Acrysof IQ PanOptix group and 20 patients in the AT LISA tri 839MP group. The uncorrected distance visual acuity (UDVA) for the PanOptix group was 0.092 ± 0.10, whereas for AT LISA tri was 0.050 ± 0.06 (P=0.229). The uncorrected intermediate visual acuity (UIVA) for the PanOptix group was 0.173 ± 0.18, whereas for AT LISA tri, it was 0.182 ± 0.11 (P=0.669). Uncorrected near visual acuity (UNVA) was 0.068 ± 0.04 and 0.085 ± 0.07, respectively (P=0.221). Also, correlation coefficient between HOAs and the Strehl ratio for each group were −0.768 (P < 0.0001) and −0.863 (P=0.0001). Patients implanted with both trifocal IOLs showed excellent postoperative visual performance at all distances at the six-month follow-up visit. No association was found between angle κ distance and postoperative visual acuity regardless of the angle κ magnitude or the two trifocal IOLs inner optical diameter. Also, internal aberrations demonstrated a significant inverse correlation with the Strehl ratio for both trifocal IOLs.

Comparative Analysis of Clinical and Functional Results and Position of Intraocular Lens after Femtolaser-Assisted and Standard Cataract Phacoemulsification

Modern surgical treatment of cataracts provides effective results. The study of the position of the intraocular lens (IOL) in the capsule bag can be considered as one of the most important factors influencing the final visual and refractive result of the operation.

Aim: comparative analysis of clinical and functional results and position of the IOL in the capsular bag, namely decentration and tilt, when performing femtolazer-assisted phacoemulsification (FLACS) and standard phacoemulsification (CPCS). 

Materials and methods. We surveyed 57 patients (57 eyes). FLACS was performed in 27 patients, CPCS – in 30 patients. Standard methods of research were used, determination of the position of the IOL (decentration and tilt) in the capsular bag on the device OCT-Casia2 (TOMEY, Germany) and study of wave front were conducted.

Results. Comparative analysis of the obtained results showed no significant difference between groups in postoperative visual acuity, however, there was the trend towards higher performance corrected distance visual acuity and uncorrected distance in the group FLACS (0.68 ± 0.18 and 0.74 ± 0.2) compared to the group CPCS (0.58 ± 0.28 and 0.65 ± 0.24). Internal higher order aberrations were significantly low in the group with femtolazer accompaniment: in 3 mm zone almost 2 times (p = 0.041), in 5 mm zone 1.3 times (p = 0.047). Vertical decentration in a CPCS group made 0.217 ± 0.26 mm, in FLACS group – 0.118 ± 0.05 mm, the vertical tilt – 0.75 ± 0.37° and 0.54 ± 0.36 respectively. 

Conclusion. Decentralizations and IOL tilt tended to lower indices in the FLACS during the observation period up to 2 months after the operation, which was accompanied by lower values of higher order internal aberrations.

[Femtosecond laser-assisted cataract surgery and conventional phacoemulsification cataract surgery in patients with lens subluxation]

PURPOSE

To analyze the results of femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification cataract surgery (CPCS) in patients with 1-2 degree lens subluxation.

MATERIAL AND METHODS

The follow-up involved 86 patients (89 eyes). The 1^st group comprised 34 patients (35 eyes) that underwent FLACS; the 2^nd group included 52 patients (54 eyes) who underwent CPCS.

RESULTS

At day four of the follow-up central corneal thickness was significantly lower after FLACS (p_m-u=0.024), but the difference did not remain statistically reliable by 1.5 months after the surgery. At discharge day and 4 months after the surgery uncorrected visual acuity (UCVA) after FLACS reliably exceeded UCVA of the 2^nd group patients (p_m-u=0.00) with mean UCVA being 0.61±0.29 and 0.42±0.25 respectively. Internal higher order aberrations (HOA) in 5.0 mm zone in the 1^st group decreased by 4 times and amounted to 0.236±0.06 μm, in the 2^nd group increased by 4.1 times and was 4.606±8.16 μm; the difference between the groups was statistically significant (p_m-u<0.001). Mean endothelial cells density after FLACS was 2551.91±321.55 cells/mm², after CPCS - 2352.35±436.68 cells/mm² (p_m-u<0.005). Complications after FLACS included 2 cases (5.71%) of posterior capsular rupture and 1 case (2.8%) of post-op corneal edema; patients after CPCS had 6 (11.1%) and 12 (22.2%) complication cases respectively.

CONCLUSION

FLACS is the safer and more effective surgery choice for patients with 1-2 degree lens subluxation in comparison with CPCS; it decreases the risk of possible complications and provides faster postoperative rehabilitation.

Analysis of Positional Relationships of Various Centers in Cataract Surgery

Purpose

To analyze the positional relationships of various centers in patients undergoing femtosecond laser-assisted cataract surgery (FLACS).

Methods

The locations of the pupil center (PC), limbal center (LC) and lens center were analyzed in each patient using optical coherence tomography during FLACS in 35 eyes of 35 patients. Using the preoperative corneal aberrometry device, angle kappa and the location of the visual axis (VA) were calculated. After acquiring the relative horizontal and vertical coordinates of each center, the distance and location among each center were compared. The relative location and distance of each center were statistically evaluated.

Results

The distance from the PC to the lens center was 0.147 ± 0.103 mm, that from the LC to the lens center was 0.205 ± 0.104 mm, and that from the VA to the lens center was 0.296 ± 0.198 mm. The distance from the PC to the VA was 0.283 ± 0.161 mm, that from the LC to the VA was 0.362 ± 0.153 mm, and that from the lens center to the VA was 0.296 ± 0.198 mm. Among the various centers, the PC was the closest to the lens center, whereas the LC and VA were the farthest. Based on the location of the lens center, the PC, LC, and VA exhibited differences in the X and Y coordinate positions (vertical p = 0.004, horizontal p < 0.001). Among them, the LC was significantly inferior and temporal compared to the PC (vertical p = 0.026, horizontal p = 0.023). Based on the location of the VA, the respective locations of the PC, LC and lens center in two dimensions did not significantly differ (vertical p = 0.310, horizontal p = 0.926).

Conclusions

This study demonstrated the positional and locational relationships between the centers regarding FLACS. The locations of the PC, LC, and VA were different from the lens center with the PC being the closest. Surgeons should be aware of these positional relationships, especially in FLACS.

Long-term intraocular pressure changes after femtosecond laser-assisted cataract surgery in healthy eyes and glaucomatous eyes

PURPOSE

To examine the long-term effect of femtosecond laser-assisted cataract surgery on intraocular pressure (IOP) in healthy (control) and glaucomatous eyes.

SETTING

University of Colorado, Aurora, Colorado, and Vanderbilt University, Nashville, Tennessee, USA.

DESIGN

Retrospective case series.

METHODS

The study comprised patients aged 18 to 89 years meeting the inclusion criteria. Combination procedures were excluded. The main outcome measure was the change in the mean IOP from baseline to postoperatively.

RESULTS

Of the 504 eyes meeting the criteria, 278 were in the glaucoma/glaucoma suspect group and 226 in the control group. Both groups had an initial mean increase in IOP 1 day postoperatively (control: +2.0 mm Hg; 95% confidence interval [CI], 1.4-2.6; glaucoma/glaucoma suspect: +3.4 mm Hg; 95% CI, 2.5-4.2) (both P < .001). The increase was significantly higher in the glaucoma/glaucoma suspect group. The IOP returned to baseline levels at 1 week. At 1 month, both groups had a significant decrease in IOP that persisted until year 1 in the control group and through 3 years in the glaucoma group. The number of IOP medications was unchanged in the glaucoma group during follow-up. The glaucoma/glaucoma suspect group achieved significantly greater IOP lowering than the control group after 6 months.

CONCLUSIONS

Control eyes and eyes with glaucoma had an initial mean IOP rise 1 day after femtosecond laser-assisted cataract surgery. This was followed by a significant decrease starting at 1 month. The reduction was sustained through 3 years in the glaucoma group.

Cataract refractive surgery: Innovative technology provides more choices for Canadian cataract patients

Historically, cataract surgery was aimed at removing the clouded lens of the eye and replacing it with an artificial lens; this provided clear vision to patients but without regard to their refractive error-their need for spectacles or contact lenses after surgery. Modern diagnostic and surgical instrumentation now makes it possible to address these refractive errors at the time of surgery, introducing a new paradigm-cataract refractive surgery. Although not medically necessary, many patients appreciate the chance to reduce or eliminate their need for spectacles after surgery, even if some personal cost is involved.

Femtosecond laser-assisted cataract surgery versus standard phacoemulsification cataract surgery: Study from the European Registry of Quality Outcomes for Cataract and Refractive Surgery

PURPOSE

To compare the visual, refractive, and adverse outcomes of femtosecond laser-assisted cataract surgery and conventional phacoemulsification cataract surgery.

SETTING

Cataract surgery clinics in 9 European countries and Australia (femtosecond-assisted) and 18 European countries and Australia (conventional).

DESIGN

Multicenter case-control study.

METHODS

Eyes having femtosecond laser-assisted cataract surgery were matched to eyes from the European Registry of Quality Outcomes for Cataract and Refractive Surgery phacoemulsification cataract surgery database for preoperative corrected distance visual acuity (CDVA), age, and preoperative risk factors. Intraoperative and postoperative complications, postoperative CDVA, and refractive outcome were compared. The follow-up was 7 to 60 days.

RESULTS

The study matched 2814 femtosecond-assisted cases to 4987 conventional phacoemulsification cases. Femtosecond-assisted surgery compared as follows to conventional phacoemulsification: posterior capsule complications, 0.7% versus 0.4%; postoperative logMAR CDVA, 0.05 (6/6^-3) versus 0.03 (6/6^-2); worse postoperative CDVA at follow-up (by 5 letters or more), 1.0% versus 0.4%; CDVA 0.3 (6/12) or better, 96.3% versus 97.1%; absolute biometry prediction error, 0.43 diopter (D) versus 0.40 D; within ±0.5 D of target, 72% versus 74.3%; and postoperative complications, 3.4% versus 2.3%.

CONCLUSIONS

Femtosecond laser-assisted cataract surgery did not yield better visual or refractive outcomes than conventional phacoemulsification cataract surgery. Intraoperative complications were similar and low in both groups. Postoperative complications were lower in conventional phacoemulsification cataract surgery.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Comparison of clinical outcomes between femtosecond laser-assisted versus conventional phacoemulsification

Background

To compare femtosecond laser-assisted versus conventional phacoemulsification in terms of visual and refractive outcomes, cumulative dissipated energy, anterior chamber inflammation and endothelial cell loss.

Methods

In this retrospective cohort study, records of eyes that underwent femtosecond laser-assisted cataract surgery (FLACS) or conventional phacoemulsification (CP) were reviewed. The Victus femtosecond laser (Bausch and Lomb, Germany) was used to carry out corneal incisions, anterior capsulotomy, and lens fragmentation in FLACS procedures. Manifest refraction spherical equivalence (MRSE), uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), cumulative dissipated energy (CDE), postoperative cells and flare and endothelial cell count data were collected. Subgroup analysis of the visual acuity tests was performed based on the type of intraocular lens implanted (monofocal, monofocal toric, multifocal, multifocal toric, accommodating).

Results

A total of 735 eyes were included in the study (296 eyes for the FLACS group and 439 eyes for the CP group). At one year follow-up, 120 eyes comprised the FLACS group and 265 eyes for the CP group. MRSE in the FLACS group was - 0.16 ± 0.58 D and - 0.20 ± 0.52 D in the CP group (P = 0.50). UDVA in the FLACS group was 20/25 (mean logMAR 0.12 ± 0.13) and 20/25 (mean logMAR 0.11 ± 0.13) in the CP group (P = 0.48). CDVA was 20/20 (mean logMAR 0.03 ± 0.07) in the FLACS group and 20/20 (mean logMAR 0.02 ± 0.06) in the CP group (P = 0.15). No statistically significant trend was seen for FLACS versus CP by intraocular type for visual acuity. CDE for the different cataract grades ranged from 6.97 ± 5.74 to 29.02 ± 16.07 in the FLACS group and 7.59 ± 6.42 to 35.69 ± 18.30 in the CP group. The FLACS group was significantly lower for post-operative central corneal edema (P = 0.05), cells and flare (P = 0.01), and endothelial cell loss (P = 0.04).

Conclusions

Femtosecond laser-assisted cataract surgery and conventional phacoemulsification had similar refractive and visual outcomes. Phacoemulsification energy, anterior chamber inflammation and corneal endothelial cell loss were less in the femtosecond laser group.

Reviewing the visual benefits of femtosecond laser-assisted cataract surgery: Can we improve our outcomes?

Femtosecond laser-assisted cataract surgery (FLACS) was introduced in 2009 and has increasingly been incorporated into surgical practice. The automation of three key aspects of cataract surgery was expected to deliver a significant improvement in both refractive and safety outcomes. The published literature has not yet shown consistent refractive improvement above conventional techniques. The purpose of this paper is to review current FLACS refractive outcomes and explore factors that may have contributed to the current findings and whether future improvements are possible.

Optimizing outcomes with multifocal intraocular lenses

Modern day cataract surgery is evolving from a visual restorative to a refractive procedure. The advent of multifocal intraocular lenses (MFIOLs) allows greater spectacle independence and increased quality of life postoperatively. Since the inception in 1980s, MFIOLs have undergone various technical advancements including trifocal and extended depth of vision implants more recently. A thorough preoperative workup including the patients' visual needs and inherent ocular anatomy allows us to achieve superior outcomes. This review offers a comprehensive overview of the various types of MFIOLs and principles of optimizing outcomes through a comprehensive preoperative screening and management of postoperative complications.

Change of Capsulotomy Over 1 Year in Femtosecond Laser-Assisted Cataract Surgery and Its Impact on Visual Quality

PURPOSE

To compare the shape of the capsulotomy, its change, and its impact on visual quality over 1 year using the femtosecond laser system from the manual technique.

METHODS

In this two-center cross-sectional study from May 2012 to June 2013, each patient had femtosecond laser-assisted cataract surgery in one eye (FLACS group) and conventional phacoemulsification cataract surgery in the other eye (CPCS group). An evaluation of the capsulotomy was performed using retroillumination slit-lamp photographs at 7 days, 6 months, and 1 year after surgery. Effective lens position (ELP), refractive error, and corrected distance visual acuity (CDVA) were analyzed.

RESULTS

Thirty-three patients were included in the study. Diameters of capsulorhexis were more precise and deviation surfaces were lower in the FLACS group than in the CPCS group at each evaluation (P < .05). Femtosecond laser capsulotomies were less modified over time than manual continuous curvilinear capsulorhexis. No significant differences were observed for CDVA, refractive error, and ELP between groups.

CONCLUSIONS

More precise capsulotomy sizing can be achieved with the femtosecond laser compared to continuous curvilinear capsulorhexis. Femtosecond laser capsulotomies are less modified over time but did not improve ELP or visual quality. [J Refract Surg. 2017;33(1):44-49].

A Review of Laser-Assisted Versus Traditional Phacoemulsification Cataract Surgery

The use of femtosecond laser surgery improves the precision and reproducibility of corneal incisions and the capsular opening; it also reduces the amount of ultrasound energy required for lens nucleus work-up. The rate of complications reported so far appears to be low. There are a number of contraindications such as a history of cornea and/or glaucoma surgery and certain anatomical features like deep-set eyes, kyphosis, tremor, and obesity. Visual recovery and refractive results of both techniques are excellent. Comparing laser cataract surgery (LCS) with manual cataract surgery (conventional phacoemulsification) based on meta-analysis currently reveals slight differences in refractive and visual outcome. Both methods are extremely successful and safe. LCS is a technique still on the rise, with its full potential not yet tapped.

Current and effective advantages of femto phacoemulsification

PURPOSE OF REVIEW

The purpose is to review the current and effective advantages of femtosecond laser-assisted cataract surgery (FLACS).

RECENT FINDINGS

FLACS has advantages over manual phacoemulsification in its precision, and predictability and may be especially advantageous in difficult situations such as shallow anterior chamber, subluxated cataracts, white cataracts, and so on. However, the femtosecond capsulorhexis may not be as strong as a manual rhexis. Laser-induced miosis is also a potential disadvantage.

SUMMARY

There may be increased surgeon confidence and patient satisfaction with FLACS and it may be friendlier to the internal structures of the eye. However, it is not superior to manual phacoemulsification in terms of primary outcomes such as visual and refractive outcomes or overall complications. Further refinements in technology may be needed to give it distinct advantages over manual phacoemulsification and to make it the norm in cataract surgery.

Comparison of Maximum Stretch Forces between Femtosecond Laser-Assisted Capsulotomy and Continuous Curvilinear Capsulorhexis

The current study reports comparing the postoperative mechanical properties of the anterior capsule between femtosecond laser capsulotomy (FLC) and continuous curvilinear capsulorhexis (CCC) of variable size and shape in porcine eyes. All CCCs were created using capsule forceps. Irregular or eccentric CCCs were also created to simulate real cataract surgery. For FLC, capsulotomies 5.3 mm in diameter were created using the LenSx® (Alcon) platform. Fresh porcine eyes were used in all experiments. The edges of the capsule openings were pulled at a constant speed using two L-shaped jigs. Stretch force and distance were recorded over time, and the maximum values in this regard were defined as those that were recorded when the capsule broke. There was no difference in maximum stretch force between CCC and FLC. There were no differences in circularity between FLC and same-sized CCC. However, same-sized CCC did show significantly higher maximum stretch forces than FLC. Teardrop-shaped CCC showed lower maximum stretch forces than same-sized CCC and FLC. Heart-shaped CCC showed lower maximum stretch forces than same-sized CCC. Conclusively, while capsule edge strength after CCC varied depending on size or irregularities, FLC had the advantage of stable maximum stretch forces.