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

Argentinian flag sign during refractive laser-assisted cataract surgery - A case report

Purpose

The Argentinian flag sign, or radial capsular tear extensions, is a rare complication when performing capsulorhexis during cataract surgery. Identifying and managing this complication early is important to prevent the tear from propagating around the periphery leading to posterior capsular rupture or vitreous loss.

Observations

The Argentinian flag sign was previously reported in a case of femtosecond laser-assisted cataract surgery (FLACS). However, our report presents the first case after FLACS using the Catalys™ Precision Laser System, a platform which has been associated with a larger percentage of complete capsulotomies when compared to other platforms. Radial extensions of the capsular tear were observed in a 27-year-old male patient with an intumescent cataract in left eye. The complication was managed by manually redirecting and completing the radial extension flaps, along with delicate phacoemulsification and manual cutting of capsular edge in areas with significant capsular-IOL overlap.

Conclusions and importance

Our case report highlights that despite the Catalys™ Precision Laser System success rates, radial tears may occur, especially in highly pressurized intumescent cataract. Therefore, surgeons must be prepared to optimize the surgical techniques to prevent the occurrence of this complication, as well as identify and manage it when it presents.

Femtosecond laser-assisted capsulotomy with capsular marks for toric IOL alignment: Comparison of tensile strength with standard femtosecond laser capsulotomy

PURPOSE

To compare the capsulotomy rim strength with capsular marks (CMs) to the rim strength without CMs in porcine eyes, and to demonstrate the practicality of CMs for intraoperative toric intraocular lens (IOL) alignment.

SETTING

LENSAR facility, Orlando, Florida, USA.

DESIGN

Laboratory study.

METHODS

The biomechanical strength of the capsulotomy with CMs was tested under two different load orientations (orthogonal to or in-line with CMs). Thirty-six porcine eyes were randomly assigned to three treatment cohorts: (1) standard capsulotomy with no CMs, (2) capsulotomy with CMs for in-line tensile testing and (3) capsulotomy with CMs for orthogonal tensile testing. Study parameters were capsulotomy break force and maximum extensibility. The ease of using CMs for toric IOL alignment was also evaluated.

RESULTS

There was no significant difference between the mean break force for standard capsulotomy (180.57 mN ± 22 [SD]), capsulotomy with CMs with orthogonal load (178.04 ± 20 mN, P = 1.000), and with in-line load (181.05 ± 15 mN, P = 1.000). Likewise, the mean extensibility at the break point for standard capsulotomy (6.47 ± 0.33 mm) was equivalent to the mean extensibility with CMs with orthogonal load (6.49 ± 0.45 mm, P = 1.000) and with in-line load (6.3 ± 0.47 mm, P = .960). In the implanted eyes, toric IOLs were found to be easily aligned with the CMs.

CONCLUSION

The femtosecond laser capsulotomies with CMs were equivalent in tensile strength and extensibility to standard femtosecond laser capsulotomies and showed high potential for effective alignment of toric IOLs.

Advances in capsulorhexis

PURPOSE OF REVIEW

Continuous curvilinear manual capsulorhexis is currently the standard of cataract surgery. In the past several years, new technologies have been developed to improve the consistency and safety of capsulorhexis creation. This article reviews the most recent technologies in capsulotomy formation and their advantages and disadvantages.

RECENT FINDINGS

Guidance devices, femtosecond laser capsulotomy and precision pulse capsulotomy improve the centration, circularity and precision of anterior capsulorhexis and capsulotomy. These developments show particular promise for complex cataract surgeries, though clinical data on the refractive outcomes and complication rates of these technologies are currently limited and warrant additional investigation.

SUMMARY

New technological advances in capsulorhexis help surgeons achieve a more ideal capsulotomy geometry. Whether this translates into more predictable refractive outcomes and safer surgeries remains an area of future study.

Scanning Electron Microscopy Analysis of the Anterior Capsulotomy Edge: A Comparative Study between Femtosecond Laser-Assisted Capsulotomy and Manual Capsulorhexis

Purpose

To compare the capsule edges ultrastructure obtained by two femtosecond laser-assisted cataract surgery (FLACS) platforms and manual continuous curvilinear capsulorhexis (CCC) using scanning electron microscopy (SEM).

Setting

Eye Clinic, University of Trieste, Italy.

Design

Experimental comparative study.

Methods

150 anterior capsules were collected and divided into three groups as follows: Group 1 (50 capsules) obtained with manual CCC, Groups 2 and 3 (each with 50 capsules) obtained with the Catalys Laser and the LenSx Laser, respectively. All samples were imaged by means of SEM and regularity of the cut surface, and thickness of the capsule edge were evaluated and compared.

Results

All femtosecond laser (FSL) capsules were perfectly circular, whereas some alteration of the circular shape was observed in the manual ones. Group 1 showed a smooth and regular capsule edge without any surface irregularity, conversely Groups 2 and 3 showed postage-stamp perforations on the capsule edge. The cut surface irregularity value in Group 2 was 1.4 ± 0.63, while it was 0.7 ± 0.49 in Group 3 (p < 0.05). Group 1 had a significantly lower thickness of the capsule edge than the FSL groups (p < 0.05). No statistically significant difference in the capsule edge thickness between the FSL groups was found (p=0.244).

Conclusions

Despite the presence of slight cut surface irregularities, both FSL capsulotomies showed a better geometry and circularity than the manual ones. Capsulotomy specimens obtained using both FSL capsulotomies showed laser-induced alterations of the capsule edge when compared with smooth and regular edges obtained using manual CCC.

A randomized controlled trial comparing femtosecond laser-assisted cataract surgery versus conventional phacoemulsification surgery

PURPOSE

To compare the clinical results of conventional phacoemulsification surgery (CPS) with femtosecond laser-assisted cataract surgery.

SETTING

Guy's & St Thomas' NHS Foundation Trust, London, United Kingdom.

DESIGN

Single-center prospective randomized interventional case-controlled trial.

METHODS

Patients undergoing cataract surgery were randomized to receive either CPS or femtosecond laser-assisted cataract surgery. The surgery was performed with a femtosecond laser (Lensx), and all operations were performed with a gravity-fluidics torsional phacoemulsification machine (Infiniti). The visual acuity, refraction, central corneal thickness (CCT), central foveal thickness (CFT), endothelial cell loss, and rates of intraoperative and postoperative events were recorded. Quality of life outcomes were measured with the EuroQOL 5 dimensions questionnaire (EQ-5D) and patient-reported quality of vision was assessed with a cataract surgery patient-reported outcome measures questionnaire (Cat-PROM5).

RESULTS

The study comprised 400 eyes of 400 patients who had CPS (n = 200) or femtosecond laser-assisted cataract surgery (n = 200). Seven patients (3.5%) in the femtosecond laser-assisted group were not able to complete the treatment and received CPS. The mean uncorrected distance visual acuity (logarithm of the minimum angle of resolution [logMAR]) 0.15 ± 0.21 (SD) and 0.15 ± 0.19 logMAR after CPS and femtosecond laser-assisted surgery, respectively (P = 1.0); the pinhole-corrected visual acuity was 0.04 ± 0.12 and 0.04 ± 0.12, respectively (P = 1.0); the increase in CCT was 13 ± 19 μm and 15 ± 25 μm, respectively (P = .5); and the endothelial cell loss was 9.7 ± 13.7 % and 10.2% ± 13.7, respectively (P = .76). The manifest refraction spherical equivalent error was -0.14 ± 0.60 diopters (D) after CPS and -0.12 ± 0.60 D after femtosecond laser-assisted surgery (P = .74); the mean change in CFT was 9 ± 35 μm and 6 ± 35 μm, respectively (P = .55); and the rate of posterior capsule rupture was 3% and 0%, respectively (P = .03).

CONCLUSIONS

This study confirms the nonsignificant differences between 2 treatment modalities, notwithstanding a significant reduction in posterior capsule ruptures in the femtosecond laser-assisted surgery group.

Comparison of diathermic high-frequency capsulorhexis and continuous curvilinear capsulorrhexis in white cataract surgery

AIM

To compare the corneal endothelial cell counts pre- and post-operation, ultrastructure of anterior lens capsule and surgical completion after diathermic high-frequency capsulorhexis (DHC) and continuous curvilinear capsulorrhexis (CCC) applied in phacoemulsification (PHACO) of white cataract surgery.

METHODS

Sixty-six eyes of 66 patients (33 males and 33 females) with cataract aged between 60 and 80y (mean 72.5±5.5) were recruited and undergone the surgery from June 2014 to November 2016. Anterior lens capsule, derived from two kinds of capsulorhexis, were randomly divided into two groups according to random number table. The ultrastructure of the capsule edge and its closer tissue were observed by transmission electron microscopy (TEM) and optical microscopy respectively. The surgical completion conditions and corneal endothelial cell counts were analyzed pre- and post-operation after two capsulorhexis.

RESULTS

The capsule derived from CCC had smooth edge, well-organized cellular structure and the cells filling into the cutting edge under TEM and optical microscopy. The capsule derived from DHC had an approximate 60 banded area of cell degeneration and necrosis, with dentiform prominences at the edge of the capsule, and no cell structure was observed at this area. The corneal endothelial cell counts of both groups were slightly declined 1wk post-operation compared with that of pre-operation. There was no statistical difference between the two groups (t=1.63, P>0.05).

CONCLUSION

DHC shows good clinical value in white mature and hypermature cataract surgery.