Precision pulse capsulotomy in challenging cataract surgery cases

Preventing the Argentinian flag sign and managing anterior capsular tears: A review

The Argentinian flag sign (AFS) is a feared complication during cataract extraction. Intralenticular pressures, especially excessive posterior pressure, have been identified as potential mechanisms for capsular stress and tearing associated with AFS. Capsular tension is created by positive intralenticular pressures, which cause the irido-lens diaphragm to move anteriorly once the manual capsulorhexis has been initiated. This tension can cause inadvertent tears that self-propagate to the lens equator, causing an AFS, among other intraoperative complications. Thus, this review highlights the importance of identifying intumescent cataracts as well as a combination of techniques to relieve intracapsular pressures needed to prevent AFS. However, some instances of anterior capsular tears are unavoidable. Therefore, focus will also be placed on techniques during cataract extraction used to manage anterior capsular tears, mitigating extension to the posterior capsule.

Endothelial Cell Loss Following Cataract Surgery Using Continuous Curvilinear Capsulorhexis or Precision Pulse Capsulotomy

Purpose

To compare endothelial cell density (ECD), percentage of hexagonal cells (%Hex) and coefficient of variation (CV) in cell size following lens cataract surgery with phacoemulsification performed using Continuous Curvilinear Capsulorhexis (CCC) or Precision Pulse Capsulotomy (PPC).

Patients and Methods

Sixty-seven subjects were randomly assigned to undergo lens cataract removal with the capsulotomy step performed using either CCC or PPC. Specular microscopy images were obtained pre-operatively, 1 month and 3 months after surgery. ECD, %Hex and CV were analyzed in a masked fashion by an independent reading center.

Results

The mean percentage ECD loss at 1 month was 11.5% in the CCC group and 12.3% in the PPC group (P = 0.818; t-test). At 3 months, the mean percentage ECD loss was 11.7% in the CCC group and 12.4% in the PPC group (P = 0.815; t-test). The mean %Hex at 1 month was 54.3% in the CCC group and 54.7% in the PPC group (P = 0.695; t-test). At 3 months, the mean %Hex was 56.2% in the CCC group and 54.7% in the PPC group (P = 0.278; t-test). The CV at 1 month was 34.4% in the CCC group and 34.3% in the PPC group (P = 0.927; t-test). At 3 months, the CV was 32.7% in the CCC group and 33.4% in the PPC group (P = 0.864; t-test).

Conclusion

No differences in ECD loss, %Hex and CV were observed between patients who received CCC or PPC. PPC use during cataract surgery does not result in any increased endothelial cell loss beyond that normally associated with this surgery.

Automated precision pulse capsulotomy vs manual capsulorhexis in white cataracts: reduction in procedural time and resource utilization

PURPOSE

To compare the utility of precision pulse capsulotomy (PPC) with manual capsulorhexis for capsulotomy in white cataracts.

SETTING

Hospital-based academic practice.

DESIGN

Retrospective analysis of surgical case records and surgical videos from a single surgeon.

METHODS

Cases involving intumescent and nonintumescent white cataracts were identified. Capsulotomy outcomes, surgical outcomes, procedural time, and resource utilization, as well as patient demographic and health data, were analyzed and subjected to statistical testing.

RESULTS

15 cases of white cataract (10 intumescent and 5 nonintumescent) performed using continuous curvilinear capsulorhexis (CCC) were compared with 20 cases (9 intumescent and 11 nonintumescent) performed using PPC. The cases covered a period of 14 months before and 30 months after surgeon adoption of PPC. There were no significant differences between the 2 groups in patient age, sex, ethnicity, ocular history, medical history, and medications. PPC resulted in complete capsulotomies without tags or tears and intracapsular intraocular lens implantation with 360-degree capsular overlap in all 20 cases. There was 1 CCC case resulting in the Argentinian flag sign. Compared with CCC, PPC white cataract cases also demonstrated significant advantages in capsulotomy time, reduced use of trypan blue and ophthalmic viscosurgical device, and less overall procedural time.

CONCLUSIONS

PPC is a safe and highly effective method to create consistent capsulotomies in both intumescent and nonintumescent white cataracts. The use of PPC provides benefits of significant reductions in capsulotomy time, overall procedural time, and resource utilization, resulting in a streamlined treatment of these complex cataract surgery cases.

Efficacy of femtosecond laser for anterior capsulotomy in complex white cataracts

OBJECTIVE

To determine the advantages and complication rate of capsulotomy performed with femtosecond laser in white complex cataract cases.

STUDY DESIGN

Retrospective case series.

PARTICIPANTS

Sixteen eyes of 16 patients.

METHODS

This was a single-center retrospective review of white cataract surgery cases in which the femtosecond laser (LenSx, Alcon Laboratories, Fortworth, Texas, USA) was used between May 2019 and February 2021. Outcome measures included an assessment of the capsulotomy, identification of tags, surgical time, cumulative dispersed energy (CDE) and postoperative management.

RESULTS

Sixteen eyes of 16 patients were included in this study; capsule tags occurred in six patients (37.5%). In 2 patients, the capsule presented small adhesions that were identified and removed. One patient presented a very significant contraction of the anterior capsule with an incomplete cut zone of 2 to 4hours. In a patient with nystagmus, the capsulotomy was performed without complications under peribulbar anesthesia.

CONCLUSIONS

The femtosecond laser permitted capsulotomies of better shape, size and regularity in complex cases of white cataract and in combination with conditions such as nystagmus and prior corneal transplantation. The microadhesions and untreated areas were identified with trypan blue, which is essential to use in these cases to avoid associated complications.

Limits of the precision in refractive results after cataract surgery

BACKGROUND AND OBJECTIVE

In order to improve refractive results in cataract surgery with an intraocular lens implant, it is important to know the sources of error as well as the limit of this process. Therefore, the objective of the present work is to approximate the theoretical limit in the precision in the refractive result after cataract surgery with the currently available means and to assess the impact of different sources of error in this process.

MATERIALS AND METHODS

We conducted a search of the literature to determine the variability provided by each component of the process. Based on the Barrett Universal-II formula, we performed an error propagation analysis. The theoretical limit was defined as the situation in which the refractive result is only affected by the variability in the parameters introduced in the formula, the tolerance of the intraocular lens and the subjective refraction.

RESULTS

The main contributors to the error were (1) intraoperative and postoperative variability variables not considered by the formulas (49.33%), (2) postoperative subjective refraction (38.29%), (3) mean keratometry (5.98%) and (4) the variability in the labelling of the power of the intraocular lens (5.09%). The theoretical limit obtained for the intraocular lens calculation with the means available today was 91.9% of the eyes between ±0.50D.

CONCLUSIONS

We found a theoretical limit for the intraocular lens calculation of 91.9% of the eyes between ±0.50D. Approaching the precision limit described in the study requires the use of optical biometrics and state-of-the-art formulas, a reproducible surgical technique, and the compensation of systematic errors by adjusting constants.

Recent developments in anterior capsulotomy for cataract surgery

PURPOSE OF REVIEW

Successful anterior capsulotomy is an important step in cataract surgery. This article reviews the various anterior capsulotomy techniques available to surgeons to optimize the step, including those that have become available since the introduction of femtosecond-laser-assisted cataract surgery (FLACS). Studies comparing the relative advantages of each technique will be emphasized.

RECENT FINDINGS

Manual continuous curvilinear capsulorhexis (CCC) and FLACS remain the two most widely studied techniques for achieving anterior capsulotomy. Each technique has been shown to be effective for a wide range of patients and cataract surgery complications. Meta-analyses have shown that FLACS provides similar results to manual CCC for long-term cataract surgery outcomes. Several alternative methods for anterior capsulotomy have been described, which aim to provide some of the advantages of laser capsulotomy at a lower cost; among these, precision pulse capsulotomy (PPC) and selective laser capsulotomy (SLC) have been investigated the most in the literature so far.

SUMMARY

Cataract surgeons have an increasing number of techniques for anterior capsulotomy available. Manual CCC and FLACS remain the most widely used, and most well studied. The latest techniques, PPC and SLC, have shown promise in the few studies performed since they were introduced.

Use of P1-P4 Purkinje reflections as a surrogate sign for intraoperative patient fixation

Circumferential, even anterior capsular overlap maximizes intraocular lens stability and posterior capsular opacification mitigation and provides best long-term outcomes for the cataract patient. P1 and P4 Purkinje reflections at patient fixation may provide a reliable marker for capsulotomy centration. However, patient fixation may be hindered during surgery because of anesthesia or light sensitivity. In this study, we demonstrate that the relationship between the P1 and P4 Purkinje reflections previewed prior to surgery when the patient is fixating may be recreated intraoperatively if fixation becomes difficult. The final position of P1 and P4 relative to one another at fixation is invariant in a given patient, but there are variations among patients. Knowledge of the P1 and P4 relationship can be used as a surrogate sign of patient fixation to assist in capsulotomy centration during cataract surgery.

Precision Pulse Capsulotomy During Combined Penetrating Keratoplasty With Cataract Surgery and Intraocular Lens in Small Nondilating Pupil

OBJECTIVE

To demonstrate precision pulse capsulotomy (PPC) in an open-sky procedure and to evaluate its use during triple procedure keratoplasty in small nondilating pupils.

METHODS

This single-center retrospective case series study included 10 eyes (from 10 patients) with corneal opacity and poorly dilated pupils who were scheduled to undergo triple procedure keratoplasty. The main outcome measures were capsulotomy performance of the PPC device and intraoperative complications. Secondary outcome measures included postoperative best-corrected visual acuity, intraocular pressure, and other postoperative complications.

RESULTS

Complete free-floating capsulotomy was achieved in all 10 eyes. There were no cases of anterior capsule tears or tags. There were no postoperative complications that occurred in association with the PPC device.

CONCLUSIONS

The PPC device facilitates creation of a smooth, round, and appropriately sized anterior capsulotomy in open-sky surgeries, particularly in presence of small nondilating pupils.

Precision pulse capsulotomy: performance metrics and utility in routine and complex cases

PURPOSE

To evaluate precision pulse capsulotomy (PPC) performance.

SETTING

University and private practice in the United States and South Korea.

DESIGN

Multicenter retrospective analysis.

METHODS

The surgical videos of 337 cataract surgeries with PPC capsulotomy performed by 4 surgeons at 4 centers were used to assess capsulotomy outcomes including completion rate, diameter, roundness (ovality), and quality of capsular overlap.

RESULTS

PPC use resulted in 99.4% free-floating capsulotomies from 337 cases. Video image analysis in a subset (n = 52) yielded a mean capsulotomy diameter of 5.0 mm ± 0.16 mm SD (95% CI, 4.96-5.04 mm). Capsulotomies were round to slightly oval at the end of the case with a mean ovality of 3.0% ± 2.86% (95% CI, 2.22%-3.78%; 360 degrees capsular overlap was obtained in 98% of cases. The offset of the capsulotomy center with the intraocular lens (IOL) optic center was 197 μm ± 122 μm (SD) (95% CI, 148-246 μm). PPC was used successfully in traumatic cataracts with compromised anterior and posterior capsule, phacodonesis, intumescent cataract with constricted pupil, and zonular dialysis and in penetrating keratoplasty with open-sky extracapsular cataract extraction.

CONCLUSIONS

Surgeons obtained good PPC capsulotomy outcomes in routine and challenging cases. Little variation was observed in achieving free-floating capsulotomies with approximately 5.0 mm diameter and complete capsular overlap. Variation was observed in the amount of offset between the capsulotomy center and the center of the IOL optic. PPC was useful in cases with multiple comorbidities that challenge capsulotomy performance.

Early results of circularity and centration of capsulotomy prepared by three different methods

AIM

To compare the difference of capsulotomy produced by precision pulse capsulotomy (PPC), manual (M-CCC), and femtosecond laser assisted capsulotomy (FLAC) in relation to intraocular lens (IOL) centration, circularity and its effect on visual outcomes.

METHODS

Prospective, non-randomized comparative study conducted at LV Prasad Eye Institute, Hyderabad, India. Sixty eyes of 52 patients were grouped into 3 (FLAC, PPC and M-CCC) based on capsulotomy techniques used. Twenty consecutive eyes with uneventful phacoemulsification and with no comorbidities affecting the capsulotomy or visual outcome were included in each group. The main outcome measure was IOL centration in relation to capsulotomy and pupil. Secondary outcome measures were post-operative visual acuity, manifest refraction and aberration profile between groups.

RESULTS

At 5wk the visual, refractive outcomes and endothelial cell density were comparable between the 3 groups. The median circularity index of FLAC was statistically significantly different to M-CCC or PPC (1-10) groups (P<0.01) but PPC (11-20) was comparable to FLAC. Decentration of IOL center in relation to capsulotomy was seen only between the PPC (1-10) group and FLAC group (P=0.02). The IOL was well centered in relation to the pupil in all the groups (P=0.46). The quality of vision parameters like the higher order aberrations, spherical aberration, coma, trefoil, modular transfer function, and Strehl ratio were comparable between the groups.

CONCLUSION

Our study shows that despite differences in the morphology of capsulotomy produced by PPC, M-CCC, FLAC a well-centered IOL can be achieved. The measured capsular morphology parameters do not affect visual outcomes.

Clinical Results After Precision Pulse Capsulotomy

Purpose

To compare residual refractive error and complication rates between eyes undergoing a manual capsulotomy and those receiving a precision pulse capsulotomy using an automated device.

Patients and Methods

This study was a non-interventional two-arm retrospective chart review of clinical results after bilateral cataract surgery or refractive lens exchange (RLE) surgery with a monofocal toric intraocular lens (IOL) or a trifocal IOL where a manual capsulorhexis (Manual) or automated precision pulse capsulotomy (PPC) was performed.

Results

Exams from 243 eyes (122 PPC, 121 Manual) from 124 patients were reviewed; about 75% of which had a trifocal IOL implanted. There was no statistically significant difference in the MRSE with either IOL type, or overall. The overall percentage of eyes with residual refractive cylinder ≤ 0.50 D was significantly higher in the PPC group (89% vs. 79% in the manual group, p = 0.03), primarily driven by results with the toric IOL. Best corrected distance visual acuity was not statistically significantly different by group. Capsulotomy-related complications were lower in the PPC group relative to the manual group (4.1% vs. 6.6%), but this result was not statistically significant (p = 0.38).

Conclusion

Significantly more eyes had refractive cylinder ≤0.50 D in the PPC group. For all other measures, the automated PPC device produced clinical results equivalent to those achieved with a manual capsulorhexis.