Continuous curvilinear capsulorhexis

The Ganesh-Grewal cystitome maker - A step in standardizing cataract surgery

A well-centered, adequately sized continuous curvilinear capsulorhexis (CCC) is a prerequisite for successful cataract surgery. A perfect capsulorhexis ensures safe and effective performance of various steps of surgery as well as a correctly positioned intraocular lens (IOL) with optimal rotational stability. Ganesh and Grewal (GG) cystitome maker is a step toward standardizing the creation of a cystitome to reduce variations and complications associated with the crucial step of CCC in cataract surgery. We conducted a study to measure the repeatability and precision of cystitomes made by the GG cystitome maker versus those made manually with a needle holder. The results showed that the cystitomes made with GG cystitome maker had a lesser degree of variation. This indicates a more repeatable cystitome, which will inadvertently help in reducing the error caused by the instrument in making a good CCC during cataract surgery.

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.

Continuous Curvilinear Capsulorhexis - A Practical Review

BACKGROUND

Continuous curvilinear capsulorhexis (CCC) has become the gold standard technique for anterior capsulotomy, a cardinal development in modern cataract surgery. CCC enables safer and relatively convenient access to the crystalline lens, however it is more challenging to master than older methods. Understanding the physics underlying this procedure is key to achieving the desired results and avoiding complications.

PURPOSE

To review and present the established information about CCC, and to create a practical guide to this important step in cataract surgery.

METHODS

A literature review was conducted using PubMed, Embase, Cochrane and Scopus databases, with emphasis on up-to-date information. The first part of this review describes the evolution of CCC and discusses the different approaches, the various instruments available, tips and pearls and the general setup for best results. The second half covers more recent innovations and common complications, and strategies to prevent or manage them. This paper provides a practical review of all aspects of CCC.

A practical continuous curvilinear capsulorhexis self-training system

Purpose

To describe a practical, self-assembled continuous curvilinear capsulorhexis (CCC) self-training system to facilitate resident self-training and shorten the CCC learning curve.

Methods

This was a prospective experimental study that included a total of 600 capsulorhexis cases. A device for CCC practice was self-assembled and used for training and testing. Based on capsulorhexis manipulation experience, three main groups of residents (A, capsulorhexis experience with <50 cases; B, capsulorhexis experience with 400-500 cases; and C, capsulorhexis experience with >1000 cases) were created. Furthermore, based on different capsulorhexis conditions, each main group was divided into four subgroups (1, CCC without an anterior chamber cover and capsulorhexis marker; 2, CCC with an anterior chamber cover without a capsulorhexis marker; 3, CCC with an anterior chamber cover and a capsulorhexis marker; and 4, CCC with an anterior chamber cover and a capsulorhexis marker under 2.5 times magnification). Three CCC-related parameters, including acircularity index (AI), axis ratio (AR), and capsulorhexis time, were statistically evaluated.

Results

We compared the differences in study parameters among 50 consecutively completed capsulorhexis cases by one trainee with different capsulorhexis experience in each subgroup. The CCC-related parameter values in subgroups 1 and 4 were significantly different among the three groups (P < 0.001). The capsulorhexis time in subgroup 2 was significantly different among the three groups (P < 0.001). The capsulorhexis time and AI in subgroup 3 were significantly different among the three groups (P < 0.001). Moreover, with increasing manipulation experience (from group A-C), the capsulorhexis time, the AI, and AR tended to decrease. With the help of the CCC marker, in subgroups 3 and 4, the AI and AR were closer to 1.0.

Conclusion

This self-assembled CCC self-training system is practical. The CCC marker seems helpful for size specification and centration during self-training.

Thermal Profile of Pulse Precision Capsulotomy: In vivo and in vitro Infrared Thermography Study

Purpose

This study aimed to elucidate the thermal safety of precision pulse capsulotomy (PPC) via in vivo and in vitro evaluation of the thermal profile using infrared thermography.

Methods

This prospective observational study enrolled 15 eyes from 15 participants who underwent cataract surgery using the Zepto PPC. All patients underwent temperature measurements of the incision site and the entire cornea using an infrared thermographer during the capsulotomy procedure. To accurately analyze the temperature change of the Zepto PPC, infrared thermography was performed with the Zepto handpiece while exposed to air and then in porcine eyes. Moreover, in each case, the difference in temperature change according to the use of an ophthalmic viscosurgical device (OVD) was also checked to determine the temperature buffering effect.

Results

In the clinical evaluations, the mean temperature elevation around the corneal incision and time duration from baseline to peak temperature during the Zepto capsulotomy were 4.0 ± 1.9℃ and 4.43 ± 1.26 s, respectively, with a mean peak temperature of 32.6 ± 2.0℃. The mean peak temperature and rise time of the naïve Zepto nitinol ring, as measured from the bottom side, were 109.0 ± 22.9℃ and 43.40 ± 11.06 s in the experimental procedures, respectively. In the porcine eyes, the mean elevation of temperature and rise time of the Zepto nitinol ring were 6.2 ± 1.6℃ and 11.67 ± 2.08 s with the use of OVDs, and 10.5 ± 3.3℃ and 14.00 ± 3.61 s without OVDs, respectively.

Conclusions

Zepto PPC has the potential to generate extremely high thermal energy, according to an in vitro study. However, the temperature rise of the Zepto capsulotomy can be minimized by using OVDs.

Late in-the-bag intraocular lens dislocation

This review aimed to evaluate the cumulative incidence, patient characteristics, predisposing conditions, and treatment outcomes for late in-the-bag intraocular lens (IOL) dislocation. Literature searches in PubMed (MEDLINE), Embase, and Cochrane Library Central database identified 1 randomized clinical trial, 1 prospective case series, 2 prospective cohort studies, and 36 retrospective studies of this condition, which showed that the cumulative incidence was 0.5% to 3%, it occurred on average 6 to 12 years after cataract surgery, and mean patient age was 65 to 85 years. Pseudoexfoliation syndrome, myopia, and previous vitreoretinal surgery were the most common predisposing conditions. Studies indicated that IOL repositioning and IOL exchange provided similar visual outcomes and were equally safe. The long-term visual outcome seemed satisfactory. However, the quality of evidence regarding treatment was in general quite low. More studies of late in-the-bag IOL dislocation are needed, and in particular, different surgical techniques should be included in high-quality clinical trials.

A study for lens capsule tearing during capsulotomy by finite element simulation

BACKGROUND AND OBJECTIVE

During capsulotomy, the force applied to the anterior capsule is a crucial parameter controlling capsule tears, that affects the clinical performance. This study aims to investigate the tear force in capsulotomy and analyze the effects of different tearing conditions on the tear force.

METHODS

A three-dimensional model of the human lens was constructed based on published clinical data using the finite element (FE) method. The lens model consisted of four layers: the anterior and posterior lens capsule, the cortex, and the nucleus. Distortion energy failure criterion combined with the bilinear interface law was used to express the crack propagation process at the edge of the anterior lens capsule. At the clamping position, a local coordinate system was established to parameterize the capsule tearing. The simulation results were then validated by conducting a capsulorhexis experiment using isolated porcine eyes with force-sensing forceps.

RESULTS

The simulation results showed a good agreement with the experimental data of two porcine specimens (No. 6 and 9) during a stable tearing process (p-values = 0.76 and 0.10). The mean force differences between the experimental data and the simulation were 3.10 ± 2.24 mN and 2.14 ± 1.73 mN, respectively. The tear direction with a minimum mean tear force was at θ₁ = 0° and θ₂ = 30°. The tear velocity was not significantly different to the variation in the tear force. However, an appropriate capsulorhexis diameter was found to contribute to the reduction of tear force.

CONCLUSIONS

The outcome of this paper demonstrates that our FE model could be used in modeling lens capsule tearing and the theoretical study of tear mechanism.

Modified bandage-contact-lens used as a guide-marker for performing continuous-curvilinear-capsulorhexis by a first-year-post-graduate-ophthalmology-resident

Purpose

To define the use of modified bandage-contact-lens as a guide-marker for performing continuous-curvilinear-capsulorhexis by a first-year-post-graduate-ophthalmology-resident.

Observation

Phacoemulsification has now become the standard cataract surgery in which anterior capsulorhexis is the first and most crucial step. A perfect capsulorhexis is difficult to learn and even more difficult to master with a steep learning curve when performed free-hand especially by a first-year post-graduate ophthalmology-resident. There is paucity of simple, single-use, easily portable, cost-effective and affordable devices designed especially for performing CCCs in a safe and reproducible way.

In our technique, the bandage contact lens (BCL) is trephined using a 6mm corneal trephine. After topical or peribulbar block (as the case may be), the 6mm-guide-marker (trephined BCL) is placed on the cornea. The CCC is then completed using the edge of the contact-lens as a guide for CCC.

Conclusion

AND IMPORTANCE: CCC with contact-lens-guide-marker is expected to yield better results in carrying out the procedure more accurately being closer to the target in terms of size, circularity and centration as compared to contact-lens-unassisted conventional CCC. This would eventually facilitate better surgical outcomes and we recommend this to be applied as the standard protocol for first-year post-graduate ophthalmology-resident performing the surgery.

Intraocular lens tilt and decentration after Nd:YAG laser posterior capsulotomy: Femtosecond laser capsulorhexis versus manual capsulorhexis

PURPOSE

To compare intraocular lens (IOL) tilt and decentration after Nd:YAG laser posterior capsulotomy in eyes that had femtosecond laser-assisted capsulotomy versus manual capsulorhexis.

SETTING

Ekol Eye Hospital, Izmir, Turkey.

DESIGN

Retrospective case series.

METHODS

Intraocular lens decentration and angle of tilt were measured using a Scheimpflug camera before and 1 month after Nd:YAG capsulotomy.

RESULTS

Eighteen eyes had a femtosecond laser-assisted capsulotomy and 25 eyes a manual capsulorhexis. The mean age was 58.2 years ± 10.2 (SD) (range 44 to 69 years) and 60.6 ± 8.3 years (range 45 to 70 years), respectively. Before capsulotomy, the angle of tilt and decentration at both meridians did not differ significantly between the 2 groups (P > .05). After capsulotomy, the angle of tilt was significantly decreased in both groups (femtosecond: vertical 1.5 degrees and horizontal 1.2 degrees; manual: vertical 1.1 degrees and horizontal) and decentration was significantly increased (femtosecond: vertical 0.085 mm and horizontal 0.096 mm; manual: vertical 0.2 mm and horizontal 0.2 mm) at both meridians (P < .05). After capsulotomy, all tilt and decentration parameters were significantly different between the 2 groups (P < .05) except decentration on the horizontal meridian (P = .669).

CONCLUSIONS

Nd:YAG posterior capsulotomy performed after femtosecond laser-assisted capsulotomy resulted in better mechanical stability of the IOL. This suggests that a femtosecond laser-created capsulotomy better maintains a proper IOL position. Although the differences were statistically significant, the tilt and decentration values were small and might not be clinically significant.

Biomechanical Stability of Three Intraocular Lenses With Different Haptic Designs: In Silico and In Vivo Evaluation

PURPOSE

To assess the biomechanical stability of three different marketed intraocular lenses (IOLs) with different haptic designs (four-loop IOL [Micro F FineVision model] and double C-loop IOL [POD F and POD FT models], all manufactured by PhysIOL), in silico (computer simulation) and in vivo (in the context of lens surgery).

METHODS

An in silico simulation investigation was performed using finite element modeling (FEM) software to reproduce the compression test defined by the International Organization for Standardization and in vivo implantation in patients in the context of lens surgery was evaluated 1 day and 3 months postoperatively. IOL decentration and rotation were tested. In addition, the stress and strains were analyzed with the finite element method.

RESULTS

In the in silico evaluation, the compression force for the POD F IOL was slightly lower than for the POD FT IOL and Micro F IOL for all compression diameters. The axial displacement was maximum for the POD FT IOL and the tilt, rotation, and lateral decentration were substantially lower than the acceptable tolerance limits established in ISO 11979-2. In the in vivo evaluation, a total of 45 eyes from 45 patients were selected, 15 eyes for each IOL model under assessment. Statistically significant differences were found between the Micro F and POD F IOLs for lateral decentration in x-direction (in absolute value) at 3 months postoperatively (P = .03).

CONCLUSIONS

Although statistically significant differences have been found when comparing the displacement, tilt, and rotation between the different lenses, these differences cannot be considered clinically relevant, which would suggest that all three IOL models yield excellent stability in those terms. FEM appears to be a powerful tool for numerical studies of the biomechanical properties of IOLs. [J Refract Surg. 2020;36(9):617-624.].

Precision pulse capsulotomy complicated by radial tear of the anterior capsule: a proposed mechanism

Zepto precision pulsed capsulotomy is an emerging technology aimed at providing a safer and more reproducible anterior capsulorhexis, with potential advantages in challenging cases. Initial reports suggest high safety, and thus far to our knowledge, no complications have been reported. Herein we report an unexpected complication. After the pulse delivery phase on a routine cataract case, a radial tear of the anterior capsule was observed. Upon careful review of the surgery video, an air bubble was noted, at the precise clock hour of the radial tear, trapped between the device wire and capsule. This air bubble presumably prevented the transfer of rapid phase transition at this site, interfering with capsule cleavage, and resulting in incomplete capsulotomy. Based on this observation, if a trapped air bubble is observed after the vacuum phase, we recommend applying more vacuum or disengaging and reattaching, before proceeding to the pulse delivery stage.

Cataract surgeon viewpoints on the need for novel preventative anti-inflammatory and anti-posterior capsular opacification therapies

Purpose: To determine cataract surgeon viewpoints on the efficacy of available therapies/preventatives for two common sequelae of cataract surgery: inflammation and posterior capsular opacification (PCO). Methods: Cataract surgeons practicing worldwide specializing in adult, pediatric and veterinary patients were interviewed between March and August 2018. Results: Ocular inflammation following cataract surgery is treated by either corticosteroids and/or nonsteroidal anti-inflammatories (NSAIDs). Adult and pediatric cataract surgeons are satisfied with current treatments whereas this inflammation is still considered a problem by some in veterinary practice due to its slow resolution. Yttrium-aluminum-garnet (YAG) laser therapy is the PCO treatment of choice for adult cataract surgeons and they are generally pleased with its outcome. However, pediatric cataract surgeons find YAG problematic, especially in patients under 6 years of age, and invasive surgery is often needed to correct PCO/visual axis opacification (VAO). Veterinary ophthalmologists report that YAG is not effective for PCO in animals, especially dogs, due to the density of the fibrotic plaques; 86% of adult and 100% of veterinary and pediatric cataract surgeons surveyed agree that effective anti-PCO therapeutics would improve clinical care. Conclusions: Surgeons treating human patients are pleased with the available treatments for ocular inflammation following cataract surgery, although some veterinary ophthalmologists disagree. The surgeons surveyed agree that PCO/VAO remains an unsolved problem in pediatric and veterinary cataract surgery while the long-term outcome of adult cataract surgery could be improved by additional attention to this issue.

Techniques of anterior capsulotomy in cataract surgery

Optimal outcomes of a cataract surgery largely depend on the successful performance of an anterior capsulotomy. It is one of the most important steps of modern cataract surgery which reduces the risk of capsular tears and ensures postoperative stable intraocular lens (IOL). Anterior capsulotomy is considered ideal if it is round, continuous, well-centered, and overlaps the implanted IOL around its circumference. If any of these features is missing, it can be a cause of impedance for desired surgical and visual outcomes. Manual can opener and manual capsulorhexis are the routine standard techniques employed for manual extracapsular cataract extraction and phacoemulsification, respectively. Recent increasing use of femtosecond laser cataract surgery has allowed cataract surgeons to obviate inherent inaccuracies of manual anterior capsulotomy techniques. There is an ongoing quest to find an ideal, risk free, and surgeon-friendly technique of anterior capsulotomy that can be employed for surgery in all types of cataracts.

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.

[Precision pulse capsulotomy : The new capsulorhexis?]

The manual capsulorhexis created by Neuhann is still the standard procedure for opening the anterior capsule for cataract surgery. A limitation is the inaccuracy in the size and placement of the opening due to manual execution. In addition to the femtosecond laser a possible improvement in the standardization of capsulorhexis is provided by the Zepto procedure (precision pulse capsulotomy, PPC). In this case a 5.25 mm rhexis is created in a standardized fashion with a flexible suction adapter in which a nitinol ring is located. Whether the strength of PPC is comparable or better than that of the manual technique and how it behaves in terms of capsule shrinkage has not yet been finally clarified.

Precision pulse capsulotomy in phacoemulsification: Clinical experience in Indian eyes

Purpose:

To evaluate the surgical outcome of precision pulse capsulotomy (PPC) in phacoemulsification surgery.

Methods:

One hundred twenty-three eyes of 99 consecutive patients who underwent phacoemulsification with PPC through a 2.8 mm clear corneal incision were prospectively studied at a tertiary care centre. The size, shape of capsulotomy and intraoperative capsulotomy, and surgery-related complications were noted. Visual outcome, IOL stability, and signs of capsular opacification/contraction were evaluated at 3 and 6 months.

Results:

The mean age of patients was 49.5 ± 7.77 years. Complete, circular capsulotomy averaging 5.5 mm diameter was achieved in 117 of 123 eyes. In seven eyes, we experienced complications like capsulorhexis tear (n = 6) and inadvertent iris capture (n = 1). Probe malfunction occurred in six cases. Stable intracapsular intraocular lens (IOLs) fixation and centration was achieved in all eyes. None of the eyes had any significant posterior capsular opacification or capsular contraction at 3 and 6 months. In one eye anterior capsular opacification at the capsulotomy edge was noted at 6 months.

Conclusion:

PPC is a useful device for achieving a perfectly round capsulorrhexis. However, it has a learning curve and chances of skip areas in capsulorhexis, capsular tag, and its extension should be kept in mind. Special care should be taken in initial cases and while operating on eyes with poorly dilating pupil and mature cataracts.

Review of manual small-incision cataract surgery

Cataract surgery has undergone many changes with the size of incision progressively decreasing over time with an incision of 12.0 mm for intracapsular cataract extraction to 2.2–2.8 mm in phacoemulsification. However, phacoemulsification due to high cost and equipment maintenance cannot be employed widely in developing countries. Manual small-incision cataract surgery (MSICS) offers similar advantages with the merits of wider applicability, less time consuming, a shorter learning curve, and lower cost. MSICS can be performed in high-volume setups due to fast technique. Here, we review the various techniques, safety and efficacy of MSICS, and its progress and utility in developing and underdeveloped countries.

Modified 30 G needle trypan blue staining technique under air for a uniform and consistent anterior capsule staining

PURPOSE

To describe a trypan blue dye staining technique under air, a modification of the previously described 30 G needle under-air technique.

DESIGN

This is a prospective, randomized study of 1,000 eyes of 952 patients undergoing phacoemulsification in a private practice setting from January 2015 to August 2016. Three variants as a modification of the previously known 30 G needle technique are described. In our technique, after injecting one drop of the dye under air, the needle is kept in the anterior chamber (AC) for 15 seconds. In the second variation, along with the additional hold time, 0.05 mL air is injected prior to dye injection to deepen the AC in eyes with shallow ACs or in cases with increased posterior pressure. The third variation is the selective painting approach in which more than one drop is injected for a homogenous staining.

MAIN OUTCOME MEASURES

The main outcome measures were safety and reproducibility of the technique along with homogeneity and uniformity of the anterior capsule staining.

RESULTS

AC remained stable during the hold time of 15 seconds with no egress of air. No iatrogenic trauma occurred in any of the cases. All cases had a homogeneously stained anterior capsule. The staining intensity was excellent in 80.8% of the eyes and good in 19.2% of the eyes.

CONCLUSION

This is a safe, simple, and cost-effective technique which achieves consistent, uniform, and reproducible staining. It overcomes the shortcomings of the known 30 G needle technique.

The 100 most influential papers about cataract surgery: a bibliometric analysis

AIM

To identify the 100 most cited papers in cataract surgery, we performed a comprehensive bibliometric analysis basing on the literature search on the Thomson Reuters Web of Knowledge.

METHODS

The number of citations, including the total citations, latest 5y citations and average citation number per year (ACY), authorship, year of publication, major topics, journal of publication, country and institution of origin of each paper were recorded and then analyzed. Pearson's correlation analysis was conducted to evaluate the correlation between the published year and the number of citations. The correlation between journal's impact factor (IF) and number of citations was assessed as well.

RESULTS

The most cited paper was the classic paper done by the European Society of Cataract & Refractive Surgeons (ESCRS) group. This paper focused on the topic of endophthalmitis. Not only the most cited papers originated from the USA, but also some American institutions like Johns Hopkins University, Harvard Medical School, etc. had the most citations. Pearson's correlation analysis indicated that the latest 5y citations and ACY were significantly related with the published year (5y citations: r=0.615, P<0.001; ACY: r=0.657, P<0.001), whereas no association between the total number of citations and published year was found (r=0.045). Moreover, the IFs of journals were found to have no significant effect on the number of total citations.

CONCLUSION

To our knowledge, this is the first study on the most influential papers in cataract surgery after a comprehensive research of relevant literatures. The present work may provide us concise information concerning the development history of cataract surgery over the past 66y.

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].

Novel device for creating continuous curvilinear capsulorhexis

Purpose

The purpose of this paper is to develop a novel capsulorhexis system.

Setting

Mechatronics Laboratory, University of Erciyes and Kayseri Maya Eye Hospital.

Design

A 3D model was created and simulations were conducted to develop a new device which was designed, fabricated and tested for continuous curvilinear capsulorhexis (CCC). The name of this system is the electro-mechanical capsulorhexis system (EMCS).

Methods

The 3D model was created by using a commercial design software and a 3D printer was used to fabricate the EMCS Finite element analysis and geometrical relation tests of the EMCS for different sized lenses were performed.

Results

The results show that the EMCS is a perfect solution for capsulorhexis surgeries, without mechanical or geometrical problems.

Conclusions

The EMCS can open the anterior lens capsule more easily and effectively than manual CCC applications and needs less experience.

Comparison of Manual, Femtosecond Laser, and Precision Pulse Capsulotomy Edge Tear Strength in Paired Human Cadaver Eyes

PURPOSE

To compare the anterior lens capsulotomy edge tear strength created by manual continuous curvilinear capsulorhexis (CCC), femtosecond laser capsulotomy (FSLC), and a new automated precision pulse capsulotomy (PPC) device.

DESIGN

A 3-arm study in paired human cadaver eyes.

PARTICIPANTS

A total of 44 eye specimens from 22 donors in the United States.

METHODS

Capsulotomy was performed in all eye specimens using manual CCC, a femtosecond laser (LenSx, Alcon, Fort Worth, TX), or an automated PPC device (Zepto, Mynosys Inc., Fremont, CA). The first study arm consisted of 8 pairs of eyes in which 1 eye received PPC and the fellow eye received FSLC. The second study arm consisted of 8 pairs of eyes, with 1 eye receiving PPC and the fellow eye receiving manual CCC. The third study arm consisted of 6 pairs of eyes, with 1 eye receiving a manual CCC and the fellow eye receiving FSLC. After phacoemulsification, 2 capsulotomy edge retractors attached to force transducers were used to stretch the capsulotomy edge of each eye and to measure the resisting force until the capsulotomy edge was torn.

MAIN OUTCOME MEASURES

Capsulotomy edge tear strength in millinewtons.

RESULTS

The PPC edge tear strength was greater than that of FSLC for all 8 pairs of eyes by an average factor of 3.1-fold (PPC mean 73.3±24.9 mN vs. femtosecond laser mean 26.1±6.8 mN; P = 0.012, Wilcoxon matched-pairs, signed-ranks test). The PPC tear strength was greater than that of manual CCC for all 8 pairs of eyes by an average factor of 4.1-fold (PPC mean 95±35.2 mN vs. manual CCC mean 29.1±23.1 mN; P = 0.012, Wilcoxon matched-pairs signed-ranks test). There was no significant difference in the tear strength of capsulotomies produced by manual CCC (mean 21.3±4.9 mN) and FSLC (mean 24.5±11.4 mN) (P = 0.75, Wilcoxon matched-pairs signed-ranks test).

CONCLUSIONS

The strength of the PPC capsulotomy edge was significantly stronger than that produced by femtosecond laser or manual CCC.

Pre-surround division technique: precise cracks surrounding the posterior opacity prior to phacoemulsification in posterior polar cataract surgery

Three methods are currently used for posterior polar cataract surgery: intracapsular cataract extraction, posterior approach, and anterior approach. A high level of skill is required to divide the lens in the anterior approach, and few studies have investigated safer or simpler division methods. We focused on the division method in posterior polar cataract and developed a pre-surround division technique that divides the nucleus and avoids the posterior opacity. This technique creates precise cracks that surround the posterior opacity prior to phacoemulsification and does not cause intraoperative complications, resulting in successful intraocular lens implantation in all eyes. This pre-surround division method is a safe and easy technique that can be used in patients with posterior polar cataract.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.

Optical coherence tomography and 3-dimensional confocal structured imaging system-guided femtosecond laser capsulotomy versus manual continuous curvilinear capsulorhexis

PURPOSE

To compare the features of capsulotomy obtained during femtosecond laser-assisted cataract surgery with those of continuous curvilinear capsulorhexis (CCC) obtained using a standard manual technique.

SETTING

Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D'Annunzio Chieti-Pescara, Chieti, Italy.

DESIGN

Prospective randomized clinical study.

METHODS

Candidates for cataract extraction were randomized into 1 of 3 groups as follows: Lensx femtosecond laser-assisted cataract surgery capsulotomy (laser group 1), Lensar femtosecond laser-assisted cataract surgery capsulotomy (laser group 2), and manual CCC (manual group).

RESULTS

Each group comprised 30 eyes (30 patients). The capsulotomies in laser group 1 and laser group 2 showed significantly better circularity than the manual CCCs at 7 days (P<.001). There was a significant correlation between the intended versus achieved capsulotomy size in the 2 laser groups. Both laser groups had better intraocular lens (IOL) centration than the manual group at all timepoints (P<.001). Between-group differences in uncorrected and corrected distance visual acuities were not statistically significant. The residual spherical equivalent and mean absolute error were statistically significantly smaller in the 2 laser groups than in the manual group (P=.038) and increased significantly over time in all the groups (P<.001).

CONCLUSIONS

Femtosecond laser capsulotomies showed better circularity with more predictable size than manual CCCs. In addition, IOL centration was better immediately after surgery and over time with better refractive results in the 2 laser groups.

Capsulorhexis: Pearls and pitfalls

A critical step in phacoemulsification (as well as extracapsular cataract extraction) is making a window in anterior capsule wall (i.e. anterior capsulotomy). Continuous Curvilinear Capsulorhexis (CCC) has become recognized as the standard method of anterior capsulectomy. Techniques employed for CCC have undergone sustained evolution. The present review evaluates elementary principles of CCC. Management of CCC in the presence of small pupil and pseudoexfoliation syndrome is discussed. Main differences of pediatric CCC from its adult-style counterpart and finally several techniques of rescue of an extending capsulorhexis are also reviewed.

A novel technique of rescuing capsulorhexis radial tear-out using a cystotome

PART 1:

PURPOSE

To demonstrate a capsulorhexis radial tear out rescue technique using a cystotome on a virtual reality cataract surgery simulator and in a human eye. PART 2:

METHOD

Steps: When a capsulorhexis begins to veer radially towards the periphery beyond the pupillary margin the following steps should be applied without delay. 2.1) Stop further capsulorhexis manoeuvre and reassess the situation. 2.2) Fill the anterior chamber with ophthalmic viscosurgical device (OVD). We recommend mounting the cystotome to a syringe containing OVD so that the anterior chamber can be reinflated rapidly. 2.3) The capsulorhexis flap is then left unfolded on the lens surface. 2.4) The cystotome tip is tilted horizontally to avoid cutting or puncturing the flap and is engaged on the flap near the leading edge of the tear but not too close to the point of tear. 2.5) Gently push or pull the leading edge of tear opposite to the direction of tear. 2.6) The leading tearing edge will start to do a 'U-Turn'. Maintain the tension on the flap until the tearing edge returns to the desired trajectory. PART 3:

RESULTS

Using our technique, a surgeon can respond instantly to radial tear out without having to change surgical instruments. Changing surgical instruments at this critical stage runs a risk of further radial tear due to sudden shallowing of anterior chamber as a result of forward pressure from the vitreous. Our technique also has the advantage of reducing corneal wound distortion and subsequent anterior chamber collapse. PART 4:

DISCUSSION

The EYESI Surgical Simulator is a realistic training platform for surgeons to practice complex capsulorhexis tear-out techniques. Capsulorhexis is the most important and complex part of phacoemulsification and endocapsular intraocular lens implantation procedure. A successful cataract surgery depends on achieving a good capsulorhexis. During capsulorhexis, surgeons may face a challenging situation like a capsulorhexis radial tear-out. A surgeon must learn to tackle the problem promptly without making the situation worse. Some other methods of rescuing the situation have been described using a capsulorhexis forceps. However, we believe our method is quicker, more effective and easier to manipulate as demonstrated on the EYESi surgical simulator and on a human eye.

A novel capsulorhexis technique using shearing forces with cystotome

Purpose:

To demonstrate a capsulorhexis technique using predominantly shearing forces with a cystotome on a virtual reality simulator and on a human eye.

Method:

Our technique involves creating the initial anterior capsular tear with a cystotome to raise a flap. The flap left unfolded on the lens surface. The cystotome tip is tilted horizontally and is engaged on the flap near the leading edge of the tear. The cystotome is moved in a circular fashion to direct the vector forces. The loose flap is constantly swept towards the centre so that it does not obscure the view on the tearing edge.

Results:

Our technique has the advantage of reducing corneal wound distortion and subsequent anterior chamber collapse. The capsulorhexis flap is moved away from the tear leading edge allowing better visualisation of the direction of tear. This technique offers superior control of the capsulorhexis by allowing the surgeon to change the direction of the tear to achieve the desired capsulorhexis size.

Conclusions:

The EYESI Surgical Simulator is a realistic training platform for surgeons to practice complex capsulorhexis techniques. The shearing forces technique is a suitable alternative and in some cases a far better technique in achieving the desired capsulorhexis.

Mikroinzisionsintraokularlinse mit Plattenhaptik

BACKGROUND

Evaluation of rotational stability of a microincision intraocular lens with plate haptic design (*Acri. Smart 46S, *Acri.Tec AG) and its centering in the capsular bag after implantation.

MATERIAL AND METHOD

In a total of 43 eyes in 37 patients a foldable, spherical microincision cataract surgery (MICS) intraocular lens (IOL) with plate haptic design was implanted through a 1.4-mm microincision by means of an injector system. The IOL was marked prior to implantation to allow exact determination of its endocapsular position. After 1 1/2 years the best corrected visual acuity, refraction, centering and rotational stability of the IOL were determined.

RESULTS

No rotation or decentration was observed in any of the 42 eyes 12-19 months postoperatively. On the first postoperative day 1 IOL rotated in the counterclockwise direction by approx. 6 degrees as a result of flattening of the anterior chamber. Its position then remained stable. No unwanted complications occurred.

CONCLUSIONS

Conclusions: *Acri. Smart 46S is a safe, effective and stable IOL that can also be used as the basis of complex refractive optical systems, e.g. for correction of astigmatism.

Calculation of intraocular lens power: a review

This review describes the principles and practices involved in the calculation of intraocular lens (IOL) power. The theories behind formulas for calculating IOL power are described, using regression and optical methods employing 'thin lens' and 'thick lens' models, as well as exact ray-tracing methods. Numerical examples are included to illustrate the points made. The paper emphasizes the importance of establishing an accurate estimation of corneal power as well as an accurate technique for the measurement of axial length and accurate methods of predicting postoperative anterior chamber depth (ACD). It is concluded that current improvements in diagnostic and surgical technology, combined with the latest generation IOL power formulas, make the calculation and selection of appropriate IOL power among the most effective tools in refractive surgery today.

[Teaching phacosection in a tropical setting]

PURPOSE

The aim of this study was to prospectively evaluate the training of a Malagasy ophthalmologist, already proficient in classic manual extracapsular cataract extraction (ECCE), in a small incision manual technique (phacosection).

MATERIALS AND METHODS

Within the activity of the Sight First program to fight blindness in Madagascar, the ophthalmologist of Majunga recruited patients presenting total white cataracts. These patients were operated by phacosection using the local hospital's usual instrumentation along with two specific phacosection instruments and extra single-use material (a precalibrated 3.2 mm knife and viscoelastic products). Peribulbar anesthesia with eye pressure was provided. Postoperative follow-up (visual acuity and corneal status) was conducted on days 1, 7 and 30.

RESULTS

Forty-four eyes were operated, the first seven by the instructor assisted by the local ophthalmologist, the next 36 by the local ophthalmologist assisted by the instructor. Five postoperative complications were noted: two cases of posterior capsular rupture (one during implantation) and three cases needing reoperation with aspiration of residual cortical masses. Induced astigmatism was low and visual rehabilitation was good, with all corneas clear at day 30.

DISCUSSION

The results are quite acceptable given the training period, with only two marked complications (one not related to the operative technique) and good visual rehabilitation in less than 2 weeks. This small incision technique allowed reduction of induced astigmatism and risk-free management of total white cataracts (independent of operator).

CONCLUSION

Small incision manual ECCE by phacosection is a safe, possible management option for difficult cataracts in a tropical setting with only a small increase in cost. Moreover, the training of an ophthalmologist mastering classic manual ECCE appears rapid and risk-free for patients.

Changes in the area of the anterior capsule opening after intraocular lens implantation

PURPOSE

To evaluate the reduction rate of the area of the anterior capsule opening after continuous curvilinear capsulorhexis (CCC) with 3 types of intraocular lenses (IOLs).

SETTING

St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.

METHODS

Sixty-five eyes of 51 patients having phacoemulsification and IOL implantation were assigned to 1 of 3 groups based on type of IOL: 1-piece acrylic (n = 16), 3-piece acrylic (n = 26), or silicone (n = 23). The area of the anterior capsule opening was measured 1 day and 1, 2, 3, 6, and 12 months postoperatively.

RESULTS

There was significant reduction in the area of the anterior capsule opening 1 day to 3 months postoperatively in all 3 groups (P <.001). There was no further reduction after 3 months in any group. The reduction in the area of the anterior capsule opening was significantly less in both acrylic IOL groups than in the silicone IOL group at 3 months (P =.040) and 12 months (P =.023); however, there was no significant difference between the 2 types of acrylic IOLs (P =.933).

CONCLUSIONS

Although there was a reduction in the area of the anterior capsule opening in all patients, the amount was significantly less in the 2 acrylic IOL groups than in the silicone IOL group. This should be considered when selecting an IOL, especially for eyes at risk for capsule contraction.

Phaco one-chop nucleotomy

Phaco one-chop, a hybrid of the phaco-chop, stop-and-chop, and phaco-flip techniques, has 3 main phaco phases: embedding the phaco tip and chopping, flipping the right heminucleus without nucleus rotation, and evacuating the remaining left heminucleus in the bag. Of 198 eyes evaluated, 86% had a Lens Opacities Classification System III cataract grade of 3 to 6. The mean equivalent phaco time (EPT) was 1.9 seconds; for the densest cataracts, the highest phaco power needed was 5.3%. The mean overall power was 2.1%. Thus, the phaco one-chop method requires less EPT and phaco power and allows greater surgeon control for efficiency and predictability than the techniques from which it was derived.

Phacoemulsification in the anterior chamber

PURPOSE

To evaluate anterior chamber phacoemulsification as an alternative to an endocapsular procedure.

SETTING

Instituto Oftalmológico de Alicante, Alicante, Spain.

METHODS

In this prospective randomized masked clinical trial, 60 eyes of 30 patients had cataract extraction by phacoemulsification. A conventional stop-and-chop technique was used in 30 eyes; the other 30 had surgery by the phaco-out technique in which the nucleus was prolapsed into the anterior chamber using extensive hydrodissection. Copious sodium hyaluronate 3.0%-chondroitin sulfate 4.0% (Viscoat) and hydroxypropyl methylcellulose were used to protect the cornea and iris. The phaco time and power, postoperative inflammation, corneal edema (clinically and by pachymetry), and endothelial cell count between groups preoperatively and postoperatively were compared. All patients completed a 3-month follow-up. Postoperative examinations were at 3 days, 2 weeks, and 1 and 3 months.

RESULTS

The mean nuclear hardness was 2.67 +/- 0.61 (SD) in the stop-and-chop group and 2.65 +/- 0.71 in the phaco-out group. The power-to-time ratio was 18.47 and 18.80, respectively. The mean endothelial cell loss was 11.18% +/- 4.24% in the stop-and-chop group and 11.20% +/- 5.60% in the phaco-out group. There were no significant differences between groups in any parameter (P >.05, independent-sample t test).

CONCLUSION

Phacoemulsification in the anterior chamber was as safe as endocapsular phacoemulsification using a stop-and-chop technique. This technique is fast and easier to learn than endocapsular phacoemulsification.

Capsule contraction after continuous curvilinear capsulorhexis: poly(methyl methacrylate) versus silicone intraocular lenses

PURPOSE

To evaluate the progressive contraction of the anterior capsule opening after in-the-bag implantation of 2 types of intraocular lenses (IOLs).

SETTING

Department of Ophthalmology, University of Brest, Brest, France.

METHODS

In this prospective study, 32 single-piece poly(methyl methacrylate) (PMMA) (Pharmacia 812 C) and 30 3-piece silicone IOLs with PMMA haptics (Allergan SI-40NB) were implanted in the bag after standardized phacoemulsification performed by the same surgeon. All patients were older than 70 years, and none had zonular weakness. The surface of continuous curvilinear capsulorhexis (CCC) was measured 1, 30, and 150 days postoperatively using a 3 charge-coupled device camera and a digitized computer analysis system.

RESULTS

A significant progressive constriction was observed at 150 days in 70% in the silicone group and 32% in the PMMA group. In addition, CCC contraction was greater in silicone group (P < .05). The mean surface decrease was 4.20 mm2 in the silicone group and 1.53 mm2 in the PMMA group. There was no correlation between sex, age, initial capsulorhexis area, final capsule shrinkage. In some eyes, especially in those with a single-piece PMMA IOL (41%), there was no constriction, but fine changes in the capsule opening were seen.

CONCLUSION

Evolutive anterior capsulorhexis modifications were observed in all patients; however, the contraction rate was statistically higher in the silicone group. These results suggest that silicone IOL implantation should be avoided in eyes at risk for CCC constriction.

Histology of anterior capsule fibrosis following phacoemulsification

PURPOSE

To determine the histology and immunohistochemistry of anterior capsule fibrosis.

SETTING

Department of Ophthalmology and Neurosurgery and Institute of Pathology, University of Siena, Siena, Italy.

METHODS

Tissue sections from 3 patients with anterior capsule fibrosis after phacoemulsification and intraocular lens implantation were examined histologically.

RESULTS

The proliferating tissue was devoid of vessels and composed of dense fibrous tissue and numerous activated fibroblasts with contractile capacity (myofibroblasts). No TGF-beta, which is the most important cytokine in modulating myofibroblasts, was present in the fibrotic tissue.

CONCLUSION

The absence of the cytokine TGF-beta and inflammatory cells in the proliferating tissue confirms the unique character of the reparative activity within the eye.

Blunt, bent needle for continuous curvilinear capsulorhexis

We describe an anterior continuous curvilinear capsulorhexis (CCC) technique that uses a dull needle. The needle's blunt tip prevents inadvertent tearing of the anterior capsule, and its rough surface allows the surgeon to transmit a power vector of different amplitude and direction to the edge of the capsulorhexis to continue the tear as desired. For biomechanical reasons, we prefer an arcade-shaped CCC because this configuration provides a greater circumference than a circular CCC. The blunt needle allows one to perform a single-step capsulorhexis in a safe and controlled manner and reduces surgical time. Even in cases of white and liquified cortex, the dull needle has proved a useful, safe tool.