Analysis of the capsule edge after Fugo plasma blade capsulotomy, continuous curvilinear capsulorhexis, and can-opener capsulotomy

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.

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.

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.

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.

Ultrastructural Integrity of Human Capsulotomies Created by a Thermal Device

PURPOSE

To investigate the ultrastructural features of anterior capsulotomy performed with a thermal device, the precision pulse capsulotomy (PPC).

DESIGN

Prospective, multicenter case series.

PARTICIPANTS

Consecutive patients undergoing capsulotomy with the PPC device.

METHODS

Prospective study of patients undergoing capsulotomy with the PPC by 2 surgeons, followed up by routine phacoemulsification cataract surgery, was undertaken. All capsulotomy specimens were collected for scanning electron microscopy (SEM). Observations were made regarding uniformity of the capsular edge and the presence of irregularities that may compromise integrity. Comparisons were made with manual continuous curvilinear capsulorrhexis.

MAIN OUTCOME MEASURES

Ultrastructural features of PPC and presence of irregularities.

RESULTS

Frayed appearance of the anterior capsule edge was noted in postoperative visits under slit-lamp examination. Scanning electron microscopy sampling showed a generally uniform rolled capsular edge, but interspersed with areas of irregularity with frayed appearance at the capsule margin.

CONCLUSIONS

The PPC device is capable of creating reproducible, central, and precise circular capsulotomy. The ultrastructural features in ex vivo human capsulotomy specimens generally show eversion of the capsulotomy edge, but in some cases, this was accompanied by areas of irregular capsule margin with frayed edges, likely caused by dissipated thermal energy. The postoperative appearance and SEM features warrant further assessment of the PPC integrity and clinical correlation.

New device for creating a continuous curvilinear capsulorhexis

PURPOSE

To describe the evolution of a new device to facilitate continuous curvilinear capsulorhexis (CCC) creation.

SETTING

Department of Ophthalmology, University of Colorado School of Medicine, Aurora, Colorado, USA.

DESIGN

Experimental study.

METHODS

Bench-side ex vivo testing of unique prototypes for guidance and assistance of CCC in bovine and human eyes was performed. Five designs were sequentially tested as follows: a flexible circular blade of nickel-titanium alloy (nitinol), a flexible nitinol guide wire, a flexible elastomeric suction device, a combination approach of a nitinol guide wire and flexible silicone ring, and a freestanding micropatterned silicone ring.

RESULTS

The first 3 designs were not amenable to insertion through a sub-2.4 mm corneal incision and failed to maintain adequate downward force to cut the capsule and/or prevent radial tears. The fourth design was successfully inserted through a 2.4 mm incision and maintained adequate downward pressure and contact to guide a manual CCC without radial tears. The final design was insertable through a 2.4 mm incision and exhibited self-adhesive characteristics after placement on the anterior capsule of an ophthalmic viscosurgical device-filled anterior chamber.

CONCLUSIONS

Given the steep learning curve of manual capsulorhexis and the high cost of capsulotomy-assistive devices, such as the femtosecond laser, an alternative approach for creating a CCC is desirable. Performance of a highly precise manual CCC through a small incision using a medical-grade silicone device with an adhesive micropatterned design is a viable and cost-effective option for use in cataract surgery across a wide range of user experience.

FINANCIAL DISCLOSURE

All authors are named as the inventors in a patent filed by the University of Colorado covering the details in this report.

Results of cataract surgery and plasma ablation posterior capsulotomy in anterior persistent hyperplastic primary vitreous

PURPOSE

To report the feasibility and outcome of lens aspiration, and Fugo blade-assisted capsulotomy and anterior vitrectomy in eyes with anterior persistent hyperplastic primary vitreous (PHPV).

MATERIALS AND METHODS

In this case series, 10 eyes of 10 patients with anterior PHPV underwent lens aspiration. The vascularized posterior capsule was cut with a Fugo blade (plasma knife) and removed with a vitrector. A foldable posterior chamber intraocular lens (IOL) was implanted in eight eyes and the outcomes were evaluated.

RESULTS

The mean age of patients was 16.8 ± 6.37 months (range: 5 to 28 months). The surgery was completed successfully in all eyes. There were no cases of intraocular hemorrhage intraoperatively. Foldable acrylic IOL was implanted in the bag in 3 eyes and in the sulcus in 5 eyes. Two eyes were microphthalmic and did no undergo IOL implantation (aphakic). None of the eyes had a significant reaction or elevated intraocular pressure postoperatively. The follow-up ranged from 4 to 21 months. All the pseudophakic eyes achieved a best corrected visual acuity of ≥20/200 with 50% (4/8) of these eyes with ≥20/60 vision.

CONCLUSION

Lens aspiration followed by posterior capsulotomy with Fugo blade-assisted plasma ablation is a feasible technique for performing successful lens surgery in cases with florid anterior PHPV.

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.

Experimental femtosecond laser-assisted nanosurgery of anterior lens capsule

PURPOSE

To investigate femtosecond laser-assisted nanosurgery of the anterior lens capsule in a prospective in vitro study.

METHODS

Eight anterior lens capsules obtained during conventional phaco surgery were irradiated with a nonamplified 80-MHz near-infrared 800-nm titanium:sapphire femtosecond laser. Line intratissue laser cuts were examined by femtosecond multiphoton laser scanning microscopy (MLSM) and transmission electron microscopy (TEM).

RESULTS

Speed parameters of the laser beam, laser ablation time, and pulse power determined the width of the lesions, which ranged from 220±40 nm (SD) to 1.49±0.15 µm. Both MLSM and TEM revealed minimal collateral alterations in the tissue surrounding the laser cuts.

CONCLUSIONS

Nonamplified near-infrared femtosecond laser pulses at low pulse energies may be a promising strategy for precise noncontact nanosurgery of the anterior lens capsule with minimal collateral damage to surrounding tissue. High-resolution MLSM offers 3-dimensional, noninvasive, nondestructive imaging at submicrometer resolution within seconds before and after ablation.

Femtosecond laser-assisted cataract surgery with integrated optical coherence tomography

About one-third of people in the developed world will undergo cataract surgery in their lifetime. Although marked improvements in surgical technique have occurred since the development of the current approach to lens replacement in the late 1960s and early 1970s, some critical steps of the procedure can still only be executed with limited precision. Current practice requires manual formation of an opening in the anterior lens capsule, fragmentation and evacuation of the lens tissue with an ultrasound probe, and implantation of a plastic intraocular lens into the remaining capsular bag. The size, shape, and position of the anterior capsular opening (one of the most critical steps in the procedure) are controlled by freehand pulling and tearing of the capsular tissue. Here, we report a technique that improves the precision and reproducibility of cataract surgery by performing anterior capsulotomy, lens segmentation, and corneal incisions with a femtosecond laser. The placement of the cuts was determined by imaging the anterior segment of the eye with integrated optical coherence tomography. Femtosecond laser produced continuous anterior capsular incisions, which were twice as strong and more than five times as precise in size and shape than manual capsulorhexis. Lens segmentation and softening simplified its emulsification and removal, decreasing the perceived cataract hardness by two grades. Three-dimensional cutting of the cornea guided by diagnostic imaging creates multiplanar self-sealing incisions and allows exact placement of the limbal relaxing incisions, potentially increasing the safety and performance of cataract surgery.

Rescue of an extending capsulorrhexis by creating a midway tangential anterior capsular flap: a novel technique in 22 eyes

OBJECTIVE

To show how an extending capsulorrhexis can be rescued by a midway tangential capsular flap in order to achieve an uneventful phacoemulsification.

DESIGN

Consecutive case series.

PARTICIPANTS

Twenty-two eyes of 22 patients with extending capsulorrhexis treated at the Farabi Eye Hospital, Tehran.

METHODS

First, a tangential capsular opening was created on the border of the presumed continuous curvilinear capsulorrhexis just midway between the beginning of the capsulorrhexis and the edge of the extending capsulorrhexis, to make a tangential flap of the anterior capsule. Second, the centre of this new flap was grasped and pulled centripetally until the edges of the new flap joined the edges of the extending flap to complete the capsulorrhexis.

RESULTS

The technique was successfully performed in all cases, leading to an uneventful phacoemulsification.

CONCLUSIONS

Midway tangential capsular flap is a safe and effective technique to rescue an extending capsulorrhexis and leads to an uneventful phacoemulsification.

Crossed-swords, capsule-pinch technique for capsulotomy in pediatric and/or loose lens cataract extraction

Puncturing the anterior capsule in a patient with a very soft lens, an elastic capsule, and/or deficient zonular countertraction can be challenging even with a sharp needle or blade. The crossed-swords, capsule-pinch technique capitalizes on opposing forces from 2 needles directed toward each other with a "pinch" of the capsule between their tips. This affords a controlled and facile puncture of the capsule without creating stress on the zonules or anteroposterior displacement of the lens.

Anterior capsulotomy with a pulsed-electron avalanche knife

PURPOSE

To evaluate a new pulsed-electron avalanche knife design for creating a continuous curvilinear capsulotomy (CCC) and compare the CCC with a mechanical capsulorhexis.

SETTING

Department of Ophthalmology, Stanford University, Stanford, California, USA.

METHODS

In this study, CCCs were created in freshly enucleated bovine eyes and in rabbit eyes in vivo. The cutting velocity was adjusted by controlling the burst repetition rate, voltage amplitude, and burst duration. Tissue samples were fixed and processed for histology and scanning electron microscopy (SEM) immediately after surgery.

RESULTS

The study included 50 bovine eyes and 10 rabbit eyes. By adjusting the electrosurgical waveforms, gas-bubble formation was minimized to permit good surgical visualization. The optimum voltage level was determined to be +/-410 V with a burst duration of 20 mus. Burst repetition rate, continuously adjustable from 20 to 200 Hz with footpedal control, allowed the surgeon to vary linear cutting velocity up to 2.0 mm/s. Histology and SEM showed that the pulsed-electron avalanche knife produced sharp-edged capsule cutting without radial nicks or tears.

CONCLUSIONS

The probe of the pulsed-electron avalanche knife duplicated the surgical feel of a 25-gauge cystotome and created a histologically smooth capsule cut. It may improve precision and reproducibility of creating a CCC, as well as improve its proper sizing and centration, especially in the face of surgical risk factors, such as weak zonules or poor visibility.

FINANCIAL DISCLOSURES

Drs. Palanker and Vankov hold patents to the pulsed electron avalanche knife technology, which are licensed to PEAK Surgical by Stanford University. Drs. Palanker and Chang are consultants to PEAK Surgical. Dr. Vankov is an employee of PEAK Surgical. Neither of the other authors has a financial or proprietary interest in any material or method mentioned.

Four-incision capsulorhexis in pediatric cataract surgery

Pediatric cataract surgery is challenging, with multiple differences from cataract surgery in adults; however, an ideal capsulorhexis is the major prerequisite for both. Capsulorhexis in children is more difficult due to the more elastic nature of the anterior capsule. I describe a technique for anterior and posterior continuous curvilinear capsulorhexes in pediatric cataract surgery using 4 arcuate incisions. The results in 10 eyes of 10 children are presented.

Pulsed electron avalanche knife: new technology for cataract surgery

BACKGROUND

The pulsed electron avalanche knife (PEAK-fc) is a new pulsed electrosurgical device that allows for precise, "cold" and traction-free tissue dissection.

AIM

To evaluate the surgical applicability, safety and potential complications of PEAK-fc in complicated cataract surgery.

METHODS

The study included five children with congenital cataracts, two patients with advanced senile cataracts, six adults with mature cataracts, three of them with posterior iris synechia, three patients with post-traumatic cataracts with zonulolysis, one patient with intumescent traumatic cataract and three patients with massive anterior capsule opacification. Anterior and posterior capsulotomies, iris synechiolysis, dissection of anterior capsule opacification and fibrotic scar tissue were performed. PEAK-fc was set at voltages of 500-700 V, pulse duration of 0.1 m and repetition rate of 40-100 Hz.

RESULTS

Anterior and posterior capsulotomies were successfully and safely performed in all eyes. The edges of capsulotomies appeared sharp, showing only limited collateral damage. PEAK-fc worked best by just gently touching the capsule, thereby avoiding tractional forces or pressure on the lens capsule. Posterior iris synechiae could be released and anterior capsule opacification was dissected without complications.

CONCLUSIONS

PEAK-fc is a very helpful cutting device for complicated cases of cataract surgery, especially for mature and congenital cataracts, traumatic zonulolysis or anterior segment complications after intraocular inflammation.

Completion rate of primary posterior continuous curvilinear capsulorhexis and vitreous disturbance during congenital cataract surgery

PURPOSE

We sought to document the completion rate of primary posterior continuous curvilinear capsulorhexis during congenital cataract surgery and determine the incidence of disruption of vitreous face during this procedure.

METHODS

One hundred six consecutive eyes of patients undergoing posterior continuous curvilinear capsulorhexis (PCCC) during congenital cataract surgery were evaluated prospectively for completion of PCCC and disruption of vitreous face. PCCC was performed under high-viscosity sodium hyaluronate (Healon GV 1.4%) initiated with 26 g of cystotome and later completed with Kraff-Uttrata forceps by frequent grasping and regrasping of the flap. Completion of PCCC and disruption of vitreous face during the procedure was noted. Even in cases of disrupted vitreous face, PCCC was performed and completed with forceps and, later, disruption of vitreous face was managed with 2-port automated limbal anterior vitrectomy. The size of PCCC was measured. An Alcon AcrySof SA30AL was implanted in-the-bag if the PCCC was 4 mm or smaller and in the sulcus when the PCCC was larger than 4 mm.

RESULTS

The mean age of the 106 pediatric patients was 17 +/- 26 months (median, 6 months; range, 1 month to 8 years). PCCC was completed in all the eyes. Disruption of vitreous face during PCCC was noted in 5 of 106 (4.7%) eyes. The mean size of PCCC was 3.6 +/- 0.7 mm. A total of 98 (92.5%) had in-the-bag, and 8 (7.5%) eyes had sulcus implantation of IOL.

CONCLUSION

PCCC was completed in all eyes with minimal disruption of vitreous face in a well-controlled manner under high-viscosity viscoelastics.

Pulsed electron avalanche knife for capsulotomy in congenital and mature cataract

The pulsed electron avalanche knife (PEAK-fc, Carl Zeiss Meditec) is an electrosurgical cutting device that allows precise "cold" and traction-free tissue dissection. We describe its applicability and safety for anterior capsulotomy in a child with congenital cataract and an adult patient with mature cataract. The PEAK-fc was set at a voltage of 600 V and a pulse repetition rate of 80 Hz. Anterior capsulotomies were successfully and safely performed in both cases, with the edges of capsulotomies appearing sharp and showing only limited collateral damage. The PEAK-fc appears to be a helpful cutting device for complicated cases of cataract surgery, especially for mature and congenital cataracts.

Extensibility and scanning electron microscopy evaluation of 5 pediatric anterior capsulotomy techniques in a porcine model

PURPOSE

To compare the extensibility and scanning electron microscopy (SEM) of 5 currently used pediatric anterior capsulotomy techniques: vitrectorhexis, manual continuous curvilinear capsulorhexis (CCC), can-opener, radio frequency diathermy, and plasma blade in a porcine model.

SETTING

Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Extensibility was determined by stretching each capsulotomy until it ruptured and measuring it by calculating the mean stretch-to-rupture circumference of each capsulotomy (20 eyes per technique) as a percentage of its baseline circumference. Edge characteristics were evaluated using SEM.

RESULTS

The mean extensibility of each technique tested (vitrectorhexis 161%, CCC 185%, can opener 149%, radio frequency 145%, plasma blade 170%) was significantly different (P<.001, 1-way analysis of variance). The SEM examination found that the vitrectorhexis had a scalloped edge with the whole edge rolled over, presenting a smooth surface toward the inside of the capsulotomy; the manual CCC produced the smoothest edge, with no irregularities noted; the can-opener edge was irregular, showing each puncture of the needle had created a small arc, with occasional regions of the edge rolled over in a "hit-and-miss" fashion; the radio-frequency diathermy capsulotomy edge was ragged, rough, and irregular; and the plasma blade capsulotomy edge was rougher than the manual CCC, but there were fewer irregularities than the radio-frequency diathermy edge had.

CONCLUSIONS

The manual CCC technique produced the most extensible porcine capsulotomy, followed by the plasma blade, vitrectorhexis, can-opener, and radio-frequency techniques, in a porcine model. The manual CCC technique also produced the smoothest anterior capsulotomy edge according SEM evaluation.