A comparative study of the elastic properties of continuous tear curvilinear capsulorhexis versus capsulorhexis produced by radiofrequency endodiathermy

Precision pulse capsulotomy: an automated alternative to manual capsulorhexis in paediatric cataract

Objective

To report our operative experience with precision pulse capsulotomy (PPC) for anterior capsulotomy in a paediatric cataract series.

Methods and analysis

This study is a retrospective interventional, descriptive series of consecutive paediatric eyes (≤16 years) undergoing cataract surgery using PPC. Surgical time and the time required to perform PPC was recorded. Any intraoperative and postoperative adverse events were noted. Postoperatively, visual acuity, anterior segment examination and intraocular pressure (IOP) were recorded for all children at day 1, 1 week and 1 month.

Results

21 eyes of 14 patients were included in the study, with the median age at surgery of 6.0 years (IQR; 5-7.75, range=1–16 years). Male to female ratio was 11:3. 13 eyes had lamellar cataract, 3 eyes had total cataract, 2 had posterior subcapsular cataract, 2 had traumatic cataract, while 1 eye had sutural cataract. Median surgical time was 26 min (IQR 21-32) and median PPC time was 75.0 secs (IQR 56-86.5). The anterior capsulotomy was round and complete in most cases, except in one case due to faulty suction. All patients underwent a successful in the bag implantation of intraocular lens with capsulotomy margins overlapping the optic edges in 19 eyes (90%). Median PPC size was 5.54 mm (n=9, IQR 5.39 -5.75) which was slightly larger than expected. None of the cases had any intraoperative or postoperative adverse events with no radial tears of capsulotomy. Postoperatively, the mean final follow-up was 5.71+3.20 weeks.

Conclusion

To conclude PPC can be used as an alternative to manual continuous curvilinear capsulorhexis in paediatric cataract surgery producing round well- centred and strong capsulotomy with an easier learning curve.

Updates on managements of pediatric cataract

Purpose

A comprehensive review in congenital cataract management can guide general ophthalmologists in managing such a difficult situation which remains a significant cause of preventable childhood blindness. This review will focus on surgical management, postoperative complications, and intraocular lens (IOL)-related controversies.

Methods

Electrical records of PubMed, Medline, Google Scholar, and Web of Science from January 1980 to August 2017 were explored using a combination of keywords: "Congenital", "Pediatric", "Childhood", "Cataract", "Lens opacity", "Management", "Surgery", "Complication", "Visual rehabilitation”, and "Lensectomy". A total number of 109 articles were selected for the review process.

Results

This review article suggests that lens opacity obscuring the red reflex in preverbal children and visual acuity of less than 20/40 is an absolute indication for lens aspiration. For significant lens opacity that leads to a considerable risk of amblyopia, cataract surgery is recommended at 6 weeks of age for unilateral cataract and between 6 and 8 weeks of age for bilateral cases. The recommended approach in operation is lens aspiration via vitrector and posterior capsulotomy and anterior vitrectomy in children younger than six years, and IOL implantation could be considered in patients older than one year. Most articles suggested hydrophobic foldable acrylic posterior chamber intraocular lens (PCIOL) for pediatrics because of lower postoperative inflammation. Regarding the continuous ocular growth and biometric changes in pediatric patients, under correction of IOL power based on the child's age is an acceptable approach. Considering the effects of early and late postoperative complications on the visual outcome, timely detection, and management are of a pivotal importance. In the end, the main parts of post-operation visual rehabilitation are a refractive correction, treatment of concomitant amblyopia, and bifocal correction for children in school age.

Conclusions

The management of congenital cataracts stands to challenge for most surgeons because of visual development and ocular growth. Children undergoing cataract surgery must be followed lifelong for proper management of early and late postoperative complications. IOL implantation for infants less than 1 year is not recommended, and IOL insertion for children older than 2 years with sufficient capsular support is advised.

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.

Histologic Evaluation of in vivo Femtosecond Laser–Generated Capsulotomies Reveals a Potential Cause for Radial Capsular Tears

Purpose

To compare histologically the size and appearance of capsule disks after femtosecond laser–assisted cataract surgery and conventional cataract surgery.

Methods

In 100 eyes of 100 patients with visually significant cataracts, a femtosecond laser capsulotomy or a capsulorhexis with an aimed diameter of 5.0 mm was performed by one experienced surgeon. The diameter, area, circularity, and cut quality was histologically examined with light microscopy and scanning electron microscopy.

Results

The mean diameter of the manual and the femtosecond laser capsule disk group were not statistically significantly different (manual 4.91 ± 0.34; femtosecond: 4.93 ± 0.03; p = 0.58). The mean area of the capsule disks was 18.85 ± 2.69 mm2 in the manual and 19.03 ± 0.26 mm2 in the femtosecond group (p = 0.64). The capsules of the femtosecond group (0.95 ± 0.02) were significantly more circular than the ones of the manual group (0.81 ± 0.07; p<0.0001). The femtosecond laser capsule disks displayed a more saw blade–like structure created through the single laser spots. The histologic examination combined with prospective video analysis revealed respiratory movement of the eye during the capsulotomy as a potential risk factor for redial tears.

Conclusions

Femtosecond laser can perform a capsulotomy with high reliability. In comparison to a highly experienced cataract surgeon, the achieved results in size are similar. In terms of circularity, the femtosecond laser was superior the manual procedure. Better refractive outcomes based on a 360°-degree optic overlap seem to be possible, especially for less experienced surgeons.

In-the-bag intraocular lens placement via secondary capsulorhexis with radiofrequency diathermy in pediatric aphakic eyes

Pediatric ophthalmologists increasingly recognize that the ideal site for intraocular lens (IOL) implantation is in the bag for aphakic eyes, but it is always very difficult via conventional technique. We conducted a prospective case series study to investigate the success rate and clinical outcomes of capsular bag reestablishment and in-the-bag IOL implantation via secondary capsulorhexis with radiofrequency diathermy (RFD) in pediatric aphakic eyes, in which twenty-two consecutive aphakic pediatric patients (43 aphakic eyes) enrolled in the Childhood Cataract Program of the Chinese Ministry of Health were included. The included children underwent either our novel technique for secondary IOL implantation (with RFD) or the conventional technique (with a bent needle or forceps), depending on the type of preoperative proliferative capsular bag present. In total, secondary capsulorhexis with RFD was successfully applied in 32 eyes (32/43, 74.4%, age 5.6±2.3 years), of which capsular bag reestablishment and in-the-bag IOL implantation were both achieved in 30 eyes (30/43, 70.0%), but in the remaining 2 eyes (2/32, 6.2%) the IOLs were implanted in the sulcus with a capsular bag that was too small. Secondary capsulorhexis with conventional technique was applied in the other 11 eyes (11/43, 25.6%, age 6.9±2.3 years), of which capsular bag reestablishment and in-the-bag IOL implantation were both achieved only in 3 eyes(3/43, 7.0%), and the IOLs were implanted in the sulcus in the remaining 8 eyes. A doughnut-like proliferative capsular bag with an extensive Soemmering ring (32/43, 74.4%) was the main success factor for secondary capsulorhexis with RFD, and a sufficient capsular bag size (33/43, 76.7%) was an additional factor in successful in-the-bag IOL implantation. In conclusion, RFD secondary capsulorhexis technique has 70% success rate in the capsular bag reestablishment and in-the-bag IOL implantation in pediatric aphakic eyes, particularly effective in cases with a doughnut-like, extensively proliferative Soemmering ring.

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.

Efficacy of sub-Tenon's block using an equal volume of local anaesthetic administered either as a single or as divided doses. A randomised clinical trial

Background

Sub-Tenon's anaesthetic is effective and reliable in producing both akinesia and anaesthesia for cataract surgery. Our clinical experience indicates that it is sometimes necessary when absolute akinesia is required during surgery to augment the block with 1–2 ml of local anaesthetic. Hypothesis was that after first injection some of the volume injected may spill out and before second injection the effect of hyaluronidase has taken place and second volume injectate will have desired effect.

Methods

A prospective, randomised, control trial in which patients were randomly allocated to one of two groups. In group 1, single injection of 5 ml of local anaesthetic was injected. In group 2, 3 ml of the same anaesthetic solution was injected followed by application of gentle orbital pressure for 2 minutes. A further 2 ml of the same anaesthetic solution was injected through the same conjunctival incision. Measurement of movement in four quadrants of eye was done by the surgeon at 3 and 6 minutes. Intraocular pressure, chemosis, and subconjuctival haemorrhage were also measured.

Results

Significant differences at 3 minutes between groups for overall movement, medial, superior, and lateral quadrants occurred. At 6 minutes no significant group differences emerged for the overall movement or for any of four quadrants.

Conclusion

Single injection of local anaesthesia for sub-Tenon's block with mixture of lignocaine with adrenaline, bupivacaine and hyaluronidase was found to be superior to provide akinesia of ocular muscles compared to divided dose given by two injections. No difference in groups in terms of haemorrhage, chemosis, patient's satisfaction and intraocular pressure was found.

Trial registration

Trial registration no-ISRCTN73431052

Assessment of the strength of minicapsulorhexes

PURPOSE

To evaluate the effect of age, size, position, and species on the strength of minicapsulorhexes.

SETTING

Surgical Suite and Laser Laboratory, Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA.

METHODS

Capsulorhexes 0.7 to 2.3 mm in diameter were made centrally or peripherally in 35 eye-bank eyes and 32 rabbit eyes. A custom-made instrument stretched the capsulorhexes until rupture. Load and stretch at rupture were recorded.

RESULTS

Maximum load and stretch were 26.3 mN +/- 20.3 (SD) and 50% +/- 18% for central and 50.8 +/- 20.5 mN and 69% +/- 17% for peripheral capsulorhexes in eye-bank eyes and 19.8 +/- 15.2 mN and 38% +/- 13% for central and 13.5 +/- 9.5 mN and 30% +/- 7% for peripheral capsulorhexes in rabbit eyes. Peripheral capsulorhexes were stronger and more elastic than central capsulorhexes in eye-bank eyes, and maximum load and stretch increased statistically with the capsulorhexis diameter.

CONCLUSIONS

Peripheral minicapsulorhexes were more resistant to rupture than central capsulorhexes in eye-bank eyes, probably because of increased lens capsule thickness at the periphery. An increase in capsulorhexis diameter increased the resistance to rupture.

Five-year experience of the 2-incision push-pull technique for anterior and posterior capsulorrhexis in pediatric cataract surgery

PURPOSE

To describe the authors' 5-year experience of the 2-incision push-pull (TIPP) technique for pediatric anterior and posterior capsulorrhexis formation.

DESIGN

Retrospective descriptive study over a 5-year period.

PARTICIPANTS

A total of 84 eyes of 63 patients who had undergone cataract surgery in 1 center.

METHODS

Retrospective review of all consecutive patients who underwent pediatric cataract extraction with planned intraocular lens implantation and TIPP rhexis between January, 1999, and August, 2004. Any lost capsulorrhexis, or capsular tears at any stage of the operation, and the relation of optic size to anterior capsulorrhexis size were noted.

MAIN OUTCOME MEASURES

Complications during TIPP rhexis formation and any late complications at last visit.

RESULTS

The mean age at operation was 70.21 months (range, 4 weeks-18 years). All eyes had anterior TIPP rhexis; 41 eyes also had posterior TIPP rhexis, and there were no anterior or posterior capsulorrhexis loss or tears while performing the technique. In no patient in whom TIPP rhexis was performed for the posterior capsule was there an inadvertent vitreous loss during rhexis formation. All eyes had anterior rhexis diameters that were smaller than the optic diameter (5.5-6.0 mm), approximately 4 to 4.5 mm in diameter. Four capsular tears were reported; 1 tear occurred during irrigation and aspiration and the others during rigid lens insertion. No late complications were noted.

CONCLUSIONS

Our 5-year experience with the TIPP rhexis in pediatric cataract surgery has shown this to be a reliable method for producing a consistent-size capsulorrhexis opening in both anterior and posterior capsulorrhexis.

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.

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.

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

PURPOSE

To compare the quality of the edges of anterior capsulotomies performed in porcine eyes using 3 different techniques.

SETTING

David J. Apple, MD Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA.

METHODS

Four porcine eyes were submitted to the center in 10% neutral buffered formalin. The cornea of the eyes had been removed, and a continuous capsulotomy had been performed in each eye using the Fugo plasma blade. To provide morphologic correlation, 4 additional porcine eyes were used in the study. In 2, a manual continuous curvilinear capsulorhexis (CCC) was performed after the cornea or cornea/iris was removed and in the other 2, a can-opener capsulotomy (COC) was performed. The eyes were then placed in 10% neutral buffered formalin. Gross (macroscopic) and microscopic analysis of each eye was performed, and photographs were taken. One eye in each group was also prepared and analyzed under scanning electron microscopy (SEM).

RESULTS

The capsulotomy margin in the Fugo blade group presented some regularly spaced tags directed centrally with smooth edges at the base. Such a configuration would not interfere with the dynamics of the capsulorhexis sphincter and would generally not lead to radial tears. The smooth and regular nature of the capsulotomy margin in the CCC group was confirmed by gross and microscopic examinations of the eyes. The capsulotomy margin in the COC group presented some sharp notches directed outward, irregularly spaced, and irregular in shape. These are known to have a tendency to extend and form radial tears.

CONCLUSION

Although performance of an anterior capsulotomy with the Fugo blade was associated with some margin irregularities, the geometry of the centrally directed tags prevented them from becoming the site of radial tear formation. The base of the capsulotomy performed with the Fugo blade appeared to be almost as smooth and regular as in the CCC under SEM evaluation.

Anterior lens capsule management in pediatric cataract surgery

PURPOSE

To describe and analyze pediatric anterior capsulotomy techniques and make recommendations.

METHODS

Five anterior capsulotomy techniques were compared using a porcine model. Extensibility was measured by calculating the mean stretch-to-rupture circumference of each capsulotomy (20 eyes per technique) as a percentage of its circumference at rest. Edge characteristics were reviewed using scanning electron microscopy. A 10-year review of consecutive pediatric cataract surgeries performed by the author focused on the anterior capsulotomy results. A worldwide survey was used to determine current practice patterns.

RESULTS

Manual continuous curvilinear capsulorrhexis (CCC) produced the most extensible porcine capsulotomy (185%) with the most regular edge and is preferred by surgeons for patients aged 2 years and older. In the pseudophakic clinical cases reviewed, a radial tear developed in 3 (6.5%) of 46 manual CCC cases. Vitrectorhexis (porcine extensibility, 161%) is preferred by surgeons during the first 2 years of life. A radial tear developed in 16 (7.7%) of 208 vitrectorhexis pseudophakic eyes (29 tears in 284 pseudophakic eyes [10.2%] overall). The Kloti diathermy unit, Fugo plasma blade, and "can-opener" technique produced porcine capsulotomies of 145%, 170%, and 149% extensibility, respectively, and radial tears numbering 4 (21%) of 19, 5 of 8, and 1 of 2, respectively, in the clinical series.

CONCLUSIONS

All five capsulotomy techniques are recommendable for children. Only the vitrectorhexis and manual CCC are commonly used today. Vitrectorhexis is well suited for use in infants and young children; manual CCC is best used beyond infancy, and it produces the most stable edge.

Tissue damage at anterior capsule edges after continuous curvilinear capsulorhexis, high-frequency capsulotomy, and erbium:YAG laser capsulotomy

PURPOSE

To compare the effect of erbium:YAG laser photocapsulotomy (ELC), continuous curvilinear capsulorhexis (CCC), and high-frequency capsulotomy (HFC) on anterior capsule edges using light microscopy (LM) and transmission electron microscopy (TEM).

SETTING

Department of Ophthalmology, Department of Histology and Embryology II, University of Vienna, Vienna, Austria.

METHODS

Five anterior capsule membranes were obtained experimentally by ELC, which was performed with the Oertli MicroLaser photoemulsification tip in eyes from 5 human cadavers. Thirty anterior capsule membranes were obtained during cataract surgery by CCC (n = 15) or, in cases with poor or missing red fundus reflexes, by HFC (n = 15). Continuous curvilinear capsulorhexis was performed conventionally with a manual, bent, 27-gauge cannula, and HFC was performed according to Klöti. Membranes were processed and examined by LM and TEM according to standard procedures.

RESULTS

The edges obtained by ELC showed mild signs of denaturation and mechanical disruption, tears, and micro-tears. Lens capsule edges obtained by CCC were smooth with no irregularities in any specimen; the edges were beveled anteriorly to posteriorly with no evidence of tearing. Edges produced by HFC were considerably wider; the surfaces showed distinct denaturation, preformed tears, and micro-tears. The edges were surrounded by a nonhomogeneous mass, which consisted mainly of denatured lens capsule material.

CONCLUSIONS

Of the 3 techniques, CCC produced the mildest tissue damage. The histological damage at ELC edges was relatively mild and intermediate compared with that seen at CCC and HFC edges. These observations suggest that ELC is an appropriate option for anterior capsulotomy in cataract surgery.

Gentian violet solution for staining the anterior capsule

PURPOSE

To evaluate the histopathological changes after injecting gentian violet solution into the anterior chamber of rats and to describe a technique that uses gentian violet to allow a clear view of the anterior capsule during continuous curvilinear capsulorhexis (CCC) in human eyes with white mature cataract.

SETTING

Department of Ophthalmology, University of Dicle, Diyarbakir, Turkey.

METHODS

In this masked, experimental study (first stage), 0.05 mL of gentian violet 0.01% or 0.001% solution or balanced salt solution (BSS) (control group) was injected into the anterior chamber of 30 eyes of 30 Wistar albino rats. One, 24, and 48 hours after injection, 4 eyes in each group and 2 eyes in the control group were enucleated, and histopathological examination was performed. In the second stage, these solutions were used for staining the anterior capsule in the 18 human eyes with white mature cataract. The success rate of CCC and intraoperative and postoperative complications were evaluated.

RESULTS

Histopathological examination revealed no pathology in any group. A CCC was completed in all cases. No intraoperative or postoperative complications were observed in human eyes except mild corneal edema and mild inflammatory reaction in the anterior chamber that improved within 1 week. Mean follow-up was 3.4 months. Visualization of the anterior capsule was better with gentian violet 0.01% solution.

CONCLUSIONS

Gentian violet solutions at 0.01% and 0.001% concentrations had no evident toxic effect that caused significant histopathological changes. The staining technique was practical and helped the surgeon visualize the anterior capsule. However, gentian violet may have adverse effects that lead to corneal edema.

Small peripheral anterior continuous curvilinear capsulorhexis

Cataract surgery is routinely performed using an anterior continuous curvilinear capsulorhexis (CCC). A manual surgical technique is described for performing a small (less than 1.5 mm diameter) anterior CCC. This technique's applications extend from Phaco-Ersatz, a cataract surgical technique designed to restore accommodation to pediatric cataract surgery. An experimental rabbit study was conducted to determine the feasibility of the technique. Up to 9 small peripheral anterior CCCs were made in the same lens capsule without the capsule tearing. The mean diameter of the CCCs was 1.1 mm +/- 0.3 (SD). A 30 gauge needle and Utrata capsulorhexis forceps were used to construct the CCC. This technique shows promise for the successful performance of small CCCs in Phaco-Ersatz procedures and pediatric cataract surgery.

Elastic properties and scanning electron microscopic appearance of manual continuous curvilinear capsulorhexis and vitrectorhexis in an animal model of pediatric cataract

PURPOSE

To compare the tear resistance of anterior capsulotomies using manual continuous curvilinear capsulorhexis (CCC) and vitrector-cut capsulotomy (vitrectorhexis) techniques in an animal model of the pediatric eye and in 2 pairs of human infant eyes.

SETTING

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

METHODS

Continuous curvilinear capsulorhexis and automated vitrectorhexis capsulotomy techniques were performed in 20 pig eyes, 10 with each technique. The capsules were then stretched until they ruptured. The forces required for rupture after each technique were compared. The forces required for rupture of the pig eye lens capsule were also compared with those required for the human infant eye lens capsule. Scanning electron microscopy was performed in each group following intraocular lens (IOL) insertion.

RESULTS

All capsules stretched adequately for IOL insertion. The percentage of stretch prior to rupture was higher in the capsulorhexis group (mean 157%, range 147% to 169%) than in the vitrectorhexis group (mean 135%, range 124% to 147%) (P < .001). The percentage of stretch in the human infant eyes was not statistically different from that in the porcine eyes (P > .05).

CONCLUSIONS

The manual CCC offered greater resistance to capsule tearing than the vitrectorhexis and also revealed a more smooth, regular edge. It therefore remains the gold standard. However, the vitrectorhexis displayed more than adequate resistance to unwanted anterior capsule tears when used for IOL insertion through capsulotomy sizes currently used in clinical practice.

Surgical techniques for difficult cataracts

This article reviews some of the advances that have taken place in the surgical techniques for difficult cataracts such as rock-hard, white, and posterior polar cataracts. Fashioning a central space, modified chopping maneuvers, and creation of multiple small fragments have enabled the surgeon to consistently achieve a successful outcome. A judicious combination of chop and separation movement in a step-by-step manner reduce the stress of the procedure and make it safer. Raised intracapsular pressure and poor visibility are dealt with through various innovative techniques. Use of high-viscosity sodium hyaluronate and double capsulorhexis allow the surgeon to achieve capsulorhexis with a high success rate. A controlled and gentle approach to phacoemulsification has proven to be the key factor for success in posterior polar cataracts.

Viscoelastic-injecting cystotome

This continuous curvilinear capsulorhexis (CCC) technique is for use in complicated surgical cases such as when the anterior chamber is shallow, the red reflex is not good, or eye movements are present. This technique is easier and safer in such cases because it uses a cystotome connected to a viscoelastic syringe. First, the anterior chamber is filled with viscoelastic material using a conventional cannula. The cannula is replaced with a bent needle (or cystotome), and the CCC is performed in the usual way. This instrument allows the surgeon to inject small amounts of viscoelastic material exactly where and when it is needed. The anterior chamber remains deep while the CCC is performed, and the anterior capsule tear is done in a more controlled fashion.

Anterior capsulotomy created by radiofrequency endodiathermy and continuous curvilinear posterior capsulorhexis in a patient with intumescent cataract and primary capsular fibrosis

A 62-year-old woman with intumescent cataract and primary posterior capsular fibrosis was operated on using two different techniques to create continuous curvilinear capsule openings in the same eye. The biomicroscopic appearance of the edge after continuous tear and radiofrequency endodiathermy capsulotomy were compared.

Phacoemulsification of white mature cataracts

PURPOSE

To evaluate the intraoperative difficulties associated with phacoemulsification of white mature cataracts and develop a strategy for consistently achieving continuous curvilinear capsulorhexis (CCC) in these cases.

SETTING

Raghudeep Eye Clinic, Iladevi Cataract & IOL Research Centre, Ahmedabad, India.

METHODS

This prospective study comprised 60 eyes of 60 patients with senile white mature cataract. Mean follow-up was 7 months. Detailed preoperative and intraoperative notes were made including intraoperative subjective assessment of the intracapsular pressure and cataract hardness. A small capsulorhexis was attempted initially. Endophacoemulsification was performed using the stop, chop, chop, and stuff technique. The capsulorhexis was enlarged before intraocular lens implantation. An initial cut in the capsulorhexis margin was made with a cystotome needle while a spatula supported the anterior capsule. The capsulorhexis was then enlarged with forceps.

RESULTS

A CCC was achieved in 57 eyes (95%). Intracapsular pressure was judged to be raised in 24 eyes (40%). Of these, CCC was accomplished in 21 eyes (88%). Statistical analysis confirmed that raised intracapsular pressure was a significant factor. Capsule opacification or plaque was detected at the end of the surgery in 20 eyes (33%); 50% of the nuclei were of grade 5 hardness.

CONCLUSION

If a CCC can be achieved, the results of white cataract phacoemulsification are comparable to those of routine cataract surgery. When using the two-stage technique, one should be prepared to deal with a hard cataract through a small capsulorhexis.

Forceps-puncture continuous curvilinear capsulorhexis

Forceps-puncture continuous curvilinear capsulorhexis uses a single instrument. Using less instrumentation during the procedure decreases the chance of inadvertent damage to ocular structures and reduces surgical time. Complications related to this technique are rare.

Diathermic capsulotomy versus capsulorhexis: a biomechanical study

PURPOSE

To compare the mechanical quality of a capsulotomy opening performed by diathermy with that made by capsulorhexis (tearing).

SETTING

Department of Ophthalmology, Vejle Hospital, Denmark.

METHODS

This study included 12 pairs of human cadaver eyes and 20 pairs of pig eyes. One in each pair was randomly selected for one capsulotomy technique. The capsulotomy edge was stretched in a materials testing machine until break; force and elongation values were continuously recorded.

RESULTS

In humans, the extensibility of the diathermic capsulotomy edge was approximately half that of the capsulorhexis edge (mean 38% +/- 4 [SD] versus 68% +/- 6), and the force required to break the edge was reduced by a factor of five (26 +/- 8 mN versus 134 +/- 36 mN).

CONCLUSION

The mechanical quality of the diathermic capsulotomy edge is significantly less than that of the capsulorhexis edge, which indicates that the diathermic capsulotomy edge would withstand less surgical manipulation.

Radiofrequency diathermy capsulorhexis of the anterior and posterior capsules in pediatric cataract surgery: preliminary results

PURPOSE

To assess the effectiveness of radiofrequency diathermy capsulorhexis in preventing opacification of the posterior capsule in pediatric cataract extraction.

SETTING

The Children's Hospital, Dublin, Ireland.

METHODS

Radiofrequency diathermy capsulorhexis to the anterior capsule followed by injection of sodium hyaluronate behind the posterior capsule and primary posterior capsule diathermy capsulorhexis were performed in 14 eyes of 7 children requiring cataract surgery.

RESULTS

Six patients had bilateral congenital and 1 patient bilateral developmental cataracts. Ten eyes (5 patients) received heparin-surface-modified intraocular lenses, and 4 eyes (2 patients) were left aphakic. There were no intraoperative complications, and only mild anterior segment inflammation was noted postoperatively.

CONCLUSION

With follow-up from 7 to 16 months (mean 12.1 months), our results showed no epithelial regrowth or opacification of the posterior capsule following diathermy capsulorhexis.