Posterior continuous curvilinear capsulorhexis. An experimental study with clinical applications

Postoperative intraocular lens stability following cataract surgery with or without primary posterior continuous curvilinear capsulorrhexis: an intra-individual randomized controlled trial

PURPOSE

To evaluate the effect of primary posterior continuous curvilinear capsulorrhexis (PPCCC) on the positional stability of IOLs.

METHODS

This study is a prospective intra-individual comparative randomized controlled trial including 31 patients (62 eyes). Eyes of the same patient were randomly assigned to the PPCCC group (18 right eyes and 13 left eyes) or group without PPCCC (NPCCC group). Eyes in both groups were implanted with a one-piece foldable hydrophobic acrylic IOL via routine cataract surgery. Patients in the PPCCC group underwent additional manual PPCCC before IOL implantation. Examinations were performed 1 day, 1 week, 1 month and 3 months postoperatively. IOL tilt (x, y), decentration (x, y), anterior chamber depth (z) and refractive prediction error data were collected and analyzed with Pentacam.

RESULTS

Postoperatively, the range of IOL position change over 3 months in PPCCC group was comparable to NPCCC group, which indicated smaller value in every tilt and decentration index. PPCCC eyes showed comparable tilt and decentration with NPCCC eyes in this study endpoint: mean tilt (x, y), decentration (x, y) and anterior chamber depth (ACD) were 1.04 ± 0.56°, 0.90 ± 0.64°, 0.239 ± 0.140 mm, 0.233 ± 0.133 mm and 4.01 ± 0.32 mm, respectively, in the PPCCC group vs. 1.09 ± 0.76°, 1.10 ± 0.82°, 0.252 ± 0.153 mm, 0.244 ± 0.155 mm and 4.01 ± 0.38 mm, respectively, in the NPCCC group. Refractive prediction error in the PPCCC group demonstrated a mild hyperopic shift vs. the NPCCC group (0.13 ± 0.50 vs. 0.05 ± 0.39; p = 0.208), and corrected distance visual acuity (CDVA) did not differ between the two groups (0.027 ± 0.014 vs. 0.059 ± 0.185; p = 0.377).

CONCLUSIONS

Comparable IOL tilt, decentration, ACD and refractive prediction error were observed in PPCCC eyes with that underwent routine cataract surgery. Little IOL position fluctuation and good visual acuity were shown in PPCCC group over time.

TRAIL REGISTRATION

The study was registered at the Chinese Clinical Trial Register Center on May 27th, 2020 (protocol code ChiCTR2000033304, 27/05/2020).

Primary Posterior Continuous Circular Capsulorhexis without the Use of Ophthalmic Viscosurgical Device

Performing primary posterior capsulorhexis (PPCCC) during cataract surgery is an effective prevention of secondary cataracts. It is important not to damage the anterior vitreous membrane to minimize the possible complications and adverse side effects of this step of the surgery. Most authors use a viscoelastic material to protect the anterior vitreous membrane, injected into the space between the posterior lens capsule and the vitreous membrane through a small hole in the posterior capsule. The creation of posterior capsulorhexis using 25G forceps under an implanted intraocular lens while continuously filling the anterior chamber with irrigation fluid from an irrigation cannula, without the use of a viscoelastic material is, in our opinion, a safe, fast and cheap technique of PPCCC. This technique could theoretically lead to a lower incidence of postoperative complications such as higher postoperative intraocular pressure or anterior segment inflammatory response.

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.

Primary posterior continuous curvilinear capsulorhexis combined with diffractive multifocal intraocular lens implantation

PurposeTo evaluate the effect of mild posterior capsule opacity (PCO) on visual acuity (VA) in eyes implanted with a diffractive multifocal intraocular lens (IOL) compared with a monofocal IOL, and the effect of posterior continuous curvilinear capsulorhexis (PCCC) combined with diffractive multifocal IOL implantation.MethodsFor the initial evaluation, we compared charge-coupled device (CCD) camera photographs taken through both a monofocal IOL-loaded model eye and a diffractive IOL-loaded model eye under the conditions of both with and without an opaque filter for the simulation of mild PCO. The clinical evaluation involved 20 patients who underwent bilateral implantation of the same diffractive multifocal IOL. In all 20 cases, PCCC was performed in 1 eye (PCCC group) and not performed in the fellow eye (NCCC group). Postoperative clinical results were then compared between the two groups.ResultsThe CCD photographs revealed that the diffractive IOL-loaded eye was more strongly affected by the simulated PCO than was the monofocal IOL-loaded eye. In the clinical setting, the PCCC group registered better results than NCCC group in distance and near VA, low-contrast VA, and contrast sensitivity testing.ConclusionsDiffractive multifocal IOLs tend to be more influenced by mild PCO than do monofocal IOLs, and PCCC prior to IOL implantation can contribute to the avoidance of this effect.

Intraocular pressure rise after primary posterior continuous curvilinear capsulorhexis with a fixed dorzolamide–timolol combination

PURPOSE

To assess the safety, in terms of the intraocular pressure (IOP), of cataract surgery with primary posterior continuous curvilinear capsulorhexis (PPCCC) and a postoperative dose of a fixed dorzolamide-timolol combination and evaluate the effect of intraocular lens (IOL) haptic angulation.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

In this prospective randomized double-masked bilateral study, 88 eyes of 44 consecutive patients with age-related cataract were included in an intraindividual comparison study. All patients had standardized cataract surgery with PPCCC and IOL implantation in the capsular bag followed by a postoperative dose of a fixed dorzolamide-timolol combination. Patients were randomly assigned to receive an ACR6D SE IOL (Laboratoires Cornéal) in 1 eye and a Centerflex (C-flex) 570C IOL (Rayner Surgical GmbH) in the contralateral eye. The IOP was measured at baseline and postoperatively at 6 and 24 hours as well as 1 week.

RESULTS

Intraindividual comparison showed statistically significantly higher IOP measurements in the C-flex 570C nonangulated IOL group than in the ACR6D SE angulated IOL group at 24 hours (P = .003) and 1 week (P = .043). The highest IOP spikes (34 mm Hg) were at 6 hours in 2 eyes with a C-flex 570C IOL. The ACR6D SE group had statistically significant changes in IOP between preoperative and all postoperative time points. In the C-flex 570C group, the only statistically significant change in IOP was between preoperatively and 6 hours postoperatively.

CONCLUSIONS

Cataract surgery with PPCCC was safe in terms of the postoperative IOP course. Haptic angulation slightly decreased the overall IOP rise and the incidence of IOP rises above 30 mm Hg.

Effect of primary posterior continuous curvilinear capsulorhexis on clinical performance of ACR6D SE single-piece hydrophilic acrylic intraocular lenses

PURPOSE

To evaluate the effects of a primary posterior continuous curvilinear capsulorhexis (PCCC) on the clinical performance of a single-piece hydrophilic acrylic intraocular lens (IOL) with haptic angulation.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

A prospective study of 52 patients with bilateral age-related cataract was conducted. Patients had standard cataract surgery with implantation of the same IOL in both eyes. Randomly, a PCCC was created in 1 eye and the posterior capsule was left intact in the fellow eye. Assessed parameters were visual axis opacification (VAO) in eyes with a PCCC or regeneratory posterior capsule opacification (PCO) in eyes without PCCC (scale 0 to 10) in the central (3.0 mm eccentricity), intermediate (3.0 to 4.5 mm eccentricity), and peripheral (>4.5 mm eccentricity [capsulorhexis edge]) areas; neodymium:YAG (Nd:YAG) laser capsulotomy or laser polishing of ongrowing lens epithelium; anterior capsule opacification (ACO); best corrected visual acuity (BCVA); and contrast sensitivity.

RESULTS

Thirty patients completed the 2(1/2)-year follow-up. Visual axis opacification was significantly lower in the central region in the PCCC group (mean 0.5 +/- 0.7 [SD]) than PCO in the central region of the non-PCCC group (mean 1.1 +/- 1.1) (P = .02). Forty percent in the non-PCCC group had an Nd:YAG laser capsulotomy during the follow-up period; none in the PCCC group had laser polishing. There were no significant differences in ACO, SE, BCVA, or contrast sensitivity. There was no additional gain in BCVA or contrast sensitivity in eyes with a PCCC compared with eyes without a PCCC when VAO and PCO were low.

CONCLUSION

A PCCC significantly reduced PCO formation within the central 3.0 mm eccentricity as well as the need for Nd:YAG laser capsulotomy in eyes with a single-piece hydrophilic acrylic IOL with angulated haptics.

Clinical effects of primary posterior continuous curvilinear capsulorhexis in eyes with single-piece hydrophilic acrylic intraocular lenses with and without haptic angulation

PURPOSE

To evaluate the clinical effects of a primary posterior continuous curvilinear capsulorhexis (PCCC) on the intraocular performance of hydrophilic acrylic single-piece intraocular lenses (IOLs) with and without haptic angulation.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

A prospective study comprised 52 patients with bilateral age-related cataract who had standard cataract surgery including a PCCC. One eye of each patient was randomized to receive a hydrophilic acrylic IOL with haptic angulation (ACR6D SE, Laboratoires Cornéal) and the contralateral eye, a hydrophilic acrylic IOL without haptic angulation (C-flex 570C, Rayner). The following parameters were assessed: regeneratory posterior opacification (RPO) in the central, intermediate, and peripheral areas (scale 0 to 10); anterior capsule opacification (ACO); best corrected visual acuity (BCVA); and contrast sensitivity (CSF).

RESULTS

Thirty-one patients completed the 1(1/2)-year follow-up. In both IOL groups, RPO within the PCCC was slight in the central area, with a mean score of 0.33 +/- 0.84 (SD) in the angulated IOL group and 0.16 +/- 0.57 in the nonangulated IOL group (P = .29). The mean RPO score in the peripheral area was 2.07 +/- 1.37 and 2.35 +/- 1.45, respectively (P = .12). The difference between the central and peripheral areas was 1.74 in the angulated IOL group (P<.00001) and 2.19 in the nonangulated IOL group (P<.00001). Haptic deformation occurred in 9 eyes (29%) with an angulated IOL and no eye with a nonangulated IOL. There was significantly more ACO in the nonangulated IOL group (P = .012). There were no significant differences in BCVA or CSF between the 2 groups.

CONCLUSIONS

Creating a PCCC led to significantly lower RPO intensity within the PCCC area than in the peripheral area in eyes with hydrophilic acrylic IOLs with and without haptic angulation. Haptic angulation had no apparent significant influence on the intensity of RPO or on BCVA and CSF. Haptic deformation may occur in hydrophilic IOLs with angulated haptics.

Efficacy of trypan blue in posterior capsulorhexis with optic capture in pediatric cataracts [ISRCTN48221688]

Background

To evaluate the efficacy of trypan blue (0.06%) in posterior capsulorhexis with optic capture in pediatric cataracts.

Methods

In this prospective randomized controlled study, trypan blue dye assisted posterior capsulorhexis with optic capture was performed in 18 eyes (group 1) and no dye was used for posterior capsulorhexis (group 2) in 17 eyes.

Results

The mean size of the posterior capsulorhexis was 4.6 +/-1.77 mm and 4.0 +/- 0.93 mm in the group 1 and 2 respectively. Optic capture was possible in 17 eyes in the group 1 and 11 eyes in the group 2.

Conclusion

Trypan blue facilitates posterior capsulorhexis with optic capture of AcrySof IOL in cases of pediatric cataracts.

Surgical management and histologic and immunohistochemical features of a cataract and retrolental plaque secondary to persistent hyperplastic tunica vasculosa lentis/persistent hyperplastic primary vitreous (PHTVL/PHPV) in a Bloodhound puppy

The objective of this study was to describe the clinical, histologic and immunohistochemical features, the surgical treatment, and outcome of a cataract secondary to persistent hyperplastic tunica vasculosa lentis/persistent hyperplastic primary vitreous (PHTVL/PHPV) in a dog. A 4-month-old male Bloodhound dog presented for evaluation of a cataract. A complete ophthalmic examination and ocular ultrasonography were performed. A resorbing cataract with intralenticular hemorrhage, lens induced uveitis, and PHTVL/PHPV were diagnosed. Extracapsular cataract extraction using phacoemulsification was performed. A primary posterior capsulectomy was performed to remove a retrolental plaque with the posterior capsule; the excised plaque was submitted for histopathology and immunohistochemical staining. A 41-Diopter intraocular lens (IOL) was implanted. Functional vision was maintained postoperatively during the 21-month follow-up period. Histologically, the posterior capsule was coiled and exhibited duplication. The retrolental plaque was comprised of dense fibrous connective tissue, blood vessels, free red blood cells, hemosiderin-laden macrophages, a pocket of neural tissue and numerous perivascular mast cells. With immunohistochemical staining, the neural elements were determined to be glial cells compatible with astrocytes. Cataract secondary to PHTVL/PHPV can be successfully treated using phacoemulsification and planned posterior capsulectomy. Posterior lens capsule duplication, mast cells and astrocytic glial cells may be normal components of the fibrovascular retrolental plaque associated with PHTVL/PHPV.

Functional outcomes of acrylic intraocular lenses in pediatric cataract surgery

PURPOSE

To evaluate the functional outcomes of in-the-bag implantation of acrylic intraocular lenses (IOLs) with posterior continuous curvilinear capsulorhexis (PCCC), without PCCC, with PCCC and anterior vitrectomy, and with PCCC and optic capture in pediatric cataract surgery.

SETTING

Pediatric Ophthalmology Service, Guru Nanak Eye Centre, New Delhi, India.

METHODS

Forty-two eyes of 25 children were included in this prospective study. All eyes had in-the-bag implantation of an AcrySof IOL (Alcon). Twenty-five eyes had had an anterior continuous curvilinear capsulorhexis (ACCC) (Group A). Seventeen eyes had PCCC along with ACCC (Group B), 4 had anterior vitrectomy combined with PCCC (Group C), and 6 had PCCC with IOL optic capture through the PCCC (Group D). Secondary opacification of the visual axis, visual acuity, and possible complications were observed and analyzed.

RESULTS

The mean age of the patients was 78 months (range 36 to 144 months). The mean follow-up was 13 months (range 6 to 18 months). Four eyes (16%) in Group A developed visually significant posterior capsule opacification (PCO) involving the central visual axis and required secondary capsulotomy. All eyes in Groups B, C, and D had a clear visual axis at the last follow-up and did not require a secondary procedure. Minimal postoperative inflammation (ie, aqueous flare and IOL deposits ) was seen in all groups. The mean preoperative decimal best corrected visual acuity (BCVA) in Groups A, B, C, and D was 0.095, 0.055, 0.174, and 0.039, respectively. Postoperatively, the BCVA was 0.54, 0.66, 0.66, and 0.66, respectively.

CONCLUSIONS

An optimal-sized ACCC followed by in-the-bag implantation of a foldable acrylic IOL helped maintain a clear visual axis by delaying the onset of PCO and leading to milder PCO. The benefits of a foldable acrylic IOL in pediatric cataract surgery can be increased by combining it with PCCC, with or without anterior vitrectomy, or with optic capture of the IOL.

After-cataract in adults with primary posterior capsulorhexis: comparison of hydrogel and silicone intraocular lenses with round edges after 2 years

PURPOSE

To evaluate the potential of primary posterior continuous curvilinear capsulorhexis (PCCC) to prevent after-cataract 2 years after surgery and perform a bilateral comparison of 2 intraocular lens (IOL) materials, silicone and hydrogel.

SETTING

Department of Ophthalmology, University of Vienna, Medical School, Vienna, Austria.

METHODS

In this randomized patient- and examiner-masked study, 37 patients (74 eyes) with age-related cataract had bilateral small-incision cataract surgery with PCCC. Randomly, 1 eye received a hydrogel IOL and the contralateral eye, a silicone IOL. Both IOLs had open-loop haptics and a round-edged optic. Standardized digital retroillumination photographs were taken 1 day and 1, 6, 12, and 24 months after surgery to evaluate development of after-cataract on the anterior and posterior capsules by subjective grading. Opacification of the PCCC area was also objectively evaluated using new software.

RESULTS

Twenty-nine patients (58 eyes) completed the 2-year follow-up. Partial closure with ongrowth at the edge of the PCCC was found in 55% in the hydrogel group and 28% in the silicone group. Total closure of the PCCC was observed in 3 eyes, 2 in the hydrogel group and 1 in the silicone group.

CONCLUSION

Ongrowth onto the PCCC area was dependent on IOL material. Because of less ongrowth and more fibrotic after-cataract with silicone IOLs, the efficacy of the PCCC was higher in this group.

Techniques for managing common complications of cataract surgery

Cataract surgery has evolved dramatically over the last two decades, largely as a result of technological advances. As a result, visual outcomes and patient convalescence have improved significantly. A second consequence of increased instrumentation and technology, however, is increased complexity of cataract surgery and the advent of complications unique to these advances. Cataract surgeons must be aware and capable of managing the many possible adverse events that can occur during cataract surgery. This review identifies many of the common complications of cataract surgery, describes methods to avoid these complications and discusses techniques to address complications that do occur. It is the ability to avoid, quickly identify, and properly manage complications that defines the accomplished cataract surgeon.

Posterior continuous curvilinear capsulorhexis with hydrogel and silicone intraocular lens implantation: development of capsulorhexis size and capsule opacification

PURPOSE

To evaluate the influence of primary posterior continuous curvilinear capsulorhexis (PCCC) on capsule opacification development and capsular bag changes within the first year after cataract surgery with 2 intraocular lenses (IOLs) of comparable design but different material.

SETTING

Department of Ophthalmology, University of Vienna, Medical School, Vienna, Austria.

METHODS

Thirty-seven patients with age-related cataract had bilateral small incision cataract surgery with a PCCC performed after capsular tension ring insertion. One eye was randomly assigned to receive a hydrogel IOL and the other eye, a silicone IOL. Standardized digital retroillumination photographs were taken 1 day, 1 week, and 1, 3, 6, and 12 months after surgery to evaluate changes in the dimensions of the anterior and posterior capsulorhexis opening area and the presence of anterior and posterior capsule opacification.

RESULTS

The area of the anterior continuous curvilinear capsulorhexis (ACCC) opening was significantly reduced during the first 6 postoperative months. The shrinkage was more pronounced (-25%) in the silicone IOL group than in the hydrogel IOL group. Ten percent of eyes with a silicone IOL had marked shrinkage of the ACCC. The area of the PCCC did not change in eyes with a hydrogel IOL but was larger (+20%) in eyes with a silicone IOL. Anterior ongrowth was observed in 60% in the hydrogel group and in no eye in the silicone group. Anterior capsule fibrosis was observed in 90% in the silicone group and in 20% in the hydrogel group. Total closure of the PCCC was not observed within the first year, but posterior ongrowth was observed in 40% in the hydrogel group and 10% in the silicone group.

CONCLUSIONS

Anterior capsulorhexis shrinkage with concomitant posterior capsulorhexis enlargement was observed in eyes with a silicone IOL. The hydrogel IOL induced more ongrowth on the anterior and posterior IOL surfaces, whereas the silicone IOL induced more anterior capsule fibrosis. Total closure of the PCCC was not observed within the first year after surgery.

Dye-enhanced cataract surgery. Part 3: posterior capsule staining to learn posterior continuous curvilinear capsulorhexis

PURPOSE

To evaluate the use of 2 dyes for staining the posterior capsule to enhance visualization during posterior continuous curvilinear capsulorhexis (PCCC).

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Indocyanine green 0.5% (ICG) and trypan blue 0.1% were used to stain the posterior capsule for performing PCCC in 8 human eyes obtained postmortem. The eyes were prepared according to the posterior video technique of Miyake-Apple. After CCC and hydrodissection/delineation were performed, the nucleus was carefully delivered by hydroexpression. Cortical cleanup was completed by irrigation/aspiration. The posterior capsule was stained by instilling 1 microdrop of ICG (4 eyes) or trypan blue (4 eyes) in the capsular bag. A PCCC was then performed by 2 independent surgeons (4 eyes/surgeon) not familiar with this technique. Each surgeon also performed PCCC in 2 eyes without the use of dye.

RESULTS

Both dyes facilitated the performance of PCCC after staining the otherwise transparent posterior capsule. It was easier to differentiate the stained posterior capsule flap from the underlying transparent anterior hyaloid phase of the vitreous. In addition, optic capture of an intraocular lens, with or without anterior vitrectomy, was easily accomplished because of the enhanced visualization by posterior capsule staining.

CONCLUSIONS

Posterior capsule staining can be successfully used to learn and perform the PCCC procedure, combined with optic capture, anterior vitrectomy, or both.

Surgical prevention of posterior capsule opacification. Part 2: Enhancement of cortical cleanup by focusing on hydrodissection

PURPOSE

To experimentally analyze the role and efficacy of hydrodissection in achieving maximal cortical cleanup.

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Phacoemulsification and irrigation/aspiration were performed in 10 pairs of human eyes (20 eyes) obtained postmortem. Ten eyes had previous hydrodissection and 10 eyes, no hydrodissection. The time (seconds) required for complete lens substance removal in each procedure was measured. In addition, a qualitative evaluation of difficulty of surgery was noted.

RESULTS

Phacoemulsification required 28.6% less time in eyes with previous hydrodissection than in those without. Irrigation/aspiration time was reduced by 50.9% when hydrodissection was performed. The total time of each procedure required for complete evacuation of the capsular bag was reduced by an average of 37.7% in eyes with hydrodissection. Furthermore, qualitatively the procedure was far easier, less stressful, and caused less posterior capsule stress or rupture when copious hydrodissection was performed.

CONCLUSIONS

Hydrodissection enhances the general safety and efficiency of cortical cleanup, especially at 12 o'clock. Hydrodissection is the best available, practical, immediately implementable, and inexpensive means to help remove equatorial E-cells and thus alleviate the incidence of posterior capsule opacification.

Surgery for cataracts

The advent of phacoemulsification has substantially improved the success rate of cataract surgery in dogs, whereas the development of artificial lens implantation has equally improved postoperative visual acuity. In this chapter information pertaining to the etiology, diagnosis, and management of canine cataracts is provided for the general practitioner. More detailed information on phacoemulsification and artificial lens implantation is provided for residents in training or practicing ophthalmologists that may be converting from extracapsular extraction.

Endophthalmitis: immediate management using posterior capsulorhexis and anterior vitrectomy through reopened cataract surgery incision

An alternative tap/biopsy technique for early management of endophthalmitis is described. The technique uses the cataract surgery wound for anterior chamber washout and for a posterior continuous curvilinear capsulorhexis through which anterior vitrectomy, removal of part or all the vitreous abscess, and injection of antibiotics can be performed. The approach is safe, avoids pars plana incisions, and maintains capsule support for the intraocular lens or for removal and reimplantation of a posterior chamber lens in the bag.

Posterior capsulorhexis with optic capture in pediatric cataract and intraocular lens surgery

BACKGROUND

A major concern in pediatric intraocular lens implantation surgery is the high incidence of posterior capsule opacification. The purpose of this article is to investigate a surgical technique for maintaining a clear visual axis after pediatric cataract and intraocular lens surgery.

METHODS

In a prospective evaluation, posterior capsulorhexis with optic capture as a surgical technique for preventing secondary membrane formation after pediatric cataract extraction is investigated. This technique involves capture of an intraocular lens optic through a posterior curvilinear capsulorhexis opening. Perioperative complications and incidence of secondary cataract are presented. Results will be compared to an historic cohort of patients with pediatric cataract-intraocular lens who did not have posterior continuous curvilinear capsulorhexis with optic capture.

RESULTS

In 13 consecutive eyes operated on in children aged 2 to 12 years (mean, 5.8 years), there was no opacification of the visual axis at a mean follow-up of 19 months after surgery (range, 8-30 years).

CONCLUSION

Posterior capsulorhexis with optic capture holds promise as a technique for preventing secondary membrane formation. This maneuver ensures centration of the posterior chamber intraocular lens while eliminating the need for an anterior vitrectomy. Apposition of the anterior and posterior capsule leaflets anterior to the optic may limit the migration of Elschnig pearls, reducing the incidence of secondary membranes and the need for additional procedures.

Pediatric cataract surgery and intraocular lens implantation techniques: a laboratory study

The use of primary posterior capsulectomy and anterior vitrectomy during pediatric intraocular lens (IOL) implantation has been advocated as a means of preventing the development of posterior capsule opacification. In this study, we used pediatric eyes obtained postmortem to compare two different sequences in the surgical procedure: (1) anterior capsulectomy, lens substance removal, primary posterior capsulectomy with anterior vitrectomy, and IOL implantation in the capsular bag; (2) anterior capsulectomy, lens removal, IOL implantation in the capsular bag, and primary posterior capsulectomy with anterior vitrectomy. Both sequences could be safely performed in the laboratory setting while maintaining stable capsular fixation of the IOL. Placing the IOL in the capsular bag was easier when the posterior capsule was intact (sequence 2). However, both techniques appear feasible for clinical use. Surgeons not familiar with mechanized primary posterior capsulectomy can gain clinically relevant experience by operating on pediatric autopsy eyes in a laboratory setting.

Posterior capsulorhexis with optic capture: maintaining a clear visual axis after pediatric cataract surgery

We describe a technique for preventing secondary membrane formation after pediatric cataract extraction. This technique involves capture of an intraocular lens (IOL) optic through a posterior curvilinear capsulorhexis opening in an attempt to maintain a clear visual axis in children after cataract surgery. This maneuver ensures centration of the posterior chamber IOL because the haptics remain in the capsular bag and the optic is captured in the posterior capsular opening. Also, the need for an anterior vitrectomy may be eliminated. Apposition of the anterior and posterior capsule leaflets anterior to the optic may limit the migration of Elschnig pearls, reducing the incidence of secondary membranes and the need for additional procedures.

Inhibition of posterior capsule opacification: the effect of colchicine in a sustained drug delivery system

We investigated the effect of colchicine in a sustained drug delivery system on posterior capsule opacification (PCO) in rabbit eyes. A polymer matrix wafer, which diffused colchicine at a steady rate, was implanted in the capsular bag of 34 eyes after the lens material was removed by endocapsular phacoemulsification. Three different drug concentrations were used in the rabbit eyes, which were compared with control eyes containing the polymer matrix wafer without colchicine. The mean PCO score was highest in the control group without colchicine and increased steadily over 12 weeks. The rate of PCO formation in all eyes treated with colchicine was significantly lower than in the control group. There was no statistically significant improvement in PCO inhibition with the higher colchicine dosages. Side effects included inflammatory anterior chamber reaction and corneal and retinal complications and were most notable with the highest drug concentration. Slow release of colchicine reduces PCO formation in the rabbit. The optimal biocompatible dosage must be carefully determined and warrants further investigation.

Posterior capsule opacification

A complication of extracapsular cataract extraction with or without posterior chamber intraocular lens (PC-IOL) implantation is posterior capsule opacification. This condition is usually secondary to a proliferation and migration of residual lens epithelial cells. Opacification may be reduced by atraumatic surgery and thorough cortical clean-up. Clinical, pathological and experimental studies have shown that use of hydrodissection, the continuous curvilinear capsulorhexis and specific IOL designs may help reduce the incidence of this complication. Capsular-fixated, one-piece all-polymethylmethacrylate PC-IOLs with a C-shaped loop configuration and a posterior convexity of the optic are effective. Polymethylmethacrylate loops that retain "memory" create a symmetric, radial stretch on the posterior capsule after in-the-bag placement, leading to a more complete contact between the posterior surface of the IOL optic and the taut capsule. This may help form a barrier against central migration of epithelial cells into the visual axis. Various pharmacological and immunological methods are being investigated but conclusive data on these modalities are not yet available.