Decrease of capsular opacification with adjunctive mitomycin C in combined glaucoma and cataract surgery

Antimetabolites in cataract surgery to prevent failure of a previous trabeculectomy

BACKGROUND

Patients having cataract surgery have often earlier undergone a trabeculectomy for glaucoma. However, cataract surgery may be associated with failure of the previous glaucoma surgery and antimetabolites may be used with cataract surgery to prevent such failure. There is no systematic review on whether antimetabolites with cataract surgery prevent failure of a previous trabeculectomy.

OBJECTIVES

To assess the effects of antimetabolites with cataract surgery on functioning of a previous trabeculectomy.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2014), EMBASE (January 1980 to June 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to June 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 June 2014. We also searched the Science Citation Index database (July 2013) and reference lists of potentially relevant studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of antimetabolites with cataract surgery in people with a functioning trabeculectomy.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the titles and abstracts from the electronic searches. Two review authors independently assessed relevant full-text articles and entered data.

MAIN RESULTS

We identified no RCTs to test the effectiveness of antimetabolites with cataract surgery in individuals with the intention of preventing failure of a previous trabeculectomy.

AUTHORS' CONCLUSIONS

There are no RCTs of antimetabolites with cataract surgery in people with a functioning trabeculectomy. Appropriately powered RCTs are needed of antimetabolites during cataract surgery in patients with a functioning trabeculectomy.

Intraocular lens as a drug delivery reservoir

PURPOSE OF REVIEW

To describe the development and use of intraocular lenses (IOLs) as drug delivery systems and to review the current literature on their application and efficacy.

RECENT FINDINGS

Many drugs have been loaded onto IOLs by coating or by attachment in a separate reservoir. With incorporation of polymeric materials either as a coating or by attachment as a separate reservoir, it is possible to achieve a sustained and controlled release of drugs. Experimental evidence in animal models has shown that IOL drug delivery systems are effective in the prevention and treatment of inflammation, infection and posterior capsule opacification after cataract surgery.

SUMMARY

The use of IOLs as drug delivery reservoirs appears to show great promise. Although excellent results with therapeutic potential have been reported in experimental animal studies, further studies are needed to reach clinical use.

Updates on the Surgical Management of Paediatric Cataract with Primary Intraocular Lens Implantation

With the advent of modern surgical techniques, paediatric cataract has become much more manageable. Intraocular lens (IOL) implantation is the standard of care for patients over the age of 2 years. The use of IOL in young infants is still controversial. In addition, there are still unresolved issues, such as the minimum age at which IOL can be safely implanted, IOL power selection and IOL power calculation. The current trends in the management of the above challenges are discussed. Although numerous reports on the prevention and management of posterior capsule opacification have been published, there are ongoing intensive debates and research. Long-term postoperative complications like glaucoma and rhegmatogenous retinal detachment are problems that cannot be overemphasised and these issues are also reviewed. Key words: Congenital cataract, Intraocular lens, Posterior capsule opacification

Mitomycin: clinical applications in ophthalmic practice

Mitomycin (mitomycin C; MMC) is an antibiotic isolated from Streptomyces caespitosus. The drug is a bioreductive alkylating agent that undergoes metabolic reductive activation, and has various oxygen tension-dependent cytotoxic effects on cells, including the cross-linking of DNA. It is widely used systemically for the treatment of malignancies, and has gained popularity as topical adjunctive therapy in ocular and adnexal surgery over the past 2 decades. In ophthalmic medicine, it is principally used to inhibit the wound healing response and reduce scarring of surgically fashioned ostia. Hence, it has been used as adjunctive therapy in various ocular surgeries, such as glaucoma filtering surgeries, dacryocystorhinostomy, corneal refractive surgery and surgeries for ocular cicatrisation. In addition, it has been used as an adjunct in the surgical management of pterygia, ocular surface squamous neoplasia, primary acquired melanosis with atypia and conjunctival melanoma. In many of these surgeries and ophthalmic pathologies, MMC showed a significant beneficial effect.

[New methods for the prevention of posterior capsule opacification]

Even though tremendous advances have been made especially during the last 10-15 years in terms of surgical techniques and improvement of implant technology, posterior capsule opacification (PCO) still remains a serious long-term complication. New clinical and laboratory studies (especially of autopsy eyes) have improved our understanding of how IOL design and material influence PCO. Sharp edge optic designs of IOLs of various materials have been shown to significantly reduce secondary cataract. The application of pharmacological substances selectively into the capsular bag is now possible due to the development of the PerfectCapsule System for vacuum-sealed capsule irrigation. Major advances in other areas of biotechnology and immunology including gene therapeutic methods offer totally new approaches for the future in the elimination of lens epithelium cells from the capsular bag. This survey gives an update on current and future means and trends to reduce or prevent PCO formation.

Efficacy of various drugs in the prevention of posterior capsule opacification: experimental study of rabbit eyes

PURPOSE

To assess the efficacy of various drugs in the prevention of posterior capsule opacification (PCO) in a closed capsular bag technique.

SETTING

Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA.

METHODS

Lens material was removed using phacoaspiration or phacoemulsification through a microcapsulorhexis according to the hardness of the crystalline lens correlated with the weight and age of the rabbits. A mixture of an ophthalmic viscosurgical device (sodium hyaluronate 1.4% [SHA]) and a drug was injected into the empty capsular bag, allowed to remain inside for 3 minutes, and removed. The capsular bag was rinsed with balanced salt solution (BSS) and refilled with SHA. In a group of rabbits, the capsulorhexis was sealed with a minicapsulorhexis valve (MCV). Rabbits were treated with 1 of the following: SHA (control), BSS, mitomycin-C (MMC, 0.2 mg/mL), ethylenediaminetetraacetic acid (EDTA) (10 mM and 15 mM), 5-fluorouracil (5-FU, 33 mg/mL), acetic acid (3%, 0.3%, and 0.003%), and distilled water.

RESULTS

Upon completion of the study, the control and treated eyes had PCO and new lens material (not residual). Anterior capsule proliferation was observed in eyes treated with 5-FU. The order of PCO appearance (earliest to latest) was as follows: 15 mM EDTA, SHA, MMC, acetic acid 0.3%, acetic acid 3%, BSS, distilled water (small animals; no MCV), acetic acid 0.003%, 5-FU, 10 mM EDTA, and distilled water (large animals; MCV). The earliest appearance was day 1 postoperatively and the latest, day 47.

CONCLUSIONS

Distilled water and 10 mM EDTA treatments were the most efficient in retarding the appearance of PCO.

Posterior capsule opacification after phacoemulsification in patients with postoperative steroidal and nonsteroidal treatment

PURPOSE

To evaluate the effect of dexamethasone, diclofenac, and a placebo given for 3 weeks after phacoemulsification and intraocular lens (IOL) implantation on the formation of posterior capsule opacification (PCO).

SETTING

St. Erik's Eye Hospital, Stockholm, Sweden.

METHODS

In a 2-year prospective randomized double-blind study, a laser flare meter was used to measure aqueous flare intensity preoperatively and 3 days, 2 weeks, and 2 years after phacoemulsification and IOL implantation. Posterior capsule opacification was evaluated 2 years postoperatively using retroillumination images taken with a Scheimpflug camera. The Evaluation of Posterior Capsule Opacification system was used to score the areas of PCO density.

RESULTS

The median rate of PCO 2 years after phacoemulsification was 0.72 (range 0.32 to 1.57) in the dexamethasone group, 0.78 (range 0.19 to 2.14) in the diclofenac group, and 0.70 (range 0.35 to 1.70) in the placebo group. The differences were not statistically significant (P>.05; Kruskal-Wallis analysis of variance, multiple comparisons). The rate of neodymium:YAG laser posterior capsulotomy during the 2 years after surgery was not statistically different between groups (P>.05, chi-square test). There was no correlation (Spearman rank coefficient) between laser flare measurements and PCO formation in any group during the study (P>.05).

CONCLUSION

Topical instillation of diclofenac, dexamethasone, or a placebo in the immediate period after phacoemulsification and IOL implantation did not seem to influence the formation of PCO 2 years after cataract surgery.

Methodologic rigor of clinical trials on surgical management of eyes with coexisting cataract and glaucoma

OBJECTIVE

To assess the methodologic quality of published studies of the surgical management of coexisting cataract and glaucoma.

DESIGN

Literature review and analysis.

METHOD

We performed a systematic search of the literature to identify all English language articles pertaining to the surgical management of coexisting cataract and glaucoma in adults. Quality assessment was performed on all randomized controlled trials, nonrandomized controlled trials, and cohort studies. Overall quality scores and scores for individual methodologic domains were based on the evaluations of two experienced investigators who independently reviewed articles using an objective quality assessment form.

MAIN OUTCOME MEASURES

Quality in each of five domains (representativeness, bias and confounding, intervention description, outcomes and follow-up, and statistical quality and interpretation) measured as the percentage of methodologic criteria met by each study.

RESULTS

Thirty-six randomized controlled trials and 45 other studies were evaluated. The mean quality score for the randomized, controlled clinical trials was 63% (range, 11%-88%), and for the other studies the score was 45% (range, 3%-83%). The mean domain scores were 65% for description of therapy (range, 0%-100%), 62% for statistical analysis (range, 0%-100%), 58% for representativeness (range, 0%-94%), 49% for outcomes assessment (range, 0%-83%), and 30% for bias and confounding (range, 0%-83%). Twenty-five of the studies (31%) received a score of 0% in the bias and confounding domain for not randomizing patients, not masking the observers to treatment group, and not having equivalent groups at baseline.

CONCLUSIONS

Greater methodologic rigor and more detailed reporting of study results, particularly in the area of bias and confounding, could improve the quality of published clinical studies assessing the surgical management of coexisting cataract and glaucoma.

Comparison of long-term incidence of posterior capsular opacification between phacoemulsification and phacotrabeculectomy

PURPOSE

To investigate the long-term incidence of posterior capsular opacification after phacoemulsification compared with phacotrabeculectomy with or without adjunctive subconjunctival mitomycin C.

METHODS

This was a retrospectively conducted long-term, observational, case-control study. One hundred eyes of 100 cataract patients who underwent phacoemulsification and posterior chamber intraocular lens implantation and 100 eyes of 100 primary open-angle glaucoma patients with cataract that underwent phacotrabeculectomy and posterior chamber intraocular lens implantation, matched with respect to age, intraocular lens type, prevalence of diabetes mellitus, and length of follow-up. The main outcome measure was the rate of clinically significant posterior capsular opacification as determined by slit-lamp biomicroscopy and necessity to perform neodynium:yttrium aluminum garnet (Nd:YAG) capsulotomy and as calculated by Kaplan-Meier survival analysis. Postoperative visual acuity and maintenance of intraocular pressure control were also measured.

RESULTS

There was no significant difference in the rate of posterior capsular opacification requiring Nd:YAG capsulotomy between the phacoemulsification and phacotrabeculectomy groups (P =.77). However, a significant difference in the rate of posterior capsular opacification was found between those patients without diabetes mellitus and those with a preoperative diagnosis of diabetes mellitus (P =.016). Also, survival analysis comparing use of mitomycin C with no use of mitomycin C in the phacotrabeculectomy group showed a higher survival in the mitomycin C subgroup (P =.03).

CONCLUSION

There was no significant difference in long-term posterior capsular opacification between phacoemulsification and phacotrabeculectomy in the study population. Intraoperative, adjunctive use of mitomycin C in the phacotrabeculectomy group and the presence of diabetes mellitus in the overall patients were beneficial (protective) factors against posterior capsular opacification.

Prevention of posterior capsule opacification by intraoperative single-dose pharmacologic agents

PURPOSE

To determine whether an intraoperative single dose of dexamethasone, diclofenac, ethylenediaminetetraacetic acid (EDTA), a combination of EDTA and RGD peptide (arginine-glycin-aspartic acid sequence), or mitomycin-C (MMC) is a pharmacological means of preventing or reducing the development of posterior capsule opacification (PCO).

SETTING

Department of Ophthalmology, Celal Bayar University, School of Medicine, Manisa, and Department of Pathology, Dokur Eylül University, School of Medicine, Izmir, Turkey.

METHODS

Fifty-four rabbits were randomly divided into 6 groups. Dexamethasone (4 mg/cc), diclofenac (2.5 mg/cc), EDTA (8 mg/cc), a combination of EDTA and RGD peptide (2.5 mg/cc), or MMC (0.04 mg/cc) was given, 0.1 cc by hydrodissection and 0.9 cc into the capsular bag after phacoemulsification. The sixth group served as a control group. After 3 months, the PCO was graded clinically and the proliferation of lens epithelial cells (LECs) was evaluated histologically.

RESULTS

The drugs were significantly effective in preventing PCO compared with the control (P <.005). Dexamethasone had a weaker effect than the other drugs. In histological analysis, although monolayer LECs in the dexamethasone and diclofenac groups were observed, there was no proliferative activity on the posterior capsules in the EDTA, EDTA+RGD, and MMC groups in contrast to the multilayer cells in the control.

CONCLUSIONS

Intraoperative single-dose application of EDTA, EDTA+RGD peptide combination, and MMC significantly prevented the development of PCO in rabbit eyes. Diclofenac was less effective but also reduced PCO. Although dexamethasone did not prevent the proliferation of LECs, it decreased PCO clinically.

Posterior capsule opacification and anterior capsule opacification

Posterior capsule opacification (PCO) is still the most frequent complication of cataract surgery. A variety of studies has led to a better understanding of the pathogenesis of PCO, and strategies of molecular biology have produced new therapeutic options, such as immunological techniques or gene therapeutic approaches. Surgical strategies and intra-ocular lens-dependent factors also are capable to reduce the rate of PCO. In-the-bag implantation of intra-ocular lenses with a sharp optic edge seems to be effective in inhibiting equatorial lens epithelial cell migration to the center of the posterior capsule. Several PCO documentation systems have been developed that will lead to more exact and better comparable recording of PCO rates. In the year 2000, PCO or secondary cataract is still the most frequent complication after extracapsular cataract surgery. In a 1998 meta-analysis, PCO rates of 11.8% 1 year after extracapsular cataract surgery with intraocular lens implantation, 20.7% after 3 years, and 28.4 % after 5 years have been reported. For the United States, it has been estimated that the overall expenses for treatment of PCO are only exceeded by the costs for cataract treatment itself. In the past decade, a lot of experimental and clinical studies have been performed on this topic. They have led to 1) to a better understanding of the pathogenesis of the development of anterior and posterior capsule opacification; 2) more objective and better comparable systems of documentation and analysis of PCO; and a number of 3) surgical and 4) pharmaceutical strategies to prevent PCO.

Effect of mitomycin-C on posterior capsule opacification in rabbit eyes

PURPOSE

To determine whether mitomycin-C can inhibit posterior capsule opacification (PCO) without causing ocular toxicity.

SETTING

Yonsei Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.

METHODS

Mitomycin-C dissolved in sodium hyaluronate (0.2 cc of 0.2 mg/mL) was injected into the empty capsular bag for 3 minutes after endocapsular phacoemulsification in rabbit eyes. Three months after surgery, the obstruction rate of visible light caused by PCO was measured using an optical power meter.

RESULTS

The mean obstruction rate of visible light was 81.0% +/- 8.3% (SD) in the control group in which sodium hyaluronate without mitomycin-C was used, 30.5% +/- 10.1% in the group in which mitomycin-C was dissolved in sodium hyaluronate, and 71.9% +/- 6.8% in the group in which mitomycin-C was dissolved in a balanced salt solution. Statistically significant differences were found among all 3 groups.

CONCLUSIONS

Our results suggest that the application of mitomycin-C dissolved in sodium hyaluronate effectively reduces PCO in rabbit eyes.

Posterior capsular opacification in phacotrabeculectomy : a long-term comparative study of silicone versus acrylic intraocular lens

PURPOSE

To investigate the long-term outcomes of silicone versus acrylic intraocular lens (IOL) implantation in phacotrabeculectomy (PT) with special emphasis on posterior capsular opacification.

DESIGN

Long-term follow-up on prior 1-year prospective, randomized study.

PARTICIPANTS

A total of 200 eyes of 200 consecutive primary open-angle glaucoma patients who had undergone primary PT with capsular bag implantation of either a silicone IOL (102 eyes) or an acrylic IOL (98 eyes) according to the initial short-term prospective, randomized study protocol.

INTERVENTION

The study eyes underwent primary trabeculectomy, phacoemulsification, and posterior chamber IOL implantation. Adjunctive mitomycin C was used selectively, primarily in patients with one or more risk factors for filtration failure.

MAIN OUTCOME MEASURES

Incidence of posterior capsular opacification (PCO), best-corrected visual acuity (BCVA), intraocular pressure (IOP), number of pressure-lowering medications, and filtration success rates, defined as maintenance of target IOP while on one (criteria 1) or zero (criteria 2) pressure-lowering medications without further surgical intervention.

RESULTS

At 3-year follow-up, the PCO rate and BCVA did not differ significantly between the two groups (P: > 0.05 for both). In addition, there were no significant differences in IOP, number of medications, and filtration success rate between the two groups (P: > 0.05 for each).

CONCLUSIONS

There were no significant long-term differences between the silicone and acrylic IOL groups in PCO, BCVA, IOP, number of medications, and success of filtration surgery after PT. Both groups attained significant improvement in BCVA and IOP control after surgery.

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.

Outcome of trabeculectomy with mitomycin-C in the iridocorneal endothelial syndrome

PURPOSE

Eyes with iridocorneal endothelial (ICE) syndrome have a high risk of failure in glaucoma filtering surgery failing. We investigated the efficacy of trabeculectomy with intraoperative mitomycin-C application in these patients.

DESIGN

Retrospective nonrandomized comparative trial with historical controls.

PARTICIPANTS AND CONTROLS

Ten patients with unilateral iridocorneal endothelial (ICE) syndrome were reviewed. Their intraocular pressures could not be controlled medically. In five eyes, this was the primary surgery performed. Five of the patients had undergone prior intraocular pressure-(IOP) lowering surgery that had failed at the time enrolled. Results were compared with previously published case series of similar patients treated with trabeculectomy alone or trabeculectomy and subconjunctival 5-fluorouracil injections.

INTERVENTION

Intervention consisted of trabeculectomy with a limbus-based conjunctival flap and mitomycin-C application. The dosage of mitomycin-C was 0.4 mg/ml for 1 to 4 minutes (mean, 1.9 min).

MAIN OUTCOME MEASURES

Adequate control of IOP (without medication lower than 21 mm Hg).

RESULTS

In eight eyes the IOP remained well controlled (mean IOP, 12.1 mm Hg) over the entire length of available of follow-up (mean, 14.9 months). Two eyes required implantation of an aqueous tube shunt at 4 and 11 months, respectively, after trabeculectomy with mitomycin-C. One eye experienced visual loss of 3 Snellen lines because of hypotony maculopathy.

CONCLUSIONS

Trabeculectomy with mitomycin-C application offers a reasonable intermediate-term success rate in ICE patients, who are otherwise at high risk for failure of filtering surgery.

Posterior capsule opacification. Part 2: Clinical findings

The incidence of posterior capsule opacification (PCO), the most common complication of modern cataract surgery with intraocular lens implantation, seems to have decreased slightly as a result of improved surgical and cortical cleanup techniques. However, the reported incidence is still significant. The diverse findings on PCO are the result in part of studies using different criteria to clinically judge and quantify the condition. In addition, the influence of intraocular and systemic factors are only now being identified. This second of a 2-part review of PCO focuses on (1) less subjective morphological and patient-dependent means to evaluate and quantify PCO; (2) the influence of ocular factors on PCO; (3) the influence of systemic factors on PCO; (4) available means and approaches to prevent or delay PCO.

Update on fixation of rigid and foldable posterior chamber intraocular lenses. Part II: Choosing the correct haptic fixation and intraocular lens design to help eradicate posterior capsule opacification

PURPOSE

Posterior capsule opacification (PCO) is one of the most common complications of cataract surgery, and there is an urgent need to reduce its incidence. Its main treatment, neodymium:YAG (Nd:YAG) laser posterior capsulotomy, may be associated with significant morbidity and is expensive. In this study, the authors ascertain the effect of posterior chamber intraocular lens (PC-IOL) fixation and various IOL designs (rigid polymethyl methacrylate [PMMA] optic and small-incision foldable designs) on the pathogenesis of PCO.

DESIGN

Prospective analysis of pseudophakic eyes obtained postmortem.

PARTICIPANTS

A total of 3493 eyes with PC-IOLs obtained postmortem and received between 1984 and 1998.

METHODS

Miyake-Apple posterior photographic technique.

MAIN OUTCOME MEASURES

Peripheral Soemmering's ring, central PCO in the visual axis, and eyes that have had Nd:YAG laser posterior capsulotomy were analyzed and scored, and these findings were correlated with the type of fixation and IOL design.

RESULTS

The degree of formation of peripheral Soemmering's ring was not influenced by IOL fixation. The acrylic design revealed relatively low Soemmering's ring scores. In contrast, central PCO and Nd:YAG laser capsulotomy scores were consistently influenced by fixation. The scores were significantly lower in eyes with in-the-bag fixation. The bag-bag fixated acrylic-PMMA design and the three modern silicone IOL designs analyzed in this study had less central PCO and lower posterior capsulotomy scores than did the PMMA IOLs.

CONCLUSIONS

The formation of peripheral PCO (the Soemmering's ring), the precursor of clinically significant, vision-threatening PCO, is not significantly influenced by the haptic fixation pattern. It is much more dependent on the quality and thoroughness of surgical cortical cleanup. Reduction of Soemmering's ring is an important goal because the retained regenerative cortical cells within this lesion are the cells of origin of PCO. The acrylic IOL design was associated with a lessor amount of peripheral Soemmering's ring as compared with all other designs. In sharp contrast to peripheral PCO, fixation of the IOL was a highly significant factor affecting the formation and quantity of central PCO-the clinically significant opacity behind the IOL optic, measured in this series either by scoring an intact retro-optical membrane or by documenting the presence of a Nd:YAG laser posterior capsulotomy orifice. The quantity of central PCO was consistently much lower in eyes with in-the-bag fixated IOLs compared with lenses with one or both haptics out of the bag. This is best explained by the fact that secure in-the-bag fixation positions the IOL optic in the best possible position to create a barrier effect. The lowest PCO rates were generally noted with the acrylic and modern silicone IOL designs.