A systematic overview of the incidence of posterior capsule opacification

The effect of femtosecond laser capsulotomy on the development of posterior capsule opacification

PURPOSE

To evaluate and compare the effects of femtosecond laser-assisted anterior capsulotomy and manual anterior capsulorhexis on posterior capsule opacification (PCO) development.

METHODS

Femtosecond laser-assisted anterior capsulotomy was performed in 40 eyes of 40 patients (FS group) and manual anterior capsulorhexis was performed in 39 eyes of 39 patients (CCC group). An AcrySof one-piece hydrophobic acrylic intraocular lens (Alcon Laboratories, Inc., Fort Worth, TX) was implanted in all eyes. The PCO level was measured using Open-Access Systematic Capsule Assessment (OSCA) software 18 to 26 months after surgery. Postoperative intraocular lens position (ie, tilt and decentration) was measured using Scheimpflug images (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany).

RESULTS

There was no statistically significant difference in age, axial length, and follow-up time between the two groups (P > .05). Vertical tilt, horizontal and total decentration of intraocular lenses, and PCO proved to be significantly higher in the CCC group (P = .03, .04, .03, and .01, respectively). After adjusting for axial length and follow-up time, manual anterior capsulorhexis was found to be a significant predictor of higher PCO scores in the multivariable regression model (β: 0.33; 95% CI: 0.01 to 0.65; P = .04). Vertical tilt affected PCO scores after adjusting for axial length and follow-up time (β: 0.07; 95% CI: 0.01 to 0.12; P = .02). No capsulotomies were performed during follow-up in either group.

CONCLUSIONS

Femtosecond laser-assisted anterior capsulotomy proved to be a safe procedure for postoperative PCO rates. Due to better intraocular lens position, femtosecond laser-assisted anterior capsulotomy resulted in slightly decreased PCO scores; however, evaluating its clinical significance requires further studies.

Matrix metalloproteinase-9-null mice are resistant to TGF-β-induced anterior subcapsular cataract formation

Epithelial-mesenchymal transition (EMT) is associated with fibrotic diseases in the lens, such as anterior subcapsular cataract (ASC) formation. Often mediated by transforming growth factor (TGF)-β, EMT in the lens involves the transformation of lens epithelial cells into a multilayering of myofibroblasts, which manifest as plaques beneath the lens capsule. TGF-β-induced EMT and ASC have been associated with the up-regulation of two matrix metalloproteinases (MMPs): MMP-2 and MMP-9. The current study used MMP-2 and MMP-9 knockout (KO) mice to further determine their unique roles in TGF-β-induced ASC formation. Adenoviral injection of active TGF-β1 into the anterior chamber of all wild-type and MMP-2 KO mice led to the formation of distinct ASC plaques that were positive for α-smooth muscle actin, a marker of EMT. In contrast, only a small proportion of the MMP-9 KO eyes injected with adenovirus-expressing TGF-β1 exhibited ASC plaques. Isolated lens epithelial explants from wild-type and MMP-2 KO mice that were treated with TGF-β exhibited features indicative of EMT, whereas those from MMP-9 KO mice did not acquire a mesenchymal phenotype. MMP-9 KO mice were further bred onto a TGF-β1 transgenic mouse line that exhibits severe ASC formation, but shows a resistance to ASC formation in the absence of MMP-9. These findings suggest that MMP-9 expression is more critical than MMP-2 in mediating TGF-β-induced ASC formation.

A new technique for Nd:YAG laser posterior capsulotomy

AIM

To investigate the effects of a new opening pattern in neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy on visual function.

METHODS

This technique was conducted along a circular pattern. The energy ranged between 0.8 and 1.2 mJ/pulse was consumed and mean total energy levels were 74±21 mJ (mean±standard deviation: SD, from 40 to 167) and laser shots aimed at 150 µm away behind a datum point and went along an imaginary line which extends 0.5 mm inside from optic margin and into the circular en bloc pattern. Vitreous stands were attached with fragment and then they were cut off by the laser after circular application. The circular fragment was completely separated from vitreous, and then this fragment was quickly sunk in intravitreal space.

RESULTS

The follow-up period ranges from at least a week to 40mo, making 15.8mo on average. The procedural outcome showed 96% (74 eyes out of the 77 eyes) enhancement in patients' visual acuity. Cystoid macular edema or retinal detachment was not observed in any of the patients during follow-up periods.

CONCLUSION

This new technique is expected to improve the weaknesses that the conventional procedures have by adding the process to cut off vitreous stands attached with the fragment by the laser to the circular application.

Efficacy of COX-2 inhibitors in controlling inflammation and capsular opacification after phacoemulsification cataract removal

OBJECTIVE

To evaluate the efficacy of 0.9% bromfenac (Xibrom™) or a celecoxib-impregnated intraocular lens (celecoxib-IOL) compared with 1% prednisolone acetate (PA) in controlling postoperative inflammation and posterior capsule opacification (PCO).

ANIMAL STUDIED

Fifty-nine dogs undergoing cataract extraction by phacoemulsification.

PROCEDURE

Bilateral patients received bromfenac or celecoxib-IOL plus PA in one eye, and PA in the contralateral eye. Unilateral patients received bromfenac or PA. Complete ophthalmic examination including tonometry, slit-lamp grading of flare and PCO, and digital image acquisition for masked PCO evaluation was performed within 24 h and 1, 4, 12, 24, and 56 weeks following surgery.

RESULTS

Celecoxib-IOL/PA-treated eyes had significantly less flare than PA-treated eyes, which had significantly less flare than bromfenac-treated eyes 24 h postoperatively. There was no significant difference in intraocular pressure (IOP) postoperatively, or at 1, 24, or 56 weeks. Celecoxib-IOL/PA-treated eyes had significantly lower IOP measurements than bromfenac and PA-treated eyes at 4 and 12 weeks. There was no significant difference in PCO level between groups using slit-lamp biomicroscopy at any time point. Masked evaluation of digital images revealed significantly less PCO in celecoxib-IOL/PA- vs. bromfenac-treated eyes at 4 weeks, and in bromfenac- vs. PA-treated eyes at 56 weeks.

CONCLUSIONS

Eyes receiving celecoxib-IOL/PA had better initial control of inflammation. Bromfenac was equally effective compared with PA in controlling inflammation. There was no association between COX-2 inhibitor administration and ocular hypertension. Celecoxib-IOL/PA-treated eyes showed better initial control of PCO (up to 12 weeks), while eyes receiving bromfenac had better long-term control of PCO (56 weeks).

The intraocular lens: challenges in the prevention and therapy of infectious endophthalmitis and posterior capsular opacification

Cataract is the leading cause of visual impairment worldwide. In the UK, some 30% of the population over 65 years of age have visually impairing cataract. Importantly, 88% of those with treatable visual impairment from cataract are not in contact with any ocular healthcare service, representing a major potential healthcare need [1]. In the USA, it has been estimated that 17.2% of the population (approximately 20.5 million) over 40 years of age have cataract in either eye and by 2020, this number is expected to rise to 30.1 million. Currently, cataract is responsible for 60% of Medicare costs associated with vision [2]. Furthermore, as the populations of industrialized countries such as the UK and the USA continue to age, the costs associated with treatment of cataract can only be expected to increase. Consequently, the development of the intraocular lens to replace the cataractous lens and the advances in intraocular lens design and implantation represent a major development in cataract treatment. However, despite such advances, cataract surgery is not without complications, such as postoperative infectious endophthalmitis, a rare but potentially devastating condition, and posterior capsular opacification, a less serious but much more common problem. This review will examine the epidemiology of cataracts, the polymeric construction of intraocular lenses implanted during cataract surgery and the complications of postoperative infectious endophthalmitis and posterior capsular opacification with regard to therapeutic interventions and prophylactic strategies. Advances in biomaterial design and function will be discussed as novel approaches to prevent such postoperative complications.

Influence of a variable overall diameter hydrophilic acrylic sharp-edged single-piece intra-ocular lens on capsule opacification one year after surgery

BACKGROUND

To investigate the influence of the overall intraocular lens (IOL) diameter on posterior capsule opacification (PCO) formation.

METHODS

In this prospective randomized clinical trial, 124 eyes of 62 patients with bilateral age-related cataract were included. Each patient received a Corneal A501D IOL in one eye and a Corneal J501D IOL in the fellow eye. Best corrected visual acuity (BCVA) and digital slitlamp photographs were taken a 1 h, 1 week, 1, 3, 6 and 12 months postoperatively. The amount of PCO was assessed subjectively at the slitlamp and objectively using automated image-analysis software.

RESULTS

We found a mean BCVA of 0.81 ± 0.2 for the Corneal A501D group and 0.79 ± 0.21 for the Corneal J501D group. There was no significant difference 12 months after surgery between the two IOLs (p > 0.05). Objective PCO assessment resulted in a mean PCO score (scale 0-10) of 1.65 ± 1.71 was found for the Corneal J501D group and a score of 1.54 ± 1.64 was found for the Corneal A501D group (p > 0.05). The subjective PCO assessment at 1 year resulted in a mean PCO score of 2.0 ± 1.74 in the Corneal J501D group and 2.13 ± 1.64 in the Corneal A501D group (p > 0.05).

CONCLUSION

Both investigated IOLs showed good clinical performance regarding PCO and BCVA. Our study suggests that the use of an IOL with variable total diameter seems not to influence the rate of PCO formation.

RNA Interference Targeting Snail Inhibits the Transforming Growth Factor β 2-Induced Epithelial-Mesenchymal Transition in Human Lens Epithelial Cells

Epithelial-msenchymal transition (EMT) contributes to posterior capsule opacification (PCO) type of cataract. Transcription factors Snail is a key trigger of EMT activated by transforming growth factor β (TGFβ). This study was done to investigate the effect of Snail targeting siRNA on TGFβ2-induced EMT in human lens epithelial cells. TGFβ2 treatment of cultured human epithelial cell line (HLEB3) upregulated the expression of Snail and the EMT relevant molecules such as vimentin and α-SMA but downregulated the expression of keratin and E-cadherin. After the stimulation of TGFβ2, the HLEB3 cells became fibroblast-like in morphology, and the junctions of cell-cell disappeared. TGFβ2 treatment also enhanced migration ability of HLEB3 cells. TGFβ2-induced Snail expression and EMT were significantly inhibited by Snail siRNA. By analyzing the response characteristics of HLEB3 in TGFβ2-induced EMT model with/without Snail-specific siRNA, we concluded that Snail is an element in the EMT of HLEB3 cells induced by TGFβ2. Snail siRNA targeting can block the induced EMT and therefore has the potential to suppress the development of PCO.

Bimanual anterior segment revision surgery for anterior capsule contraction syndrome associated with anterior flexion of intraocular lens haptics

PURPOSE

To report the incidence of anterior capsule contraction syndrome (ACCS) and to present a novel minimally invasive bimanual technique for anterior segment revision surgery associated with ACCS with anterior flexion of the intraocular lens haptics.

METHODS

A consecutive cohort of 268 eyes of 161 patients undergoing phacoemulsification and implantation of the same type of hydrophilic acrylic aspheric intraocular lens cohort were analysed and a novel technique of minimally invasive bimanual technique for anterior segment revision surgery is described.

RESULTS

We identified four eyes (1.5%) of three patients with advanced ACCS. Successful restoration of a clear visual axis with minimal induction of astigmatism and rapid visual rehabilitation was achieved in all four cases.

CONCLUSION

This technique is a safe and minimally invasive alternative to laser or vitrector-cut capsulotomy to restore a clear visual axis. In cases of advanced ACCS, it offers the option for haptic reposition or amputation.

Outcomes and projected impact on vision restoration of the China Million Cataract Surgeries Program

PURPOSE

The recently completed Chinese "Million Cataract Surgeries Program" (MCSP) is among the largest such campaigns ever, providing 1.05 million operations. We report MCSP outcomes for the first time, in Jiangxi, the province with the greatest program output.

METHODS

Ten county hospitals participating in MCSP were selected in Jiangxi (range of gross domestic product per capita US$743-2998). Each hospital sought to enroll 75 consecutive MCSP patients aged ≥ 50 years. Data recorded included type of cataract procedure, bilateral uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), and refractive error pre- and ≥ 50 days postoperatively.

RESULTS

Among 715 patients (mean age 72.3 ± 9.1 years, 55.5% female), preoperative UCVA was <3/60 (legally blind) bilaterally in 13.3% and unilaterally in the operated eye in 50.9%. No subjects had UCVA >6/18 preoperatively. Small incision cataract surgery was performed in 92.3% patients. Among 662 patients (92.6%) completing follow-up was ≥ 40 days after surgery, BCVA was ≥ 6/18 in 80.1%, UCVA was ≥ 6/18 in 57.1% and UCVA was <3/60 in 2.1%. Older age (p < 0.001), female sex (p = 0.04), worse refractive error (p = 0.02) and presence of intra- (p = 0.002) and postoperative surgical complications (p < 0.001), were independently associated with worse postoperative UCVA. Based on these results, the MCSP cured an estimated 124,950 cases (13.3% × [100-2.1%] × 1.05 million) of bilateral and 502,500 (50.9% × [100-2.1%] × 1.05 million) of unilateral blindness.

CONCLUSIONS

Due to relatively good outcomes and the large number of surgeries performed on blind persons, the sight-restoring impact of the MCSP was probably substantial.

Posterior capsule opacification with the iMics1 NY-60 and AcrySof SN60WF 1-piece hydrophobic acrylic intraocular lenses: 3-year results of a randomized trial

PURPOSE

To compare the intensity of posterior capsule opacification (PCO) 3 years after implantation of 2 different 1-piece foldable hydrophobic acrylic intraocular lenses (IOLs).

DESIGN

Randomized, prospective, patient- and examiner-masked clinical trial with intraindividual comparison.

METHODS

One hundred patients with bilateral age-related cataract (200 eyes) had standard cataract surgery with implantation of an iMics1 NY-60 IOL (Hoya Corp) in one eye and an AcrySof SN60WF IOL (Alcon Laboratories) in the other eye. Follow-up examinations were performed at 1 week and 3 years. Digital retroillumination images were obtained of each eye. The main outcome measure was PCO score (scale, 0 to 10) assessed subjectively at the slit lamp and objectively using automated image analysis software (Automated Quantification of After-Cataract) 3 years after surgery.

RESULTS

The objective PCO score (mean ± standard deviation) was 3.0 ± 2.0 for the iMics1 NY-60 IOL and 1.9 ± 1.4 for the AcrySof SN60WF IOL (P < .001). Three years after surgery, 35.6% of patients underwent a neodymium:yttrium-aluminum-garnet capsulotomy in the iMics1 NY-60 eye and 13.7% underwent a capsulotomy in the AcrySof SN60WF eye (P = .001). There was no statistically significant difference in best-corrected visual acuity, rhexis-IOL overlap, capsular folds, or anterior capsule opacification. Glistening formations were found in no iMics1 NY-60 IOLs, but in 97% of the AcrySof SN60WF IOLs.

CONCLUSIONS

Comparison of 2 sharp-edged single-piece IOLs of similar design and hydrophobic acrylic material indicated a statistically significant difference in PCO and neodymium:yttrium-aluminum-garnet capsulotomy rate 3 years after surgery.

Risk potentiality of frontline radiotherapy associated cataract in primary ocular adnexal mucosa-associated lymphoid tissue lymphoma

PURPOSE

To elucidate risk potentiality of frontline radiotherapy associated cataracts in primary ocular adnexal mucosa-associated lymphoid tissue lymphoma (OAML).

METHODS

Data from eight consecutive patients of 41 total OAML patients who had undergone cataract surgery after frontline radiotherapy were analyzed.

RESULTS

The median patient age was 46 years (range, 36 to 69 years). The median total radiation dose was 3,780 cGy (range, 3,060 to 4,500 cGy), and the mean duration from radiation irradiation to cataract surgery was 36.60 ± 8.93 months. Preoperative lens opacification was primarily at the posterior lens subcapsule, and best-corrected visual acuity (BCVA) was 0.43 ± 0.21. Patients underwent the phacoemulsification surgical procedure with posterior chamber intraocular lens insertion. The average BCVA improved to 0.90 ± 0.14 after cataract surgery. Two patients underwent posterior continuous curvilinear capsulorhexis, and one had posterior capsule rupture. For posterior capsule opacification (PCO), three patients received Nd:YAG laser posterior capsulotomy after the initial surgery, and one patient is currently under consideration for laser posterior capsulotomy.

CONCLUSIONS

Radiotherapy increased posterior subcapsule opacification at a relatively young age in primary OAML. Phacoemulsification was a manageable procedure without severe complications, and final visual outcomes were good. However, because after-cataracts progressed earlier than did senile cataracts, close follow-up should be considered for PCO management.

Impact of bilateral cataract surgery on vision-related activity limitations

PURPOSE

To evaluate patients' vision-related activity limitation before and after bilateral cataract surgery using the German version of the Catquest-9SF questionnaire.

SETTING

Hanusch Hospital, Vienna, Austria, and Ophthalmic Clinic, Minden, Germany.

DESIGN

Questionnaire development.

METHODS

This prospective 2-center study included patients who were scheduled for bilateral cataract surgery and attended their preassessment appointment approximately 1 week before cataract surgery. All patients self-administered the Catquest-9SF at the preassessment session and a second time 3 months after cataract surgery. The questionnaire includes 9 items and is a revised short form of the Catquest, scored using Rasch analysis. The Catquest-9SF includes questions concerning vision-associated problems in everyday life, general satisfaction with vision, and difficulties performing activities.

RESULTS

The study comprised 210 patients, 120 in Austria and 90 in Germany. The mean age of all patients was 74.1 years (range 41 to 92 years). Patients mostly had difficulties doing handwork (42%) or recognizing uneven surfaces (30%). Sixty percent of the patients in Austria and approximately 50% in Germany were very unsatisfied with their vision preoperatively. Postoperatively, all patients recognized a subjective improvement in their vision.

CONCLUSIONS

Patients having bilateral cataract surgery achieved marked improvements in vision-related activity limitation and satisfaction with vision. A subset of patients with less vision-related activity limitation before surgery was satisfied with first-eye surgery only.

Application of sustained delivery microsphere of cyclosporine A for preventing posterior capsular opacification in rabbits

AIM

To explore the inhibitory effect of a sustained cyclosporin A (CsA) delivery microsphere (CsA-MS) on posterior capsular opacification (PCO) in rabbit eyes after cataract extraction.

METHODS

Twenty New Zealand white rabbits accepted cataract extraction plus intraocular lens implantation and their left eyes were intraoperatively injected CsA-MS prepared using polymer polylactioglycolic acid (PLGA) as a carrier and their right eyes were injected with empty MS. The changes in cornea, anterior chamber reaction, intraocular pressure, PCO and CsA concentration in aqueous humor were examined postoperatively and all the eyes were enucleated 3 months after surgery for histopathological and morphological examination with light microscopy and electron microscopy.

RESULTS

Conjunctival hyperemia, corneal edema, intraocular pressure and anterior chamber response of experimental and control eyes were similar, while PCO in CsA-MS injected eyes was greatly improved compared with that in control eyes. Posterior capsules in CsA-MS injected eyes were smooth and lens epithelial cells (LEC) did not proliferate significantly (P>0.05), while LEC in posterior capsule of control eyes had different degrees of proliferation and cortical regeneration. LEC in CsA-MS injected eyes were not functionally active and underwent apoptosis, whereas LEC in control eyes were functionally active (F-test, P=0.025). In addition, the corneal ultrastructure showed no differences between CsA-MS and MS injected eyes.

CONCLUSION

CsA-MS has high bioavailability in rabbit eyes and could inhibit postoperative PCO occurrence and development during the study period, suggesting that CsA-MS may be a promising, effective and safe administration route to prevent PCO in clinic.

Curcumin inhibits proliferation of human lens epithelial cells: a proteomic analysis

OBJECTIVE

The incidence of after-cataracts [also known as posterior capsular opacification (PCO)] is between 30% and 50% three years following cataract surgery. Suppressing the proliferation of lens epithelial cells (LECs) is a primary goal in preventing PCO. Here, we investigated the proteomic regulation of the inhibitory effects of curcumin (Cur) on the proliferation of human lens epithelial B3 (HLE-B3) cells.

METHODS

Recombinant human basic fibroblast growth factor (rhbFGF) was used to induce proliferation of HLE-B3 cells, which were incubated with 20 mg/L Cur in a CO(2) incubator for 24 h.

RESULTS

We found that the absorbance (A) value of rhbFGF group was significantly higher than the A value of the control group. Furthermore, the A value of the Cur group was significantly lower compared to the rhbFGF group, with an inhibition of 53.7%. Five different protein spots were obtained from proliferative HLE-B3 cells induced by rhbFGF. Eight different protein spots were obtained in HLE-B3 cells incubated with Cur. There were the common variational protein spots at mass/charge (m/z) ratios of 8093 and 13767 between rhbFGF group and control group as well as between the Cur group and rhbFGF group.

CONCLUSIONS

These results show that Cur effectively inhibited HLE-B3 cell proliferation induced by rhbFGF. The protein spots at m/z of 8093 and 13767 may be the targets of Cur-induced inhibition of HLE-B3 cell proliferation. Cur may be a reliable and effective drug for prevention and treatment of polymerase chain reaction (PCR).

BAX gene over-expression via nucleofection to induce apoptosis in human lens epithelial cells

Despite significant advances in cataract surgery techniques, posterior capsule opacification (PCO) remains a common complication. In PCO, remaining epithelial cells cloud the lens capsule and impair postoperative vision. This in vitro study was designed to investigate the potential of a gene-based approach, specifically over-expression of the proapoptotic BAX gene, to prevent PCO. Human lens epithelial cells (HLECs) were transfected by nucleofection with a plasmid encoding a fusion protein of green fluorescent protein and human BAX. The expression levels of BAX and its antiapoptotic counterpart BCL2 were determined by realtime reverse transcription polymerase chain reaction, Western blotting and immunofluorescence. BAX over-expression-induced cell death was analyzed by fluorescence-activated cell sorting using the Annexin V antibody. Fluorescence microscopy and transmission electron microscopy were used to assess changes in morphology and ultrastructure. Differential expression of the downstream apoptosis-related factor, caspase 3, was detected by Western blotting. Nucleofection efficiency was high (nearly 80%). BAX-transfected HLECs showed remarkably enhanced BAX gene expression and BAX:BCL2 ratio, but relatively little change in endogenous BCL2 expression. BAX over-expression also led to significant cytotoxicity, induction of apoptosis-related characteristics and activation of caspase 3. In conclusion, our results indicate that BAX gene over-expression can trigger cell death in HLECs via an apoptotic pathway. Thus, BAX may be a promising candidate for human gene therapy to treat PCO.

Fixed combination brimonidine-timolol versus brimonidine for treatment of intraocular pressure elevation after neodymium:YAG laser posterior capsulotomy

PURPOSE

To evaluate the efficacy of fixed combination brimonidine-timolol (FCBT) in comparison with brimonidine tartrate 0.2% and control for the treatment of intraocular pressure (IOP) spikes after neodymium:YAG (Nd:YAG) laser posterior capsulotomy.

METHODS

One hundred five eyes of 105 patients were enrolled in the study. Patients were randomized to 3 groups (each group, including 35 patients): the FCBT group that received 1 drop of FCBT, the brimonidine group that received 1 drop of brimonidine tartrate 0.2%, and the control group that received 1 drop of artificial tear, 1 h before the laser procedure. Postoperative IOP measurements were performed at 1st, 2nd, 3rd, 24th hours, and seventh day.

RESULTS

The mean IOP changes from baseline were statistically different between the study groups at first, second, and third hours (all P<0.001). Pairwise comparisons showed that although the mean IOP changes of the treatment groups were similar at 1st and 24th hours and seventh day (all P>0.05), the IOP levels of the brimonidine group were less reduced from baseline than the FCBT group at second and third hours (P=0.01 and P=0.03, respectively). The differences among the study groups concerning the incidence of IOP elevations of ≥5 or ≥10 mmHg were statistically significant (P=0.007, P=0.04, respectively). However, the differences between the treatment groups were not statistically significant (both P>0.05).

CONCLUSION

This study has shown that preoperative instillation of 1-drop FCBT was safe and effective for preventing IOP spikes after Nd:YAG laser posterior capsulotomy. FCBT may be a better option than brimonidine tartrate 0.2%, which is one of the current standard prophylaxes for these spikes.

Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event

BACKGROUND

Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention.

METHODS

Using a collection of reviews identified previously, 166 references including a meta-analysis were selected for review. At least one of the primary outcomes in each review was an adverse or unintended event. The nature of the intervention, source of funding, number of individual meta-analyses performed, number of primary studies included in the review, and use of meta-analytic methods were all recorded. Specific areas of interest relating to the methods used included the choice of outcome metric, methods of dealing with sparse events, heterogeneity, publication bias and use of individual patient data.

RESULTS

The 166 included reviews were published between 1994 and 2006. Interventions included drugs and surgery among other interventions. Many of the references being reviewed included multiple meta-analyses with 44.6% (74/166) including more than ten. Randomised trials only were included in 42.2% of meta-analyses (70/166), observational studies only in 33.7% (56/166) and a mix of observational studies and trials in 15.7% (26/166). Sparse data, in the form of zero events in one or both arms where the outcome was a count of events, was found in 64 reviews of two-arm studies, of which 41 (64.1%) had zero events in both arms.

CONCLUSIONS

Meta-analyses of adverse events data are common and useful in terms of increasing the power to detect an association with an intervention, especially when the events are infrequent. However, with regard to existing meta-analyses, a wide variety of different methods have been employed, often with no evident rationale for using a particular approach. More specifically, the approach to dealing with zero events varies, and guidelines on this issue would be desirable.

Nd:YAG laser capsulotomy: a survey of UK practice and recommendations

PURPOSE

To determine national trends in YAG laser capsulotomy practice in the NHS.

METHODS

A total of 300 consultants were randomly selected, based on a list from the Royal College of Ophthalmologists, to receive a postal questionnaire. It included 10 questions about YAG capsulotomy technique and postcapsulotomy management.

RESULTS

A total of 158 (53%) replies were received; 132 (83.5%) questionnaires were completed correctly. Most consultants dilate the pupil prior to treatment (98.5%) and use contact lens (87.9%), with 63.5% reporting using contact lenses for more than one indication. Nearly half of the consultants used cruciate laser pattern (47.0%). Most aimed for capsulotomy size larger than undilated pupil size (64.4%). A total of 42.4% used postoperative steroid drops, 61.8% for 1 week. Half used postlaser intraocular pressure-lowering drops with the majority used as 1-stat dose (85.1%). A total of 60% are not reviewing cases. Cases reviewed are mostly seen by doctors, with 50% reviewed 1 month postlaser.

CONCLUSIONS

Though commonly practiced, there is still considerable variation in YAG laser capsulotomy practice among NHS consultant ophthalmologists. Evidence-based guidelines are warranted to lessen any unnecessary complications.

Systematic overview of the efficacy of nonpenetrating glaucoma surgery in the treatment of open angle glaucoma

BACKGROUND

To evaluate the intraocular pressure (IOP)-lowering effects achieved by nonpenetrating glaucoma surgery (NPGS) and its modifications in patients with open angle glaucoma.

MATERIAL/METHODS

Randomized controlled trials evaluating patients with primary and secondary open angle glaucoma treated with NPGS were identified through systematic searches. The main outcome measures were the percentage IOP reduction and the complete success rate. Complete success was defined as target endpoint IOP (usually less than 21 mm Hg) without medications. The pooled estimates were calculated using the random effects model.

RESULTS

Both deep sclerectomy (DS) and viscocanalostomy (VCO) were less effective than trabeculectomy (TE) in lowering IOP, with the percentage IOP reductions at 2 years being 35.2% for DS, 30.2% for VCO, and 45.6% for TE. Intraoperative use of implants and mitomycin C (MMC) increased IOP-lowering effects of DS, with IOP reductions at 2 years of 41.1% and 41.7%, respectively. The complete success rates at 4 years were 35.4% for DS, and 22.7% for VCO, lower than that of TE (47.6%). The complete success rates of DS with implants and MMC of 64.6% and 52.1%, respectively, at 4 years, were greater than that of primary DS. NPGS caused major complications in fewer patients than did TE.

CONCLUSIONS

Primary deep sclerectomy and primary viscocanalostomy, which can significantly lower IOP, were associated with fewer complications than was TE. However, the IOP-lowering effects of both NPGS seem to be lower than that of primary TE. The efficacy of DS can be improved with the intraoperative use of implants and MMC.

Primary lens extraction for glaucoma management: A review article

Recently, primary lens extraction alone gained more acceptance as an alternative surgical approach for glaucoma management. This view was supported by the advances in phacoemulsification and intraocular lenses with greater safety and visual recovery, in addition to a substantial reduction of intraocular pressure and deepening of the anterior chamber and filtration angle. The decrease in IOP after cataract surgery in primary open-angle glaucoma (POAG) is mild, less predictable, related to baseline levels, and may return to presurgical values after an initial period of reduction. Therefore, the IOP-lowering effect of primary cataract extraction in POAG may be insufficient to achieve adequate IOP control. The IOP reduction after lens extraction is consistently greater in eyes with primary angle closure glaucoma (PACG) than in eyes with POAG. Primary lens extraction in acute PACG eliminates, or at least, reduces the risk of recurrence of acute attacks and deepens the anterior chamber and widens the angle which reduces the risk of progression of peripheral anterior synechiae and development of chronic PACG. Primary lens extraction may be more preferable to glaucoma incisional surgery in mild to moderate PACG eyes with appositional angle closure. The decision to do lens extraction as a primary treatment for glaucoma should be individualized based upon several factors other than the effect on IOP. These factors include patients' characteristics, surgeons' skills and preferences, status of glaucoma control, type of cataract and intraocular lens implanted, and potential harm of laser treatment for late capsular opacification and fibrosis.

Secondary cataract: an epidemiologic and clinical survey at the Yaounde Gynaeco-obstetric and Paediatric Hospital

Objective:

To determine the incidence and risk factors of secondary cataract.

Materials and methods:

A retrospective study involving a review of medical records in the ophthalmology unit of the Yaoundé Gynaeco-obstetric and Paediatric Hospital in Yaoundé, Cameroon, was carried out. All patients who had cataract surgery between January 2006 and September 2010 were included. Variables included age, sex, past medical history, morphology of primary cataract, type of surgery, intraocular lens implantation, site of implantation, intra- and postoperative complications, and the time lapse for the presentation of secondary cataract. Both univariate and bivariate analyses were carried out. The χ² test was used to compare proportions, and P-values <0.05 were considered statistically significant.

Results:

A total of 864 eyes of 718 patients had cataract surgery. Ninety-two eyes developed posterior capsule opacification, giving an incidence of 10.65%. The mean age of patients who developed secondary cataract was 52.3 ± 23.05 years, with a range of 4 years to 84 years. Secondary cataract was more frequent in the age group of 0–20 years. The time lapse for presentation of secondary cataract was 64.7 ± 9.53 days, with a range of 1 to 504 days. Risk factors for the development of secondary cataract were age (P = 0.000), sex (P = 0.011), cortical cataract (P = 0.000), and postoperative inflammation (P = 0.000).

Conclusion:

The incidence of secondary cataract, though high in this study, is lower than that reported in other studies.

Posterior capsule opacification and neovascularization treated with intravitreal bevacizumab and Nd:YAG capsulotomy

We reported a 75-year-old diabetic man, who developed opacification and neovascularization of the posterior capsule after extracapsular cataract extraction and posterior chamber intraocular lens implantation. The patient was treated with two injections of 2.5 mg of intravitreal bevacizumab. The treatment produced an important regression of the posterior capsular new vessels, allowing us to perform a successful Nd:YAG capsulotomy, clearing the visual axis and improving the visualization of the posterior pole. Even though, best corrected visual acuity was 20/200 due to diabetic macular edema.

Reduction of Nd:YAG capsulotomy rates after implantation of a single-piece acrylic hydrophilic intraocular lens with 360° squared optic edge: 24-month results

BACKGROUND AND OBJECTIVE

Posterior capsule opacification remains a significant problem following cataract surgery. The aim of the study was to evaluate the incidence of symptomatic posterior capsule opacification requiring Nd:YAG capsulotomy in patients who underwent cataract extraction and implantation of the Rayner C-flex 570C intraocular lens (IOL) (Rayner Intraocular Lens, Ltd., Sussex, UK).

PATIENTS AND METHODS

A retrospective study of 3,461 eyes that underwent cataract extraction and insertion of the Rayner C-flex IOL from January 2004 to December 2005. The cases that received Nd: YAG capsulotomies were evaluated.

RESULTS

Over a 24-month period, 3,461 Rayner C-flex IOLs were implanted. Nd:YAG capsulotomy was performed in 58 of these cases. The rate of Nd:YAG capsulotomy was 0.6% at 12 months and 1.7% at 24 months. The mean time to Nd:YAG capsulotomy was 9.3 months (range: 1.3 to 22.7 months). The follow-up period was 5.3 to 29.0 months.

CONCLUSION

The incidence of symptomatic posterior capsule opacification with the Rayner C-flex IOL is low.

Ablation of lens epithelial cells with a laser photolysis system: histopathology, ultrastructure, and immunochemistry

PURPOSE

To evaluate efficacy of a neodymium:YAG (Nd:YAG) laser photolysis system in removing lens epithelial cells (LECs) and characterize the effect of the laser on laminin and fibronectin involved in LEC adhesion and migration.

METHODS

Cadaver eyes were evaluated using the Miyake technique. The lenses were removed with phacoemulsification. The modified Nd:YAG laser was used to clean the LECs from the capsule. Only the fornix was cleaned in some eyes and the anterior subcapsular area in other eyes. Some areas were not treated and acted as controls. Standard irrigation/aspiration (I/A) removal of LECs was performed in additional eyes. The eyes were analyzed using light microscopy and immunohistochemical staining.

RESULTS

Histopathologic evaluation showed that the laser removed the LECs from the anterior lens capsule and from the fornix. Immunohistochemical staining showed fibronectin and laminin staining in the untreated areas that was absent in the treated areas. Standard I/A removal of the LECs showed absence of cells but persistent laminin and fibronectin. Electron microscopy showed epithelial cells in untreated areas with an absence of the LECs and debris in treated areas.

CONCLUSIONS

The laser photolysis system removed LECs from the anterior lens capsule and capsule fornix. Along with the cells, laminin, fibronectin, and cell debris remained in the untreated areas but were removed by the treatment. This treatment may be useful in preventing posterior capsule opacification.

Macular thickness changes after phacoemulsification combined with primary posterior curvilinear capsulorhexis

PURPOSE

To evaluate the changes in central macular thickness measured with optical coherence tomography (OCT) after cataract surgery combined with primary posterior continuous curvilinear capsulorhexis (PCCC).

METHODS

Forty-six eyes of 40 consecutive patients who had uneventful phacoemulsification and in-the-bag intraocular lens implantation surgery with primary PCCC, taking place between August 2005 and January 2006 in Beyoglu Eye Training and Research Hospital, were enrolled. Patients with a history of previous ocular surgery, eye trauma, uveitis, or glaucoma, or any systemic disease such as diabetes mellitus, were excluded from the study. None of the cases had macular pathology before surgery. OCT was performed in all patients preoperatively and postoperatively on the first day, first week, and first, third, and sixth months.

RESULTS

Significant quantitative changes from the preoperative examination were observed in the postoperative first week, first month, and third month (p<0.05). The difference between the mean preoperative and postoperative sixth month central macular thickness was not statistically significant (p=0.20). The greatest change in mean macular thickness was noted in the first month visit. No patient developed cystoid macular edema.

CONCLUSIONS

Because primary PCCC does not have an adverse effect on macular integrity, this procedure may be preferred especially in patients with a high risk of posterior capsular opacification.

Prevention of lens capsule opacification with ARC neodymium:YAG laser photolysis after phacoemulsification

We describe a technique that uses a neodymium:YAG (Nd:YAG) laser photolysis system to prevent lens capsule opacification. The photolysis instrument consists of a 1064 nm Nd:YAG laser transmitted along a fiber-optic cable into a handpiece containing an angulated titanium plate that the laser beam strikes, creating plasma and a shockwave that exits the handpiece through an aperture. Under direct visualization, the shockwave is aimed at the inner surface of the anterior capsule, where it removes LECs and proteoglycan attachment molecules; the shockwave probably extends to the capsule fornix, destroying germinal epithelial cells. We report preliminary results in 12 eyes followed for approximately 2.5 years in which the treated nasal anterior capsule remained clear or with only slight opacity and the untreated temporal capsule developed moderate to severe opacification.

Perception of difficulties with vision-related activities of daily living among patients undergoing unilateral posterior capsulotomy

OBJECTIVES

To assess the influence of Nd:YAG (neodymium: yttrium-aluminum- garnet) laser unilateral posterior capsulotomy on visual acuity and patients' perception of difficulties with vision-related activities of daily life.

METHODS

We conducted an interventional survey that included 48 patients between 40 and 80 years of age with uni- or bilateral pseudophakia, posterior capsule opacification, and visual acuity <or=0.30 (logMAR) in one eye who were seen at a Brazilian university hospital. All patients underwent posterior capsulotomy using an Nd:YAG laser. Before and after the intervention, patients were asked to complete a questionnaire that was developed in an exploratory study.

RESULTS

Before posterior capsulotomy, the median visual acuity (logMAR) of the included patients was 0.52 (range 0.30-1.60). After posterior capsulotomy, the median visual acuity of the included patients improved to 0.10 (range 0.0-0.52). According to the subjects' perceptions, their ability to perform most of their daily life activities improved after the intervention (p<0.05).

CONCLUSIONS

After patients underwent posterior capsulotomy with an Nd:YAG laser, a significant improvement in the visual acuity of the treated eye was observed. Additionally, subjects felt that they experienced less difficulty performing most of their vision-dependent activities of daily living.

Interventions for preventing posterior capsule opacification

BACKGROUND

Posterior capsule opacification (PCO) remains the most common long-term complication after cataract surgery. It can be treated by Nd:YAG laser capsulotomy, however this may lead to other complications and laser treatment is not available in large parts of the developing world. Therefore, many studies try to find factors influencing the development of PCO.

OBJECTIVES

To summarise the effects of different interventions to inhibit PCO. These include modifications of surgical technique and intraocular lens (IOL) design, implantation of additional devices and pharmacological interventions.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, LILACS in March 2009 and reference lists of identified trial reports.

SELECTION CRITERIA

We included only prospective, randomised and controlled trials with a follow-up time of at least 12 months. Interventions included modifications in surgical technique explicitly to inhibit PCO, modifications in IOL design (material and geometry), implantation of additional devices and pharmacological therapy compared to each other, placebo or standard treatment.

DATA COLLECTION AND ANALYSIS

We extracted data and entered it into RevMan. We compared visual acuity data, PCO scores and YAG capsulotomy rates and performed a meta-analysis when possible.

MAIN RESULTS

Sixty six studies were included in the review. The review was divided into three parts. 1. Influence of IOL optic material on the development of PCO. There was no significant difference in PCO development between the different IOL materials (PMMA, hydrogel, hydrophobic acrylic, silicone) although hydrogel IOLs tend to have higher PCO scores and silicone IOLs lower PCO scores than the other materials. 2. Influence of IOL optic design on the development of PCO. There was a significantly lower PCO score (-8.65 (-10.72 to -6.59), scale 0 to 100) and YAG rate (0.19 (0.11 to 0.35)) in sharp edged than in round edged IOLs, however not between 1-piece and 3-piece IOLs. 3. Influence of surgical technique and drugs on the development of PCO. There was no significant difference between different types of intraoperative/postoperative anti-inflammatory treatment except for treatment with an immunotoxin (MDX-A) which led to a significantly lower PCO rate.

AUTHORS' CONCLUSIONS

Due to the highly significant difference between round and sharp edged IOL optics, IOLs with sharp (posterior) optic edges should be preferred. There is no clear difference between optic materials. The choice of postoperative anti-inflammatory treatment does not seem to influence PCO development.

Ten-year longitudinal visual function and Nd: YAG laser capsulotomy rates in patients less than 65 years at cataract surgery

PURPOSE

To investigate the longitudinal subjective and objective visual functional results in adult cataract patients younger than 65 years at surgery. To evaluate the 10-year cumulative incidence of neodymium-yttrium-aluminum-garnet (Nd:YAG) laser treatment.

DESIGN

A prospective, longitudinal, population-based cohort study.

METHODS

The study comprised 116 patients younger than 65 years who had cataract surgery during 1 year at Norrlands University Hospital, Umeå, Sweden. Most patients (94%) had received implantation with a hydrophobic acrylic intraocular lens. Evaluated were visual acuity (VA) and visual function questionnaire (VF-14) results before and after surgery. A comparison with patients 65 years or older at surgery was made. Ten years later, 102 survivors were offered eye examinations and again asked to fill out the questionnaire. Past Nd:YAG laser treatment, as well as high- and low-contrast VA results, were analyzed.

RESULTS

Ten years postoperatively, 37% of the patients under 65 at surgery had been treated with Nd:YAG in comparison to 20% of the older patients. The cumulative incidence for not having Nd:YAG over 10 years was 72% for those under 65 and 85% for the patients 65 years or more at surgery. Eighteen percent of the younger patients had lost more than 0.1 logarithm of the minimal angle of resolution (logMAR) units of the operated eye, compared with 37% of the older (P = .00003). A reduction in VF-14 score of 10 points or more was found in 9% of the younger and 28% of the older cataract surgery patients (P = .00004).

CONCLUSION

Ten years after surgery, subjective and objective visual function remained stable in most patients younger than 65 years at surgery. More than one-third had received a posterior capsulotomy. Only a few patients with posterior capsular opacification requiring Nd:YAG were untreated at the 10-year follow-up.