Surgical interventions for age-related cataract

BACKGROUND

Cataract accounts for 50% of blindness globally and remains the leading cause of visual impairment in all regions of the world, despite improvements in surgical outcomes (WHO 2005). This number is expected to rise due to an aging population and increase in life expectancy. Although cataracts are not preventable, their surgical treatment is one of the most cost-effective interventions in healthcare.

OBJECTIVES

To compare the effects of different surgical interventions for age-related cataract.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE up to July 2006, NRR Issue 3 2005, the reference lists of identified trials and we contacted investigators and experts in the field for details of published and unpublished trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTS).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and discrepancies were resolved by discussion. Where appropriate, risk ratios, odds ratios and weighted mean differences were summarised after assessing heterogeneity between the studies.

MAIN RESULTS

We identified 17 trials that randomised a total of 9627 people. Phacoemulsification gave a better visual outcome than extracapsular surgery but similar average cost per procedure in Europe but not in poorer countries. Extracapsular surgery with posterior chamber lens implant and ICCE with or without an anterior chamber intraocular lens (IOL) implant gave acceptable visual outcomes but extracapsular surgery had less complications. Manual small incision surgery provides better visual outcome than ECCE but slightly inferior unaided visual acuity compared to phacoemulsification.

AUTHORS' CONCLUSIONS

This review provides evidence from seven RCTs that phacoemulsification gives a better outcome than ECCE with sutures. We also found evidence that ECCE with a posterior chamber lens implant provides better visual outcome than ICCE with aphakic glasses. The long term effect of posterior capsular opacification (PCO) needs to be assessed in larger populations. The data also suggests that ICCE with an anterior chamber lens implant is an effective alternative to ICCE with aphakic glasses, with similar safety. Phacoemulsification provides the best visual outcomes but will only be accessible to the poorer countries if the cost of phacoemulsification and foldable IOLs decrease. Manual small incision cataract surgery provides early visual rehabilitation and comparable visual outcome to PHACO. It has better visual outcomes than ECCE and can be used in any clinic that is currently carrying out ECCE with IOL. Further research from developing regions are needed to compare the cost and longer term outcomes of these procedures e.g. PCO and corneal endothelial cell damage.

Longitudinal farm study of extended-spectrum beta-lactamase-mediated resistance

Extended-spectrum beta-lactamase (ESBL)-mediated resistance is of considerable importance in human medicine. Recently, such enzymes have been reported in bacteria from animals. We describe a longitudinal study of a dairy farm suffering calf scour with high mortality rates. In November 2004, two Escherichia coli isolates with resistance to a wide range of beta-lactams (including amoxicillin-clavulanate and cefotaxime) were isolated from scouring calves. Testing by PCR and sequence analysis confirmed the isolates as being both bla(CTX-M14/17) and bla(TEM-35) ((IRT-4)) positive. They had indistinguishable plasmid and pulsed-field gel electrophoresis (PFGE) profiles. Transferability studies demonstrated that bla(CTX-M) was located on a conjugative 65-MDa IncK plasmid. Following a farm visit in December 2004, 31/48 calves and 2/60 cows were positive for E. coli with bla(CTX-M). Also, 5/48 calf and 28/60 cow samples yielded bla(CTX)- and bla(TEM)-negative E. coli isolates that were resistant to cefotaxime, and sequence analysis confirmed that these presented mutations in the promoter region of the chromosomal ampC gene. Fingerprinting showed 11 different PFGE types (seven in bla(CTX-M)-positive isolates). Six different PFGE clones conjugated the same bla(CTX-M)-positive IncK plasmid. One clone carried a different-sized, bla(CTX-M)-positive, transformable plasmid. This is the first report of bla(CTX-M) from livestock in the United Kingdom, and this report demonstrates the complexity of ESBL epidemiology. Results indicate that horizontal plasmid transfer between strains as well as horizontal gene transfer between plasmids have contributed to the spread of resistance. We have also shown that some clones can persist for months, suggesting that clonal spread also contributes to the perpetuation of resistance.

Rapid assessment of avoidable blindness and needs assessment of cataract surgical services in Satkhira District, Bangladesh

AIMS

To estimate the magnitude and causes of blindness in people aged > or =50 years in Satkhira district, Bangladesh, and to assess the availability of cataract surgical services.

METHODS

106 clusters of 50 people aged > or =50 years were selected by probability-proportionate to size sampling. Households were selected by compact segment sampling. Eligible participants had their visual acuity measured. Those with visual acuity <6/18 were examined by an ophthalmologist. A needs assessment of surgical services was conducted by interviewing service providers.

RESULTS

4868 people were examined (response rate 91.9%). The prevalence of bilateral blindness was 2.9% (95% confidence interval (CI) 2.4% to 3.5%), that of severe visual impairment was 1.6% (95% CI 1.2% to 2.0%) and that of visual impairment was 8.4% (95% CI 7.5% to 9.3%). 79% of bilateral blindness was due to cataract. The cataract surgical coverage was moderate; 61% of people with bilateral cataract blindness (visual acuity <3/60) had undergone surgery. 20% of the 213 eyes that had undergone cataract surgery had a best-corrected poor outcome (visual acuity <6/60). The cataract surgical rate (CSR) in Satkhira was 547 cataract surgeries per million people per year.

CONCLUSIONS

Although the prevalence of blindness and visual impairment was lower than expected, the CSR is inadequate to meet the existing need, and the quality of surgery needs to be improved.

Erlotinib-associated rash correlates with plasma levels at steady state

13008

Background: Erlotinib is a small molecule epidermal growth factor receptor tyrosine kinase inhibitor that is approved for non-small cell lung cancer as a single agent and for pancreatic cancer in combination with gemcitabine. Significant inter-individual variation in drug exposure may explain differential patient outcomes. Genetic polymorphisms of metabolizing enzymes of erlotinib may explain this variability in exposure. Biotransformation assays have implicated cytochrome 3A4/5 (CYP3A4/5) as the predominant metabolizing enzyme. Methods: Patients were enrolled onto a phase-1 dose-escalation study of weekly docetaxel with fixed oral daily dosing (150 mg) of erlotinib. Pharmacodynamic data regarding grade of rash per CTCAE v. 2 were recorded on all 23 patients. Samples for erlotinib pharmacokinetics were obtained after 28 days of continuous daily dosing. Pharmacokinetic (PK) data was attained in 21 patients using LC/MS/MS and analyzed using noncompartmental analysis. Genomic DNA was available for analysis in all 23 patients. Analysis for single nucleotide polymorphisms CYP3A5*3 and CYP2D6*4 were performed by real-time polymerase chain reaction and confirmed by restriction fragment length polymorphism analysis when needed. Results: Average age of patients was 56 (34–76). Nine patients had grade 0–1 rash and 12 had grade 2 rash. As summarized in the table below, the AUC for patients exhibiting grade 2 rash was approximately twice that of patients with grade 0–1 rash. No significant association was found between PK parameters and either CYP3A5 or CYP2D6 polymorphisms. Conclusions: In patients treated with erlotinib the pharmacodynamic endpoint of rash, which has been previously linked with improved patient outcomes, is significantly correlated to the degree of exposure to the drug at steady state. Preliminary data in this small study analyzing pharmacogenetics of erlotinib found no significant correlation between CYP3A5*3 and CYP2D6*4 polymorphic status in either PK or pharmacodynamic measures.

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Prevalence and causes of blindness and visual impairment in Muyuka: a rural health district in South West Province, Cameroon

AIM

To estimate the prevalence and causes of blindness and visual impairment in the population aged 40 years and over in Muyuka, a rural district in the South West Province of Cameroon.

METHODS

A multistage cluster random sampling methodology was used to select 20 clusters of 100 people each. In each cluster households were randomly selected and all eligible people had their visual acuity (VA) measured by an ophthalmic nurse. Those with VA <6/18 were examined by an ophthalmologist.

RESULTS

1787 people were examined (response rate 89.3%). The prevalence of binocular blindness was 1.6% (95% CI: 0.8% to 2.4%), 2.2% (1.% to 3.1%) for binocular severe visual impairment, and 6.4% (5.0% to 7.8%) for binocular visual impairment. Cataract was the main cause of blindness (62.1%), severe visual impairment (65.0%), and visual impairment (40.0%). Refractive error was an important cause of severe visual impairment (15.0%) and visual impairment (22.5%). The cataract surgical coverage for people was 55% at the <3/60 level and 33% at the <6/60 level. 64.3% of eyes operated for cataract had poor visual outcome (presenting VA<6/60).

CONCLUSIONS

Strategies should be developed to make cataract services affordable and accessible to the population in the rural areas. There is an urgent need to improve the outcome of cataract surgery. Refractive error services should be provided at the community level.

Reducing incision length or intensifying rehabilitation: what makes the difference to length of stay in total hip replacement in a UK setting?

Minimal-incision surgery for hip arthroplasty and intensive post-op physiotherapy have both been shown to allow early mobilisation and to reduce hospital stay. Forty-five patients undergoing primary total hip arthroplasty using a standard posterior approach were compared with 51 patients using a minimal incision. In both groups, physiotherapy involved either a routine or intensive regime. Patients were matched in age, sex and body mass index. There was no significant difference in blood loss, post-operative stay and change in Oxford hip scores at one year between the mini- and standard-incision groups. There was a significant difference (P=0.003) in length of stay between routine- and intensive-physiotherapy groups (11.4 vs. 7.9 days). The dislocation rate was higher in the mini-incision group. This study suggests that in a standard UK setting, intensive physiotherapy can significantly decrease in-patient stay, but reducing the incision length does not.

Distance to water source and altitude in relation to active trachoma in Rombo district, Tanzania

OBJECTIVES

To investigate the relationship between distance to water source, altitude and active trachoma in children in Rombo district, Tanzania.

METHODS

In each of Rombo's 64 villages, 10 balozis (groups of 8-40 households) were selected at random and all resident children aged 1-9 years were examined for clinical signs of active trachoma. The households of these children and village water sources were mapped using differentially corrected global positioning system data to determine each household's altitude and distance to the nearest water supply.

RESULTS

We examined 12 415 children and diagnosed 1171 cases of active trachoma (weighted prevalence=9.1%, 95% CI: 8.0, 10.2%). Active trachoma prevalence ranged from 0% to 33.7% across villages. Increasing distance to the nearest water source was significantly associated with rising trachoma prevalence (age-adjusted odds ratio for infection (OR) for highest quartile compared to lowest=3.56, 95% CI 2.47, 5.14, P for trend <0.0001). Altitude was significantly inversely associated with trachoma prevalence (age-adjusted OR for highest quartile compared to lowest=0.55, 95% CI 0.41, 0.75, P for trend <0.0001). These associations remained significant after adjustment in multivariate analysis.

CONCLUSIONS

Trachoma is endemic in Rombo district, although the prevalence varies considerably between villages. Spatial mapping is a useful method for analysing risk factors for active trachoma.

The impact of Vision 2020 on global blindness

INTRODUCTION

Recent data suggest that there are 37 million blind people and 124 million with low vision, excluding those with uncorrected refractive errors. The main causes of global blindness are cataract, glaucoma, corneal scarring (from a variety of causes), age-related macular degeneration, and diabetic retinopathy.

CONCLUSION

It would appear that the global Vision 2020 initiative is having an impact to reduce avoidable blindness particularly from ocular infections, but more needs to be done to address cataract, glaucoma, and diabetic retinopathy.

Responses to human CD40 ligand/human interleukin-2 autologous cell vaccine in patients with B-cell chronic lymphocytic leukemia

PURPOSE

Human CD40 ligand activates the malignant B-cell chronic lymphocytic leukemia cells and enhances their capacity to present tumor antigens. Human interleukin-2 further potentiates the immunogenicity of human CD40 ligand in preclinical murine models.

EXPERIMENTAL DESIGN

We prepared autologous B-cell chronic lymphocytic leukemia cells that expressed both human CD40 ligand (>90% positive) and human interleukin-2 (median secretion, 1,822 pg/mL/10(6) cells; range, 174-3,604 pg). Nine patients were enrolled in a phase I trial, receiving three to eight s.c. vaccinations.

RESULTS

Vaccinations were administered without evidence of significant local or systemic toxicity. A B-cell chronic lymphocytic leukemia-specific T-cell response was detected in seven patients. The mean frequencies of IFN-gamma, granzyme-B, and IL-5 spot-forming cells were 1/1,230, 1/1,450, and 1/4,500, respectively, representing a 43- to 164-fold increase over the frequency before vaccine administration. Three patients produced leukemia-specific immunoglobulins. Three patients had >50% reduction in the size of affected lymph nodes. Nonetheless, the antitumor immune responses were observed only transiently once immunization ceased. High levels of circulating CD4+/CD25+/LAG-3+/FoxP-3+ immunoregulatory T cells were present before, during and after treatment and in vitro removal of these cells increased the antileukemic T-cell reactivity.

CONCLUSIONS

These results suggest that immune responses to B-cell chronic lymphocytic leukemia can be obtained with human CD40 ligand/human interleukin-2-expressing s.c. vaccines but that these responses are transient. High levels of circulating regulatory T cells are present, and it will be of interest to see if their removal in vivo augments and prolongs the antitumor immune response.

A randomised controlled trial of azithromycin following surgery for trachomatous trichiasis in the Gambia

BACKGROUND/AIM

Trachomatous trichiasis frequently returns following surgery. Several factors may promote recurrence: preoperative disease severity, surgeon ability, surgical procedure, healing responses, and infection. This study investigates whether enhanced control of infection, both of Chlamydia trachomatis and other bacteria, with azithromycin can improve surgical outcome in a trachoma control programme.

METHODS

Individuals with trachomatous trichiasis were examined and operated. After surgery patients were randomised to the azithromycin or control group. The azithromycin group and children in their household were given a dose of azithromycin. Antibiotic treatment was repeated at 6 months. All patients were reassessed at 6 months and 12 months. Samples were collected for C trachomatis polymerase chain reaction and general microbiology at each examination.

RESULTS

451 patients were enrolled. 426 (94%) were reassessed at 1 year, of whom 176 (41.3%) had one or more lashes touching the eye and 84 (19.7%) had five or more lashes. There was no difference in trichiasis recurrence between the azithromycin and control group. Recurrent trichiasis was significantly associated with more severe preoperative trichiasis, bacterial infection, and severe conjunctival inflammation at 12 months. Significant variability in outcome was found between surgeons. Visual acuity and symptoms significantly improved following surgery.

CONCLUSION

In this setting, with a low prevalence of active trachoma, azithromycin did not improve the outcome of trichiasis surgery conducted by a trachoma control programme. Audit of trichiasis surgery should be routine.

Long term outcome of trichiasis surgery in the Gambia

BACKGROUND

Trichiasis surgery is believed to reduce the risk of losing vision from trachoma. There are limited data on the long term outcome of surgery and its effect on vision and corneal opacification. Similarly, the determinants of failure are not well understood.

METHODS

A cohort of people in the Gambia who had undergone surgery for trachomatous trichiasis 3-4 years earlier was re-assessed. They were examined clinically and the conjunctiva was sampled for Chlamydia trachomatis polymerase chain reaction (PCR) and general bacterial culture.

RESULTS

In total, 141/162 people were re-examined. Recurrent trichiasis was found in 89/214 (41.6%) operated eyes and 52 (24.3%) eyes had five or more lashes touching the globe. Corneal opacification improved in 36 of 78 previously affected eyes. There was a general deterioration in visual acuity between surgery and follow up, which was greater if new corneal opacification developed or trichiasis returned. Recurrent trichiasis was associated with severe conjunctival inflammation and bacterial infection. C trachomatis was detected in only one individual.

CONCLUSIONS

Recurrent trichiasis following surgery is a common potentially sight threatening problem. Some improvement in the cornea can occur following surgery and the rate of visual loss tended to be less in those without recurrent trichiasis. The role of conjunctival inflammation and bacterial infection needs to be investigated further. Follow up of patients is advised to identify individuals needing additional surgical treatment.

The household distribution of trachoma in a Tanzanian village: an application of GIS to the study of trachoma

The distribution of active trachoma in Kahe Mpya, Tanzania, an endemic village of approximately 1000 people, was mapped spatially and analysed for associated risk factors and evidence of clustering. An association between distance to water source and active disease was demonstrated, although this was reduced after accounting for the lack of independence between cases in the same household. Significant clustering of active trachoma within households was demonstrated, adding support to the hypothesized importance of intra-familial transmission. The spatial distribution of trachoma was analysed using the spatial scan statistic, and evidence of clustering of active trachoma cases detected. Understanding the distribution of the disease has implications for understanding the dynamics of transmission and therefore appropriate control activities. The demonstrated spatial clustering suggests inter-familial as well as intra-familial transmission of infection may be common in this setting. The association between active trachoma and geographical information system (GIS) measured distance to water may be relevant for planning control measures.

An index of community ocular Chlamydia trachomatis load for control of trachoma

Quantitative PCR (Q-PCR) technology has recently been applied to the measurement of ocular loads of Chlamydia trachomatis. We present an index called the community ocular C. trachomatis load (COCTL) which is similar to the community microfilarial load (CMFL) of onchocerciasis. Our index has the advantage of being scale-independent so that, for example, percentage changes are the same whether calculated per eye swab or per Q-PCR capillary. The COCTL for a population or subgroup is formed by adding the arbitrary concentration of 1 organism per ml to each individual Q-PCR quantification, calculating the geometric mean, and finally subtracting 1 per ml again. The use of the COCTL is illustrated in a study of trachoma in northern Tanzania. The COCTL is higher in people with clinical trachoma than those without (5.8 organisms per swab vs. 0.1), and in children aged six months to ten years than in the overall population (1.1 vs. 0.4). The COCTL index is potentially useful for sentinel sites, operational research and calibration of clinical measures of trachoma.

Routine monitoring of visual outcome of cataract surgery. Part 2: Results from eight study centres

AIM

To determine whether monitoring of cataract outcome can be implemented as a routine activity in different hospital settings in Africa and Asia, and to assess the impact of routine monitoring.

METHODS

Eight eye centres in Asia and Africa were involved in the study between 1 June and 31 December 2000. Seven centres used a specifically designed cataract surgery record form with computerised data entry and analysis (CCSRF), and one centre used a manual recording form (MCSRF). Data were used to evaluate quality of data entry, follow up after surgery, and to assess trends in the proportion of complications and visual outcome after surgery.

FINDINGS

The reporting systems were accepted and used by all centres, and data were recorded for 5198 cataract operations. Overall, 54% of eyes were followed for 8 weeks or more and 41% for 6 months. Follow up rates varied between centres from nil to almost 100%. Visual acuity tended to improve over time. The outcome could be improved at all follow up periods by providing best spectacle correction. At 8 weeks or more follow up, surgical complications or inadequate spectacle correction accounted for 72% of the causes of poor outcome. Three centres showed a significant reduction in complication rates over the course of the 6 month study. Data entry was identified as a problem and the CCSRF software has been modified to include consistency checks to reduce data entry errors.

CONCLUSION

A simple system to monitor cataract outcome has been successfully field tested. The results suggest that monitoring can sensitise surgeons to quality control, which can lead to a decrease in complication rates and improved visual outcomes.

Routine monitoring of visual outcome of cataract surgery. Part 1: Development of an instrument

AIM

To develop a system for routine monitoring of visual outcome after cataract surgery.

METHODS

Staff from eight eye centres in Asia and Africa defined the data collection form and report formats to be used for monitoring visual outcome after cataract surgery. Several operational research questions were raised and methods developed to address them. The system was field tested for 6 months and the operational studies undertaken. The system was finalised based upon the experience gained.

FINDINGS

Two different systems for data collection were developed: a manual paper tally system and a computer system (cataract surgery record forms (CSRF)). Both systems report on operative complications; the proportion with good outcome (can see 6/18) and poor outcome (cannot see 6/60); and causes of poor outcome. Data are collected at discharge and at specified time intervals at follow up. Both systems were well accepted.

CONCLUSION

The major problem in field testing was data entry errors in centres using the computerised system. Routine monitoring of cataract outcome should be used by individual surgeons or centres to follow trends in their own results over time, and not to compare surgeons, in an atmosphere of trust and support. Visual acuity at discharge, which can readily be collected on all patients, can be used providing it is appreciated that the final results will be much better. Rapid feedback of results can enhance the consciousness of the eye surgeons to causes of poor outcome. Accuracy in data entry and an efficient flow of record forms are essential.

Changes in arthroscopic findings in the anterior cruciate ligament deficient knee prior to reconstructive surgery

We retrospectively compared the arthroscopic findings of 75 patients at the time of diagnosis of ACL rupture and the findings at the time of ACL reconstruction. We found that in the ACL deficient knee the deterioration in meniscal tears and osteochondral lesions was statistically greater with increased interval between diagnosis of ACL rupture and reconstruction. This study implies that in those patients where ACL reconstruction is indicated, a delay in reconstructive surgery can have a deleterious effect on the articular surface of the knee.

Using social judgement theory to model nurses' use of clinical information in critical care education

Understanding the learning needs of students is a vital step in planning the delivery of effective education. Evaluating the impact of such interventions is not always easy and many methods rely on self-reported behaviour or simple changes in knowledge--whose relationship to action is not always clear. Using conjoint analysis, within the theoretical framework of social judgement theory, this study illustrates a novel means of examining nurses' use of clinical information when diagnosing hypovolemic shock in a series of simulated cases presented via computer. The study examines changes in information usage before and after a traditional lecture. The results show that nurses' information use is not linear and the utility for decision judgement derived from clinical information is not distributed equally. The study also suggests that some clinical information (for example, the Glasgow Coma Score) is not well understood and incorporated into clinical judgement. The study has implications for those designing and evaluating educational interventions and those studying information use, clinical judgement and decision making.

Cataract in children

Of the estimated 1.4 million children world-wide who are blind, cataract is responsible for an estimated 190,000 (14%). The incidence varies from 1 to 3/10,000 live births or 10 per million of the total population in low-income countries. Early diagnosis, referral and surgery are important in improving results. A recent study from Sweden indicates that examination of babies in maternity wards results in earlier referral compared with well-baby clinics or no formal screening.

CONCLUSION

It is important that standardized protocols be developed and implemented to screen children for ocular anomalies, especially cataract, before discharge from maternity units.

Validation of night blindness reports among children and women in a vitamin A deficient population in rural Tanzania

OBJECTIVE

This study validates different definitions of reported night blindness (XN) in a vitamin A deficient African population with no local term for XN.

DESIGN

Case-control study with follow-up after treatment.

SETTING

Eight primary schools and health centres in rural Tanzania.

SUBJECTS

A total of 1214 participants were screened for reported XN and other eye signs of xerophthalmia: 461 children aged 24-71 months, 562 primary school-age children and 191 pregnant or breast-feeding women. All 152 cases of reported XN were selected for the validation study and group matched with 321 controls who did not complain of XN. XN reports were validated against serum retinol concentrations and pupillary dark adaptation measurements in cases and controls.

INTERVENTION

All children and women who reported XN or had other signs of active xerophthalmia were treated with vitamin A and followed up 3-4 weeks later. Half of the untreated control group who had their serum retinol examined in the baseline examination were also followed up.

RESULTS

The overall prevalence of reported XN was 12.5%. At baseline, mean pupillary threshold (-1.52 vs -1.55 log cd/m(2), P=0.501) and median serum retinol concentrations (0.95 vs 0.93 micromol/l, P=0.734) were not significantly different in cases and controls either overall or in each population group. More restricted case definitions reduced the prevalence of reported XN to 5.5% (P<0.001), but there was still no significant difference between cases and controls although the results were in the expected direction. After treatment, the median serum retinol concentration improved significantly only in the most deficient group, the young children. Dark adaptation improved in all the subgroups but the difference was only significant for young children and primary school-age children when the restricted case definitions were used.

CONCLUSIONS

XN reports are a poor indicator of vitamin A deficiency in this population.

SPONSORSHIP

Task Force Sight and Life, Basel, Switzerland.