Genetic variation among 82 pharmacogenes: The PGRNseq data from the eMERGE network

Genetic variation can affect drug response in multiple ways, although it remains unclear how rare genetic variants affect drug response. The electronic Medical Records and Genomics (eMERGE) Network, collaborating with the Pharmacogenomics Research Network, began eMERGE‐PGx, a targeted sequencing study to assess genetic variation in 82 pharmacogenes critical for implementation of “precision medicine.” The February 2015 eMERGE‐PGx data release includes sequence‐derived data from ∼5,000 clinical subjects. We present the variant frequency spectrum categorized by variant type, ancestry, and predicted function. We found 95.12% of genes have variants with a scaled Combined Annotation‐Dependent Depletion score above 20, and 96.19% of all samples had one or more Clinical Pharmacogenetics Implementation Consortium Level A actionable variants. These data highlight the distribution and scope of genetic variation in relevant pharmacogenes, identifying challenges associated with implementing clinical sequencing for drug treatment at a broader level, underscoring the importance for multifaceted research in the execution of precision medicine.

Effect of hoof angle on joint contact area in the equine metacarpophalangeal joint following simulated impact loading ex vivo

REASONS FOR PERFORMING STUDY

To add to the existing data on impact loading of the metacarpophalangeal (MCP) joint as a precursor to assessing the potential role of impact in joint disease.

OBJECTIVES

To examine the effect of impact loading on contact areas of the first phalanx (P1) and proximal sesamoids (PS) with the third metacarpal (McIII) under 3 hoof-strike conditions (toe-first, flat, heel-first).

STUDY DESIGN

Randomised, repeated controlled experiment using cadaver material.

METHODS

Eight cadaver limbs were subjected to randomised, repeated controlled trials where the hoof was struck by a pendulum impact machine (impact velocity 3.55 m/s) under 3 strike conditions. Data from pressure sensitive film placed over medial and lateral McIII condyles and lateromedially across the dorsal aspect of McIII were quantified: total areas of P1 and PS contact (cm(2) ) at maximum recorded pressure; centroid locations of contact areas relative to the sagittal ridge (cm) and transverse ridge (cm) and dispersion of pixels (cm(4) ) for each McIII condyle (medial/lateral). The effect of the strike conditions on each variable were statistically tested using repeated-measures ANOVA (α = 0.05).

RESULTS

Contact area between P1 and McIII condyles fell in well-defined areas bounded by the sagittal and transverse ridge, contact areas from PS were smaller and widely dispersed across McIII palmar border. Ratio of contact area of P1 to PS was 2.83 (P<0001). Hoof strike had no significant effect on contact area (P>0.54) CONCLUSIONS: Contact at impact (primarily from P1 and distally situated on McIII), contrasts with contact areas at midstance from both P1 and PS, symmetrically placed. Under impact, the greatest contact area was on the dorsal aspect of the medial condyle and coincides with the area subjected to the greatest increase in subchondral bone stiffening in joint disease.

Genetic variation in the HLA region is associated with susceptibility to herpes zoster

Herpes zoster, commonly referred to as shingles, is caused by the varicella zoster virus (VZV). VZV initially manifests as chicken pox, most commonly in childhood, can remain asymptomatically latent in nerve tissues for many years and often re-emerges as shingles. Although reactivation may be related to immune suppression, aging and female sex, most inter-individual variability in re-emergence risk has not been explained to date. We performed a genome-wide association analyses in 22 981 participants (2280 shingles cases) from the electronic Medical Records and Genomics Network. Using Cox survival and logistic regression, we identified a genomic region in the combined and European ancestry groups that has an age of onset effect reaching genome-wide significance (P>1.0 × 10⁻⁸). This region tags the non-coding gene HCP5 (HLA Complex P5) in the major histocompatibility complex. This gene is an endogenous retrovirus and likely influences viral activity through regulatory functions. Variants in this genetic region are known to be associated with delay in development of AIDS in people infected by HIV. Our study provides further suggestion that this region may have a critical role in viral suppression and could potentially harbor a clinically actionable variant for the shingles vaccine.

Design and anticipated outcomes of the eMERGE-PGx project: a multicenter pilot for preemptive pharmacogenomics in electronic health record systems

We describe here the design and initial implementation of the eMERGE-PGx project. eMERGE-PGx, a partnership of the eMERGE and PGRN consortia, has three objectives : 1) Deploy PGRNseq, a next-generation sequencing platform assessing sequence variation in 84 proposed pharmacogenes, in nearly 9,000 patients likely to be prescribed drugs of interest in a 1–3 year timeframe across several clinical sites; 2) Integrate well-established clinically-validated pharmacogenetic genotypes into the electronic health record with associated clinical decision support and assess process and clinical outcomes of implementation; and 3) Develop a repository of pharmacogenetic variants of unknown significance linked to a repository of EHR-based clinical phenotype data for ongoing pharmacogenomics discovery. We describe site-specific project implementation and anticipated products, including genetic variant and phenotype data repositories, novel variant association studies, clinical decision support modules, clinical and process outcomes, approaches to manage incidental findings, and patient and clinician education methods.

Characterization of statin dose response in electronic medical records

Efforts to define the genetic architecture underlying variable statin response have met with limited success, possibly because previous studies were limited to effect based on a single dose. We leveraged electronic medical records (EMRs) to extract potency (ED50) and efficacy (Emax) of statin dose-response curves and tested them for association with 144 preselected variants. Two large biobanks were used to construct dose-response curves for 2,026 and 2,252 subjects on simvastatin and atorvastatin, respectively. Atorvastatin was more efficacious, was more potent, and demonstrated less interindividual variability than simvastatin. A pharmacodynamic variant emerging from randomized trials (PRDM16) was associated with Emax for both. For atorvastatin, Emax was 51.7 mg/dl in subjects homozygous for the minor allele vs. 75.0 mg/dl for those homozygous for the major allele. We also identified several loci associated with ED50. The extraction of rigorously defined traits from EMRs for pharmacogenetic studies represents a promising approach to further understand the genetic factors contributing to drug response.

Coronary risk assessment among intermediate risk patients using a clinical and biomarker based algorithm developed and validated in two population cohorts

BACKGROUND

Many coronary heart disease (CHD) events occur in individuals classified as intermediate risk by commonly used assessment tools. Over half the individuals presenting with a severe cardiac event, such as myocardial infarction (MI), have at most one risk factor as included in the widely used Framingham risk assessment. Individuals classified as intermediate risk, who are actually at high risk, may not receive guideline recommended treatments. A clinically useful method for accurately predicting 5-year CHD risk among intermediate risk patients remains an unmet medical need.

OBJECTIVE

This study sought to develop a CHD Risk Assessment (CHDRA) model that improves 5-year risk stratification among intermediate risk individuals.

METHODS

Assay panels for biomarkers associated with atherosclerosis biology (inflammation, angiogenesis, apoptosis, chemotaxis, etc.) were optimized for measuring baseline serum samples from 1084 initially CHD-free Marshfield Clinic Personalized Medicine Research Project (PMRP) individuals. A multivariable Cox regression model was fit using the most powerful risk predictors within the clinical and protein variables identified by repeated cross-validation. The resulting CHDRA algorithm was validated in a Multiple-Ethnic Study of Atherosclerosis (MESA) case-cohort sample.

RESULTS

A CHDRA algorithm of age, sex, diabetes, and family history of MI, combined with serum levels of seven biomarkers (CTACK, Eotaxin, Fas Ligand, HGF, IL-16, MCP-3, and sFas) yielded a clinical net reclassification index of 42.7% (p < 0.001) for MESA patients with a recalibrated Framingham 5-year intermediate risk level. Across all patients, the model predicted acute coronary events (hazard ratio = 2.17, p < 0.001), and remained an independent predictor after Framingham risk factor adjustments.

LIMITATIONS

These include the slightly different event definition with the MESA samples and inability to include PMRP fatal CHD events.

CONCLUSIONS

A novel risk score of serum protein levels plus clinical risk factors, developed and validated in independent cohorts, demonstrated clinical utility for assessing the true risk of CHD events in intermediate risk patients. Improved accuracy in cardiovascular risk classification could lead to improved preventive care and fewer deaths.

The effect of novel promoter variants in MATE1 and MATE2 on the pharmacokinetics and pharmacodynamics of metformin

Interindividual variation in response to metformin, first-line therapy for type 2 diabetes, is substantial. Given that transporters are determinants of metformin pharmacokinetics, we examined the effects of promoter variants in both multidrug and toxin extrusion protein 1 (MATE1) (g.-66T → C, rs2252281) and MATE2 (g.-130G → A, rs12943590) on variation in metformin disposition and response. The pharmacokinetics and glucose-lowering effects of metformin were assessed in healthy volunteers (n = 57) receiving metformin. The renal and secretory clearances of metformin were higher (22% and 26%, respectively) in carriers of variant MATE2 who were also MATE1 reference (P < 0.05). Both MATE genotypes were associated with altered post-metformin glucose tolerance, with variant carriers of MATE1 and MATE2 having an enhanced (P < 0.01) and reduced (P < 0.05) response, respectively. Consistent with these results, patients with diabetes (n = 145) carrying the MATE1 variant showed enhanced metformin response. These findings suggest that promoter variants of MATE1 and MATE2 are important determinants of metformin disposition and response in healthy volunteers and diabetic patients.

The emerging role of electronic medical records in pharmacogenomics

Health-care information technology and genotyping technology are both advancing rapidly, creating new opportunities for medical and scientific discovery. The convergence of these two technologies is now facilitating genetic association studies of unprecedented size within the context of routine clinical care. As a result, the medical community will soon be presented with a number of novel opportunities to bring functional genomics to the bedside in the area of pharmacotherapy. By linking biological material to comprehensive medical records, large multi-institutional biobanks are now poised to advance the field of pharmacogenomics through three distinct mechanisms: (i) retrospective assessment of previously known findings in a clinical practice-based setting, (ii) discovery of new associations in huge observational cohorts, and (iii) prospective application in a setting capable of providing real-time decision support. This review explores each of these translational mechanisms within a historical framework.

Intake of meat, meat mutagens, and iron and the risk of breast cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Background:

Epidemiological evidence on meat intake and breast cancer is inconsistent, with little research on potentially carcinogenic meat-related exposures. We investigated meat subtypes, cooking practices, meat mutagens, iron, and subsequent breast cancer risk.

Methods:

Among 52 158 women (aged 55–74 years) in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, who completed a food frequency questionnaire, 1205 invasive breast cancer cases were identified. We estimated meat mutagen and haem iron intake with databases accounting for cooking practices. Using Cox proportional hazards regression, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) within quintiles of intake.

Results:

Comparing the fifth to the first quintile, red meat (HR=1.23; 95% CI=1.00–1.51, P trend=0.22), the heterocyclic amine (HCA), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), (HR=1.26; 95% CI=1.03–1.55; P trend=0.12), and dietary iron (HR=1.25; 95% CI=1.02–1.52; P trend=0.03) were positively associated with breast cancer. We observed elevated, though not statistically significant, risks with processed meat, the HCA 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx), mutagenic activity, iron from meat, and haem iron from meat.

Conclusion:

In this prospective study, red meat, MeIQx, and dietary iron elevated the risk of invasive breast cancer, but there was no linear trend in the association except for dietary iron.

Healthy People 2010 disease prevalence in the Marshfield Clinic Personalized Medicine Research Project cohort: opportunities for public health genomic research

OBJECTIVES

The purpose of this study was to estimate the prevalence of Healthy People 2010 disease conditions in a large population-based cohort in central Wisconsin (WI, USA) and to consider how these conditions can be prioritized for research based on the use of healthcare services, the prevalence of various disease states and the resulting study power.

METHODS

Healthy People 2010 diagnoses were estimated for participants in the Personalized Medicine Research Project (PMRP), a large population-based biobank for residents aged 18 years and older living in central Wisconsin. By interrogating the electronic medical record, three parameters were calculated for each diagnosis: mean number of concomitant diagnoses, mean number of annual clinic visits before diagnosis and mean number of clinic visits after diagnosis.

RESULTS

A total of 18,239 adults enrolled in PMRP from September 2002 to May 2005 and were included in the study. They had a mean age of 49 years (standard deviation: 18.5), ranging from 18-98 years; 57% were female. At least one Healthy People 2010 disease was diagnosed in 86.4% of the participants; 13.6% had never been diagnosed with any of these conditions. The median number of diagnoses per subject was three (range: 1-15). The median number of annual visits after diagnosis was lowest for chronic obstructive pulmonary disease (9.1) and highest for sleep apnea (17.9). Subjects with a diabetic retinopathy diagnosis had the highest number of concomitant diagnoses (mean: 6.8).

DISCUSSION

All of the diseases within the Healthy People 2010 list are purported to have at least some genetic component, with the exception of injuries. The PMRP cohort is large enough that diseases of public health importance can be studied in the context of a variety of clinical and environmental covariates. This database is being developed as a national resource and is particularly useful where the estimated disease prevalence is 5% or greater. For less common diseases, additional cases can be recruited from throughout the Marshfield Clinic system of care, with population-based controls selected from the main PMRP study cohort.

Characteristics of progression of early age-related macular degeneration: the cardiovascular health and age-related maculopathy study

AIMS

To determine the risk of age-related macular degeneration (AMD) progression posed by the presence of each early AMD characteristic.

METHODS

A prospective cohort study of 254 participants aged 50 years and older, all with early AMD features at their baseline visit followed for an average of 7 years. Stereoscopic colour fundus photographs were graded for early AMD features using the International Classification System. AMD status was stratified into six exclusive levels along a continuum of disease severity according to drusen type, pigmentary abnormalities, or late AMD. Progression was assessed according to three definitions: a change between or within a severity level, or by side by side grading.

RESULTS

The progression rate of early AMD ranged between 3.4 and 4.67% per annum depending upon the definition used. In total, 15 (6%) cases progressed from early AMD to the late complication of AMD. After controlling for age and smoking, cases with soft indistinct drusen at baseline were at a greater risk of progressing from early to late AMD than were cases without this characteristic (OR=3.72, 95%CI 1.20-11.54; P=0.02).

CONCLUSION

Our proposed definitions of AMD progression give rates that are consistent with current knowledge of progression and its determinants. Each early AMD characteristic conveys its own risk of progression to an eye, with soft indistinct drusen carrying the greater risk. An international consensus on what defines AMD progression would greatly help the research community when trying to assess the importance of new risk factors and the effectiveness of novel interventions.

Impact of unilateral and bilateral vision loss on quality of life

AIM

To investigate whether unilateral vision loss reduced any aspects of quality of life in comparison with normal vision and to compare its impact with that of bilateral vision loss.

METHODS

This study used cluster stratified random sample of 3271 urban participants recruited between 1992 and 1994 for the Melbourne Visual Impairment Project. All predictors and outcomes were from the 5 year follow up examinations conducted in 1997-9.

RESULTS

There were 2530 participants who attended the follow up survey and had measurement of presenting visual acuity. Both unilateral and bilateral vision loss were significantly associated with increased odds of having problems in visual functions including reading the telephone book, newspaper, watching television, and seeing faces. Non-correctable by refraction unilateral vision loss increased the odds of falling when away from home (OR = 2.86, 95% CI 1.16 to 7.08), getting help with chores (OR = 3.09, 95% CI 1.40 to 6.83), and becoming dependent (getting help with meals and chores) (OR = 7.50, 95% CI 1.97 to 28.6). Non-correctable bilateral visual loss was associated with many activities of daily living except falling.

CONCLUSIONS

Non-correctable unilateral vision loss was associated with issues of safety and independent living while non-correctable bilateral vision loss was associated with nursing home placement, emotional wellbeing, use of community services, and activities of daily living. Correctable or treatable vision loss should be detected and attended to.

Vision impairment and older drivers: who's driving?

AIM

To establish the association between impaired vision and drivers' decisions to stop driving, voluntarily restrict driving, and motor vehicle accidents.

METHODS

Driving related questions were included in a population based study that determined the prevalence and incidence of eye disease. Stratified random cluster samples based on census collector districts were selected from the Melbourne Statistical Division. Eligible participants aged 44 years and over were interviewed and underwent a comprehensive ophthalmic examination. The outcomes of interest were the decision to stop driving, limiting driving in specified conditions, and driving accidents. The associations between these outcomes and the legally prescribed visual acuity (<6/12) for a driver's licence were investigated.

RESULTS

The mean age of the 2594/3040 (85%) eligible participants was 62.5 (range 44-101). People with visual acuity less than 6/12 were no more likely to have an accident than those with better vision (chi(2) = 0.175, p>0.9). Older drivers with impaired vision, more so than younger adults, restrict their driving in visually demanding situations (p<0.05). Of the current drivers, 2.6% have vision less than that required to obtain a driver's licence. The risk of having an accident increased with distance driven (OR 2.57, CL 1.63, 4.04 for distance >31 000 km) but not with age.

CONCLUSION

There was no greater likelihood of self reported driving accidents for drivers with impaired vision than those with good vision. While many older drivers with impaired vision limit their driving in adverse conditions and some drivers with impaired vision stop driving, there are a significant number of current drivers with impaired vision.

Moderate visual impairment in India: the Andhra Pradesh Eye Disease Study

AIM

To assess the prevalence and demographic associations of moderate visual impairment in the population of the southern Indian state of Andhra Pradesh.

METHODS

From 94 clusters in one urban and three rural areas of Andhra Pradesh, 11 786 people of all ages were sampled using a stratified, random, cluster, systematic sampling strategy. The eligible people were invited for interview and detailed dilated eye examination by trained professionals. Moderate visual impairment was defined as presenting distance visual acuity less than 6/18 to 6/60 or equivalent visual field loss in the better eye.

RESULTS

Of those sampled, 10,293 (87.3%) people participated in the study. In addition to the previously reported 1.84% prevalence of blindness (presenting distance visual acuity less than 6/60 or central visual field less than 20 degrees in the better eye) in this sample, 1237 people had moderate visual impairment, an adjusted prevalence of 8.09% (95% CI 6.89 to 9.30%). The majority of this moderate visual impairment was caused by refractive error (45.8%) and cataract (39.9%). Increasing age, female sex, decreasing socioeconomic status, and rural area of residence had significantly higher odds of being associated with moderate visual impairment.

CONCLUSIONS

These data suggest that there is a significant burden of moderate visual impairment in this population in addition to blindness. Extrapolation of these data to the population of India suggests that there were 82 million people with moderate visual impairment in the year 2000, and this number is likely to be 139 million by the year 2020 if the current trend continues. This impending large burden of moderate visual impairment, the majority of which is due to the relatively easily treatable refractive error and cataract, would have to be taken into account while estimating the eye care needs in India, in addition to dealing with blindness. Specific strategies targeting the elderly population, people with low socioeconomic status, those living in the rural areas, and females would have to be implemented in the long term to reduce moderate visual impairment.

Prevalence and predictors of open-angle glaucoma: results from the visual impairment project

PURPOSE

To determine the prevalence and investigate predictors of open-angle glaucoma in Victoria, Australia.

DESIGN

Two-site, population-based cross-sectional study.

PARTICIPANTS

Permanent residents aged 40 years and older at recruitment from 1992 through 1996.

METHODS

A cluster-stratified random sample of 4744 participants from two cohorts, urban and rural, participated. Participants completed a standardized interview regarding demographic, lifestyle, and medical characteristics and a dilated eye examination including measurement of intraocular pressure, visual fields, cup-to-disc ratios, and paired stereo photography of the optic discs. A consensus panel of six ophthalmologists determined glaucoma diagnosis.

MAIN OUTCOME MEASURE

Diagnosis of glaucoma (possible, probable, definite).

RESULTS

The prevalence of possible glaucoma cases was 1.2% (95% confidence interval [CI], 0.60, 1.7), of probable cases was 0.70% (95% CI, 0.39, 1.0), and of definite cases was 1.8% (95% CI, 1.4, 2.2). There was a significant increase in glaucoma prevalence with age across all definitions, but there was no difference in age-standardized rates between genders. A total of 60% of probable and definite glaucoma cases were undiagnosed before this study. Adjusted for age, the strongest risk factor for glaucoma was a positive family history of glaucoma (odds ratio, 3.1; 95% CI, 1.6, 5.3). Glaucoma patients who had not attended an eye care provider in the last 2 years were eight times (95% CI, 3.2, 20.4) more likely to have undiagnosed disease.

CONCLUSIONS

These results support the importance of the genetic or familial basis of many glaucoma cases and highlight the need to develop appropriate techniques to screen for undiagnosed disease.

Correction of refractive error in the Victorian population: the feasibility of "off the shelf" spectacles

AIMS

To assess the feasibility of providing a stock of ready made spectacles for correction of refractive error in the general population.

METHODS

Data were collected in the Visual Impairment Project, a population based survey of Victorian residents aged 40 years or older in randomly selected urban and rural sample areas. This included a refractive eye examination and the proportion of subjects with hypermetropia, emmetropia (defined as -1.0 to +1.0D spherical equivalent), and myopia documented in the 40-60 year age group.

RESULTS

2595 (54.8%) participants were aged between 40 and 60 years. Those with a best corrected visual acuity of less than 6/12, astigmatism of more than 1.25D, and anisometropia of more than 0.5D were excluded. 516 participants had refractive error which was deemed suitable for correction by "off the shelf" spectacles. This represents 19.9% of all participants between 40 and 60 years of age. Provision of spectacles in 0.5D increments would provide suitable stock spectacles for 85.5% of a -3.0 to +3.0D range or 89.2% of a -3.50 to +3.50D range.

CONCLUSIONS

Ready made "off the shelf" spectacles could significantly alleviate visual morbidity due to refractive error in up to 20% of an urban population in Australia. This approach may also be useful in developing countries with poor access to optometric services.

Risk factors for age-related maculopathy: the Visual Impairment Project

OBJECTIVE

To describe the risk factors and associated population attributable risk for age-related maculopathy (ARM) and age-related macular degeneration (AMD) in Australians aged 40 years and older.

METHODS

Residents were recruited from 9 randomly selected urban clusters and 4 randomly selected rural clusters in Victoria, Australia. At locally established test sites, the following information was collected: visual acuity, medical and health history, lifetime sunlight exposure, dietary intake, and fundus photographs. Age-related maculopathy and AMD were graded from the fundus photographs using an international classification and grading system. Backwards logistic regression was used to identify the independent risk factors for ARM and AMD.

RESULTS

The participation rate was 83% (n = 3271) among the urban residents and 92% (n = 1473) among the rural residents. Gradable fundus photographs of either eye were available for 4345 (92%) of the 4744 participants. There were 656 cases of ARM, giving a weighted prevalence of 15.1% (95% confidence limit [CL], 13.8, 16.4); and there were 30 cases of AMD, giving a weighted prevalence of 0.69% (95% CL, 0.33, 1.03). In multiple logistic regression, the risk factors for AMD were as follows: age (odds ratio [OR], 1.23; 95% CL, 1.17, 1.29), smoked cigarettes for longer than 40 years (OR, 2.39; 95% CL, 1.02, 5.57), and ever taken angiotensin-converting enzyme inhibitors (OR, 3.26; 95% CL, 1.33, 8.01). The magnitude of all of these risk factors was slightly less for ARM, and having ever taken blood cholesterol-lowering medications was also significant (OR, 1.67; 95% CL, 1.12, 2.47; P =.001).

CONCLUSION

Smoking is the only modifiable risk factor for ARM and AMD, among the many environmental and systemic factors that were assessed.

Changes in management of diabetic retinopathy by Australian ophthalmologists as a result of the NHMRC clinical guidelines

PURPOSE

To document changes in management of diabetic retinopathy by Australian ophthalmologists after release of the National Health and Medical Research Council (NHMRC) clinical guidelines.

METHODS

Self-administered questionnaires were mailed to Australian ophthalmologists prior to release of the NHMRC guidelines for the management of diabetic retinopathy, and at one and 2.5 years after release of the guidelines. The questionnaires elicited information about current management practices in relation to diabetic retinopathy

RESULTS

The response rate for the baseline and two follow-up surveys was 82%, 81%, and 80%, respectively. More than 85% of the ophthalmologists responded that the guidelines were useful in improving management, were easy to understand, and were already part of their routine clinical practice. A relatively small percentage (12%) felt that the guidelines made recommendations that were not practical or feasible. Contrary to the NHMRC guidelines, at the second follow-up survey, only 50% of the ophthalmologists said that they would almost never perform fluorescein angiography in eyes with mild non-proliferative diabetic retinopathy. The change from baseline to the second follow-up in the percentage of ophthalmologists who would perform cataract surgery after treating clinically significant macular oedema (as advised by the NHMRC guidelines) was statistically significant (baseline = 83.7%, 95% confidence limit = 80.4, 87.0; second follow up = 90.4, 95% confidence limit = 87.3, 93.5).

CONCLUSIONS

Distribution of the printed NHMRC Clinical Practice Guidelines: Management of Diabetic Retinopathy and full colour Retinopathy Chart resulted in a significant change in the recommended order of treatment of clinically significant macular oedema. However no significant change in the use of fluorescein angiography was documented.

Costs of mobile screening for diabetic retinopathy: a practical framework for rural populations

Australia's rural and remote residents experience considerably higher hospitalisation and death rates due to diabetes than their metropolitan counterparts. There is clearly a need for improved diabetes care services in these areas and interventions that target conditions associated with diabetes will yield beneficial results for the community. All people with diabetes are at risk for diabetic retinopathy, which can cause vision loss and blindness. Although vision loss and blindness due to diabetes is nearly 100% preventable through regular eye examinations, 35% of Victoria's rural population with diabetes do not have their eyes examined on a regular basis. A pilot, mobile screening program for the early detection of diabetic eye disease was conducted in rural Victoria and proved to be a successful model of adjunct eye care for people with diabetes. Actual costs from the pilot screening were applied to a permanent model for rural eye care. At A$41 per participant, costs for mobile screening were competitive with Medicare rebate costs for eye examinations. The model addresses barriers of accessibility and availability, targets a portion of the rural population with diabetes that is not otherwise having eye examinations, and is cost-saving to the Government.

Intraocular pressure before and after cataract surgery in participants of the Melbourne Visual Impairment Project

The purpose of this study was to investigate the effect of cataract surgery on intraocular pressure (IOP) in a cluster-stratified random sample of the population of Victoria, Australia. A total of 3271 participants aged 40 years or older were examined at baseline for the Visual Impairment Project. The baseline study (1992-1994) was followed by a 5-year incidence study The IOP data were compared between participants who had cataract surgery between the two stages of the study and participants with and without cataract at follow up. The IOP was also compared before and after cataract extraction in glaucoma participants. An eligible 89 non-glaucoma and 24 glaucoma participants had cataract surgery between the two time points. The analyses showed that IOP increases with age in non-operated eyes in both glaucoma and non-glaucoma groups. However IOP decreased significantly after cataract surgery in eyes with glaucoma but did not change significantly in non-glaucoma participants.

Association of demographic, familial, medical, and ocular factors with intraocular pressure

OBJECTIVE

To describe the distribution and associations of demographic, familial, medical, and ocular factors with intraocular pressure (IOP).

METHODS

A cluster stratified random sample of urban and rural residents of Victoria, Australia, aged 40 years and older. Participants completed an interview and underwent a standardized dilated ophthalmic examination including measurement of IOP with an electronic applanation tonometer (Tono-Pen). Glaucoma status (possible, probable, definite) was determined by a consensus panel. The main outcome measure was IOP.

RESULTS

The mean age of the 4576 participants was 59 years, 53% were women, 32% were born overseas, and 132 had open-angle glaucoma. Geometric mean (SD) IOP was 14.3 (+/-1.5) mm Hg. The relationship between IOP and nuclear sclerosis, iris color, and family history of glaucoma depended on glaucoma status. In those with glaucoma, family history of glaucoma and country of birth were significantly associated with IOP in multivariate models (model: r(2) = 0.08, P =.01). In the group without glaucoma, place of residence, use of alcohol, iris color, vitamin E intake, and spherical equivalent were associated with IOP (model: r(2) = 0.01, P =.006).

CONCLUSION

In participants with glaucoma, genetic factors seem to be stronger predictors of IOP, whereas in those without glaucoma, lifestyle and physiological factors seem to play a greater role.

Can the specificity of the FDT for glaucoma be improved by confirming abnormal results?

PURPOSE

To determine whether the specificity of the frequency-doubling technology (FDT) perimeter in the screening mode for glaucoma can be improved by repeating abnormal screening results.

METHODS

The FDT perimeter was used in C-20-5 screening mode, and the right eye was tested first. After both eyes were tested, the screening was repeated in eyes with any abnormal visual field defects on FDT perimetry. The printouts were categorized as possible visual field abnormality (zero or one miss), probable visual field abnormality (two to four misses), and definite visual field abnormality (more than five misses). A clinical ophthalmologic examination was conducted on the day of the FDT perimetry screening.

RESULTS

Complete data were available for 223 people. The participants ranged in age from 23 to 91 years (mean, 68.5 years; standard deviation. 13.7 years), and 119 (53%) were women. The sensitivity of the FDT perimetry screening was 100%; both cases of glaucoma showed an abnormality on FDT perimetry both times. The specificity improved moderately from the first screening to the second screening. The specificity the first time was 62% (95% confidence interval, 53.1-71.2). The specificity the second time was 68.5% (95% confidence interval, 59.8-77.1). Improvement on FDT perimetry rescreening varied by the language spoken at home. Seven of the 19 non-English speakers without glaucoma improved on rescreening, compared with none of the 23 English speakers (P = 0.002). Seven of the 25 right eyes with FDT perimetry abnormalities both times and no glaucoma had no other detectable diseases. Three of 24 left eyes with FDT perimetry abnormalities both times and no glaucoma had no other detectable diseases. Of the 85 patients who did not have glaucoma but had FDT perimetry abnormalities both times, only one did not have some other detectable disease.

DISCUSSION

In summary, the sensitivity for glaucoma of the C-20-5 screening mode is excellent, but a paradigm for screening with the FDT perimeter to improve the overall specificity for glaucoma still must be developed.

Changes in attitudes and practices of optometrists in their management of diabetic retinopathy after the release of NHMRC guidelines. National Health and Medical Research Council

The purpose of this study was to document attitudes and practices of Australian optometrists in their management of diabetic retinopathy prior to the release of the National Health and Medical Research Council (NHMRC) Clinical Practice Guidelines for the Management of Diabetic Retinopathy and at two time points following their release. A self-administered questionnaire was mailed to a stratified random sample of 500 Australian optometrists at the three time points. The same sample was used for the first two surveys and a new random sample was drawn for the second follow-up survey. The response to the three questionnaires was 86%, 80% and 84%, respectively. More than 90% of optometrists reported receiving a copy of the guidelines and 82% reported receiving the supplementary Retinopathy Chart. Fifty-seven per cent reported having read the guidelines at least once in entirety and 65% reported that they refer to the Retinopathy Chart at least monthly in their clinical practice. There was a significant decrease in the number of optometrists who reported that patient unwillingness to be dilated and their fear of precipitating angle closure glaucoma were moderate or major barriers to performing dilated ophthalmoscopy. Concomitantly, the percentage of optometrists who reported that they often or always perform dilated ophthalmoscopy on new patients with diabetes increased significantly from 74.5% (95% confidence limit = 70.2, 78.8) to 81.5% (95% confidence limit = 77.5, 85.5). There have been some significant changes in the self-reported management practices of optometrists in relation to diabetic retinopathy since the release of the NHMRC guidelines and Retinopathy Chart.

Cause-specific prevalence of bilateral visual impairment in Victoria, Australia: the Visual Impairment Project

PURPOSE

To study the cause-specific prevalence of eye diseases causing bilateral visual impairment in Australian adults.

DESIGN

Two-site, population-based cross-sectional study.

PARTICIPANTS

Participants were aged 40 years and older and resident in their homes at the time of recruitment for the study. The study was conducted during 1992 through 1996.

METHODS

The study uses a cluster stratified random sample of 4744 participants from two cohorts, urban, and rural Victoria. Participants completed a standardized interview and eye examination, including presenting and best-corrected visual acuity, visual fields, and dilated ocular examination. The major cause of vision loss was identified for all participants found to be visually impaired. Population-based prevalence estimates are weighted to reflect the age and gender distribution of the two cohorts in Victoria.

MAIN OUTCOME MEASURES

Visual impairment was defined by four levels of severity on the basis of best-corrected visual acuity or visual field: <6/18 > or =6/60 and/or <20 degrees > or =10 degrees radius field, moderate vision impairment; severe vision impairment, <6/60 > or =3/60 and/or <10 degrees > or =5 degrees radius field; and profound vision impairment <3/60 and/or <5 degrees radius field. In addition, less-than-legal driving vision, <6/12 > or =6/18, and/or homonymous hemianopia were defined as mild vision impairment. In Australia, legal blindness includes severe and profound vision impairment.

RESULTS

The population-weighted prevalence of diseases causing less-than-legal driving or worse impairment in the better eye was 42.48/1000 (95% confidence interval [CI], 30.11, 54.86). Uncorrected refractive error was the most frequent cause of bilateral vision impairment, 24.68/1000 (95% CI, 16.12, 33.25), followed by age-related macular degeneration (AMD), 3.86/1000 (95% CI, 2.17, 5.55); other retinal diseases, 2.91/1000 (95% CI, 0.74, 5.08); other disorders, 2.80/1000 (95% CI, 1.17, 4.43); cataract, 2.57/1000 (95% CI, 1.38, 3.76); glaucoma, 2.32/1000 (95% CI, 0.72, 3.92); neuro-ophthalmic disorders, 1.80/1000 (95% CI, 0, 4.11); and diabetic retinopathy, 1.53/1000 (95% CI, 0.71, 2.36). The prevalence of legal blindness was 5.30/1000 (95% CI, 3.24, 7.36). Although not significantly different, the causes of legal blindness were uncorrected refractive errors, AMD, glaucoma, other retinal conditions, and other diseases.

CONCLUSIONS

Significant reduction of visual impairment may be attained with the application of current knowledge in refractive errors, diabetes mellitus, cataract, and glaucoma. Although easily preventable, uncorrected refractive error remains a major cause of vision impairment.

Control-related beliefs and depressive symptoms in clinic-referred children and adolescents: developmental differences and model specificity

The contingency-competence-control (CCC) model links contingency and competence beliefs to perceived control and, in turn, to depression. However, a developmental perspective suggests that noncontingency may be too abstract a concept to be directly tied to depression before adolescence. We tested the CCC model and this developmental notion, using structural equation modeling, with 360 clinic-referred 8- to 17-year-olds. The CCC model fit the data well for the full sample accounting for 46% of the variance in depression. Separate analyses by age group placed perceived contingency in the best-fit model for adolescents (ages 12-17 years) but not for children (8-11 years). This suggests that abstract cause-effect concepts may have more direct affective impact after the cognitive changes of adolescence (e.g., formal operations) than before. Finally, the CCC model accounted for much more variance in depression than conduct problems, suggesting diagnostic specificity.

Diabetic retinopathy: effects of national guidelines on the referral, examination and treatment practices of ophthalmologists and optometrists

OBJECTIVE

To investigate the changes in referral, examination and treatment practices for diabetic retinopathy by ophthalmologists and optometrists following the release of national guidelines.

METHODS

A two-page self-administered questionnaire was mailed to all Australian ophthalmologists and a random sample of 500 Australian optometrists prior to and 1 year after release of the National Health and Medical Research Council of Australia (NHMRC) clinical practice guidelines for the management of diabetic retinopathy. The questionnaires elicited information about current practice related to the management of patients with diabetic retinopathy.

RESULTS

Of the 464 contactable ophthalmologists who responded to the baseline survey, 374 (80.6% response) completed the follow-up survey The response rate for the contactable optometrists was 80.1% (310 of 384). There were almost no significant changes in management practices from baseline to follow up. For example, the percentage of ophthalmologists who reported that they were often or almost always confident in detecting moderate retinal thickening near the macula remained nearly identical from baseline to follow up (80.2% vs 79.1 %). The rate was also similar from baseline to follow up for optometrists (31.1% vs 28.8%). The one area in which ophthalmologists reported significant changes in management towards agreement with the NHMRC guidelines was use of angiography; they were less likely to manage their patients this way (20.4% vs 14.2% with laser and 48.9% vs 38.4% without laser for increasing level of severity in clinical signs; both P < 0.05).

CONCLUSIONS

The NHMRC guidelines for diabetic retinopathy have been successfully distributed to ophthalmologists and optometrists in Australia. However, the mere provision of the guidelines has had little impact on management practices. It will be important to determine if ongoing dissemination and implementation strategies not only increase awareness of health-care practitioners to the guidelines, but also change behaviours.

Blindness in the Indian state of Andhra Pradesh

PURPOSE

To determine the current prevalence and causes of blindness in the Indian state of Andhra Pradesh to assess if blindness has decreased since the last survey of 1986-1989.

METHODS

A population-based epidemiology study, using a stratified, random, cluster, systematic sampling strategy, was conducted in the state of Andhra Pradesh in India. Participants of all ages (n = 10,293), 87.3% of the 11,786 eligible, from 94 clusters in one urban and three rural areas representative of the population of Andhra Pradesh, underwent interview and a detailed dilated ocular evaluation by trained professionals. Blindness was defined as presenting distance visual acuity < 6/60 or central visual field < 20(o) in the better eye.

RESULTS

Two hundred seventy-five participants were blind, a prevalence of 1.84% (95% confidence interval, 1.49%-2.19%) when adjusted for the age, sex, and urban-rural distribution of the population in 2000. The causes of this blindness were easily treatable in 60.3% (cataract, 44%; refractive error, 16.3%). Preventable corneal disease, glaucoma, complications of cataract surgery, and amblyopia caused another 19% of the blindness. Blindness was more likely with increasing age and decreasing socioeconomic status, and in female subjects and in rural areas. Among the 76 million population of Andhra Pradesh, 714,400 are estimated to have cataract-related blindness (615,600 cataract, 53,200 cataract surgery-related complications, 45,600 aphakia), and 228,000 refractive error-related blindness (159,600 myopia, 22,800 hyperopia, 45,600 refractive error-related amblyopia). If 95% of the cataract and refractive error blindness in Andhra Pradesh had been treated effectively, 3.4 and 7.4 million blind-person-years, respectively, could have been prevented. If 90% of the blindness due to preventable corneal disease and glaucoma had been prevented, another 2.7 million blind-person-years could have been prevented.

CONCLUSIONS

The prevalence of blindness in this Indian state has increased from 1.5% in the late 1980s to 1.84% currently, as against the target of the National Program for Control of Blindness to reduce the prevalence to 0.3% by 2000. The number of people with cataract-related blindness has not reduced even with the eye care policy focus on cataract. Reduction of blindness in India will require strategies that are more effective than those that have been pursued so far.

Management of diabetic retinopathy by general practitioners in Victoria

PURPOSE

To compare the self-reported management of diabetic retinopathy by general practitioners to the National Health and Medical Research Council of Australia (NHMRC) Guidelines for the Management of Diabetic Retinopathy.

METHODS

In 1994, a stratified (by urban/rural practice location) sample of 500 general practitioners in Victoria was surveyed in regard to their management of diabetic retinopathy. Following the release of the NHMRC Guidelines for the Management of Diabetic Retinopathy in 1997, these same general practitioners were sent a two-page questionnaire related to their management of diabetic retinopathy.

RESULTS

Completed questionnaires were received from 228 general practitioners (59% of original participants). Only 37% (79/216) of the general practitioners reported that they had received a copy of the guidelines. Of the general practitioners who had received the guidelines, 18% (14/79) said that they had not read them at all, while 65% (51/79) had read them partially and 18% (14/79) had read them in their entirety. At follow up, less than half (98/214) of general practitioners reported examining 50% or more of their patients for diabetic retinopathy, compared with 104/214 at baseline. General practitioners who had read the guidelines were more likely to report that not being sure what to do when changes were detected was a minor barrier or was not a barrier to them performing dilated ophthalmoscopy (93% vs 83%, chi2(1) = 3.67, P = 0.055). Nearly all of the general practitioners reported that they refer their patients with diabetes to an ophthalmologist or optometrist at least every 2 years as recommended. Seventy-six per cent (170/224) of the general practitioners felt that 70% or more of their patients complied with their instructions to visit an ophthalmologist or optometrist.

CONCLUSION

The NHMRC guidelines for diabetic retinopathy appear to have had a positive effect on some of the attitudes of general practitioners who have read them, but more effort is needed to disseminate the guidelines to all general practitioners and to increase their uptake.

Vision impairment predicts 5 year mortality

AIM

To describe predictors of mortality in the 5 year follow up of the Melbourne Visual Impairment Project (VIP) cohort.

METHODS

The Melbourne VIP was a population based study of the distribution and determinants of age related eye disease in a cluster random sample of Melbourne residents aged 40 years and older. Baseline examinations were conducted between 1992 and 1994. In 1997, 5 year follow up examinations of the original cohort commenced. Causes of death were obtained from the National Death Index for all reported deaths.

RESULTS

Of the original 3271 participants, 231 (7.1%) were reported to have died in the intervening 5 years. Of the remaining 3040 participants eligible to return for follow up examinations, 2594 (85% of eligible) did participate, 51 (2%) had moved interstate or overseas, 83 (3%) could not be traced, and 312 (10%) refused to participate. Best corrected visual acuity <6/12 (OR=2.34) was associated with a significantly increased risk of mortality, as were increasing age (OR=1.09), male sex (OR=1.62), increased duration of cigarette smoking (OR=2.06 for smoking >30 years), increased duration of hypertension (OR=1.51 for duration >10 years), and arthritis (OR=1.42).

CONCLUSIONS

Even mild visual impairment increases the risk of death more than twofold. Further research is needed to determine why decreased visual acuity is associated with increased risk of mortality.

Control-related beliefs and depressive symptoms in clinic-referred children and adolescents: developmental differences and model specificity

The contingency-competence-control (CCC) model links contingency and competence beliefs to perceived control and, in turn, to depression. However, a developmental perspective suggests that noncontingency may be too abstract a concept to be directly tied to depression before adolescence. We tested the CCC model and this developmental notion, using structural equation modeling, with 360 clinic-referred 8- to 17-year-olds. The CCC model fit the data well for the full sample accounting for 46% of the variance in depression. Separate analyses by age group placed perceived contingency in the best-fit model for adolescents (ages 12-17 years) but not for children (8-11 years). This suggests that abstract cause-effect concepts may have more direct affective impact after the cognitive changes of adolescence (e.g., formal operations) than before. Finally, the CCC model accounted for much more variance in depression than conduct problems, suggesting diagnostic specificity.

Awareness of eye diseases in an urban population in southern India

OBJECTIVE

To assess the level of awareness of eye diseases in the urban population of Hyderabad in southern India.

METHODS

A total of 2522 subjects of all ages, who were representative of the Hyderabad population, participated in the population-based Andhra Pradesh Eye Disease Study. Of these subjects, 1859 aged > 15 years responded to a structured questionnaire on cataract, glaucoma, night blindness and diabetic retinopathy to trained field investigators. Having heard of the eye disease in question was defined as "awareness" and having some understanding of the eye disease was defined as "knowledge".

FINDINGS

Awareness of cataract (69.8%) and night blindness (60.0%) was moderate but that of diabetic retinopathy (27.0%) was low, while that of glaucoma (2.3%) was very poor. Knowledge of all the eye diseases assessed was poor. Subjects aged > or = 30 years were significantly more aware of all eye diseases assessed except night blindness. Multivariate analysis revealed that women were significantly less aware of night blindness (odds ratio (OR) = 0.78; 95% confidence interval (CI) = 0.63-0.97). Education played a significant role in awareness of these eye diseases. Study subjects of upper socioeconomic status were significantly more aware of night blindness (OR = 2.20; 95% CI = 1.29-3.74) and those belonging to upper and middle socioeconomic strata were significantly more aware of diabetic retinopathy (OR = 2.79; 95% CI = 2.19-3.56). Muslims were significantly more aware of cataract (OR = 2.36; 95% CI = 1.84-3.02) and less aware of night blindness (OR = 0.52; 95% CI = 0.42-0.64). The major source of awareness of the eye diseases was a family member/friend/relative suffering from that eye disease.

CONCLUSION

These data suggest that there is a need for health education in this Indian population to increase their level of awareness and knowledge of common eye diseases. Such awareness and knowledge could lead to better understanding and acceptance of the importance of routine eye examinations for the early detection and treatment of eye diseases, thereby reducing visual impairment in this population.

Visual impairment and eye diseases in elderly institutionalized Australians

OBJECTIVE

To study the prevalence and distribution of visual impairment and eye diseases by age and gender in an urban institutionalized population.

DESIGN

Cross-sectional study.

PARTICIPANTS

Four hundred three residents of nursing homes and hostels.

METHODS

Fourteen nursing homes were randomly selected from 104 nursing homes and hostels located within a 5-km radius of each of nine clusters studied in the Visual Impairment Project (VIP) urban cohort. Participants completed a standardized orthoptic and dilated ophthalmic examination, including measurement of visual acuity and visual fields. The major cause of vision loss was identified for participants with visual impairment.

MAIN OUTCOME MEASURES

Presenting visual acuity and ophthalmic diagnoses.

RESULTS

The participants' mean age was 82 years (standard deviation, 9.24), with an age range of 46 years to 101 years. Women outnumbered men by 318 to 85. Seventy-one (22%) of 318 women had bilateral profound visual impairment (blindness), defined as best-corrected visual acuity <3/60 and/or visual field constriction <5 degrees compared with 10 (12%) of 85 men. However, this difference is not significant when age-standardized. Age-related macular degeneration was the principal diagnosis of vision loss in the better eye of 74 (44%) of the 167 participants with bilateral low vision (<6/18 and/or visual field constriction to <20 degrees radius). The age-adjusted rate of blindness or profound visual impairment in the VIP institutional cohort of 5.2% (95% confidence interval [CI], 1.8, 8.6) was significantly greater than in the VIP urban and rural cohorts of 0.13% (95% CI, 0, 0.25) and 0.29% (95% CI, 0, 0.57), respectively.

CONCLUSIONS

Underestimation of visual impairment may occur in residential population-based studies that exclude institutional or residential nursing homes and hostels for the aged citizens. Expanded methods are required for visual assessment in institutional populations.

Diabetes in Victoria, Australia: the Visual Impairment Project

OBJECTIVES

To establish the prevalence and characteristics of self-reported diabetes in a representative sample of Victorian residents aged 40 years and older, and to compare the vision between people with and without self-reported diabetes.

DESIGN

Cross-sectional survey.

SETTING

Nine randomly selected suburban Melbourne clusters and four randomly selected rural Victorian clusters.

PARTICIPANTS

4,744 subjects (86% participation rate) aged > or = 40 years.

MAIN OUTCOME MEASURES

Subjects answered a detailed questionnaire which provided demographic details, body mass index, and the duration and treatment of any diagnosis of diabetes. Refraction was performed and best-corrected visual acuity was measured.

RESULTS

The prevalence of self-reported diabetes was 5.1%. In a multivariate analysis, self-reported diabetes was positively associated with age (p < 0.01), male sex (p = 0.01), higher body mass index (p = 0.01), Mediterranean ethnicity (p = 0.01), unemployment (p = 0.05) and lack of private health insurance (p < 0.05). People with self-reported diabetes were more likely to have mild or moderate levels of visual impairment than people who reported no previous diagnosis of diabetes (p < 0.01).

CONCLUSIONS

Diabetes in Victoria is more prevalent among men and among people of Mediterranean origin. When planning educational programs and health service delivery, it is also important to consider that, compared with the general population, people with diabetes are less likely to be employed or to have private health insurance, and are more likely to have impaired vision.

Prevalence of amblyopia and associated refractive errors in an adult population in Victoria, Australia

The study aimed to describe the prevalence of amblyopia and associated refractive errors among an adult Australian population. The Visual Impairment Project (VIP) is a population-based study of age-related eye disease in the state of Victoria, Australia. Data were collected through standardised interviews and orthoptic and ophthalmic dilated examinations. Amblyopia was defined as best-corrected visual acuity of 6/9 or worse in the absence of any pathological cause. The participants were 3,265 urban residents and 1,456 rural residents of the VIP ranging in age from 40-92 years (mean = 59 years; 53% female). The prevalence of unilateral amblyopia was 3.06% (95% C.I. 2.59, 3.53). Amblyopia was not found to be statistically different by age group (p=0.096), gender (p=0.675), or place of birth (p=0.14). Anisometropia was statistically more common (p<0.001) in amblyopic cases (51.1%) compared to the normal population (9.7%), and 54% of amblyopic eyes had visual acuity of worse than 6/12. Amblyopia is a significant cause of unilateral reduced visual acuity in a population aged 40 years and older. Anisometropia was more prevalent and the degree of anisometropia was greater in the amblyopic group compared with the normal population. Oblique astigmatism was more prevalent in the amblyopic group compared with the normal population.

Attributable risk estimates for cataract to prioritize medical and public health action

PURPOSE

Cataract is the most common cause of blindness in the world. The purpose of this study was to estimate the population attributable risk associated with identified risk factors for cortical, nuclear, and posterior subcapsular (PSC) cataract in a representative sample of the Victorian population aged 40 years and older.

METHODS

Cluster, stratified sampling was used and participants were recruited through a household census. At locally established test sites, standardized clinical examinations were performed to assess cataract and personal interviews were conducted to quantify potential risk factors. Multivariate logistic regression was used to determine the independent risk factors associated with the three types of cataract, and the population attributable risk was calculated.

RESULTS

A total of 3271 (83% of eligible) of the urban residents and 1473 (92%) rural residents participated. The urban residents ranged in age from 40 to 98 years (mean, 59 years), and 1511 (46%) were men. The rural residents ranged in age from 40 to 103 years (mean, 60 years), and 701 (48%) were men. The overall prevalence of cortical cataract was 12.1% (95% CL 10.5, 13.8), nuclear cataract 12.6% (95% CL 9.61, 15.7), and PSC cataract 4.93% (95% CL 3.68, 6.17). Significant risk factors for cortical cataract included age, female gender, diabetes for greater than 5 years, gout for greater than 20 years, arthritis, myopia, average annual ocular UV-B exposure, and family history of cataract (parents or siblings). Significant risk factors for nuclear cataract included age, female gender, rural residence, age-related maculopathy, diabetes for greater than 5 years, smoker for greater than 30 years, and myopia. The significant risk factors for PSC cataract were age, rural residence, thiazide diuretic use, and myopia. Of the modifiable risk factors, ocular UV-B exposure explains 10% of the cortical cataract in the community, and cigarette smoking accounts for 17% of the nuclear cataract.

CONCLUSIONS

Because of the near universal exposure to UV-B in the environment, ocular protection has one of the highest modifiable attributable risks for cortical cataract and would therefore be an ideal target for public health intervention. Quit smoking campaigns can be expanded to incorporate information about the excess cataract in the community associated with long-term smoking. Nonmodifiable risk factors such as age, gender, and long-term medication use have implications for the timely referral and treatment for those at higher risk of cataract.

Methods for detecting age-related maculopathy: a comparison between photographic and clinical assessment

PURPOSE

To examine the sensitivity, specificity and overall agreement between photographic and clinical assessment in detecting age-related maculopathy (ARM) features in the context of an epidemiological study, the Vitamin E, Cataract and Age-related Maculopathy Study (VECAT).

METHODS

A total of 1204 volunteers aged between 55 and 80 years of age, who were enrolled in the VECAT Study, had both slit-lamp biomicroscopy examination and fundus photos taken as part of the baseline ophthalmic examination. The Nidek 3-DX fundus camera (Nidek, Gamagori, Japan) was used to produce paired, one-framed, coloured, 15 degrees stereoslides of the macular area at a fixed angle. An International Classification and Grading System for Age-related Maculopathy and Age-related Macular Degeneration was used to grade the stereoslides. Agreement in the detection of drusen, pigment abnormalities, and late stage ARM features was assessed using unweignted kappa statistic. Cases of disagreement were verified using clinical data records, grading documentation and the review of stereoslides.

RESULTS

Macula status was available for 2386 eyes. For drusen of size < 63 microm, sensitivity was 47%, specificity was 68% with a kappa value of 0.20. For drusden > or = 125 microm, sensitivity and specificity were > or =81%. Kappa values ranged from 0.56 to 0.71. Levels of agreement for pigment abnormalities and late ARM were in the substantial range (i.e. kappa values from 0.70 to 1.00).

CONCLUSIONS

Slit-lamp biomicroscopy was found to be comparable to photograding (using the Nidek 3-DX fundus camera) for detecting features pertaining to ARM. However, given the objectivity and permanency of stereoslides, photograding is still the more reliable and the preferred system of assessing ARM in the context of an epidemiological study.

Management of alkali burns : an 11-year retrospective review

OBJECTIVE

To review the spectrum of patients with alkali burns admitted over an 11-year period and to assess the clinical outcomes after the introduction of a standard alkali burn treatment protocol.

DESIGN

Retrospective nonrandomized comparative study.

PATIENTS AND INTERVENTIONS

A total of 121 patient records with alkali burns (n = 177 eyes) admitted to a tertiary hospital between 1987 and 1998 were reviewed. Eyes treated with a standard alkali burn treatment protocol, which included intensive topical steroids, ascorbate, citrate, and antibiotics, were compared with eyes treated by conservative management with antibiotics, and a short course of steroids.

MAIN OUTCOME MEASURES

Time to corneal reepithelialization, final best-corrected visual acuity, and time to visual recovery, length of hospital stay, and complications were analyzed.

RESULTS

The standard protocol tended to delay corneal reepithelialization by one day (P: = not significant) in eyes with grade 1 burns (n = 76) and by 2 days (P: = 0.04) in grade 2 burns (n = 52), with no difference in final visual outcome. There were 37 eyes with grade 3 burns. Those treated with the standard protocol showed a trend toward more rapid corneal reepithelialization. Twenty-seven of 29 (93%) eyes with grade 3 injuries achieved a final best-corrected visual acuity of 20/40 or better compared with 3 of 6 (50%) eyes not treated according to the standard protocol (P: = 0.02). Eyes with grade 4 burns (n = 12), whether treated with the standard protocol or not, required 10 to 12 weeks for corneal reepithelialization. There was no statistically significant difference in final visual acuity.

CONCLUSIONS

On the basis of our findings, a number of recommendations can be made for the management of alkali injuries. Patients with a grade 1 or 2 injury do not require routine admission and do not benefit from the use of intensive treatment with ascorbate and citrate. A trend toward more rapid healing and a better final visual outcome were apparent in grade 3 burns, but our standard protocol made no difference in grade 4 burns.

Ocular trauma in an urban population in southern India: the Andhra Pradesh Eye Disease Study

PURPOSE

To assess the cumulative prevalence of ocular trauma and presence of vision loss due to ocular trauma in an urban population in southern India.

METHODS

As part of the population-based Andhra Pradesh Eye Disease Study, 2522 people of all ages from 24 clusters representative of the population of Hyderabad city in southern India, underwent a detailed interview and standardized dilated ocular evaluation. An eye was considered to be blind due to trauma if best corrected distance visual acuity was worse than 6/60 due to trauma.

RESULTS

One hundred and thirteen subjects gave a history of ocular trauma and another two had evidence of ocular trauma by examination, a combined age sex-adjusted rate of 3.97% (95% CI 2.52-5.42%). Blindness in one eye due to trauma was present in 17 subjects, and in both eyes in one subject, a combined age-sex-adjusted prevalence of 0.60% (95% CI 0.23-1.04%). Visual acuity in all the blind eyes except one was worse than 3/60. With multiple logistic regression, the odds of blindness in at least one eye due to trauma were highest for current age range of 30-39 years (odds ratio 6.33, 95% CI 1.69-23.77 compared with a current age of less than 30 years), were significantly higher for lower socioeconomic status (3.74, 95% CI 1.18 -11.84), and were higher for males (2.48, 95% CI 0.91-6.82) though this did not reach statistical significance. Trauma resulting in blindness had occurred by the age of 15 years in 55% of subjects, and before the age of 40 years in 92.1% of subjects; this had occurred most commonly while playing (53.6% of the cases). With multiple logistic regression, the odds ratios for any ocular trauma were significantly higher for males (2.10, 95% CI 1.40-3.15), and for labourers than for other occupations (2.50, 95% CI 1.62-3.86).

CONCLUSIONS

Ocular trauma affects one in 25 people in this urban population in India, and one in 167 people in this population are estimated to be blind in at least one eye due to trauma. The majority of the trauma resulting in blindness occurs during childhood and young adulthood, and slightly more than half occurs while playing. Targeting mothers and children of lower socioeconomic strata in eye health awareness strategies to reduce blindness due to trauma needs to be considered in urban India.

Angle-closure glaucoma in an urban population in southern India. The Andhra Pradesh eye disease study

OBJECTIVE

To assess the prevalence and features of angle-closure glaucoma (ACG) in an urban population in southern India.

DESIGN

A population-based, cross-sectional study.

PARTICIPANTS

A total of 2522 (85.4% of those eligible) persons of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city.

TESTING

The participants underwent an interview and detailed eye examination that included logarithm of minimum angle of resolution visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, and gonioscopy; pupil dilatation and stereoscopic fundus evaluation was performed if the risk of angle-closure as a result of dilatation was not believed to be imminent. Humphrey threshold 24-2 visual fields (Humphrey Instruments Inc., San Leandro, CA) were performed when indicated by standardized criteria for disc damage or if intraocular pressure (IOP) was 22 mmHg or more.

MAIN OUTCOME MEASURES

An occludable angle was defined as pigmented posterior trabecular meshwork not visible by gonioscopy in three quarters or more of the angle circumference. Manifest primary angle-closure glaucoma (PACG) was defined as IOP of 22 mmHg or more or glaucomatous optic disc damage with visual field loss in the presence of an occludable angle. An IOP of 22 mmHg or more or glaucomatous optic disc damage in the presence of an occludable angle secondary to an obvious cause was defined as secondary ACG.

RESULTS

Manifest PACG and occludable angles without ACG were present in 12 and 24 participants, respectively, with age- and gender-adjusted prevalence (95% confidence interval [CI]) of 0.71% (0.34%-1.31%) and 1.41% (0.73%-2.09%) in participants 30 years of age or older, and 1.08% (0.36%-1.80%) and 2.21% (1.15%-3.27%) in participants 40 years of age or older, respectively. With multivariate analysis, the prevalence of these two conditions considered together increased significantly with age (P < 0.001); although not statistically significant, these were more common in females (odds ratio 1.70; 95% CI, 0.82-3.54) and in those belonging to lower socioeconomic strata as compared with middle and upper strata (odds ratio, 1.82; 95% CI, 0.88-3.74). The odds of manifest PACG were higher in the presence of hyperopia of more than 2 diopters ([D]; odds ratio, 3.69; 95% CI, 0.89-15.2). Only four of 12 participants (33.3%) with manifest PACG had been previously diagnosed, and one of 12 (8.3%) had peripheral iridotomy performed previously. Manifest PACG had caused blindness in one or both eyes in five of these 12 participants (41.7%); best-corrected distance visual acuity less than 20/400 in one or both eyes in four patients, and acuity less than 20/200 in one eye in another patient. Most (83.3%) of those with manifest PACG could be classified as having chronic form of the disease. We may have underestimated manifest PACG because visual fields were per- formed only on those with clinical suspicion of optic disc damage. Secondary ACG was present in two participants.

CONCLUSIONS

The prevalence of PACG in this urban population in southern India is close to that reported recently in a Mongolian population. A large proportion of the PACG in this population was undiagnosed and untreated. Because visual loss resulting from PACG is potentially preventable if peripheral iridotomy or iridectomy is performed in the early stage, strategies for early detection of PACG could reduce the high risk of blindness resulting from PACG seen in this urban population in India.

Recruitment methods for community-based screening for diabetic retinopathy

Regular screening of all people with diabetes is the most efficient and cost-effective way to detect early stages of diabetic retinopathy so that laser treatment can be performed at the optimal time. A major aim of the Program for the Early Detection of Diabetic Retinopathy was to increase compliance with guidelines for screening for diabetic retinopathy. This community-based screening program used non-mydriatic retinal photography and was initiated in four areas of Victoria, Australia from 1996-1998. Recruitment strategies included targeted mail-outs, provision of the program brochure in English and the main languages spoken in the areas and media promotion in ethnic newspapers and on ethnic radio stations. In Victoria, only 55% of the population with diabetes currently access eye care services at the recommended intervals. This program was able to increase compliance with guidelines to 70% among people with diabetes that had not had a recent eye examination. A total of 1,197 people with diabetes were screened for diabetic retinopathy. Of the 1,197 people who were screened, 620 (15% of the estimated number of people with diabetes) had not had their eyes examined in the past two years. This pilot study identified strategies to encourage people with diabetes to have their eyes examined at the recommended intervals.