Hugh R. Taylor

An international classification and grading system for age-related maculopathy and age-related macular degeneration

A common detection and classification system is needed for epidemiologic studies of age-related maculopathy (ARM). Such a grading scheme for ARM is described in this paper. ARM is defined as a degenerative disorder in persons > or = 50 years of age characterized on grading of color fundus transparencies by the presence of the following abnormalities in the macular area: soft drusen > or = 63 microns, hyperpigmentation and/or hypopigmentation of the retinal pigment epithelium (RPE), RPE and associated neurosensory detachment, (peri)retinal hemorrhages, geographic atrophy of the RPE, or (peri)retinal fibrous scarring in the absence of other retinal (vascular) disorders. Visual acuity is not used to define the presence of ARM. Early ARM is defined as the presence of drusen and RPE pigmentary abnormalities described above; late ARM is similar to age-related macular degeneration (AMD) and includes dry AMD (geographic atrophy of the RPE in the absence of neovascular AMD) or neovascular AMD (RPE detachment, hemorrhages, and/or scars as described above). Methods to take and grade fundus transparencies are described.

Global prevalence and major risk factors of diabetic retinopathy

OBJECTIVE To examine the global prevalence and major risk factors for diabetic retinopathy (DR) and vision-threatening diabetic retinopathy (VTDR) among people with diabetes. RESEARCH DESIGN AND METHODS A pooled analysis using individual participant data from population-based studies around the world was performed. A systematic literature review was conducted to identify all population-based studies in general populations or individuals with diabetes who had ascertained DR from retinal photographs. Studies provided data for DR end points, including any DR, proliferative DR, diabetic macular edema, and VTDR, and also major systemic risk factors. Pooled prevalence estimates were directly age-standardized to the 2010 World Diabetes Population aged 20–79 years. RESULTS A total of 35 studies (1980–2008) provided data from 22,896 individuals with diabetes. The overall prevalence was 34.6% (95% CI 34.5–34.8) for any DR, 6.96% (6.87–7.04) for proliferative DR, 6.81% (6.74–6.89) for diabetic macular edema, and 10.2% (10.1–10.3) for VTDR. All DR prevalence end points increased with diabetes duration, hemoglobin A1c, and blood pressure levels and were higher in people with type 1 compared with type 2 diabetes. CONCLUSIONS There are approximately 93 million people with DR, 17 million with proliferative DR, 21 million with diabetic macular edema, and 28 million with VTDR worldwide. Longer diabetes duration and poorer glycemic and blood pressure control are strongly associated with DR. These data highlight the substantial worldwide public health burden of DR and the importance of modifiable risk factors in its occurrence. This study is limited by data pooled from studies at different time points, with different methodologies and population characteristics.

Effect of ultraviolet radiation on cataract formation

To investigate the relation of ultraviolet radiation and cataract formation, we undertook an epidemiologic survey of 838 watermen (mean age, 53 years) who worked on Chesapeake Bay. The annual ocular exposure was calculated from the age of 16 for each waterman by combining a detailed occupational history with laboratory and field measurements of sun exposure. Cataracts were graded by ophthalmologic examination for both type and severity. Some degree of cortical cataract was found in 111 of the watermen (13 percent), and some degree of nuclear cataract in 229 (27 percent). Logistic regression analysis showed that high cumulative levels of ultraviolet B exposure significantly increased the risk of cortical cataract (regression coefficient, 0.70; P = 0.04). A doubling of cumulative exposure increased the risk of cortical cataract by a factor of 1.60 (95 percent confidence interval, 1.01 to 2.64). Those whose annual average exposure was in the upper quartile had a risk increased by 3.30 (confidence interval, 0.90 to 9.97) as compared with those in the lowest quartile. Analysis using a serially additive expected-dose model showed that watermen with cortical lens opacities had a 21 percent higher average annual exposure to ultraviolet B (t-test, 2.23; P = 0.03). No association was found between nuclear cataracts and ultraviolet B exposure or between cataracts and ultraviolet A exposure. We conclude that there is an association between exposure to ultraviolet B radiation and cataract formation, which supports the need for ocular protection from ultraviolet B.

Risk of Cardiovascular and All-Cause Mortality in Individuals With Diabetes Mellitus, Impaired Fasting Glucose, and Impaired Glucose Tolerance The Australian Diabetes, Obesity, and Lifestyle Study (AusDiab)

Background— Diabetes mellitus increases the risk of cardiovascular disease (CVD) and all-cause mortality. The relationship between milder elevations of blood glucose and mortality is less clear. This study investigated whether impaired fasting glucose and impaired glucose tolerance, as well as diabetes mellitus, increase the risk of all-cause and CVD mortality. Methods and Results— In 1999 to 2000, glucose tolerance status was determined in 10 428 participants of the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab). After a median follow-up of 5.2 years, 298 deaths occurred (88 CVD deaths). Compared with those with normal glucose tolerance, the adjusted all-cause mortality hazard ratios (HRs) and 95% confidence intervals (CIs) for known diabetes mellitus and newly diagnosed diabetes mellitus were 2.3 (1.6 to 3.2) and 1.3 (0.9 to 2.0), respectively. The risk of death was also increased in those with impaired fasting glucose (HR 1.6, 95% CI 1.0 to 2.4) and impaired glucose tolerance (HR 1.5, 95% CI 1.1 to 2.0). Sixty-five percent of all those who died of CVD had known diabetes mellitus, newly diagnosed diabetes mellitus, impaired fasting glucose, or impaired glucose tolerance at baseline. Known diabetes mellitus (HR 2.6, 95% CI 1.4 to 4.7) and impaired fasting glucose (HR 2.5, 95% CI 1.2 to 5.1) were independent predictors for CVD mortality after adjustment for age, sex, and other traditional CVD risk factors, but impaired glucose tolerance was not (HR 1.2, 95% CI 0.7 to 2.2). Conclusions— This study emphasizes the strong association between abnormal glucose metabolism and mortality, and it suggests that this condition contributes to a large number of CVD deaths in the general population. CVD prevention may be warranted in people with all categories of abnormal glucose metabolism.

The Epidemiology of Dry Eye in Melbourne, Australia

OBJECTIVE To describe the epidemiology of dry eye in the adult population of Melbourne, Australia. DESIGN A cross-sectional prevalence study. PARTICIPANTS Participants were recruited by a household census from two of nine clusters of the Melbourne Visual Impairment Project, a population-based study of age-related eye disease in the 40 and older age group of Melbourne, Australia. Nine hundred and twenty-six (82.3% of eligible) people participated; 433 (46.8%) were male. They ranged in age from 40 to 97 years, with a mean of 59.2 years. MAIN OUTCOME MEASURES Self-reported symptoms of dry eye were elicited by an interviewer-administered questionnaire. Four objective assessments of dry eye were made: Schirmers test, tear film breakup time, rose bengal staining, and fluorescein corneal staining. A standardized clinical slit-lamp examination was performed on all participants. Dry eye for the individual signs or symptoms was defined as: rose bengal > 3, Schirmers < 8, tear film breakup time < 8, > 1/3 fluorescein staining, and severe symptoms (3 on a scale of 0 to 3). RESULTS Dry eye was diagnosed as follows: 10.8% by rose bengal, 16.3% by Schirmers test, 8.6% by tear film breakup time, 1.5% by fluorescein staining, 7.4% with two or more signs, and 5.5% with any severe symptom not attributed to hay fever. Women were more likely to report severe symptoms of dry eye (odds ratio [OR] = 1.85; 95% confidence limits [CL] = 1.01, 3.41). Risk factors for two or more signs of dry eye include age (OR = 1.04; 95% CL = 1.01, 1.06), and self-report of arthritis (OR = 3.27; 95% CL = 1.74, 6.17). These results were not changed after excluding the 21 people (2.27%) who wore contact lenses. CONCLUSIONS These are the first reported population-based data of dry eye in Australia. The prevalence of dry eye varies by sign and symptom.

Causes of vision loss worldwide, 1990-2010: a systematic analysis

BACKGROUND Data on causes of vision impairment and blindness are important for development of public health policies, but comprehensive analysis of change in prevalence over time is lacking. METHODS We did a systematic analysis of published and unpublished data on the causes of blindness (visual acuity in the better eye less than 3/60) and moderate and severe vision impairment ([MSVI] visual acuity in the better eye less than 6/18 but at least 3/60) from 1980 to 2012. We estimated the proportions of overall vision impairment attributable to cataract, glaucoma, macular degeneration, diabetic retinopathy, trachoma, and uncorrected refractive error in 1990-2010 by age, geographical region, and year. FINDINGS In 2010, 65% (95% uncertainty interval [UI] 61-68) of 32·4 million blind people and 76% (73-79) of 191 million people with MSVI worldwide had a preventable or treatable cause, compared with 68% (95% UI 65-70) of 31·8 million and 80% (78-83) of 172 million in 1990. Leading causes worldwide in 1990 and 2010 for blindness were cataract (39% and 33%, respectively), uncorrected refractive error (20% and 21%), and macular degeneration (5% and 7%), and for MSVI were uncorrected refractive error (51% and 53%), cataract (26% and 18%), and macular degeneration (2% and 3%). Causes of blindness varied substantially by region. Worldwide and in all regions more women than men were blind or had MSVI due to cataract and macular degeneration. INTERPRETATION The differences and temporal changes we found in causes of blindness and MSVI have implications for planning and resource allocation in eye care. FUNDING Bill & Melinda Gates Foundation, Fight for Sight, Fred Hollows Foundation, and Brien Holden Vision Institute.

Cataract blindness--challenges for the 21st century.

Cataract prevalence increases with age. As the worlds population ages, cataract-induced visual dysfunction and blindness is on the increase. This is a significant global problem. The challenges are to prevent or delay cataract formation, and treat that which does occur. Genetic and environmental factors contribute to cataract formation. However, reducing ocular exposure to UV-B radiation and stopping smoking are the only interventions that can reduce factors that affect the risk of cataract. The cure for cataract is surgery, but this is not equally available to all, and the surgery which is available does not produce equal outcomes. Readily available surgical services capable of delivering good vision rehabilitation must be acceptable and accessible to all in need, no matter what their circumstances. To establish and sustain these services requires comprehensive strategies that go beyond a narrow focus on surgical technique. There must be changes in government priorities, population education, and an integrated approach to surgical and management training. This approach must include supply of start-up capital equipment, establishment of surgical audit, resupply of consumables, and cost-recovery mechanisms. Considerable innovation is required. Nowhere is this more evident than in the pursuit of secure funding for ongoing services.

The prevalence of glaucoma in the Melbourne Visual Impairment Project

PURPOSE The purpose of the study was to determine the prevalence of glaucoma in Melbourne, Australia. METHODS All subjects were participants in the Melbourne Visual Impairment Project (Melbourne VIP), a population-based prevalence study of eye disease that included residential and nursing home populations. Each participant underwent a standardized eye examination, which included a Humphrey Visual Field test, applanation tonometry, fundus examination including fundal photographs, and a medical history interview. Glaucoma status was determined by a masked assessment and consensus adjudication of visual fields, optic disc photographs, intraocular pressure, and glaucoma history. RESULTS A total of 3271 persons (83% response rate) participated in the residential Melbourne VIP. The overall prevalence rate of definite primary open-angle glaucoma in the residential population was 1.7% (95% confidence limits = 1.21, 2.21). Of these, 50% had not been diagnosed previously. Only two persons (0.1%) had primary angle-closure glaucoma and six persons (0.2%) had secondary glaucoma. The prevalence of glaucoma increased steadily with age from 0.1% at ages 40 to 49 years to 9.7% in persons aged 80 to 89 years. There was no relationship with gender. The authors examined 403 (90.2% response rate) nursing home residents. The age standardized rate for this component was 2.36% (95% confidence limits = 0, 4.88). CONCLUSION The rate of glaucoma in Melbourne rises significantly with age. With only half of patients being diagnosed, glaucoma is a major eye health problem and will become increasingly important as the population ages.

The epidemiology of cataract in Australia

PURPOSE To describe the prevalence and risk factors for cataract in an Australian population aged 40 years and older. METHODS Participants were recruited by a household census and stratified, random cluster sampling to represent residents of Victoria, Australia, aged 40 years and older. The following information was collected: initial visual acuity and best-corrected visual acuity, demographic details, health history, dietary intake of antioxidants, lifetime ocular ultraviolet B exposure, and clinical eye examination, including lens photography. Cortical opacities were measured in sixteenths. Cortical cataract was defined as opacity greater than or equal to 4/16 of pupil circumference. Nuclear opacities were graded according to the Wilmer cataract grading scheme, and cataract was defined as greater than or equal to nuclear standard 2.0 of four standards. The height and width of any posterior subcapsular opacity was measured and recorded. Posterior subcapsular cataract was defined as posterior subcapsular opacity greater than or equal to 1 mm2. The worse eye was selected for analysis. Backward stepwise logistic regression was used to quantify independent risk factors for cataract. RESULTS A total of 3,271 (83% of eligible) of the urban residents, 403 (90% of eligible) nursing home residents, and 1,473 (92% of eligible) rural residents participated. The urban residents ranged in age from 40 to 98 years (mean, 59 years), and 1,511 (46%) were men. The nursing home residents ranged in age from 46 to 101 years (mean, 82 years), and 85 (21%) were men. The rural residents ranged in age from 40 to 103 years (mean, 60 years), and 701 (47.5%) were men. The overall weighted rate of cortical cataract was 11.3% (95% confidence limits, 9.68%, 13.0%) excluding cataract surgery and 12.1% (95% confidence limits, 10.5%, 13.8%) including cataract surgery. The risk factors for cortical cataract that remained in the multivariate logistic regression model were age, female gender, diabetes duration greater than 5 years, gout duration greater than 10 years, arthritis diagnosis, myopia, use of oral beta-blockers, and increased average annual ocular ultraviolet B exposure. Overall, 12.6% (95% confidence limits, 9.61%, 15.7%) of Victorians aged 40 years and older had nuclear cataract including previous cataract surgery, and 11.6% (95% confidence limits, 8.61%, 14.7%) had nuclear cataract excluding previous cataract surgery. In the urban and rural cohorts, age, female gender, rural residence, brown irides, diabetes diagnosed 5 or more years earlier, myopia, age-related maculopathy, having smoked for greater than 30 years, and an interaction between ocular ultraviolet B exposure and vitamin E were all risk factors for nuclear cataract. The rate of posterior subcapsular cataract excluding previous cataract surgery was 4.08% (95% confidence limits, 3.01%, 5.14%), whereas the overall rate of posterior subcapsular cataract including previous cataract surgery was 4.93% (95% confidence limits, 3.68%, 6.17%) . The independent risk factors for posterior subcapsular cataract in the urban and rural cohorts that remained were age in years, rural location, use of thiazide diuretics, vitamin E intake, and myopia. CONCLUSIONS The expected increase in the prevalence of cataract with the aging of the population highlights the need to plan appropriate medical services and public health interventions for primary and secondary prevention. Many of the identified risk factors for cataract in the population have the potential for being modified through public health interventions.

The prevalence of age-related maculopathy: the Visual Impairment Project

PURPOSE To determine the prevalence of age-related maculopathy (ARM) lesions in residents of the state of Victoria, Australia. DESIGN Population-based cross-sectional study. PARTICIPANTS Total of 5147 residential and institutionalized persons aged 40 years and older, living in Victoria. METHODS Participants were recruited through a cluster, stratified, random sampling from nine urban clusters and four rural clusters. The presence of ARM lesions was graded from color stereo fundus photographs as well as slit-lamp stereo biomicroscopy according to the International Classification and Grading System. MAIN OUTCOME MEASURES The presence of ARM lesions. RESULTS The mean age of participants was 60.2 years, and 55% were females. Gradable fundus photographs were available for at least one eye in 4345 (92%) of the participants. The weighted prevalence of neovascular age-related macular degeneration (AMD) was 0.39% (95% confidence limits [CL] = 0.20, 0.58), atrophic AMD was 0. 27% (95% CL = 0.04, 0.50), and total AMD was 0.68% (95% CL = 0.30, 1. 1). Prevalence of AMD was strongly related to age (P < 0.001). Prevalence of early ARM was 15.1% (95% CL = 13.7, 16.4). Large drusen, 125 micrometer or more, were present in 6.3% of the participants. There was a higher prevalence of soft distinct drusen (7.5%) than soft indistinct drusen (4.3%). Retinal pigmentary abnormalities were present in 8.2% (95% CL = 7.2, 9.2). The prevalence of large drusen, soft drusen, and pigmentary abnormalities increased with age (P < 0. 001). Prevalence of retinal pigmentary abnormalities increased with increasing drusen size (P < 0.001). Soft indistinct drusen were more common in women aged 70 years or older (P < 0.001). Bilaterality of any ARM was strongly age related, and women appeared to have a higher risk of both bilateral early ARM and AMD. CONCLUSIONS These data provide age- and gender-specific prevalence of ARM and its component lesions in an ethnically diverse Australian population. Early ARM and AMD prevalence rates increased sharply from ages 70 and 80 years, respectively, in all ethnic groups. These higher rates will continue to increase the importance of AMD as our population ages.