Open-angle glaucoma in an urban population in southern India: the Andhra Pradesh eye disease study

OBJECTIVE

To assess the prevalence and features of open-angle glaucoma in an urban population in southern India.

DESIGN

A population-based cross-sectional study.

PARTICIPANTS

A total of 2522 persons (85.4% of those eligible) 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, gonioscopy, dilatation, cataract grading, and stereoscopic fundus evaluation. Automated Humphrey threshold 24-2 visual fields (Humphrey Instruments Inc., San Leandro, CA) and optic disc photography were performed when indicated by standardized criteria for disc damage or if intraocular pressure (IOP) was 22 mmHg or more.

MAIN OUTCOME MEASURES

Definite primary open-angle glaucoma (POAG) was defined as obvious glaucomatous optic disc damage and visual field loss in the presence of an open-angle, and suspected POAG was defined as suspected glaucomatous optic disc damage without definite visual field loss. Ocular hypertension (OHT) was defined as IOP of 22 mmHg or more without glaucomatous optic disc damage or visual field loss in the presence of an open-angle. Glaucomatous optic disc damage or IOP of 22 mmHg or more secondary to an obvious cause and with an open-angle was defined as secondary open-angle glaucoma.

RESULTS

Definite POAG, suspected POAG, and OHT were present in 27, 14, and 7 participants, respectively, with age- and gender-adjusted prevalence (95% confidence interval) of 1.62% (0.77%-2.48%), 0.79% (0.39%-1.41%), and 0.32% (0.10%-0.78%) in those 30 years of age or older, and 2.56% (1.22%-3.91%), 1.11% (0.43%-1.78%), and 0.42% (0.11%-1.12%) in those 40 years of age or older, respectively. The prevalence of POAG increased significantly with age using multivariate analysis (P < 0.001). Only two of 27 participants (7.4%) with definite POAG had been previously diagnosed and treated, and 66.7% of the previously undiagnosed had IOP less than 22 mmHg. Fourteen of 27 participants (51.9%) with definite POAG had severe glaucomatous damage based on optic disc and visual field criteria, of which five participants (18.5%) had at least one blind eye as a result of POAG (all with best-corrected distance visual acuity less than 20/400 or central visual field less than 10 degrees); the other 13 participants (48.1%) had moderate glaucomatous damage. Because visual fields and optic disc photography were not performed on all participants, the prevalence of POAG may have been underestimated. Secondary open-angle glaucoma was present in one participant as a result of angle recession.

CONCLUSIONS

The prevalence of open-angle glaucoma in this urban population in southern India is at least as much as that reported recently from white populations in developed countries. However, the vast majority of persons with glaucoma were undiagnosed in this population, and a large proportion of those having definite POAG already had severe glaucomatous damage.

Variability in digital assessment of cortical and posterior subcapsular cataract

To identify validity of the standardised Nidek EAS-1000 retroillumination image analysis, images of 450 consecutive patients were analysed for the standard 6.5 mm and for the maximal pupil size. The software allows for separation of cortical and posterior subcapsular opacities and defines threshold for cataract automatically at 12% below the brightest point of the histogram of pixel luminescence. The results were compared with clinical Wilmer cataract grading. Correlation between clinical and digital assessment was 0.48* for cortical opacities in maximal pupil size, 0. 47* in 6.5 mm pupil size analyses, and 0.71* for posterior subcapsular opacities (*p < 0.001). In 24.6% of maximal pupil size analyses and in 11.7% of standard pupil size analyses standardisation revealed confounding features, such as other opacities of media, refractive shadows etc., that masqueraded as cataract and interfered with the cortical opacity measurements. Automatic standardized analysis has reduced many sources of observer variation (level of illumination, pupil size and threshold adjustment), but the revealed range of confounding opacities and artifacts still requires observer interpretation.

Comparison of clinical and digital assessment of nuclear optical density

To compare the standardised Nidek EAS-1000 densitometric analysis of the lens with clinical assessment of the nucleus at an early stage of cataract development, 1,200 eyes of 1,204 participants of the VECAT study were assessed at the baseline using both subjective and objective lens grading. Standardisation of the automatic slit image analysis was achieved using a custom-designed EAS-1000 Software version 3.01c. Among 6 measurements of nuclear optical density, the mean pixel luminescence of integrated anterior nuclear density correlated best with clinical assessment (R = 0.662, p < 0.001). Variance components that interfere with the assessment are defined.

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.

Diabetic retinopathy in Victoria, Australia: the Visual Impairment Project

AIM

To establish the prevalence, severity, and risk factors for diabetic retinopathy in a representative sample of Victorian residents aged 40 years and older.

METHODS

A population based, cluster sampling method was used to recruit 4744 participants (86% participation rate). Nine randomly selected, suburban Melbourne clusters and four randomly selected, rural Victorian clusters were used. Participants provided a detailed medical and personal history and underwent an ocular examination including funduscopy and fundus photography. Rural participants provided a blood sample, from which the glycosylated haemoglobin percentage was measured. The diagnosis of diabetic retinopathy was based on fundus photographs from participants with self reported diabetes.

RESULTS

The prevalence of diabetic retinopathy among people with self reported diabetes was 29. 1%. The prevalence of untreated, vision threatening retinopathy was 2.8%. Retinopathy was positively associated with a longer reported duration of diabetes diagnosis (p<0.01) and with higher fractions of glycosylated haemoglobin (p<0.01). Retinopathy was not significantly associated with age, ethnicity, body mass index, glaucoma, myopia or intake of alcohol, tobacco, or aspirin (all p > 0.05).

CONCLUSIONS

Most people in Victoria with proliferative diabetic retinopathy or clinically significant macular oedema have received laser treatment. There remains however, a small but important group who have not received treatment and whose vision is threatened. People with diabetes should be encouraged to maintain strict glycaemic control and to undergo regular screening to delay or prevent the development of retinopathy.

Population based assessment of uveitis in an urban population in southern India

AIM

To assess the prevalence of active and inactive uveitis unrelated to previous surgery or trauma in an urban population in southern India.

METHODS

As part of the Andhra Pradesh Eye Disease Study, 2522 subjects (85.4% of those eligible), a sample representative of the population of Hyderabad city in southern India, underwent interview and detailed dilated eye examination. Presence of sequelae of uveitis without current active inflammation was defined as inactive uveitis.

RESULTS

Unequivocal evidence of active or inactive uveitis unrelated to previous surgery or trauma was present in 21 subjects, an age-sex adjusted prevalence of 0.73% (95% confidence interval (CI) 0.44-1.14%). Active uveitis was present in eight subjects, an age-sex adjusted prevalence of 0.37% (95% CI 0. 19-0.70), of which 0.06% was anterior, 0.25% intermediate, and 0.06% posterior. The 0.36% (95% CI 0.17-0.68%) prevalence of inactive uveitis included macular chorioretinitis scars (0.26%), anterior (0. 07%) and previous vasculitis involving the whole eye (0.03%). The prevalence of visual impairment due to uveitis of less than 6/18 in at least one eye was 0.27%, less than 6/60 in at least one eye was 0. 16%, and less than 6/60 in both eyes was 0.03%.

CONCLUSION

These population based cross sectional data give an estimate of the prevalence of various types of uveitis in this urban population in India. Active or past uveitis that might need treatment at some stage was present in one of every 140 people in this population.

Detection of vision impairment in people admitted to aged care assessment centres

Vision is not routinely tested when the health of older people is assessed, and the aim of this study was to detect older people with vision impairment for referral to appropriate eye care services. People admitted for assessment and or rehabilitation in three aged care assessment centres had distance and near visual acuity assessed with a simplified vision test. A pinhole test was used when necessary. Referral criteria were distance visual acuity of less than 6/12; near vision of less than N8, and people with diabetes who had not attended a dilated fundus examination in the last 2 years. Visual acuity results were obtained in 93% of patients (685/735). Those unable to perform the vision test were very ill or had severe cognitive impairment. Forty-three per cent of patients (266/646) had impaired vision and, of these, 70.6% (188/266) were referred to eye care specialists. Forty-five per cent were referred to ophthalmologists, 36% to optometrists and 20% to low vision services. This significant proportion of patients with poor vision suggests that vision screening is warranted.

Association of presbyopic correction with changes in visual fields

The purpose of this study was to investigate the effect of presbyopic correction on changes in visual fields caused by an alteration in outflow of aqueous humour Visual fields were compared before and after introduction of presbyopic correction in participants of the Melbourne Visual Impairment Project. Height and slope of the 'Hill of Vision' were assessed by calculating median thresholds in the four sets of three eccentric points. Analysis of 101 eyes in the study group and 101 eyes in the control group shows higher decrease of the 'Hill of Vision' height in the group of participants who started wearing presbyopic correction, than in the group without presbyopic correction (P = 0.02). Intraocular pressure measured irrespectively of participant's accommodative activity was not significantly different between the two groups at both time points. These data suggest that the use of presbyopic correction is associated with changes in the visual field.

Functional implications of vision impairment

This study investigated the functional implications of vision impairment. A total of 508 participants in the Visual Impairment Project completed the VF-14 questionnaire, vision-related functional tasks, an interview, and the ophthalmic examination. Participants with less than 6/12 presenting acuity were more likely to report a moderate to high degree of difficulty performing VF-14 items (odds ratios from 6 to 44). They were also more likely to be unable to recognize a 10 cent coin (OR; 7.0, 95% CL; 2.6, 19.3) or correctly read a telephone number (OR; 10.1, 95% CI; 5.6, 18.1). As demonstrated by the VF-14 and the functional tasks administered in this study, visual impairment affects the ability of people to conduct a variety of common daily tasks.

Survey of dry eye symptoms in Australian pilots

In 1996, a questionnaire was distributed to 4000 Australian commercial pilots for the quantification of symptoms of dry eye. The 1246 respondents ranged in age from 18-71 years (mean age 40.4 years), and 98.2% were men. Symptoms of dry eye during flight were reported by 901 (72.3%, 95% CI = 69.7 74.8) while only 67 (5.4%, 95% CI = 4.2-6.8) reported dry eye independent of flight. In univariate analyses, the following factors were associated with dry eye in flight: age, use of distance glasses, smoking, average weekly number of flight hours, type of aircraft usually flown, and normal cruising altitude. In a multiple logistic regression model, only the class of aeroplane (large jets vs. propeller-driven planes) (OR = 1.75, 95% CI = 1.34-2.28) and estimated number of flight hours per week (OR = 1.58, 95% CI = 1.34-1.86) were related to dry eye symptoms. In conclusion, self-reported symptoms of dry eye are common in Australian pilots and are associated with aeroplane class and flying time.

Examination compliance and screening for diabetic retinopathy: a 2-year follow-up study

Early detection and timely treatment of diabetic retinopathy can preserve vision, yet many people with diabetes do not have their eyes examined regularly. The purpose of this study was to examine eye care practices of people with diabetes who had not previously accessed eye care services on a regular basis. Screening with non-mydriatic retinal photography for diabetic retinopathy was initiated in 1996, and targeted people with diabetes who did not access eye care services on a regular basis. Each test area was revisited 2 years after the initial screening. Patients that did not attend the biennial screening were followed up by mail survey. Although none of the participants in this study had been previously accessing eye care services on a regular basis, 87% did so after attending the screening. These results indicate that mobile screening with non-mydriatic photography, as an adjunct to current eye care services, has the potential to increase examination compliance for diabetic retinopathy and to achieve sustained behaviour change.

Management of diabetic retinopathy by Australian ophthalmologists. Working Group on Evaluation of the NHMRC Retinopathy Guideline Distribution. National Health and Medical Research Council

OBJECTIVE

To describe current management practices of diabetic retinopathy used by Australian ophthalmologists.

SETTING

Two-page self-administered questionnaire mailed to 622 ophthalmologists listed with the Royal Australian College of Ophthalmologists.

METHODS

The survey included questions about practice details such as size and location; specialty; current practice with regard to management of patients with diabetes; confidence in screening for diabetic retinopathy; and a number of patient scenarios related to screening, follow-up and treatment of diabetic retinopathy.

RESULTS

Of the 577 eligible ophthalmologists, 475 (82%) completed the questionnaire. They had been practicing ophthalmology between 1 and 50 years (median 16 years) and 89 (19%) indicated that they had a subspecialty interest either in vitreo-retinal surgery or in medical retina. For 145 (30.5%) of the ophthalmologists, at least one of their practices was located in a country area. The estimated percentage of patients with diabetes ranged from 0.1 to 60% (mean = 9.9%). Retinal specialists perform between 0 and 750 macular focal photocoagulation procedures per year (mean = 94) compared with a range of 0-350 for nonretinal specialists (mean = 10.3) (t = 6.1, P < 0.001). The ophthalmologists were presented with a hypothetical patient with cataract requiring surgery and clinically significant macular oedema that would be difficult to treat (but not impossible) because of the cataract. Seventy-seven ophthalmologists (16%) said they would delay the macular laser therapy until after the cataract surgery had been performed. In multivariate logistic regression models, nonretinal specialists were 4.44 times as likely to perform the cataract surgery first (95%CL = 1.57, 12.6) and ophthalmologists who had been in practice more than 15 years were 2.50 times as likely to perform cataract surgery first (95%CL = 1.47, 4.26). There were other examples of practice that differed from the National Health and Medical Research Council (NHMRC) guidelines in patient scenarios. The majority of ophthalmologists (60%) expressed a moderate or strong need to learn more about the management of diabetic retinopathy.

DISCUSSION

The variability in the management of diabetic retinopathy by Australian ophthalmologists and the desire of ophthalmologists to learn more about diabetic retinopathy provide evidence to support the need for the NHMRC Guidelines for Diabetic Retinopathy. These data will be used to evaluate changes in practice as a result of the implementation of the guidelines.

Operated and unoperated cataract in Australia

PURPOSE

To quantify the prevalence of cataract, the outcomes of cataract surgery and the factors related to unoperated cataract in Australia.

METHODS

Participants were recruited from the Visual Impairment Project: a cluster, stratified sample of more than 5,000 Victorians aged 40 years and over. At examination sites interviews, clinical examinations and lens photography were performed. Cataract was defined in participants who had: had previous cataract surgery, cortical cataract greater than 4/16, nuclear greater than Wilmer standard 2, or posterior subcapsular greater than 1 mm2.

RESULTS

The participant group comprised 3,271 Melbourne residents, 403 Melbourne nursing home residents and 1,473 rural residents. The weighted rate of any cataract in Victoria was 21.5%. The overall weighted rate of prior cataract surgery was 3.79%. Two hundred and forty-nine eyes had had prior cataract surgery. Of these 249 procedures, 49 (20%) were aphakic, 6 (2.4%) had anterior chamber intraocular lenses and 194 (78%) had posterior chamber intraocular lenses. Two hundred and eleven of these operated eyes (85%) had best-corrected visual acuity of 6/12 or better, the legal requirement for a driver's license. Twenty-seven (11%) had visual acuity of less than 6/18 (moderate vision impairment). Complications of cataract surgery caused reduced vision in four of the 27 eyes (15%), or 1.9% of operated eyes. Three of these four eyes had undergone intracapsular cataract extraction and the fourth eye had an opaque posterior capsule. No one had bilateral vision impairment as a result of cataract surgery. Surprisingly, no particular demographic factors (such as age, gender, rural residence, occupation, employment status, health insurance status, ethnicity) were related to the presence of unoperated cataract.

CONCLUSIONS

Although the overall prevalence of cataract is quite high, no particular subgroup is systematically underserviced in terms of cataract surgery. Overall, the results of cataract surgery are very good, with the majority of eyes achieving driving vision following cataract extraction.

Digital cataract photography

This study compares the cost effectiveness of two methods of grading cataract changes in the Australian population. The conventional film-based method has comparatively low set-up costs, but is more subjective in its assessment and more reliant on manpower, while the digital method has high set-up costs, but the results are more objective and available more quickly using fewer people. By a careful assessment of all the costs involved it is possible to estimate how many participants need to be recruited to a study in order to make the digital method cost effective.

Unilateral visual impairment in an urban population in southern India

This study assessed the prevalence and causes of unilateral visual impairment in the urban population of Hyderabad city as part of the Andhra Pradesh Eye Disease Study. Stratified, random, cluster, systematic sampling was used to select 2,954 subjects from 24 clusters representative of the population of Hyderabad. Eligible subjects underwent detailed eye examination including logMAR visual acuity, refraction, slitlamp biomicroscopy, applanation tonometry, gonioscopy, dilatation, cataract grading, and stereoscopic evaluation of fundus. Automated threshold visual fields and slitlamp and fundus photography were done when indicated by standardised criteria. Unilateral visual impairment was defined as presenting distance visual acuity < 6/18 in the worse eye and > or = 6/12 in the better eye, which was further divided into unilateral blindness (visual acuity < 6/60 in the worse eye) and unilateral moderate visual impairment (visual acuity < 6/18-6/60 in the worse eye). A total of 2,522 subjects (85.4% of eligible), including 1,399 > or = 30 years old, participated in the study. In addition to the 1% blindness and 7.2% moderate visual impairment (based on bilateral visual impairment criteria) reported earlier in this sample, 139 subjects had unilateral visual impairment, an age-gender-adjusted prevalence of 3.8% (95% confidence interval 2.7-4.9%). The major causes of this visual impairment 39.9% were refractive error (42.9%), cataract (14.4%), corneal disease (11.5%), and retinal disease (11.2%). Of this unilateral visual impairment was blindness. The major causes of unilateral blindness were corneal disease (23.2%), cataract (22.5%), retinal disease (18%), and optic atrophy (12.9%). On the other hand, the predominant cause of unilateral moderate visual impairment was refractive error (67%) followed by cataract (9%). Of the total unilateral visual impairment, 34.3% was present in those < 30 years old and 36.2% in those 30-49 years old. Unilateral visual impairment afflicts approximately 1 in 25 persons in this urban population. A large proportion of this unilateral visual impairment is present in younger age groups. The causes of unilateral visual impairment, like those of bilateral visual impairment in this population, are varied, suggesting therefore, that in addition to the current focus of eye care in India predominantly on cataract, other causes of visual impairment need to be addressed as well.

Epidemiology of pterygium in Victoria, Australia

AIM

To describe the prevalence of and risk factors for pterygium in a population based sample of residents of the Australian state of Victoria who were aged 40 years and older.

METHODS

The strata comprised nine randomly selected clusters from the Melbourne statistical division, 14 nursing homes randomly selected from the nursing homes within a 5 kilometre radius of the nine Melbourne clusters, and four randomly selected clusters from rural Victoria. Pterygium was measured in millimetres from the tip to the middle of the base. During an interview, people were queried about previous ocular surgery, including surgical removal of pterygium, and their lifetime exposure to sunlight.

RESULTS

5147 people participated. They ranged in age from 40 to 101 years and 2850 (55.4%) were female. Only one person in the Melbourne cohort reported previous pterygium surgery, and seven rural residents reported previous surgery; this information was unavailable for the nursing home residents. Pterygium was present upon clinical examination in 39 (1.2%) of the 3229 Melbourne residents who had the clinical examination, six (1. 7%) of the nursing home residents, and 96 (6.7%) of the rural residents. The overall weighted population rate in the population was 2.83% (95% CL 2.35, 3.31). The independent risk factors for pterygium were found to be age (OR=1.23, 95% CL=1.06, 1.44), male sex (OR=2.02, 95% CL=1.35, 3.03), rural residence (OR=5.28, 95% CL=3. 56, 7.84), and lifetime ocular sun exposure (OR=1.63, 95% CL=1.18, 2. 25). The attributable risk of sunlight and pterygium was 43.6% (95% CL=42.7, 44.6). The result was the same when ocular UV-B exposure was substituted in the model for broad band sun exposure.

CONCLUSION

Pterygium is a significant public health problem in rural areas, primarily as a result of ocular sun exposure.

Adaptation of WHOQOL as health-related quality of life instrument to develop a vision-specific instrument

The WHOQOL instrument was adapted as a health-related QOL instrument for a population-based epidemiologic study of eye diseases in southern India, the Andhra Pradesh Eye Disease Study (APEDS). A follow-up question was added to each item in WHOQOL to determine whether the decrease in QOL was due to any health reasons including eye-related reasons. Modifications in WHOQOL and translation in local language were done through the use of the focus groups including health professionals and people not related to health care. The modified instrument has 28 items across 6 domains of the WHOQOL and was translated into the local language, Telugu, using the pragmatic approach. It takes 10-20 minutes to be administered by a trained interviewer. Reliability was within acceptable range. This health-related QOL instrument is being used in the population-based study APEDS to develop a vision-specific QOL instrument which could potentially be used to assess the impact of visual impairment on QOL across different cultures and for use in evaluating eye-care interventions. This health-related QOL instrument could also be used to develop other disease-specific instruments as it allows assessment of the extent to which various aspects of QOL are affected by a variety of health problems.

Can we trust parent reports in research on cultural and ethnic differences in child psychopathology? Using the bicultural family design to test parental culture effects

Research comparing cultural and ethnic groups on child psychopathology has relied heavily on parent reports. But don't parents' own cultural backgrounds bias their reports, undermining valid assessment of actual child behavior? The question is hard to address because parent and child culture tend to be confounded. To solve this problem, we assembled an unusual but heuristically valuable sample: 50 bicultural families, each with an ethnic Thai parent reared in Thailand and a Caucasian parent reared in the U.S. Parents in each pair independently completed standardized problem checklists on the same child in their family. Across all 10 empirically derived problem syndromes, no parental culture effect was either significant or larger than "small," by Cohen's (1988) standards; across all 140 specific problems, the mean percent of variance accounted for by parent culture was less than 1%. Results do not point to a biasing effect of parental culture.

Age-specific causes of bilateral visual impairment

OBJECTIVES

To describe the age-specific prevalence of common eye diseases causing bilateral visual impairment and estimate the total number of Australians with cause-specific visual impairment.

METHODS

Cluster-stratified random sample of 5147 residents aged 40 years and older from urban and rural areas and aged-care facilities. Participants completed a standardized interview and eye examination. Four levels of bilateral visual impairment were defined: less than 20/40 to 20/60 and/or homonymous hemianopia (mild), less than 20/60 to 20/200 or better and/or less than 20 degrees to 10 degrees radius field (moderate), less than 20/200 to 10/200 and/or less than 10 degrees to 5 degrees radius field (severe), and less than 1O/ 200 and/or less than 50 radius field (profound). The major cause of vision loss was identified for all participants found to be visually impaired.

RESULTS

Uncorrected refractive error was the most common cause of bilateral visual impairment across all decades of life, rising from 0.5% in 40- to 49-year-olds to 13% among those aged 80 years and older. Prevalence of visual impairment due to diabetic retinopathy was 0.7% in 50- to 59-year-olds and 0.8% in those older than 80 years. Visual impairment due to glaucoma had a prevalence of 0.7% among 60-year-olds and rose to 4% of those older than 90 years. The prevalence of visual impairment due to cataract (only present in those aged 70 years or older) rose from 0.6% to 11% in those older than 90 years, and the prevalence of visual impairment due to age-related macular degeneration rose from 0.8% to 16% in those older than 90 years.

CONCLUSIONS

The predominant causes of visual impairment change with age. Recognition of these patterns is fundamental for early diagnosis and treatment of eye disease and, where appropriate, referral for rehabilitation.

Vision impairment predicts five-year mortality

PURPOSE

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 3,271 participants, 231 (7.1%) were reported to have died in the intervening 5 years. Of the remaining 3,040 participants eligible to return for follow-up examinations, 2,594 (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 and cortical cataract were associated with a significantly increased risk of mortality, as were increasing age, male sex, increased duration of cigarette smoking, increased duration of hypertension, and arthritis.

CONCLUSIONS

Even mild visual impairment increases the risk of death more than twofold.

Utilisation of eyecare services in an urban population in southern India: the Andhra Pradesh eye disease study

AIM

To assess utilisation of eyecare services by people with visual impairment <6/18 or equivalent visual field loss in the better eye in the urban population of Hyderabad in southern India.

METHODS

2522 subjects of all ages, representative of the population of Hyderabad city, underwent a detailed interview and dilated examination as part of the population based Andhra Pradesh eye disease study. Subjects more than 15 years of age were interviewed regarding the use of eyecare services.

RESULTS

Of 250 subjects with presenting distance visual acuity <6/18 or equivalent visual field loss in the better eye, information on utilisation of eyecare services was available for 229 (91.6%). Of these 229 subjects, 44 (19%) had visual acuity <6/60 or equivalent visual field loss in the better eye, and 202 (88.2%) had noticed decrease in vision over the past 5 years. Multivariate analysis showed that this decrease in vision was noticed significantly less by subjects with refractive error as the cause of visual impairment (odds ratio 0.34, 95% confidence interval 0.12-0.93). Of the 229 subjects who were visually impaired, 108 (59%) did not seek treatment. Multivariate analysis revealed that the odds for seeking treatment were significantly lower for Hindus than Muslims (odds ratio 0.53, 95% confidence interval 0.28-0.98). The reasons for not seeking treatment could be classified as personal (49.5%), economic (30.8%), and social (19.6%).

CONCLUSION

A large proportion of subjects with visual impairment in this urban population in India did not seek treatment even after noticing decrease in vision. Projecting these data to the 155 million urban population >15 years of age in India, there may be 4.9 million (95% confidence interval 4.3-5.5 million) people in urban India who are not seeking treatment for their visual impairment even after noticing decrease in vision. These data suggest that efforts have to be made to better understand the reasons for this phenomenon so that optimal utilisation of the available eyecare services in urban India can be planned.

Management of diabetic retinopathy by Australian optometrists. Working Group on Evaluation of NHMRC Retinopathy Guideline Distribution. National Health and Medical Research Council

PURPOSE

To describe current practices related to the management of diabetic retinopathy by Australian optometrists.

SETTING AND METHODS

A two-page self-administered questionnaire was mailed to a random sample of 504 Australian optometrists. The survey included questions about the practice (such as size and location); current practice with regard to management of patients with diabetic retinopathy; barriers to use of dilating drops; and a number of patient scenarios related to screening, follow-up and treatment of diabetic retinopathy.

RESULTS

Completed questionnaires were returned by 407 of the 473 eligible optometrists (86%). They had been practising optometry between 1 and 50 years (median 14). Of the 243 optometrists who provided details about the location of their practices, 145 (37%) had at least one of their practices in a rural area. The estimated percentage of patients with diagnosed diabetes ranged from 0.5 to 40% (median = 5.0%). Three-hundred and twenty-two optometrists (79%) reported that they would often or almost always ask new patients over the age of 40 whether they have diabetes. The majority of optometrists (n = 387, 95%) would often or almost always ask their new patients with diabetes about their control of blood glucose levels and the majority of optometrists (n = 330, 81%) would often or almost always tell their patients with diabetes about the importance of strict glucose control in delaying retinopathy. The most common barrier to dilated ophthalmoscopy was patients not wanting to be dilated, with 38.1% of optometrists reporting this to be a moderate or major barrier. The next most common barrier was fear of precipitating angle closure glaucoma; 17.1% of optometrists reported this to be a moderate or major barrier

CONCLUSION

The National Health and Medical Research Council (NHMRC) guidelines for the management of diabetic retinopathy are timely in relation to the expressed desire of Australian optometrists to learn more about management of diabetic retinopathy These data will be used prospectively to assess changes in management of patients with diabetic retinopathy as a result of the release of the NHMRC guidelines.

Baseline ophthalmic findings in the vitamin E, cataract and age-related maculopathy (VECAT) study

PURPOSE

To describe the methodology of eye examination and the baseline eye characteristics of the Vitamin E, Cataract and Age-Related Maculopathy (VECAT) study participants.

METHODS

A sample of volunteers from an urban area of Melbourne, Australia, were recruited to participate in a randomized, controlled trial investigating the effect of vitamin E on the development of cataract and age-related maculopathy Standardized eye examinations involved clinical assessment, which included Wilmer grading of the lens, digital photography of the lens with Nidek EAS-1000 lens camera and stereo photography of the macular area with the Nidek 3-DX fundus camera. All cases of ophthalmic findings were determined on the basis of pathology in the worse eye.

RESULTS

Most eyes were free from abnormalities. The most frequent findings were cataract and age-related macular changes. Nuclear cataract (nuclear opacity grade >2) was present in 4.5%, cortical cataract (cortical opacity grade >2) in 14.3% and posterior subcapsular cataract in 3.0% of participants; in addition, coronary cataract was observed in 13.6%. Soft drusen larger than 125 pm were found in 11.4%, retinal pigment epithelium changes in 9.5%, epiretinal membrane in 6.6% and age-related macular degeneration in 0.5% of participants.

SUMMARY

Due to the selection criteria, the majority of participants had clear or minor lens changes and/or minor retinal age-related changes. Precise instrumental documentation will allow an accurate assessment of the incidence and dynamics of these changes throughout 4 years of observation.

Refractive errors in an urban population in Southern India: the Andhra Pradesh Eye Disease Study

PURPOSE

To assess the prevalence, distribution, and demographic associations of refractive error in an urban population in southern India.

METHODS

Two thousand five hundred twenty-two subjects of all ages, representative of the Hyderabad population, were examined in the population-based Andhra Pradesh Eye Disease Study. Objective and subjective refraction was attempted on subjects >15 years of age with presenting distance and/or near visual acuity worse than 20/20 in either eye. Refraction under cycloplegia was attempted on all subjects < or =15 years of age. Spherical equivalent >0.50 D in the worse eye was considered as refractive error. Data on objective refraction under cycloplegia were analyzed for subjects < or =15 years and on subjective refraction were analyzed for subjects >15 years of age.

RESULTS

Data on refractive error were available for 2,321 (92.0%) subjects. In subjects < or =15 years of age, age-gender-adjusted prevalence of myopia was 4.44% (95% confidence interval [CI], 2.14%-6.75%), which was higher in those 10 to 15 years of age (odds ratio, 2.75; 95% CI, 1.25-6.02), of hyperopia 59.37% (95% CI, 44.65%-74.09%), and of astigmatism 6.93% (95% CI, 4.90%-8.97%). In subjects >15 years of age, age-gender-adjusted prevalence of myopia was 19.39% (95% CI, 16.54%-22.24%), of hyperopia 9.83% (95% CI, 6.21%-13.45%), and of astigmatism 12.94% (95% CI, 10.80%-15.07%). With multivariate analysis, myopia was significantly higher in subjects with Lens Opacity Classification System HI nuclear cataract grade > or =3.5 (odds ratio, 9.10; 95% CI, 5.15-16.09), and in subjects with education of class 11 or higher (odds ratio, 1.80; 95% CI, 1.18-2.74); hyperopia was significantly higher in subjects > or =30 years of age compared with those 16 to 29 years of age (odds ratio, 37.26; 95% CI, 11.84-117.19), in females (odds ratio, 1.86; 95% CI, 1.33-2.61), and in subjects belonging to middle and upper socioeconomic strata (odds ratio, 2.10; 95% CI, 1.09-4.03); and astigmatism was significantly higher in subjects > or =40 years of age (odds ratio, 3.00; 95% CI, 2.23- 4.03) and in those with education of college level or higher (odds ratio, 1.73; 95% CI, 1.07-2.81).

CONCLUSIONS

These population-based data on distribution and demographic associations of refractive error could enable planning of eye-care services to reduce visual impairment caused by refractive error. If these data are extrapolated to the 255 million urban population of India, among those >15 years of age an estimated 30 million people would have myopia, 15.2 million hyperopia, and 4.1 million astigmatism not concurrent with myopia or hyperopia; in addition, based on refraction under cycloplegia, 4.4 million children would have myopia and 2.5 million astigmatism not concurrent with myopia or hyperopia.