Prevalence of diabetic macular oedema and related health and social care resource use in England.

AIMS: To address the absence from the public health ophthalmology literature of age- and sex-specific prevalence and related resource use for diabetic macular oedema (DMO) in England, UK. METHODS: Calculation of age- and sex-specific rates from primary source clinical data, and application to the demographic structure of England to estimate the number of cases affected by DMO. A public health commissioner and provider of social care perspective was adopted in a standard cost of illness study. RESULTS: The number of people with diabetes in England in 2010 was estimated at 2,342,951 of which 2,334,550 were aged ≥ 12 years. An estimated 166,325 (7.12%) had DMO in one or both eyes, and of these, 64,725 individuals had clinically significant DMO reducing the visual acuity to poorer than 6/6 in at least one eye. The overall health and social care costs in 2010, on the pathway from screening to rehabilitation and care in the home, are estimated at £116,296,038. CONCLUSIONS: The outcomes of this study should alert public health commissioners and clinical providers to the burden of DMO. The methods employed should also encourage the use of clinical ophthalmic data at the interface between local population and hospital-based recording systems.

Unmet needs for cataract surgery in Spain according to indication criteria. Evaluation through a simulation model.

AIMS: Despite the increase in cataract surgery rates, the volume of unmet needs for this type of surgery in the population is substantial due to ageing and widening of the indication criteria. Our objective was to assess future trends in needs for cataract surgery according to different scenarios of indication criteria. METHODS: A discrete-event simulation model was built for the population aged 50 years or older in five regions of Spain (45.7% of the population). Different scenarios of worse eye visual acuity thresholds for indication criteria were compared. Data from the North London Eye Study were used to project the baseline needs for surgery onto the study population. The surgery rate of each region was calculated using the Minimum Data Set. The model used data for the year 2003 and the simulation horizon was 5 years. RESULTS: The volume of need predicted for the year 2008 when scenarios of 0.5 (20/40) and 0.4 (20/50) visual acuity thresholds were used was 69,214 and 51,315 surgeries needed per million inhabitants, respectively. However, unmet needs decreased when a 0.3 (20/70) threshold was used. The increment in the cataract surgery rate needed to prevent the cataract backlog from increasing was 60% for a 0.5 threshold and 50% for a 0.4 threshold. CONCLUSION: Application of indication criteria following current guidelines would substantially increase unmet needs for surgery in the next 5 years.

Childbearing and risk of cataract in young women: an epidemiological study in central India.

BACKGROUND/AIMS: Observations in central India, over a period of more than a decade, suggested that the frequency of sight restoring cataract surgery was substantially higher in women of childbearing age compared to men of the same age. Formal surveys in the subcontinent of India have confirmed a higher prevalence of cataract in women. The present study was conducted to explore possible effects of childbearing and associated adverse factors on cataract risk. METHODS: A case-control study design was used. Cases were mothers aged 35-45 with bilateral "senile" cataract. Controls were mothers of the same age but with clear lenses, attending the hospital services with other, mostly minor, complaints. RESULTS: A significant association was found between childbearing and risk of sight impairing cataract in mothers. Having more than three babies doubled the risk (adjusted odds ratio 2.0, p=0.012), and the risk increased by an estimated 20% for each additional birth. The birth effect was independent of age, socioeconomic status (occupation and income level), body mass index, and multiple episodes of severe dehydration, all regarded as putative risk factors for cataract. CONCLUSIONS: Having more than three babies may substantially increase the risk of sight impairing cataract in mothers of childbearing age in central India. The findings open new research challenges to identify cataract risk factors to which mothers may be exposed during pregnancy and childbirth, particularly under poor socioeconomic conditions.

Increased mortality in women with cataract: a population based follow up of the North London Eye Study.

BACKGROUND/AIMS: In diabetics, cataract is associated with higher risk of death. In non-diabetics the data are conflicting, but some indicate an association between one type of cataract (nuclear) and increased mortality. The aim of this study was to estimate and compare age and sex specific mortality for elderly people with and without cataract in a population based cohort. METHODS: A random sample drawn from a defined population of elderly people (age 65 and older) registered with 17 general practice groups in north London formed the study cohort and were followed up for 4 years. The age and sex specific mortality from various causes was estimated and compared in those with and without cataract. RESULTS: In non-diabetics (n=1318), cataract (lens opacity at baseline) was significantly associated with higher mortality in women. The age standardised death rate per 1000 was 39.8 and 24.8 in women with and without cataract, respectively (age adjusted hazard ratio 1.7, confidence limits 1.1 to 2.7, p=0.032). This was not the case in non-diabetic men (hazard ratio 0.9, confidence limits 0.6 to 1.5, p=0.782). The excess mortality in women with cataract was consistent for cardiovascular, respiratory, and other non-cancer causes of death. There was no association between cataract and mortality from cancer. CONCLUSIONS: This study has shown, for the first time, that cataract is associated with higher mortality in women but not in men, among the non-diabetic population. This sex effect suggests that women may be exposed to risk factors that increase both the risk of cataract and mortality, and that men may have little or no exposure to these "sex specific" factors. Possible risk factors that warrant further investigation may be those associated with some pregnancy and childbearing experience.

Extracapsular cataract extraction compared with small incision surgery by phacoemulsification: a randomised trial.

BACKGROUND: Cataract extraction constitutes the largest surgical workload in ophthalmic units throughout the world. Extracapsular cataract extraction (ECCE), through a large incision, with insertion of an intraocular lens has been the most widely used method from 1982 until recently. Technological advances have led to the increasing use of phacoemulsification (Phako) to emulsify and remove the lens The technique requires a smaller incision, but requires substantial capital investment in theatre equipment. In this randomised trial we assessed the clinical outcomes and carried out an economic evaluation of the two procedures. METHODS: In this two centre randomised trial, 232 patients with age related cataract received ECCE, and 244 received small incision surgery by Phako. The main comparative outcomes were visual acuity, refraction, and complication rates. Resource use was monitored in the two trial centres and in an independent comparator centre. Costs calculated included average cost per procedure, at each stage of follow up. RESULTS: Phako was found to be clinically superior. Surgical complications and capsule opacity within 1 year after surgery were significantly less frequent, and a higher proportion achieved an unaided visual acuity of 6/9 or better (<0.2 logMAR) in the Phako group. Postoperative astigmatism was more stable in Phako. The average cost of a cataract operation and postoperative care within the trial was similar for the two procedures. With the input of additional spectacles for corrected vision at 6 months after surgery, the average cost per procedure was pound359.89 for Phako and pound367.57 for ECCE. CONCLUSION: Phako is clinically superior to ECCE and is cost effective.

Utility of predictive equations for estimating the prevalence and incidence of primary open angle glaucoma in the UK.

AIMS: To assess the Tuck-Crick and the Quigley-Vitale predictive regression equations against fresh independent real world data for estimating the prevalence of primary open angle glaucoma (POAG) in the UK. To apply the equations to the elderly population of England and Wales, for which there is sample survey data on glaucoma, and demographic data. METHODS: Directly measured actual prevalence of POAG in a population sample of 1530 people was compared with the predicted prevalence derived by applying the Tuck-Crick and the Quigley-Vitale equations to the sample data. The two equations were applied to the demographic data of the population to project POAG prevalence and to derive 5 year cumulative incidence for the elderly population. These were compared with estimates derived from the local survey data. RESULTS: The actual directly measured prevalence of POAG in the local sample was 3.01%. The Tuck-Crick estimate was 2. 74% (difference 0.27%), and the Quigley-Vitale was 3.50% (difference -0.49%). The three methods-projection from local survey data, Tuck-Crick, and Quigley-Vitale-gave point estimates of 2.85% (228 526 cases), 2.71% (217 375 cases), and 3.50% (280 364 cases) respectively for the prevalence of POAG in the elderly population of England and Wales (8 008 705 people aged 65 or older). Calculation of incidence from age specific prevalence gave the following results: the numbers of new cases of POAG expected (5 year cumulative incidence) in the elderly population were 71 146 and 94 485 for methods 2 and 3 respectively. CONCLUSIONS: The Tuck-Crick predictive equation performed well when applied to fresh (independent) actual data from a local sample survey using a particular definition for POAG, and its usefulness for estimation of prevalence of POAG in England and Wales has been demonstrated. The work on development of predictive equations has been very promising and further refinements could be made when more fresh survey data become available.

The deficit in cataract surgery in England and Wales and the escalating problem of visual impairment: epidemiological modelling of the population dynamics of cataract.

BACKGROUND: The pool of old cases of cataract, the expected new cases, and the shortfall in cataract surgery and consequently the numbers dying with poor vision without the benefit of cataract surgery are regarded as escalating problems worldwide. Successive governments and the professional ophthalmic bodies have not had the wherewithal to estimate the magnitude or interaction of these elements in the population of the UK. This study has collected and applied the best available epidemiological data on cataract prevalence, incidence and service utilisation, and demography to address the problem of control of the cataract pool in the population of England and Wales. METHODS: Data from recent surveys undertaken by the authors, both on prevalence of vision impairing cataract and on patterns of cataract surgery, were used together with demographic and service utilisation information obtained from government departments. These were integrated within a holistic model, which was run under varied assumed levels and patterns of service provision. RESULTS: The study shows that there is a serious pool of unoperated vision impairing cataract in the population aged 65 and older, reflecting a shortfall in cataract surgery. Continuing with the present level and pattern of service provision, the pool will increase to over 2.5 million by the year 2001. In addition, more than 700 000 will die with unoperated impaired vision. CONCLUSIONS: Targeting of existing or new additional operations to those below the visual acuity of 6/12 will have relatively little effect on numbers dying without surgery, but should have a substantial controlling effect on the pool of vision impairing cataract in the population.

National cataract surgery survey 1997-8: a report of the results of the clinical outcomes.

AIMS: A national survey of over 100 hospitals in the UK was carried out to collect routine clinical information on the outcomes of cataract surgery. The clinical outcomes of interest were: visual acuity at time of discharge from postoperative hospital follow up, visual acuity at time of final refraction; complications related to surgery occurring during the operation, within 48 hours of surgery, and within 3 months of surgery. In addition, information on age and comorbidity was obtained. This article reports on the findings of the experience of approximately 18 000 patients who had cataract surgery in the hospital eye service of the NHS. RESULTS: Of those with no ocular comorbidity, 85% achieved a visual acuity of 6/12 or better on discharge from postoperative hospital follow up, while 65% of patients with a serious co-existing eye disease achieved this level of acuity at this time. At final refraction, 92% of patients without ocular comorbidity and 77% of patients with ocular comorbidity achieved 6/12 or better visual acuity. The following main risk indicators were associated with visual outcomes and complications related to surgery: age, other eye diseases, diabetes and stroke, type of surgical procedure, and grade of surgeon. CONCLUSIONS: The acceptability of these findings could fruitfully be the subject of discussion within the ophthalmic community and hopefully issues arising out of the study can lead to research, especially in-depth studies of the outcomes of cataract surgery in those patients with co-existing serious eye conditions.

Profile of patients presenting for cataract surgery in the UK: national data collection.

AIMS/METHODS: A national data collection exercise was carried out in more than 100 hospital eye service units within the UK to provide clinical and administrative information on patients undergoing cataract surgery. This included patient clinical data such as visual acuity at the time of wait listing and at the time of admission for surgery, presence of other eye disorders, other serious medical disorders, and data on waiting time and type of admission. RESULTS: The profiles of the 18 454 patients aged 50 years or older are reported. Findings of particular note were as follows. At the time of wait listing for cataract surgery 31% had visual acuity of 6/12 or better, 54% had visual acuity between 6/18 and 6/60, and 15% had less than 6/60 vision. Considering those who had visual acuity of 6/12 or better at the time of wait listing, by the time of admission for surgery, the vision deteriorated to 6/18-6/60 in 33% and in a further 3% the vision deteriorated to below 6/60. In patients with moderately poor visual acuity (<6/12-6/60) at the time of wait listing, 13% had less than 6/60 vision by the time of admission for surgery. CONCLUSION: This type of data collection and reporting exercise provides new material that can be used in the planning and provision of cataract surgery services in the UK.

Impaired motion sensitivity as a predictor of subsequent field loss in glaucoma suspects: the Roscommon Glaucoma Study.

AIM: To determine if impaired motion sensitivity is a significant predictor of subsequent field loss in glaucoma suspects. METHOD: A population based prospective study; a 5 year follow up of all glaucoma suspects who had been identified from a population based random sample survey in the west of Ireland. 78 glaucoma suspects whose visual field function was annually measured by Henson CFS 2000 and for whom data on family history of glaucoma, ocular status, and motion impairment had been recorded. Visual field loss was defined as Henson visual field survival score of 94 or less. RESULTS: 18 people developed visual field loss in at least one eye. Motion impairment at baseline was associated with a 2-18 times greater risk of development of the visual field loss (p < 0.001). This association was independent of sex, family history of glaucoma, intraocular pressure, and C/D ratio at baseline. The Cox's proportional hazards regression analysis confirmed the above results after adjustment for age and the C/D ratio. CONCLUSION: Motion impairment is an independent predictor of visual field loss in glaucoma suspects, although it is not clear how long motion impairment precedes visual field loss.

Prevalence of serious eye disease and visual impairment in a north London population: population based, cross sectional study.

OBJECTIVE: To estimate the magnitude of serious eye disorders and of visual impairment in a defined elderly population of a typical metropolitan area in England, and to assess the frequency they were in touch with, or known to, the eye care services. DESIGN: Cross sectional survey using two stage cluster random sampling. SETTING: General practices in north London. SUBJECTS: Random sample of people aged 65 and older, drawn from a defined population of elderly people registered with 17 general practice groups. MAIN OUTCOME MEASURES: Proportions and population prevalence estimates were determined for visual acuity, assessed with the person's own spectacles (if any), classified into four categories: prevalence of cataract, age related macular degeneration, and refractive error causing visual impairment and of definite primary open angle glaucoma; and status of contact with eye services. RESULTS: 1547 of 1840 (84%) eligible people were examined. The population prevalence of bilateral visual impairment (visual acuity <6/12) was 30%, of which 72% was potentially remediable. 92 of these 448 cases (21%) had visual acuity <6/60 ("blindness") in one or both eyes. Prevalence of cataract causing visual impairment was 30%; 88% of these people were not in touch with the eye services. The prevalence of vision impairing, age related macular degeneration was 8% and of glaucoma (definite cases) was 3%. Three quarters of the people with definite glaucoma were not known to the eye services. CONCLUSIONS: Untreated visual impairment and eye disorders affect a substantial proportion of people aged 65 years and older. These findings should contribute to the setting up of future strategies for preservation of sight and eye health services in general.

Gains from cataract surgery: visual function and quality of life.

AIMS: To describe the impact of cataract surgery in terms of visual function (functioning in everyday life with respect to vision dependent activities) and health related quality of life. METHODS: An observational, longitudinal study of patients undergoing cataract surgery was carried out at three district general hospitals in outer London districts of North Thames Region with follow up at 4 and 12 months postoperatively for a clinical assessment and a standardised administered interview. Patients were admitted for surgery to the first eye for age-related cataract between 1 May 1993 and 31 August 1994. Visual functioning was assessed by the VF-14, health related quality of life was assessed by the sickness impact profile (SIP), and vision related quality of life was assessed by VR-SIP (a modification of the generic SIP). RESULTS: Significant gains in all the outcome measures were demonstrated at 4 months postoperatively. No significant change (gain or loss) was observed between 4 and 12 months after surgery to the first eye. Postoperatively, the mean visual function (VF-14) scores, and health related (SIP) and vision related (VR-SIP) quality of life scores, indicated less reported trouble with vision dependent activities and better perceived quality of life, respectively. The average gains in visual function and quality of life (health and vision related) were apparent in groups with good visual outcome and poor visual outcome. Significant additional gains were seen at 1 year in patients who had second eye surgery in the interval between the postoperative assessments. CONCLUSIONS: Gains in visual functioning and quality of life (health and vision related) have been demonstrated following cataract surgery. These gains were sustained at 1 year after surgery to the first eye, with additional gains being conferred if second eye surgery had been performed. Assessment of the outcomes of cataract surgery by clinical indicators alone may underestimate the overall benefits of surgery, particularly in patients with poor visual outcome.

Prevalence of glaucoma in the west of Ireland.

County Roscommon in the west of Ireland is a relatively remote rural area whose population of 55,000 is served by two community medical ophthalmologists and three optometrists. Eye surgical services are not available within the county. In order to assess the needs of the community for prevention of blindness from glaucoma, a simple random sample of the population of County Roscommon was taken for a community based glaucoma survey. A total of 2186 people over the age of 50 were examined which represented a 99.5% response rate. The high response rate was achieved by the community basis of the study and vigorous follow up of non-attenders. Intraocular pressure was measured using applanation tonometry, disc evaluation by both direct ophthalmoscopy and stereoscopic biomicroscopy, and visual field analysis using the Henson CFS 2000 and experimental computer controlled video perimetry. Diagnostic criteria were consistent with the preferred practice pattern of the American Academy of Ophthalmology. A crude prevalence of approximately 2% for primary open angle and normal tension glaucoma was found. The population profile of intraocular pressure showed a pattern which decreased with increasing age unlike the Framingham and Ferndale studies but similar to Japanese data.

Outcome of cataract surgery in central India: a longitudinal follow-up study.

An epidemiological follow-up study of patients who had intracapsular cataract extraction in a voluntary hospital and its associated eye camps in Central India has for the first time evaluated the outcome one year after surgery in terms of visual acuity, use of spectacles, and improvement in income and mobility. The findings indicate that under these fairly typical conditions, 92% of the cases have adequate vision of 6/18 or better one year after surgery. Information on high usage of spectacles and on considerable improvements in income and mobility after cataract surgery is also reported. The outcome for patients operated upon in eye camps was almost as favourable as for those operated upon in hospital. Although the small differences are not statistically significant, the comparative findings require cautious interpretation and give rise to the epidemiological issues which are briefly discussed in this paper.

Questioning the status quo: sickness absence research so far claims more than it should!

This article is in the nature of a cautionary tale for those working alongside any group of medics who are required to collect epidemiological data, or plan based upon data collected by medical experts without having access to that data. The field of work is occupational health and the specialised area is the relationship between socio-economic variables and absence from work due to sickness. The over-riding criticism of the sickness absence literature to date is that the use of analytical statistics is poor or in most cases almost non-existent and that there is very little understanding of the epidemiological concepts of 'confounding' and 'effect modification'. An example is given of one particular statistical procedure, multi-variate hierarchical log-linear modelling, which if used by future researchers could prevent the recurrence of some of the previous problems.

Working with mothers for change.

PIP: An evaluation of the effectiveness of teaching mothers how to prevent childhood blindness was made in the Raipur District of Madhya Pradesh, India. Of the district's 700,000 inhabitants, 1/2 live in poorly housed urban areas. Adult females in all 270 houses in 1 urban slum were interviewed twice. They were asked the same questions in April 1985, and 18 months later in September 1986. During this period of time, each family was visited twice each month, and trained in the general health of mother and child. Each child was weighed once a month, and had his eyes examined. In the training, specific emphasis was given to breastfeeding and its timing, early infant feeding practice and introduction of semi-solids and vegetables, diarrhea and oral rehydration therapy, the implication of night blindness, the role of vitamin A, and also immunization. The basis for the teaching was the Road to Health Chart. For the post-teaching survey a new worker was introduced to increase objectivity. The evaluation of impact of this training shows an improvement in the answers. Some mothers appear more aware of their child's needs. 30% of them recognize breastfeeding as important from the 1st day, know that semi-solids should be introduced early, show some understanding of oral rehydration therapy for diarrhea (20%), of the interest of suitable foods to remedy night blindness (14%), and of the value of immunization. This progress in awareness, if not of the actual practice, leaves hopes that, in time, child care will be improved markedly.^ieng

Some haematological data on pregnant Gurkha women.

In a retrospective survey of 285 pregnancies in Gurkha women living in the New Territories of Hong Kong, the mean values of Haemoglobin, Mean Cell Volume and Mean Cell Haemoglobin Concentration were examined with the aim of establishing basic data.

Marxist functionalism in medicine: a critique of the work of Vicente Navarro on health and medicine.

A detailed examination is made of the writings of Vicente Navarro dealing with health and medicine. Following a statement of criticisms these are examined in detail with reference to sources. The paper concludes with a review of Navarro's writing on Chile which is seen as an example of how a specific brand of deterministic functionalism can be reinforced by a particular political experience.