D C Minassian

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.

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.

Incidence of cases of ocular trauma admitted to hospital and incidence of blinding outcome.

AIMS: To provide epidemiological data on the current burden of serious eye injuries utilising the hospital eye service, to inform the planning and provision of eye health care, and health and safety strategies for the prevention of ocular injuries. METHODS: A prospective observational study was carried out of all patients with ocular trauma admitted to hospitals in Scotland, under the care of a consultant ophthalmologist, during a 1 year period. The population of Scotland represented the population at risk of injury. Visual outcome (Snellen visual acuity in the injured eye) was measured at the time of final discharge from ophthalmic care and at follow up. RESULTS: All ophthalmic departments in Scotland participated and a total of 415 residents of Scotland were admitted. The 1 year cumulative incidence of ocular trauma necessitating admission to hospital is estimated to be 8.14 per 100 000 population (95% CI 7.38 to 8.97). Some 13.2% (n = 26/197) of patients discharged from follow up had a poor visual outcome with a visual acuity less than 6/12 in the injured eye. Some 10.7% (21/197) patients at this time had a blinding outcome in the injured eye (visual acuity less than 6/60). No patient was registered blind or partially sighted during the study period. The home was the single most frequent place for blinding injuries to occur (52%, n = 11/21), followed by the workplace 24% (n = 5/21). The 1 year cumulative incidence of blinding outcome from serious ocular trauma is estimated to be 0.41 per 100 000 population per year (95% CI 0.26 to 0.64). CONCLUSION: The current burden of serious ocular trauma presenting to the hospital eye service has been quantified from this population based study, and for the first time, a direct estimate of the incidence of the subsequent blinding outcome from these injuries has been provided. Ocular trauma remains an important cause of avoidable and, predominantly, monocular visual morbidity (visual impairment and blindness), with over half of the blinding injuries now occurring in the home. Health education and safety strategies should now consider targeting the home for the prevention of the serious eye injuries in addition to the traditional work, sports, and leisure environments and their related activities.

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.

Epidemiology and implications of ocular trauma admitted to hospital in Scotland.

OBJECTIVES: To describe the current epidemiology of serious ocular trauma which necessitates admission to hospital so that health and safety strategies for the prevention of ocular injuries and their role within the national health strategy, The Health of the Nation, can be better informed. DESIGN: A prospective observational study of all patients with ocular trauma admitted to hospital under the care of a consultant ophthalmologist between 1 November 1991 and 31 October 1992. SETTING: All ophthalmic department in Scotland. SUBJECTS: All patients with ocular trauma admitted to hospital in Scotland. The population of Scotland represented the population at risk of injury. MEASURES AND MAIN RESULTS: Measures included the type and cause of injury, the place where it occurred, and awareness of risk and safety. All ophthalmic departments in Scotland participated and 428 admissions were reported. The home was the most common place for a serious injury to occur (30.2%), followed by the workplace (19.6%) and a sports or leisure facility (15.8%). The home was the single most frequent place of injury for the 0-15 year and 65 year and over age groups. Tools or machinery, either at home (13.9%) or at work (10.3%), were collectively (24.2%) the most frequent cause of injury, followed by assault (21.8%) and sports-related activities (12.5%). The most frequent type of injury was a blunt injury (54.4%). Six per cent (n = 25) of all injuries were bilateral. Only 13.2% of patients were aware of any risk of injury, with 5.6% aware of any risk at home. When applicable, protective eye wear was only available to 48.6% of patients and only 19.4% of these used it. CONCLUSION: Serious ocular trauma frequently occurs at home and the young and the elderly are particularly at risk. This represents a significant change in the epidemiology of serious ocular trauma and has important implications for prevention. Health and safety strategies specifically aimed at preventing eye injury should now include the home as a high risk environment in addition to the work-place and sports/leisure facilities. The target groups for accident prevention in The Health of the Nation strategy include those at risk of serious ocular trauma with potentially sight threatening sequelae. Those involved in implementing the national accident prevention strategy should be aware of this, for in this process it is possible that some serious eye injuries may also be prevented.

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.

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.

Number of incident cases of the main eye diseases of ageing in the UK Biobank cohort, projected over a 25 year period from time of recruitment

Objectives To estimate the number of new cases of age-related macular degeneration, cataract and glaucoma accruing in the UK Biobank cohort, over a period of 25 years from time of recruitment. Our secondary objective was to assess the statistical power of nested case–control studies of these eye diseases. We aimed to provide quantitative information relevant to UK Biobank’s eye disease case ascertainment efforts and to the potential for UK Biobank-based research into the causes of eye disease. Methods We constructed a Markov discrete-time state transition model to simulate the population dynamics of the eye disorders within the UK Biobank cohort, using prevalence data from population-based epidemiological studies to derive incidence, and Office for National Statistics data on mortality and migration overseas. Results By 2023, >900 new cases of each of ‘wet’ (neovascular) and ‘dry’ age-related macular degeneration, >1200 cases of primary open angle glaucoma and almost 15 000 cases of cataracts are expected to have accrued in the subcohort of 68 500 participants who had ocular assessment at baseline, with around seven times as many cases of each disease in the whole cohort of 500 000 participants. These predicted incident case numbers generate good or substantial statistical power for a range of nested case–control studies of potential genetic, lifestyle and environmental determinants of disease. Conclusions Over the next few years, UK Biobank is expected to generate sufficient numbers of new cases for statistically well-powered studies of the determinants of the major causes of sight loss: age-related macular degeneration, vision-impairing cataract and glaucoma.