Objectives

To examine and interpret the variation in the incidence of blindness and sight impairment in England by PCT, as reported by the Certificate of Vision Impairment (CVI).

Design

Analysis of national certification data.

Setting

All Primary Care Trusts, England.

Participants

23 773 CVI certifications issued from 2008 to 2009.

Main Outcome measures

Crude and Age standardised rates of CVI data for blindness and sight loss by PCT.

Methods

The crude and age standardised CVI rates per 100 000 were calculated with Spearman's rank correlation used to assess whether there was any evidence of association between CVI rates with Index of Multiple Deprivation (IMD) and the Programme Spend for Vision.

Results

There was high-level variation, almost 11-fold (coefficient of variation 38%) in standardised CVI blindness and sight impairment annual certification rates across PCTs. The mean rate was 43.7 and the SD 16.7. We found little evidence of an association between the rate of blindness and sight impairment with either the IMD or Programme Spend on Vision.

Conclusions

The wide geographical variation we found raises questions about the quality of the data and whether there is genuine unmet need for prevention of sight loss. It is a concern for public health practitioners who will be interpreting these data locally and nationally as the CVI data will form the basis of the public health indicator ‘preventable sight loss’. Poor-quality data and inadequate interpretation will only create confusion if not addressed adequately from the outset. There is an urgent need to address the shortcomings of the current data collection system and to educate all public health practitioners.

Background

UK estimates of age related macular degeneration (AMD) occurrence vary.

Aims

To estimate prevalence, number and incidence of AMD by type in the UK population aged ≥50 years.

Methods

Age-specific prevalence rates of AMD obtained from a Bayesian meta-analysis of AMD prevalence were applied to UK 2007–2009 population data. Incidence was estimated from modelled age-specific prevalence.

Results

Overall prevalence of late AMD was 2.4% (95% credible interval (CrI) 1.7% to 3.3%), equivalent to 513 000 cases (95% CrI 363 000 to 699 000); estimated to increase to 679 000 cases by 2020. Prevalences were 4.8% aged ≥65 years, 12.2% aged ≥80 years. Geographical atrophy (GA) prevalence rates were 1.3% (95% CrI 0.9% to 1.9%), 2.6% (95% CrI 1.8% to 3.7%) and 6.7% (95% CrI 4.6% to 9.6%); neovascular AMD (NVAMD) 1.2% (95% CrI 0.9% to 1.7%), 2.5% (95% CrI 1.8% to 3.4%) and 6.3% (95% CrI 4.5% to 8.6%), respectively. The estimated number of prevalent cases of late AMD were 60% higher in women versus men (314 000 cases in women, 192 000 men). Annual incidence of late AMD, GA and NVAMD per 1000 women was 4.1 (95% CrI 2.4% to 6.8%), 2.4 (95% CrI 1.5% to 3.9%) and 2.3 (95% CrI 1.4% to 4.0%); in men 2.6 (95% CrI 1.5% to 4.4%), 1.7 (95% CrI 1.0% to 2.8%) and 1.4 (95% CrI 0.8% to 2.4%), respectively. 71 000 new cases of late AMD were estimated per year.

Conclusions

These estimates will guide health and social service provision for those with late AMD and enable estimation of the cost of introducing new treatments.

Introduction

Glaucoma is characterised by progressive optic neuropathy and peripheral visual field loss. It affects 1% to 2% of white people aged over 40 years and accounts for 8% of new blind registrations in the UK. The main risk factor for glaucoma is raised intraocular pressure, but 40% of people with glaucoma have normal intraocular pressure and only 10% of people with raised intraocular pressure are at risk of optic-nerve damage. Glaucoma is more prevalent, presents earlier, and is more difficult to control in black people than in white populations.

Methods and outcomes

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for established primary open-angle glaucoma, ocular hypertension, or both? What are the effects of lowering intraocular pressure in people with normal-tension glaucoma? What are the effects of treatment for acute angle-closure glaucoma? We searched: Medline, Embase, The Cochrane Library, and other important databases up to November 2007 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

Results

We found 20 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

Conclusions

In this systematic review we present information relating to the effectiveness and safety of the following interventions: laser trabeculoplasty (alone or plus topical medical treatment); topical medical treatments; and surgical trabeculectomy.

Key Points

Glaucoma is characterised by progressive optic neuropathy and peripheral visual field loss. It affects 1% to 2% of white people aged over 40 years and accounts for 8% of new blind registrations in the UK. The main risk factor for glaucoma is raised intraocular pressure (IOP), but up to 40% of people with glaucoma have normal IOP and only about 10% of people with raised IOP are at risk of optic-nerve damage.Glaucoma is more prevalent, presents earlier, and is more difficult to control in black people (especially those of West African descent) than in white populations.Blindness from glaucoma results from gross loss of visual field or loss of central vision and, when the optic nerve is vulnerable, can progress quickly without treatment.

Lowering IOP by laser trabeculoplasty plus topical medical treatment may be more effective at reducing progression of glaucoma in people with primary open-angle or pseudoexfoliation glaucoma, compared with no treatment.

Topical medical treatment may reduce the risk of developing glaucoma in people with ocular hypertension compared with placebo.

We don't know whether topical medical treatment, laser trabeculoplasty, orsurgical trabeculectomyare more effective at maintaining visual fields and acuity in primary open-angle glaucoma. Surgery may increase the risk of developing cataracts.

We don't know whether reducing IOP with medical treatment alone or in combination with other treatments including surgery is more effective than no treatment at reducing progression of visual field loss in people with normal-tension glaucoma.

There is a consensus that medical and surgical treatments are beneficial in people with acute angle-closure glaucoma, although we don't know this for sure because it is unethical to withhold pressure-lowering treatment.

Should mass distribution of azithromycin be in topical rather than oral formulation?

Why the term “blinding” should not be used in clinical trials

Background

The use of self-report questionnaires to substitute for visual acuity measurement has been limited. We examined the association between visual impairment and self reported visual function in a population sample of older people in the UK.

Methods

Cross sectional study of people aged more than 75 years who initially participated in a trial of health screening. The association between 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ) scores and visual impairment (defined as an acuity of less than 6/18 in the better eye) was examined using logistic regression.

Results

Visual acuity and NEI-VFQ scores were obtained from 1807 participants (aged 77 to 101 years, 36% male), from 20 general practices throughout the UK. After adjustment for age, gender, practice and NEI-VFQ sub-scale scores, those complaining of poor vision in general were 4.77 times (95% CI 3.03 to 7.53) more likely to be visually impaired compared to those who did not report difficulty. Self-reported limitations with social functioning and dependency on others due to poor vision were also associated with visual impairment (odds ratios, 2.52, 95% CI 1.55 to 4.11; 1.73, 95% CI 1.05 to 2.86 respectively). Those reporting difficulties with near vision and colour vision were more likely to be visually impaired (odds ratios, 2.32, 95% CI 1.30 to 4.15; 2.25, 95% CI 1.35 to 3.73 respectively). Other NEI-VFQ sub-scale scores were unrelated to measures of acuity. Similar but weaker odds ratios were found with reduced visual acuity (defined as less than 6/12 in the better eye). Although differences in NEI-VFQ scores were small, scores were strongly associated with visual acuity, binocular status, and difference in acuity between eyes.

Conclusion

NEI-VFQ questions regarding the quality of general vision, social functioning, visual dependency, near vision and colour vision are strongly and independently associated with an objective measure of visual impairment in an elderly population.

Background

Prevention of visual impairment is an international priority agreed at the World Health Assembly of 2002- yet many countries lack contemporary data about incidence and causes from which priorities for prevention, treatment and management can be identified.

Methods

Registration as blind or partially-sighted in England and Wales is voluntary and is initiated by certification by a consultant ophthalmologist. From all certificates completed during the year April 1999 to March 2000, the main cause of visual loss was ascertained where possible and here we present information on the leading causes observed and comment on changes in the three leading causes since the last analysis conducted for 1990–1991 data.

Results

13788 people were certified as blind, 19107 were certified as partially sighted. The majority of certifications were in the older age groups. The most commonly recorded main cause of certifications for both blindness (57.2 %) and partial sight (56 %) was degeneration of the macula and posterior pole which largely comprises age-related macular degeneration. Glaucoma and diabetic retinopathy were the next most commonly recorded main causes. Overall, the age specific incidence of all three leading causes has increased since 1990–1991 – with changes in diabetic retinopathy being the most marked – particularly in the over 65's where figures have more than doubled.

Conclusion

The numbers of individuals per 100,000 population being certified blind or partially sighted due to the three leading causes – AMD, diabetic retinopathy and glaucoma have increased since 1990. This may to some extent be explained by improved ascertainment. The process of registration for severe visual impairment in England and Wales is currently undergoing review. Efforts must be made to ensure that routine collection of data on causes of severe visual impairment is continued, particularly in this age of improved technology, to allow such trends to be monitored and changes in policy to be informed.

Background

There has been debate about the cost-effectiveness of photodynamic therapy (PDT), a treatment for neovascular age-related macular degeneration. We have been monitoring trends for the provision of PDT in the UK National Health Service. The fourth annual 'tracker' survey took place as definitive National Institute for Clinical Excellence (NICE) guidance was issued. We assessed trends in PDT provision up to the point of release of the NICE guidance and identified likely sources of pressure on ophthalmologists to provide PDT.

Methods

National postal questionnaire survey of clinicians with potential responsibility for PDT provision. The survey explored reported local provision, beliefs about the effectiveness of PDT and what sources of opinion might influence attitudes towards providing PDT.

Results

The response rate was 73% (111/150). Almost half of the surveyed ophthalmology units routinely provided PDT, as part of a trend of steady growth in provision. The proportion of respondents who believed that further proof of effectiveness was required has also declined despite the absence of any new substantial evidence. Attitudes towards providing PDT were positive, on average, and were more strongly associated with perceived social pressure from local colleagues than from other sources. Local colleagues were seen as being most approving of PDT.

Conclusion

Those responsible for implementing the NICE guidance need to address ophthalmologists' beliefs about the evidence of effectiveness for PDT and draw upon supportive local individuals or networks to enhance the credibility of the guidance.

Objective To determine the effectiveness of screening for visual impairment in people aged 75 or over as part of a multidimensional screening programme.

Design Cluster randomised trial.

Setting General practices in the United Kingdom participating in the MRC trial of assessment and management of older people in the community.

Participants 4340 people aged 75 years or over randomly sampled from 20 general practices, excluding people resident in hospitals or nursing homes.

Intervention Visual acuity testing and referral to eye services for people with visual impairment. Universal screening (assessment and visual acuity testing) was compared with targeted screening, in which only participants with a range of health related problems were offered an assessment that included acuity screening.

Main outcome measures Proportion of people with visual acuity less than 6/18 in either eye; mean composite score of 25 item version of the National Eye Institute visual function questionnaire.

Results Three to five years after screening, the relative risk of having visual acuity < 6/18 in either eye, comparing universal with targeted screening, was 1.07 (95% confidence interval 0.84 to 1.36; P = 0.58). The mean composite score of the visual function questionnaire was 85.6 in the targeted screening group and 86.0 in the universal group (difference 0.4, 95% confidence interval -1.7 to 2.5, P = 0.69).

Conclusions Including a vision screening component by a practice nurse in a pragmatic trial of multidimensional screening for older people did not lead to improved visual outcomes.

Objective

To identify socioeconomic risk factors for first presentation advanced glaucomatous visual field loss.

Design

Hospital based case-control study with prospective identification of patients.

Setting

Three hospital eye departments.

Participants

Consecutive patients newly diagnosed with glaucoma (n=220). Cases (late presenters) were those presenting with advanced glaucoma (n=110), controls were those with early glaucoma (n=110).

Results

Median underprivileged area scores were higher among late presenters (29.5; interquartile range 9.0-42.2) than in the control group (21.3; 6.1-37.4) (P=0.035). Late presenters were more likely to be of lower occupational class (odds ratio adjusted for age and referral centre 20.1 (95% confidence interval 2.6 to 155) for group III compared with group I-II and 86.0 (11.0 to 673 for group IV-V compared with group I-II), to have no access to a car (2.2; 1.2 to 4.0), to have left full time education at age 14 or less (7.5; 2.3 to 24.7), and to be tenants rather than owner occupiers (local authority tenants 3.2; 1.7 to 5.8, private tenants 2.1; 0.7 to 5.8). Effects of deprivation were partly accounted for by family history of glaucoma, time since last visit to an optometrist, and lack of an initial diagnosis of glaucoma by an optometrist.

Conclusions

Area and individual level deprivation were both associated with late presentation of glaucoma. Existing evidence shows that late presentation is an important risk factor for subsequent blindness. Deprived groups thus seem to be at greater risk of going blind from glaucoma. Material deprivation may be associated with more aggressive disease as well as later presentation.