MRC Centre of Epidemiology for Child Health

Childhood eye conditions and visual impairment

Understanding of the prevalence and types of visual impairment in a population provides useful information for planning the distribution of the required medical, social and educational services. Using parental report of diagnosed eye conditions and other chronic illnesses, we investigated the prevalence and distribution of eye conditions, specifically strabismus, and visual impairment and their associations with social and biological factors, in a contemporary population of children, at age 3, participating in the UK Millennium Cohort Study (MCS).

Study Team: Jugnoo Rahi (PI and Principal contact), Phillippa Cumberland

Life course influences on visual impairment

Short-sightedness (myopia), far-sightedness (hypermetropia) and astigmatism, all forms of refractive error, comprise the most common eye conditions worldwide. Research using data from the 1958 Birth Cohort has been used to investigate how biological, environmental, and lifestyle factors influence refractive error from birth to mid-adult life, and to understand what health and social outcomes result from refractive error at different ages. In the long-term this could contribute to strategies for preventing and treating refractive errors, which are disorders with high impact on individuals and society.

Our findings have offered clues for example to understanding the global increase in myopia over the past two decades. They have identified new avenues for research, which has until recently focused on ‘visual/ocular’ risk factor, such as intense reading during formal education. They also serve to identify important environmental risk factors that should be accounted for (as co-variates) in future genetic epidemiological investigations of refractive error.

Ongoing research using data from the Millennium Cohort Study is investigating the prevalence and distribution of eye conditions and visual impairment and associations with early social and biological factors, such as socio-economic status and ethnicity. This research has been used to inform the planning and provision of healthcare services for visual impairment. 

Study Team: Jugnoo Rahi (Principal investigator), Phillippa Cumberland,  Catherine Peckham

UK Biobank (UKBB) 

This is a new and unique dataset, the world’s biggest single resource for the study of health and disease.  Data collection on 500,000 adults aged 40 to 79 was completed in July 2010 and included a range of detailed physical assessments, detailed risk factor and outcome questionnaires, and biological samples including for genetic studies.  122,000 participants have also undergone an enhanced ophthalmic assessment that includes visual acuity and autorefraction. The ophthalmic measures, combined with the depth of additional data on lifestyle, environment and other health-related outcomes will allow many novel hypotheses to be explored within UK Biobank.

The main objective of the initial research is to provide currently unavailable data on the distribution and biological, environmental and lifestyle determinants of visual function and of refractive error in adults (aged 40 and 69 years) in the UK. We will also investigate associations between refractive error (in particular myopia) and other chronic complex diseases of adult life, especially obesity, diabetes and cardiovascular disease, which may serve to identify any common early life influences or putative pathways.

Study Team: Phillippa Cumberland and Jugnoo Rahi (Co-Principal Investigators)

Cohort and Longitudinal Studies Enhancement Resources (CLOSER)

This is a £5 million ESRC funded initiative (PI: Prof Jane Elliott, Inst. of Education), to establish an enhanced resource to provide the infrastructure needed to maximise the use, value and impact of data collected through the unique and internationally renowned set of UK cohort studies spanning 65 years. The national cohort studies to be included are the 1946, 1958, 1970 birth cohorts, Millennium cohort and UK Biobank, and ALSPAC.

A set of three technical work packages will harmonise measures that are commonly used in order to facilitate cross-cohort analysis. Prof Jugnoo Rahi (co-investigator) and Phillippa Cumberland will lead the scientific work package and demonstrator project to harmonise measures of vision across cohort studies. The focus will be on measures of visual function which, together with refractive error (in particular myopia), have been prioritised in each of the national cohorts.

Study Team: Jugnoo Rahi (Principal investigator), Phillippa Cumberland and Carol Dezateux

Measuring vision-related quality of life and functional vision of children and young people

Vision-related quality of life instrument (VQoL) and Functional Vision (FV) of children and young people with visual impairment: development of age-appropriate patient reported outcome measures (PROMs) for routine use in paediatric epidemiology

The overarching aim of this programme is to investigate quality of life and functional vision of children and young people with visual impairment and develop patient-reported outcome measures.

In keeping with the increasing emphasis on PROMs for patient-led assessment of impact of illness or disability and of health care, we are developing questionnaires that children and young people with visual impairment can self-complete and which can be used to measure the real-life impact of living with a visual disability. These are intended to be complementary to the objective clinical measures (e.g. acuity) in clinical settings, as well as to play part of policy in research, thus allowing children and young people’s own perspectives of their visual loss to form part of healthcare provision and decision-making. We are currently completing the ‘foundation’ research to develop VQoL and FV instruments for 10-15 year old children and young people. We have recently been awarded a 3-year project grant by Fight for Sight to develop corresponding instruments also for younger children aged 6-9 years and older teenagers aged 16-18.

Our research has a strong user-centred ethos and involves children and young people, as well as parents and relevant professionals, at all stages, from identifying the areas of research priority to shaping the research design and methodology.

As part of this programme, we have established a new inter-departmental
 interdisciplinary grouping with colleagues from the UK Collaborative Study of Congenital Heart Defects (Rachel Knowles), to promote common understanding, further research and clinical implications relating to patient-reported outcome and experience measures for children and young people.

Study Team: Jugnoo Rahi (Principal investigator), Dr Val Tadić

Study of Optimal Perimetric Testing in Children (OPTIC)

Assessing visual fields (perimetry) in children is important to diagnosing and treating many ophthalmic and neurological disorders.  However, reliable assessment of paediatric visual fields is not straightforward and poses significantly different challenges to perimetry in adults. There is currently no agreement on optimal perimetric strategies and limited understanding or agreement on interpreting paediatric visual field data.

This programme of research on paediatric perimetry, through a collaboration between clinical and academic departments at GOSH/ICH and MEH/IO will establish national guidelines on perimetry, identifying the most accurate and efficient strategies for use in the health services.

Study team: Jugnoo Rahi (Principal Investigator), Dipesh Patel (Principal contact) and Phillippa Cumberland

UK and Ireland Epidemiological study of primary intraocular lens implantation in children under 2 years old (IOLunder2)

Congenital and infantile cataract (opacity of the natural lens of the eye) is one of the few treatable visually disabling disorders of childhood and affects 15% of blind children worldwide. In very young children, after the diseased lens is removed, vision is corrected using contact lenses or spectacles which need to be constantly in place to allow the child to mature visually.

An important and recent innovation in treating these children is implanting an artificial intra-ocular lens (IOL) immediately after removal of the cataract. However, the risks and benefits of this in a developing and maturing eye and visual system are not yet understood.

The IOLunder2 study, which is being undertaken through the British Isles Congenital Cataract Interest Group (a national clinical research network of consultant paediatric ophthalmologists) has identified and recruited over 250 children who have undergone cataract surgery in the first 2 years of life.  This prospective national study of outcomes following cataract surgery, with or without IOLs, will enable us to examine the factors which relate to good and poor outcome after surgery.

Principal investigator: Jugnoo Rahi

Visual impairment due to adverse drug reactions

Adverse drug reactions (ADR) that cause visual impairment are rare in adults and children, and there are limited data which clinicians can apply to counsel patients on the potential risks of medications. Currently, all ADR in the UK are ‘monitored’ through the Medical and Health product Regulatory Agency (MHRA) using the voluntary Yellow Card Scheme (YCS).

However, there has been no national systematic study of such ADRs, so the current study aims to increase knowledge by providing data on visual impairment due to ADR in both children and adults. Our expectation is that severe visual impairment due to ADR is a rare event and knowing this will be important.

Patients experiencing such reactions would be expected to go to an ophthalmologist, so we have conducted an active surveillance study through the British Ophthalmological Surveillance Unit (BOSU), over a two-year period (February 2010 to January 2012) and are currently completing the 6 month follow-up of cases, the aim of which is to establish the permanency of visual loss.

Study Team: Phillippa Cumberland (Principal Investigator ), Jugnoo Rahi

Genetics and epidemiology of refractive error

We are conducting research, based on data collected through the 1958 Birth Cohort, with colleagues from the  Institute of Ophthalmology, Kings College London and the University of Hong Kong into genetic influences on myopia.

This work highlights the intertwining between early-life and life course factors in the development of myopia or hyperopia, and in particular that genetic pathways associated with behaviour may contribute to refractive error. It also shows that identification of even small-effect genetic loci can greatly improve knowledge of human disease.

Professor Jugnoo Rahi, Dr Pirro Hysi and Phillippa Cumberland are members of the Consortium for Refractive Error And Myopia (CREAM) conducting meta-analyses of genome-wide association studies of refractive error undertaken in different populations throughout the world. 

Study Team: Jugnoo Rahi (Principal investigator), Phillippa Cumberland and Pirro Hysi

Resources for visually impaired children and young people, and their families

As part of our programme on vision-related quality of life and functional vision of children and young people with visual impairment we have developed a compendium of resources for children and young people and their families.  The idea came from our interviews with visually impaired children and young people and their families in which we noticed the diversity of services and resources which were accessible and useful but not universally known. The compendium pulls together this rich information.

Pupils attending the Visual Impairment Forum at Exhall Grange Science College, as well as their teachers and parents, were actively involved as advisors in the development of this resource pack and provided invaluable expert feedback on making the pack a user-friendly tool. The pack will be available more widely, initially through the Great Ormond Street Hospital website, later in 2012.

Principal contact: Jugnoo Rahi