2.3 Research Priorities

The epidemiological and service research priorities in the context of the main eye disorders are mentioned in the relevant chapter. Here, we outline the importance and direction of further epidemiological research.

In aetiological research the general approach has been to focus each study on a particular eye disorder and to investigate the possible determinants. A useful complementary approach would be to consider all disease or health outcomes of exposure to a particular risk factor or protective factor. Such exposure-oriented research should lead to a more holistic appreciation of the exposure factor's importance for public health. The approach would require the working collaboration of disease experts and exposure experts (e.g. nutritionists) or 'aetiologists', i.e. epidemiologists with special interest in public health aspects of a particular exposure or risk factor complex. The methodology would focus on major cohort follow-up studies and large-scale randomised trials with long-term outcome assessment. Potential candidates for this research approach may include nutritional / dietary factors, alcohol consumption, and hormone replacement therapy, with a wide spectrum of ocular and other health indicators included as outcomes.

Large eye surveys planned primarily for estimation of the prevalence of visual impairment and eye disease in countries within Europe would probably fail to attract major funding. Those planned to form the initial cross-sectional phase of analytical cohort studies should have a higher chance of success. Generally, the approach in the past has been to limit the study scope to matters of vision and eye disease. Future large sample surveys should be multidisciplinary, aiming to obtain data on the population burden of a broader spectrum of disability or dysfunction (hearing, mobility etc.) and the causal disorders, so that the 'general functional health' status of the population may be assessed.

Health authorities may increasingly tend to base the planning of future levels and type of service on sound epidemiological models of population need (see source 2). Such models are scarce, and the very few which exist, are in great need of more diverse, precise and reliable input data. Consequently, studies designed specifically to generate such data and to enable the development of new models may become favoured, particularly if they are made germane to the requirements of the owner-users of the intended model, i.e. the health provider / commissioner.

In general medicine several biological measures exit, which can herald the coming of a disease, indicate its presence, or quantify the severity of disease or dysfunction. Many of these measures are 'continuous'. Their population mean values (norms) have had to be established, and the cut-offs that indicate abnormality have had to be defined. Discovery and development of such new objective measures for eye disorders is a reasonable expectation, in view of the advances in molecular biology and genetics. Population-based cross-sectional studies should play a central initial role in establishing the 'norms' and critical cut-off values. Biological measures that are permanent markers for transient exposures or quantify cumulative life-time exposure may be developed, and may require initial assessment through cross-sectional studies. Other developments may also require future cross-sectional studies for assessment and exploration of relationships. An example of such new advances would be the development of a sensible scoring system for visual function or for vision related quality of life, such that may be applicable across the spectrum of the major eye disorders and cultures.

Epidemiological research will be of increasing importance in the evaluation of interventions, both preventive and curative. These large-scale studies should not only measure clinical effectiveness but should also incorporate an economic evaluation. A feature of modern epidemiological studies is that they need to be consistently and comprehensively funded. We would hope that professional bodies, universities and funding agencies continue to work collaboratively to ensure this.

  2.2.5 Diabetic eye disease // 2.4 Sources of Data and Study References