Glaucoma blindness at the end of life

Preventing a blind death is the primary intention of the ophthalmologist. Unfortunately, there are still large uncertainties on the natural history of glaucoma and, most importantly, how well people with glaucoma receiving standard care are doing. If the vast majority of patients maintain good visual function until the end of life, we can be satisfied that we are doing things right. However, if a substantial proportion of people suffer from blindness, we will need to change current practice. Studying the disease severity of deceased glaucoma patients is relevant as it shows whether the primary aim of preventing a blind death is achieved. This type of research has been conducted by only a few research groups despite its fairly ease of conduct, relevance and valuable information. We have summarized these retrospective studies and found different proportions of blindness at the end of life for patients with glaucoma. These reports showed a prevalence of 24.1% for unilateral blindness and 10.6% for bilateral blindness, which is a substantial proportion (Ang & Eke 2007; Forsman et al. 2007; Goh et al. 2011; Ernest et al. 2013; Peters et al. 2013a,b). This is especially worrisome because the worldwide prevalence of glaucoma has increased over the last decades, and with the ageing population, it will increase even further (Varma et al. 2011; Bettin & Di Matteo 2013). As a result, it is very likely that the number of blind patients will increase in the upcoming years. Research of visual outcome at the end of life is even more relevant with respect to the identification of the cause(s) of blindness. The causes for glaucoma blindness can be classified into three major domains; (i) late diagnosis, when visual field loss is already extensive before treatment is started (Grant & Burke 1982; Prior et al. 2013), (ii) visual field loss progressed in spite of treatment, or (iii) ocular comorbidity has occurred. These need to be considered in relation to the life expectancy. Due to increasing life expectancy, patients live longer with glaucoma (Varma et al. 2011) and are exposed to possible glaucoma progression over a longer period. So the longer the life expectancy the more essential it is to detect glaucoma at an early stage and to lower the IOP intensively from the start. The percentage of blindness varies also depending on the diagnostic criteria and false-positive rates of diagnostic tests as well as selection of patients in the retrospective material. In case of overdiagnosis, or stable patients followed up in another setting, it may bias the percentages. Each of these domains requires its own type of additional research and strategies to identify clues for improvement of patient outcomes. It is possible that late presentation and delayed diagnosis is due to either poor education of the public about the need for having regular eye exams or the absence of primary health care professionals (such as opticians and optometrists) to, for example measure IOP and examine the optic nerve or visual field. This type of basic eye examination is usually less expensive and more accessible than direct screening by an ophthalmologist, and might thus be more appealing to low-income patients. Simultaneously the burden of potential false positives has to be taken into account. Access to the ophthalmologist could also be limited in some health care systems, due to shortage of ophthalmologists or budgetary constraints. Also health insurance policies and waiting times in the hospitals [Health Systems and Policy Monitor (www.hspm.org)] could be of influence on late presentation and delayed diagnosis. Public health and health policy interventions are needed to improve access to eye care, and most importantly to detect glaucoma in an early stage and thereby improve its treatment and eventual prognosis. There are several possible causes of progression among treated patients. One to consider is a relatively high IOP during treatment. Outcomes research in which visual field loss or a high IOP are studied may show that this is due to failure to implement, in a timely way, effective interventions such as surgical interventions. Improvements in the quality of ophthalmic training and care, and strategies to implement evidence-based and cost-effective strategies, may be difficult to achieve. There is also evidence that simply adding more resources to glaucoma care may not have impact on quality of life (Hagman 2013). The recent improvement in outcomes for age-related macular degeneration, cataract and retinal vein obstruction will certainly have an impact in people with glaucoma. Glaucoma is an important public health disease and a few studies have shown that at the end of life, a substantial proportion of patients with glaucoma may still go blind. Causes for blindness are diverse and require several strategies to prevent this from happening. However, we need international research to identify best services and best practices. This should start with the introduction of research in deceased glaucoma patients to identify causes and monitor improvements. It requires agreement on selection of cases, methods (including health related quality of life) and definition of blindness. All of these have differed between the studies so far. We would like to introduce the term ‘epidemiologic autopsy’ for this type of research in deceased patients. One of the methods to start with could be the use of extensive visual field data across different countries. By this, we could evaluate the severity of glaucoma at diagnosis and progression and see whether there are differences according to different models of care in different countries. In conclusion, international research in deceased glaucoma patients is of great importance and will, on a large scale, give a good estimate of the proportion of patients becoming blind from glaucoma, will provide insight to factors contributing to suboptimal care and will give room for improvement.