Dr Simon Skalicky
FRANZCO MPhil MMed(Ophthal Sci) MBBS(Hons 1) BSc(Med)
Clinical Senior Lecturer, University of Melbourne
Clinical Senior Lecturer, University of Sydney
Ophthalmologist Glaucoma Care, Melbourne, VIC
Despite therapeutic advances, the global burden of glaucoma today is high and will continue to rise—60.5 million people suffered from glaucoma in 2010, and by 2020 this is predicted to reach 79.6 million.1 Glaucoma impacts quality of life (QoL) for all patients with the disease.
QoL is a reflection of an individual’s general well-being: one’s ability to pursue a fulfilled and happy life.2,3 QoL is influenced by a number of dimensions, including mental health, physical ability, general health perceptions, social and workplace function and independence. Although the components of a good QoL are unique for each person, vision is consistently a key determinant.4-6
QoL: influential factors
Loss of visual function due to glaucomatous optic neuropathy (GON) is the major determinant of health-related QoL for glaucoma patients. This can impact venturing from home, driving, walking, seeing at night, reading, adjusting from dim to bright conditions and vice versa, judging distances, walking on stairs and seeing objects coming from the side.6-10 Motor vehicle accidents and injuries related to falls are potential serious consequences of glaucomatous vision loss.11
Reduced health-related QoL begins in the earliest stages of glaucoma and deteriorates proportionally to visual field loss.12,13 Knowledge of the diagnosis only minimally influences the negative QoL effects: vision-related QoL is reduced even in individuals who are unaware that they have glaucomatous vision loss.13
The detrimental impact of loss of visual function is magnified when the vision loss is bilateral;12-14 however, the influence of the second eye may not be as great as originally thought. More recent data show that global visual field indices from the better eye are as influential on QoL as binocularly integrated visual field indices.15
Other ocular and visual factors distinct from GON influence QoL among glaucoma patients. It is important to identify and understand these factors, as unlike GON, many of these can be modified or corrected. Ocular surface discomfort, commonly exacerbated by topical glaucoma medications, contributes to the overall burden of disease.16 Cataract, frequently found among glaucoma patients,17-19 is a well-recognised cause of reversible vision impairment among glaucoma patients;9 it is also an important determinant of their QoL.20
Psychological, social, cultural and emotional factors are important. As sight deteriorates, the psychological burden grows, together with an increasing fear of blindness, social withdrawal from impaired visual function and depression.21-23 A patient’s visual dysfunction may be influenced by other debilitating medical conditions, and psychological and social constraints. These factors interact in a complex manner and are difficult to measure; however, they can be reflected in holistic QoL assessment.
QoL: clinical perspective
In clinical practice, QoL assessment can be performed routinely for glaucoma patients, without questionnaires. QoL can be assessed by enquiring about the patient’s general medical history, visual function, independence, well-being, mood and level of satisfaction with their care. A close therapeutic relationship between clinician and patient, characterised by active listening and a supportive, non-judgemental approach, leads to an accurate QoL assessment.
QoL is at the core of our role as clinicians—the goal of the therapeutic relationship with our patients is to maximise their QoL. Preventing glaucomatous vision loss is crucial to achieve this end. However, minimising the impact of treatment-related discomfort and treating other causes of visual morbidity are equally important strategies to improve QoL and visual function.
Clinicians often gauge the success or failure of glaucoma management by focusing on serial visual field testing and/or nerve fibre layer structural analysis as markers of progressive GON, yet this is only one aspect of the overall impact of glaucoma on a patient. Often the patient’s main concerns are ocular surface discomfort, blurred vision (which is typically not due to GON), and the risk of going blind.16,23 By addressing QoL concerns, patient and clinician can together reorientate towards common, realistic goals resulting in better concordance with treatment programs, a more harmonious relationship and greater patient satisfaction.24
When making clinical decisions, QoL concerns should be considered foremost. For example, a common management dilemma is when patient and clinician are faced with three choices: to commence/add a topical medication, undertake a course of laser (for example, selective laser trabeculoplasty) or continue with the current treatment.
While the intraocular pressure, the severity and progression rate of GON, the mechanism of glaucoma and the relative success of the proposed treatment must be considered, so too must other factors. These include the implications for ocular surface disease, other causes of visual morbidity, general health issues, other disability, patient knowledge, beliefs and attitudes, and the suspected adherence to any proposed treatment plan. Such decisions first require proper patient education, open and realistic discourse, clear, informed choices for the patient to make, and a frank discussion of potential QoL impact.
Table 1. The Glaucoma Activity Limitation-9 Questionnaire
QoL measurement for patients with glaucoma
- Patient reported outcome questionnaires
Formal QoL analysis typically involves questionnaires, also known as patient reported outcome (PRO) tools. A number of PROs is available for patients to systematically self-measure the effects of glaucoma on their QoL. Most PROs involve several items and each item is a question related to a specific functional ability. The respondent grades their answer reflecting the severity of the problem on a Likert scale. For example, see Table 1, the Glaucoma Activity Limitation-9 (GAL-9).
PROs typically used among glaucoma patients can reflect general health (for example, the 12-item Short Form Health Survey), broad visual function (for example, the 25-item National Eye Institute Visual Function Questionnaire [NEI-VFQ]) or can be glaucoma specific (for example, the GAL-9).25 Our group has found the latter in particular useful in quantifying visual disability related to glaucoma.6,16,20,22
- Item response theory: Rasch analysis
Increasingly sophisticated strategies for QoL analysis produce more fruitful results. In the past, QoL data analysis involved adding raw scores from each item of the PRO to create a combined QoL score; however, this approach is increasingly recognised as problematic.
For example, how can we assume that each PRO item has equal weight in reflecting QoL? Is each item equally valid, or are some items tangentially influenced by unwanted, confounding factors? Can we assume that a particular PRO is sufficiently matched for glaucoma patients of all severities, or is it sensitive only at one end of the glaucoma severity spectrum?
These problems can be addressed by Rasch analysis of the data. Rasch analysis is a type of Item Response Theory initially developed by educational psychologists in the 1960s, and applied only recently to vision-related QoL research. In Rasch analysis, questionnaire summary scores are transformed into log score intervals to permit parametric analyses to be performed on the data.26 Rasch analysis has lead to improved PROs. For example, the GAL-9 is a Rasch analysed, refined version of the Glaucoma Quality of Life-15, with improved psychometric properties.27
Utility values are increasingly used as preference-based measurements of health-related QoL. Utility values are used to grade patient health experience from zero (death) to one (perfect health), or vision-specific experience zero (complete blindness) to one (perfect vision). Utility values are easily converted to quality-adjusted life-years (QALYs), which are critical to health economic analyses.28,29 As health resources are tightening, QALYs are important metrics for cost-utility analysis for the allocation of health funding.
Future directions: clinical research guiding clinical practice
Our group has used a three-pronged research strategy to evaluate QoL among glaucoma patients.
First, in our recent research we have used only Rasch-analysed PROs and then performed Rasch analysis on our results, thereby refining the integrity of QoL information gained from clinical studies.
Second, we have systematically quantified the influence of key factors on QoL in glaucoma, some of which may be treatable or reversible. These include studies specifically evaluating the influence of depression,22 ocular surface disease,16 cataract20 and age-related macular degeneration (AMD)30 in patients with glaucoma.
That these factors influence QoL is unsurprising; however, each study has revealed additional important results with clear implications for clinical practice. For example, we demonstrated the relationship between deteriorating QoL and increasing daily dose of drop preservative. We found that cataract density determined on slitlamp examination may be a better guide than visual acuity when deciding the optimal timing of cataract surgery in glaucoma patients. We found that patients with both AMD and glaucoma have a heightened self-perceived risk of falls compared to those with glaucoma alone. Other factors we are currently investigating include the influence of patient education and location of visual field deficit on QoL in glaucoma.
Third, we have designed a new objective QoL assessment tool. Questionnaires have their limitations and can be influenced by mood, recall bias and other non-clinical factors.31 These unwanted influences can be minimised by objective vision-related QoL assessment. Using computer-based simulations, this test evaluates patients’ ability to perform visually demanding tasks under timed conditions. The test involves a series of screen images; each one reflects a real-life scenario, such as driving, matching socks, shopping at a supermarket, detecting people in a crowd or finding cutlery in a draw (Figure 1).
Figure 1. Objective quality of life assessment: each image is projected onto a large screen requiring 30 degrees of visual field. Patients are asked to: A. find a raspberry among the cherries; B. find a fork among the spoons, and a spoon among the forks; and to correctly match the sock in C with one in D.
Each image has a central fixation point, therefore the patient is required to use their peripheral vision to locate the desired object. In a sense, the test is a hybrid of a visual field test and a functional assessment of activities of daily living, This test would be a useful glaucoma education tool for patients, clinicians and the public.
QoL research in glaucoma has made considerable progress over the past few decades, providing important insights into our patients’ concerns, lifestyle and daily function in society. These insights have key implications for the way we undertake patient care. Whether explaining the nature of the condition, offering counselling for future risk, or empowering patients to make informed treatment decisions, QoL is a key ingredient for many dimensions of the patient-clinician relationship.
Understanding a patient’s psychosocial background and QoL helps the health team (patient, optometrist, general practitioner, pharmacist and ophthalmologist) work together more effectively and tailor patient- centred treatment strategies, leading hopefully to more successful glaucoma care. Continued efforts are needed to delineate better the ocular, systemic and psychological influences of QoL in glaucoma and to refine our methods of QoL assessment.
As therapeutic and diagnostic techniques in glaucoma improve, we must remember to focus on our patients as individuals, address their real-life concerns and understand the impact of glaucoma on their current and future well-being.
- Quigley H, Broman, AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol 2006; 90: 262-267.
- Elliott DB, Pesudovs K, Mallinson T. Vision-related quality of life. Optom Vis Sci 2007; 84: 656-658.
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- Altangerel U, Spaeth GL, Rhee DJ. Visual function, disability, and psychological impact of glaucoma. Curr Opin Ophthalmol 2004; 14: 100-105.
- Cahill MT, Banks AD, Stinnett SS, Toth CA. Vision-related quality of life in patients with bilateral severe age-related macular degeneration. Ophthalmology 2005; 112: 152-158.
- Goldberg I, Clement, CI, Chiang, TH, Walt, JG, Lee, LJ, Graham, S, Healey, PR. Assessing quality of life in patients with glaucoma using the Glaucoma Quality of Life-15 (GQL-15) questionnaire. J Glaucoma 2009; 18: 6-12.
- Ramulu P, Maul, E, Hochberg C et al. Real-world assessment of physical activity in glaucoma using an accelerometer. Ophthalmology 2012; 119: 1159–1166.
- Nelson P, Aspinall P, Papasouliotis O, Worton B, O’Brien C. Quality of life in glaucoma and its relationship with visual function. J Glaucoma 2003; 12: 139-150.
- Wu S, Hennis A, Nemesure B, Leske MC; Barbados Eye Studies Group. Impact of glaucoma, lens opacities, and cataract surgery on visual functioning and related quality of life: the Barbados Eye Studies. Invest Ophthalmol Vis Sci 2008; 49: 1333-1338.
- Ramulu P. Glaucoma and disability: which tasks are affected, and at what stage of disease? Curr Opin Ophthalmol 2009; 20: 92-98.
- Haymes SA, Leblanc RP, Nicolela MT, Chiasson LA, Chauhan BC. Risk of falls and motor vehicle collisions in glaucoma. Invest Ophthalmol Vis Sci 2007; 48: 1149-1155.
- McKean-Cowdin R, Varma R, Wu J et al. Severity of visual field loss and health-related quality of life. Am J Ophthalmol 2007; 143: 1013-1023.
- McKean-Cowdin R, Wang Y, Wu J et al. Impact of visual field loss on health-related quality of life in glaucoma: the Los Angeles Latino Eye Study. Ophthalmology 2008; 115: 941-948.
- Varma R, Wu J, Chong K et al. Impact of severity and bilaterality of visual impairment on health- related quality of life. Ophthalmology 2006; 113: 1846-1853.
- Arora KS, Boland MV, Friedman DS, Jefferys JL, West SK, Ramulu PY. The relationship between better-eye and integrated visual field mean deviation and visual disability. Ophthalmology 2013; 120: 2476-2484.
- Skalicky SE, Goldberg I, McCluskey P. Ocular surface disease and quality of life in patients with glaucoma. Am J Ophthalmol 2012; 153: 1-9.
- Chandrasekaran S, Cumming RG, Rochtchina E, Mitchell P. Associations between elevated intraocular pressure and glaucoma, use of glaucoma medications, and 5-year incident cataract: the Blue Mountains Eye Study. Ophthalmology 2006; 113: 417-424.
- Lai JS, Tham CC, Chan JC. The clinical outcomes of cataract extraction by phacoemulsification in eyes with primary angle-closure glaucoma (PACG) and co-existing cataract: a prospective case series. J Glaucoma 2006; 15: 47-52.
- Patel H, Danesh-Meyer HV. Incidence and management of cataract after glaucoma surgery. Curr Opin Ophthalmol 2013; 24: 15-20.
- Skalicky SE, Martin KR, Fenwick E, Crowston JG, Goldberg I, McCluskey P. Cataract and quality of life in patients with glaucoma. Clin Exp Ophthalmol 2014 Oct 8. doi: 10.1111/ceo.12454.
- Ramulu PY, van Landingham SW, Massof RW, Chan ES, Ferrucci L, Friedman DS. Fear of falling and visual field loss from glaucoma. Ophthalmology 2012; 119: 1352-1358.
- Skalicky S, Goldberg I. Depression and quality of life in patients with glaucoma: a cross-sectional analysis using the Geriatric Depression Scale-15, assessment of function related to vision, and the Glaucoma Quality of Life-15. J Glaucoma 2008; 17: 546-551.
- Janz NK, Wren PA, Guire KE et al. Fear of blindness in the Collaborative Initial Glaucoma Treatment Study: patterns and correlates over time. Ophthalmology 2007; 114: 2213-2220.
- Hahn SR, Friedman DS, Quigley HA et al. Effect of patient-centered communication training on discussion and detection of nonadherence in glaucoma. Ophthalmology 2010; 117: 1339-1347 e6.
- Spaeth G, Walt J, Keener J. Evaluation of quality of life for patients with glaucoma. Am J Ophthalmol 2006; 141: S3-14.
- Mallinson T. Why measurement matters for measuring patient vision outcomes. Optom Vis Sci 2007; 84: 675-682.
- Khadka J, Pesudovs K, McAlinden C, Vogel M, Kernt M, Hirneiss C. Reengineering the glaucoma quality of life-15 questionnaire with Rasch analysis. Invest Ophthalmol Vis Sci 2011; 52: 6971-6977.
- Brazier J, Deverill M, Green C, Harper R, Booth A. A review of the use of health status measures in economic evaluation. Health Technol Assess 1999; 3: i-iv, 1-164.
- Kymes SM. An introduction to decision analysis in the economic evaluation of the prevention and treatment of vision-related diseases. Ophthalmic Epidemiology 2008; 15: 76-83.
- Skalicky SE, Fenwick E, Martin KR, Crowston JG, Goldberg I, McCluskey P. Impact of age-related macular degeneration on quality of life in patients with glaucoma. In press
- Warrian KJ, Spaeth GL, Lankaranian D, Lopes JF, Steinmann WC. The effect of personality on measures of quality of life related to vision in glaucoma patients. Br J Ophthalmol 2009; 93: 310-315.