Evaluating Whether Sight Is the Most Valued Sense

Research

JAMA Ophthalmology | Brief Report Evaluating Whether Sight Is the Most Valued Sense

Jamie Enoch, MSc; Leanne McDonald, MSc; Lee Jones, PhD; Pete R. Jones, PhD; David P. Crabb, PhD

Supplemental content IMPORTANCE Sight is often considered to be the sense most valued by the general public, but there are limited empirical data to support this. This study provides empirical evidence for frequent assertions made by practitioners, researchers, and funding agencies that sight is the most valued sense.

OBJECTIVE To determine which senses are rated most valuable by the general public and quantify attitudes toward sight and hearing loss in particular.

DESIGN, SETTING, AND PARTICIPANTS This cross-sectional web-based survey was conducted from March to April 2016 through a market research platform and captured a heterogeneous sample of 250 UK adults ages 22 to 80 years recruited in March 2016. The data were analyzed from October to December 2018.

MAIN OUTCOMES AND MEASURES Participants were first asked to rank the 5 traditional senses (sight, hearing, touch, smell, and taste) plus 3 other senses (balance, temperature, and pain) in order of most valuable (8) to least valuable (1). Next, the fear of losing sight and hearing was investigated using a time tradeoff exercise. Participants chose between 10 years without sight/hearing vs varying amounts of perfect health (from 0-10 years).

RESULTS Of 250 participants, 141 (56.4%) were women and the mean (SD) age was 49.5 (14.6) years. Two hundred twenty participants (88%) ranked sight as their most valuable sense (mean [SD] rating, 7.8 [0.9]; 95% CI, 7.6-7.9). Hearing was ranked second (mean [SD] rating, 6.2 [1.3]; 95% CI 6.1-6.4) and balance third (mean [SD] rating, 4.9 [1.7]; 95% CI,

4.7-5.1). All 3 were ranked above the traditional senses of touch, taste, and smell (F7 = 928.4; P < .001). The time tradeoff exercise indicated that, on average, participants preferred 4.6 years (95% CI, 4.2-5.0) of perfect health over 10 years without sight and 6.8 years (95% CI, 6.5-7.2) of perfect health over 10 years without hearing (mean difference between sight and hearing, 2.2 years; P < .001).

Author Affiliations: Department of CONCLUSIONS AND RELEVANCE In a cross-sectional survey of UK adults from the general Optometry & Visual Sciences, School public, sight was the most valued sense, followed by hearing. These results suggest that of Health Sciences, City, University of people would on average choose 4.6 years of perfect health over 10 years of life with London, London, England. complete sight loss, although how this generalizes to other parts of the world is unknown. Corresponding Author: David P. Crabb, PhD, Department of Optometry and Visual Sciences, City, JAMA Ophthalmol. doi:10.1001/jamaophthalmol.2019.3537 University of London, Northampton Published online October 3, 2019. Square, London, London EC1V 0HB, England ([email protected]).

esearch in the United States has shown that members public and quantified attitudes toward sight and hearing loss of the public rate sight loss as a greater concern than in particular using a time tradeoff (TTO) exercise. R loss of memory, loss of speech/hearing, or chronic health conditions, such as HIV/AIDS and heart disease.1 Simi- larly, a longitudinal clinical study with patients experiencing Methods sensory loss has shown that loss of sight and touch cause the greatest decreases in quality of life before loss of hearing, taste, This study was approved by the City, University of London and smell.2 However, to our knowledge, the relative impor- School of Health Science’s research ethics committee. Writ- tance of sight compared with other senses has not been sys- ten informed consent was obtained from all participants be- tematically investigated in the general population in a non- fore enrollment. An online survey was delivered by an inde- clinical setting. We therefore conducted a survey to determine pendent market research company, FlexMR (FlexMR Ltd), who which senses are rated most valuable by a cross-section of the was contracted by the research team specifically to dissemi-

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nate the survey and collate responses. FlexMR sampled 250 UK-based adults in March 2016 (median [range] age: 50 years Key Points [22-80 years]; 141 women [56.4%]). The participants were Question Which sense is most valued by the general public in the selected from a pool of UK-based individuals who had United Kingdom? previously registered to receive survey invitations from Findings This cross-sectional online survey found that sight is the FlexMR and were entered into a prize draw as compensation. most valued sense, followed by hearing. On average, participants Participants’ sociodemographic characteristics were col- would choose 4.6 years of life in perfect health over 10 years of life lected (eTable in the Supplement). The survey was open to with complete sight loss, and members of the public valued individuals who may have had a sensory impairment them- balance above traditionally recognized senses, such as touch, selves or within their family. taste, and smell. This study adopted a broader definition of senses than Meaning This study supports frequent assertions made by the 5 “traditional” senses defined by Aristotle, also including practitioners, researchers, and funding agencies that sight is the balance (equilibrioception), pain (nociception), and tem- most valued sense among the general population of the United perature (thermoception). Participants were first asked to Kingdom. rank 8 senses (sight, hearing, touch, smell, taste, balance, temperature, and pain) in order of most valuable (8) to least valuable (1). Next, the fear of losing sight and hearing 4.9 [1.7]; 95% CI, 4.7-5.1), above the 3 traditional senses of touch was investigated using a TTO exercise.3 Participants chose (mean [SD] rating, 4.5 [1.7]), taste (mean [SD] rating, 3.8 [1.8]), between 10 years without sight/hearing (life A) vs varying and smell (mean [SD] rating, 3.4 [1.7]) (Wilcoxon signed rank test amounts of perfect health in 1-year decrements from 10 to 0 for pairwise comparison between balance and touch, W = 36 333; years (life B). This allowed for the calculation of the number P= .04 after Bonferroni correction). of years without sight or hearing that a participant would In the TTO exercise, participants, on average, chose 4.6 trade for perfect health over a 10-year period. Differences in years (95% CI, 4.2-5.0) of life in perfect health over 10 years years traded between groups were then analyzed using of life with complete sight loss and 6.8 years (95% CI, 6.5-7.2) Wilcoxon rank sum and Kruskal-Wallis tests. Statistical of life in perfect health as an alternative to 10 years of life with analyses were performed using R, version 3.5 (R Founda- complete hearing loss. This means that over a 10-year period, tion), and statistical significance was set at α = .05. participants were prepared to sacrifice a mean (SD) 5.4 (3.1) years without sight (95% CI, 5.0-5.8) and 3.2 (2.9) years without hearing (95% CI, 2.8–3.5) to remain in perfect health (mean Results difference between sight and hearing, 2.2 years; P < .001). Thirty-eight participants (15%) chose death (0 years of life B) As shown in Figure 1, 220 participants (88%; 95% CI, 82%-94%) over 10 years with complete sight loss and 15 participants (6%) ranked sight as their most valuable sense (mean [SD] rank, 7.8 chose death over 10 years with complete hearing loss (Figure 2). [0.9]; 95% CI, 7.6-7.9). Hearing was ranked as the second-most Men were willing to sacrifice almost 1 year more without valuable sense (mean [SD] rank, 6.2 [1.3]; 95% CI, 6.1-6.4) but was sight than women in exchange for perfect health (mean dif- rated as significantly less valuable than vision (P < .001). Balance ference, 0.94 years; P = .03) (Figure 2). There were no statis- was ranked as the third-most valuable sense (mean [SD] rank, tically significant differences in the number of years without

Figure 1. Dot Plot Showing Rankings of the 8 Senses Under Investigation

SightHearing Balance Touch Taste Smell Pain Temperature

3 Rank, Least to Most Valuable Sense Rank, Least to Most Valuable

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For hearing, people with a family history of sensory impair- Figure 2. Responses to the Time Tradeoff (TTO) Exercise ment would give up significantly fewer years without hear-

A All participants ing than those with no family history of sensory impairment

100 (mean difference, −1.46 years; P < .01). Participants with Hearing chronic conditions would give up fewer years without hear- Sight ing than those with no chronic conditions (mean difference, 75 −0.56 years; P = .04). There were no statistically significant differences in the number of years without hearing that partici-

50 pants would give up based on age (mean [SD] for age 22-40 years, 3.3 [3.0]; mean [SD] for age 41-60 years, 2.9 [2.9]; mean

[SD] for age 61-80 years, 3.3 [2.8]; Kruskal Wallis test, H2 = 1.54;

Sensory Impairment, % 25 Preferred Over 10 y With Preferred Over P = .46) or sex (mean [SD] for women, 3.1 [2.9]; mean [SD] for men, 3.3 [2.9]; Wilcoxon rank sum test, W =7247;P = .44). 0 109876543210 Perfect Health, y Discussion B Women only

100 The results suggest that sight is the most valued sense, followed by hearing. This is consistent with convergent evidence from linguistics, showing that words associated with vi- 75 sion dominate the English lexicon.4 Balance was also ranked highly as the third most important sense ahead of touch, taste, 50 and smell. This is consistent with empirical evidence showing that balance impairments and their association with mo- bility and daily activities can be a key factor in reduced qual-

Sensory Impairment, % 25 5 Preferred Over 10 y With Preferred Over ity of life. This further shows that the 5 traditional Aristotelian senses do not comprise the most valued senses. 0 The TTO exercise showed that people would choose an av- 109876543210 Perfect Health, y erage of 4.6 years of perfect health over 10 years without sight and 6.8 years of perfect health over 10 years without hearing. C Men only Men opted to sacrifice almost 1 year more without sight than

100 women. Interestingly, men’s higher valuation of sight in this study does not reflect real-world health care–seeking behav- ior, with evidence that men are more likely than women to risk 75 neglecting their eye health. For example, individuals present- ing with late-stage glaucoma are 16% more likely to be male.6

50 Regarding hearing loss, those with chronic conditions would give up fewer years without hearing than those with no chronic condition. This aligns with theories on “focusing

Sensory Impairment, % 25 Preferred Over 10 y With Preferred Over effects” whereby healthy individuals, when asked to focus on the perceived effect of a disease or disability, frequently 0 overestimate its negative association with their quality 109876543210 Perfect Health, y of life and disregard the many other contextual factors which could mitigate its effect, such as the possibilities of 7 A, All 250 participants. B, Women only (141 [56.4%]). C, Men only (109 adaptation. However, a similar pattern was not found for [43.6%]). The higher the bar, the more people opted for that number of sight loss; those with chronic conditions sacrificed only mar- years with perfect health over 10 years without sight/hearing. ginally fewer years without sight, demonstrating that sight is valued similarly highly by those with and without existing sight that participants would give up based on age group (mean chronic health conditions. [SD] for age 22-40 years, 5.3 [3.1]; mean [SD] for age 41-60 years, 5.3 [3.3]; mean [SD] for age 61-80 years, 5.6 [3.0]; Kruskal Limitations

Wallis test, H2 = 0.99; P = .61), family history of sensory im- These results may be specific to the UK population rather than pairment (mean [SD] for those with a family history, 4.8 [3.3]; universally applicable. The survey was novel but not for- mean [SD] for those without a family history, 5.5 [3.1]; Wil- mally validated. Moreover, despite efforts to recruit a broadly coxon rank sum test, W = 4491; P = .17), or having a chronic representative sample of the UK population, we cannot rule health condition (mean [SD] for those with a chronic health out potential bias introduced by drawing on a market re- condition, 5.2 [3.2]; mean [SD] for those without a chronic con- search company’s participant pool. Additionally, we did not col- dition, 5.5 [3.1]; Wilcoxon rank sum test, W = 7583.5; P =.48). lect data on the race/ethnicity of the participants.

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Furthermore, following long-standing tradition, this study considered the senses as discrete systems. Yet sensory impair- Conclusions ments are often comorbid; for example, many forms of eye disease are also associated with hearing loss8 or vestibular This study, conducted among a cross-section of the UK pub- dysfunction.9 Future work should consider the public’s con- lic, supports the notion that sight is the most highly valued cerns around multisensory impairments, ie, by using the sorts sense, followed by hearing and balance. The study suggests that of TTOs described in this study (eg, years of sight and hearing people would on average choose 4.6 years of perfect health as loss together traded off against sight and balance loss to- an alternative to 10 years without sight. Future research could gether). Such research would be valuable given the growing explore how such results generalize to other parts of the world prevalence of multisensory loss in globally aging populations.10 and public perceptions regarding multisensory loss.

ARTICLE INFORMATION Role of the Funder/Sponsor: Santen had no role in balance impairment: promises and pitfalls. Mov Accepted for Publication: July 14, 2019. the design and conduct of the study; collection, Disord. 2013;28(11):1576-1586. doi:10.1002/mds. management, analysis, and interpretation of the 25682 Published Online: October 3, 2019. data; preparation, review, or approval of the doi:10.1001/jamaophthalmol.2019.3537 6. Crabb DP, Saunders LJ, Edwards LA. Cases of manuscript; and decision to submit the manuscript advanced visual field loss at referral to glaucoma Author Contributions: Drs Crabb and Enoch had for publication. clinics—more men than women? Ophthalmic Physiol full access to all the data in the study and takes Opt. 2017;37(1):82-87. doi:10.1111/opo.12328 responsibility for the integrity of the data and the REFERENCES 7. Dolan P. Thinking about it: thoughts about health accuracy of the data analysis. 1. Scott AW, Bressler NM, Ffolkes S, Wittenborn JS, Concept and design: McDonald, L. Jones, Crabb. and valuing QALYs. Health Econ. 2011;20(12): Jorkasky J. Public attitudes about eye and vision 1407-1416. doi:10.1002/hec.1679 Acquisition, analysis, or interpretation of data: health. JAMA Ophthalmol. 2016;134(10):1111-1118. All authors. doi:10.1001/jamaophthalmol.2016.2627 8. Caban AJ, Lee DJ, Gómez-Marín O, Lam BL, Drafting of the manuscript: Enoch, P. Jones, Crabb. Zheng DD. Prevalence of concurrent hearing and Critical revision of the manuscript for important 2. Brown GC, Brown MM, Sharma S. The five visual impairment in US adults: the National Health intellectual content: All authors. senses: a patient preference-based comparative Interview Survey, 1997-2002. Am J Public Health. Statistical analysis: Enoch, McDonald, P. Jones, analysis. Clin. Res. Ophthalmol. 2018;1(1):1-8. 2005;95(11):1940-1942. doi:10.2105/AJPH.2004. Crabb. https://asclepiusopen.com/clinical-research-in- 056671 Obtained funding: McDonald, Crabb. ophthalmology/volume-1-issue-1/6.pdf. Accessed January 8, 2019. 9. Willis JR, Vitale SE, Agrawal Y, Ramulu PY. Visual Administrative, technical, or material support: impairment, uncorrected refractive error, and Enoch, McDonald, L. Jones, P. Jones. 3. Attema AE, Edelaar-Peeters Y, Versteegh MM, objectively measured balance in the United States. Supervision: P. Jones, Crabb. Stolk EA. Time trade-off: one methodology, JAMA Ophthalmol. 2013;131(8):1049-1056. doi:10. Conflict of Interest Disclosures: Prof Crabb different methods. Eur J Health Econ. 2013;14(1) 1001/jamaophthalmol.2013.316 (suppl 1):S53-S64. doi:10.1007/s10198-013-0508-x reported grants and personal fees from Santen and 10. Saunders GH, Echt KV. An overview of dual Allergan and grants from Roche UK. No other 4. Winter B, Perlman M, Majid A. Vision dominates sensory impairment in older adults: perspectives disclosures were reported. in perceptual language: English sensory vocabulary for rehabilitation. Trends Amplif. 2007;11(4):243-258. Funding/Support: This work was supported by an is optimized for usage. Cognition. 2018;179:213-220. doi:10.1177/1084713807308365 unrestricted donation from Santen UK. doi:10.1016/j.cognition.2018.05.008 5. Maetzler W, Nieuwhof F, Hasmann SE, Bloem BR. Emerging therapies for gait disability and

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