Court, Helen PhD; Greenland, Katy PhD; Margrain, Tom H. PhD
There is an increasing awareness that the success of contact lens wear is not simply determined by physiological parameters, but also by patient psychological factors such as anxiety.1–3 In fact, it has been suggested that many patients will not try contact lenses because they are anxious about having them placed into their eyes.3 Unfortunately, this obstacle prevents many patients from experiencing the potential visual and cosmetic benefits of this mode of refractive correction.
Anxiety is the adaptive response to a threat.4 Considering that eyesight is the most valued sense,5 any perceived threat is likely to result in anxiety. For example, discomfort of clinical procedures,6,7 detection of eye disease6,7 and financial cost8 have all been identified as patient concerns. A large mail survey of contact lens wearers identified some of these ‘threats’. For occasional and former contact lens wearers these ‘threats’ included; anxieties about their eyes when wearing contact lenses, inserting lenses and general discomfort.2
Although, the prevalence and effect of patient anxiety is well reported within many healthcare populations, including general practitioner patients,9,10 diabetics,11 dental patients12,13 and surgical patients14 including cataract surgery,15,16 the subject of patient anxiety has received little attention within optometry. This is surprising because patient anxiety has been associated with disrupted recall of information,17 poor attention,18 reduced patient satisfaction19 and is a barrier to effective patient-practitioner communication.20 Disrupted communication is potentially problematic for optometric patient outcomes, because good communication plays a pivotal role in determining patient motivation and satisfaction with contact lens wear.21
Margrain et al.22 reports the only previous study which has attempted to establish if there is any repeatable pattern of patient anxiety experienced during an optometric consultation. This study measured skin conductance to evaluate arousal throughout the eye examination. Arousal is the physiological response triggered by a stressful event23 and skin conductance is an established method by which it can be measured.24 Arousal is not anxiety per se, but is the physiological correlate. It can also be triggered by fear and motivation.25,26 The physiological basis is that eccrine sweat glands are mediated by the sympathetic nervous system. Therefore, upon increasing bodily arousal, the sweat ducts fill producing a more conductive path through the skin.27 The results indicated that there were specific points of heightened arousal during the eye examination for each patient, but these were not comparable across the group.22 However, as the authors suggested, this lack of comparability could have been because the patients were attending for different reasons i.e., reason for examination was not controlled.
Apart from measuring arousal, self-report questionnaires are a well established method of measuring anxiety.4,28 One of the most popular and frequently used questionnaires for the measurement of anxiety within healthcare is the Speilberger State-Trait Anxiety Inventory.28 This instrument has been widely used to measure anxiety across many disciplines including medical, dental, surgical and psychiatric patients.29–34 The questionnaire has two subscales, measuring state and trait anxiety. State anxiety is the transient experience of anxiety which is moderated by external situations, whereas trait anxiety indicates an individual’s proneness to anxiety (i.e., it is a personality trait).35 Each item in the questionnaire has four response categories and the total anxiety score is obtained by assigning numbers to each category and summing these values. Measuring patient state anxiety with a questionnaire before and after an optometric consultation would determine if the optometric experience reduces patient anxiety, possibly by modifying negative expectancies, a result which has been reported in dental research.36
This article reports a study of patient anxiety and arousal in patients who had not previously worn contact lenses. Participants recruited in the study underwent a routine contact lens fitting appointment. Throughout the duration of the consultation participant arousal was measured via skin conductance. Participant anxiety was also measured before and after the appointment using questionnaires to determine if patients are less anxious after the appointment. Identification of stressful events during the consultation will indicate when there may be an increased risk of reduced patient attention and inability to communicate. This information may allow optometrists to take steps to ensure that essential information is communicated effectively.
Study Design and Population
Participants were recruited via posters located around Cardiff University, visits to lectures and word of mouth. Each participant was provided with an information sheet and signed a consent form before the experiment. All the consultations were conducted at Cardiff University Eye Clinic. Ethical approval was obtained from the Cardiff School of Optometry and Vision Sciences Ethical Committee and all procedures adhered to the tenets of the Declaration of Helsinki. The inclusion criteria were as follows: an interest in trying contact lenses, non-contact lens wearers (with no previous experience of trying contact lenses), unknown to the optometrist and 18 years of age or more.
Skin conductance was measured by placing two silver-silver chloride cup electrodes coated with electrode gel onto the distal phalanges of the middle finger and ring finger of the left hand. Participants washed their hands in warm water with a non-abrasive soap before electrode attachment.37 A physiological amplifier (Biopac MP30) was used to amplify (×2000) and low pass filter (0 to 35 Hz) the skin conductance signals from the electrodes. The amplifier was connected to a laptop PC (Toshiba pro 4200 series) running Biopac Student Lab Pro Version 3.6.5 software. Once seated in the consulting room, the participant was instructed to rest their arm on the arm rest in a comfortable position. Following previous precedent,22 a piece of crepe paper was loosely tied around the participant’s arm and the arm of the chair. This was to remind the participant to not move their arm excessively during the consultation, which could introduce movement artifacts into the recording.
The participant was then asked to relax and wait for the optometrist to arrive; this was always a 2 min wait. Throughout the consultation the experimenter sat in the adjoining cubical (out of sight of the participant) by the laptop computer. During the recording of skin conductance, markers were added to the trace at specific points of the consultation, identified in Table 1.
Participants were also asked to complete a short form of the Speilberger state anxiety scale38 before and after the consultation. This scale incorporates six items from the original 20-item scale,28 with four response categories per item. The scale has good internal reliability (Cronbach α 0.82) and correlation with the full Spielberger State-Trait Anxiety Inventory is high (r = 0.95).38
All contact lens fitting consultations were conducted by the same female optometrist who had been qualified 4 years. Each consultation followed the same procedure order, including the same predetermined phrases spoken at key points. Furthermore, the same examination room was used for every consultation.
Analysis of the physiological data was primarily undertaken with the Biopac Student Lab Pro Version 3.6.5 software. ‘Event markers’ were added to the trace at key points during the consultation (Table 1). For each of these points a mean skin conductance response (SCR) value was calculated (based on data from a 5 s period, recorded 1 s after the mark). The rationale for this was to ensure that the peak of the SCR response was captured in the measurement. Latency of the SCR response is 1 to 3 s,37 and time until the peak is 1 to 3 s.37
Absolute skin conductance values are meaningless. Therefore, to compare skin conductance across participants some sort of normalization was required. A DC off-set approach was taken. The mean skin conductance value of the entire trace for each participant was calculated, from 30 s before optometrist entry until 30 s after the optometrist left. Subsequently, each of the values calculated for each key point of the consultation was subtracted from this value (i.e., the mean of the trace). This approach was taken as it was deemed to provide an efficient way of interpreting how each individual changed in arousal level throughout the consultation, as a function of their overall arousal.
Confidence intervals were used to describe the variation of arousal at each key point throughout the trace. Confidence intervals indicate the precision of the mean measurement,39 allowing a visual inspection of the range of values in which the population mean may lie (i.e., if confidence intervals do not overlap there is a high probability that the points are significantly different).
Questionnaire data was entered into SPSS and recoded such that all items had a consistent valance. Scores were calculated according to standard protocols; the sum of the category responses for each item.38 The non-parametric Wilcoxen signed-rank test was used when analyzing the shortened version of the Speilberger state anxiety scale.38
Forty participants (15 male, 25 female; mean age 28.3 ± 9.5) were recruited to the study. Descriptive information for the participants is presented in Table 2. None of the participants had tried contact lenses before. Fifteen of the participants were not current spectacle wearers; however, all were interested in trying contact lenses. The reasons cited by these participants wanting to try contact lenses were dislike of wearing spectacles or desire to try colored contact lenses.
Skin Conductance Results
The primary aim of this study was to identify if there are any points during the contact lens fitting appointment which are associated with higher levels of patient arousal. This data was collected during the consultation via skin conductance.
Initially all forty traces were inspected on a case-by-case basis. One of the traces was incomplete, because the patient felt faint during the routine and as such the study was stopped. The optometrist failed to insert contact lenses into the eyes of three participants, due to difficulties holding the eyelids open. A further case was removed from the analysis because the optometrist knocked the sensors on the participant’s hand half way through the routine. This resulted in a degraded trace. Therefore, there were a total of 35 cases in the final analysis (12 male, 23 female; age 27.7 ± 8.8 years).
Physiological recording began 30 s before optometrist arrival and continued until 30 s after the optometrist left. The participant had already been relaxing for a few minutes before this point. For each individual trace, a ‘pre-entry’ measurement was taken before the optometrist entered the room. This value was the mean SCR obtained during a 20 s period, which was taken 10 s before the optometrist arrived. Also, a final ‘post-entry’ measurement was calculated at completion of the consultation. This was the mean SCR over 20 s; 10 s after the optometrist had left the participant.
All the traces were grouped together for analysis. The mean SCR values across all traces were calculated for each key point in the consultation and plotted graphically (Fig. 1).
A visual inspection of Fig. 1 shows that there are four events which appear to be associated with heightened arousal. Peaks occur at history and symptoms (point 2), contact lens insertion (point 10), contact lens removal (point 17) and patient advice (point 21), suggesting that these were the most anxiety provoking parts of the fitting procedure. The error bars in Fig. 1 describe the magnitude of the 90% confidence intervals.
The data were also grouped according to gender and plotted graphically (Fig. 2). The pattern of arousal is very similar for both males and females.
The secondary aim of this study was to determine if participant state anxiety would be reduced after the contact lens appointment. Anxiety was assessed using data from questionnaires given to the same 35 participants before and after the consultation. The reliability of the short form of the Speilberger state anxiety scale was measured using Cronbach α (α = 0.70). There was no significant difference in preexamination state anxiety between males and females (Mann-Whitney U: z = −1.90; p = 0.062).
State anxiety reduced from a median value of 9 before the consultation to a median of 7 after the consultation. The non-parametric Wilcoxen test showed that the reduction was highly significant (z = −3.25, p = 0.001). This is not just a statistically significant reduction in anxiety but a clinically significant one.40
The aim of this study was primarily to detect the most stressful parts of the contact lens fitting consultation, and secondly to test if there was a significant reduction in patient state anxiety after the consultation. The results of this study highlight a formally unknown facet of the contact lens fitting consultation. That is, patient arousal levels fluctuate throughout the contact lens consultation in a characteristic way. Arousal levels peak during history and symptoms, contact lens insertion and removal and practitioner advice. This study has also shown that patient anxiety postconsultation is significantly less than before the consultation. Regarding participant trait anxiety, the participants in this study were representative of the general population (pro-rated values range from 8 to 13 for the normal population).28
The data in Fig. 1 suggest that there are two distinct types of event which cause increases in arousal. These events can be labeled as ‘communicative interaction’ and ‘contact lens insertion and removal.’
The first type of event, ‘communicative interaction’, relates to two specific periods during the consultation, both showing heightened levels of arousal. The first of the two periods is at the start of the consultation when the optometrist is asking the participant about their history and symptoms. This is an optometrist led dialogue involving questions about general health, visual problems and daily visual demands.6 Dialogue can be an anxiety provoking situation, causing some people to feel embarrassed or silly.41,42 Apart from this, it is recognized within social anxiety research that, within the context of formal encounters people generally do not want to appear foolish. As such, the desire to make a good impression fuels anxiety.43,44 The second of the two periods of ‘communicative interaction’ was at the close of the consultation when the optometrist was giving advice to the participant. This chiefly involved advising the participant about the fit of the contact lenses, instruction about lens care and also provided participants with a chance to ask questions. Again, this heightened arousal could be explained within a social anxiety framework.
However, although the explanations for heightened arousal during both these periods of ‘communicative interaction’ are valid, perhaps this result reveals a more fundamental patient concern. Namely, that patients place substantial value upon good communication with the optometrist. This is a well recognized patient concern within medicine. In that context, when patients do not feel understood by the practitioner, feel out of control or do not have their questions answered, they are less satisfied with the consultation.45–48 Communication between patients and practitioners is a dynamic and complex process.41 Considering this, perhaps it is not surprising that the participants in this study showed heightened states of arousal during these points in the consultation.
Table 2 shows that participants in this study had a range of first languages. However, although the ‘language barrier’ may disrupt communication and contribute to the generation of anxiety,45 this is unlikely to have been the case in this study because all participants were fluent English speakers.
Heightened levels of arousal are reported to be disruptive to task performance.49,50 Therefore, these findings may be clinically significant, i.e., if anxiety is a factor during these times of discourse, there is an increased risk of poor patient attention and recall of what the optometrist has said.17,18 For this reason optometrists should not assume that the patient will remember key information explained to them during the consultation. It may be beneficial for optometrists to consider providing written materials and repeating advice to patients i.e., techniques used in medical practice to improve clinical success.51–53
The second type of event which showed higher levels of participant arousal was ‘contact lens insertion and removal’. The results indicated that arousal increased when the optometrist told the participants “I am now going to select a contact lens and place it into your eye.” It is well understood that the ‘cognitive expectation’ of physical danger (e.g., pain) can evoke an anxiety response.54 This perhaps explains the increased level of arousal at this point. However, arousal reached a maximal level upon insertion of the right contact lens (the first of the two lenses to be inserted). Interestingly, the results suggest that this heightened state of arousal is not maintained upon insertion of the second contact lens, rather, mean arousal drops dramatically. There could be two possible explanations for this. Firstly, it could indicate habituation of the SCR. Habituation results in a decrease in physiological response upon repeated presentation of a stimulus.37 In other words, once the participant has experienced an event once, the second experience will never elicit the same level of response, despite their emotional state. However, it could also reflect a true reduction of participant anxiety. Experiencing the event once may create a more accurate patient “expectancy” resulting in a reduction of anxiety. Interestingly, the same pattern of arousal also occurs for the removal of the contact lenses.
Many patients avoid trying contact lenses because they are anxious about having a contact lens in their eye.3 However, these results may indicate that after the patient has experienced the event once, they are less anxious about having the second contact lens inserted (i.e., the ‘thought’ of having a contact lens in the eye is not as bad as the reality). Rigid Gas Permeable (RGP) contact lens research has shown that when the practitioner communicates information in a clear realistic way to the patient, there is an increased potential for clinical success.55 In other words, optometrists are in an influential position to help motivate patients to overcome potential barriers to contact lens wear by communicating effectively to the patient.
The gender breakdown in this study (62.4% females) is representative of the new contact lens fits in the UK, reported as 61% females in 2007.56 However, it is interesting to compare the pattern of arousal between men and women. Although, the groups are small when broken down according to gender, Fig. 2 shows the striking similarity in arousal between men and women. The biggest discrepancy between genders appears towards the end of the examination, where female arousal is less than males. This may have been because women were less anxious talking to a female optometrist. However, larger samples of males and females would be required to establish the validity of this result.
The secondary aim of the study was to ascertain if participant anxiety would be reduced after the contact lens consultation. This was confirmed by the questionnaire results which showed that patient state anxiety was significantly reduced postconsultation. This may suggest that the experience lead to more accurate patient expectancies and thus reduced anxiety, a conclusion supported by dental research36 (i.e., the experience was not as bad as expected). However, when interpreting the results of the current study it is important to recognize that there may be a ‘relief’ effect operating postconsultation. Thus, the reduction in anxiety may not be solely due to modified patient expectations. Nevertheless, these results are clinically significant for the optometrist. As previously discussed, these findings also suggest that if patients who express anxiety about trying contact lenses are motivated to try them, the experience of the contact lens fit may moderate their anxiety.
It will be noted that although physiological arousal showed a downward trend at the close of the appointment, when recording ceased the average arousal was higher than at the start of the appointment. However, because the Spielberger state anxiety scale was completed a few minutes prior and after the skin conductance recording, it is not appropriate to directly compare the physiological and questionnaire results (i.e., the measurements were not made simultaneously).
To ensure the validity of the measurements in this study it was important for the contact lens fitting consultation to be as comparable to professional practice as possible. Clearly the attachment of physiological electrodes and completion of anxiety questionnaires are not normal patient experiences. Therefore, one potential limitation of the study may be that these interventions heightened participant anxiety. However, every effort was made to reduce the impact of these interventions by providing the participant with information (written and verbal) before the consultation. Furthermore, research in dentistry has evaluated the impact of completing dental anxiety scales upon patient state anxiety. Results confirmed that completion of dental anxiety questionnaires had a non-significant effect upon patient state anxiety.57
In conclusion, this study has provided further insight into the patient experience of arousal and anxiety during a routine contact lens fitting consultation. Significantly, the results suggest that patients experience higher levels of arousal during periods of dialogue with the optometrist. It is clinically valuable information for optometrists to know that patients are potentially more anxious during such discourse, because anxiety can lead to poor attention.18 Therefore, every effort should be made to supplement verbal advice with written information.
The results also show that patient anxiety is reduced after the consultation. This suggests that patient anxiety may be moderated by experience. The clinical application is that if patients refrain from trying contact lenses simply because they are anxious, motivating them to have a consultation may lead to a reduction in their anxiety and thus remove a barrier from contact lens wear. This relies upon the optometrist initially communicating information about contact lenses in a clear and realistic way to the patient, which previous contact lens research has already shown increases in the potential for clinical success.55
This study was supported by a grant from Bausch and Lomb, Ltd. and Cardiff University.
School of Optometry and Vision Sciences
Cardiff CF24 4LU
1. Hewett TT. A survey of contact lens wearers. Part I: design and demographics. Am J Optom Physiol Opt 1984;61:65–72.
2. Hewett TT. A survey of contact lens wearers. Part II: behaviors, experiences, attitudes, and expectations. Am J Optom Physiol Opt 1984;61:73–9.
3. Hutchison G. Consumer and practitioner attitudes to contact lenses. Optician 2001;221:17–21.
4. House A, Stark D. ABC of psychological medicine: anxiety in medical patients. BMJ 2002;325:207–9.
5. De Leo D, Hickey PA, Meneghel G, Cantor CH. Blindness, fear of sight loss, and suicide. Psychosomatics 1999;40:339–44.
6. Ettinger ER. Professional Communications in Eye Care. Boston: Butterworth-Heinemann; 1994.
7. Shute R. It’s worse than going to the dentist. Opt Manage 1986:10–2.
8. Fylan F, Grunfeld EA. Visual illusions? Beliefs and behaviours of presbyope clients in optometric practice. Patient Educ Couns 2005;56:291–5.
9. Conroy RM, Smyth O, Siriwardena R, Fernandes P. Health anxiety and characteristics of self-initiated general practitioner consultations. J Psychosom Res 1999;46:45–50.
10. Southgate LJ, Bass MJ. Determination of worries and expectations of family practice patients. J Fam Pract 1983;16:339–44.
11. Lloyd CE, Dyer PH, Barnett AH. Prevalence of symptoms of depression and anxiety in a diabetes clinic population. Diabet Med 2000;17:198–202.
12. Corah NL. Dental anxiety. Assessment, reduction and increasing patient satisfaction. Dent Clin North Am 1988;32:779–90.
13. Griffiths HS, Wilson MA, Kincey JA. Anxiety levels, patient satisfaction and failed appointment rate in anxious patients referred by general practitioners to a dental hospital unit. Br Dent J 1998;185:134–6.
14. Salmon P. The reduction of anxiety in surgical patients: an important nursing task or the medicalization of preparatory worry? Int J Nurs Stud 1993;30:323–30.
15. Foggitt PS. Anxiety in cataract surgery: pilot study. J Cataract Refract Surg 2001;27:1651–5.
16. Nijkamp MD, Kenens CA, Dijker AJ, Ruiter RA, Hiddema F, Nuijts RM. Determinants of surgery related anxiety in cataract patients. Br J Ophthalmol 2004;88:1310–4.
17. Kent GG. The Psychology of Dental Care. Bristol: John Wright; 1984.
18. Taylor SE. Patient-practitioner interaction. In: Vaicunas J, Lynch L, Burns H, eds. Health Psychology, 3rd ed. Singapore: McGraw-Hill International; 1986:341–77.
19. Corah NL, O’Shea RM, Bissell GD. The dentist-patient relationship: perceptions by patients of dentist behavior in relation to satisfaction and anxiety. J Am Dent Assoc 1985;111:443–6.
20. Lang F, Floyd MR, Beine KL. Clues to patients’ explanations and concerns about their illnesses. A call for active listening. Arch Fam Med 2000;9:222–7.
21. Thompson B, Collins MJ, Hearn G. Clinician interpersonal communication skills and contact lens wearers’ motivation, satisfaction, and compliance. Optom Vis Sci 1990;67:673–8.
22. Margrain TH, Greenland K, Anderson J. Evaluating anxiety in patients attending optometric practice. Ophthalmic Physiol Opt 2003;23:287–93.
23. Tortora GJ, Grabowski S. The endocrine system. In: Roesch B, ed. Principles of Anatomy and Physiology, 9th ed. New York: Harper Collins; 2000:501–50.
24. Blascovich J, Kelsey R. Using electrodermal and cardiovascular measures of arousal in social psychological research. In: Hendrick C, Clark MS, eds. Research Methods in Personality and Social Psychology. Newbury Park, CA: Sage Publications; 1990:45–73.
25. Fimm B, Willmes K, Spijkers W. The effect of low arousal on visuo-spatial attention. Neuropsychologia 2006;44:1261–8.
26. Williams LM, Barton MJ, Kemp AH, Liddell BJ, Peduto A, Gordon E, Bryant RA. Distinct amygdala-autonomic arousal profiles in response to fear signals in healthy males and females. Neuroimage 2005;28:618–26.
27. Stern RM, Ray WJ, Quigley KS. Skin: electrodermal activity. In: Psychophysiological Recording, 2nd ed. Oxford: Oxford University Press; 2001:207–19.
28. Spielberger CD. State-Trait Anxiety Inventory: A Comprehensive Bibliography. Palo Alto, CA: Consulting Psychologists Press; 1984.
29. Abe JA. Self-esteem, perception of relationships, and emotional distress: a cross-cultural study. Pers Relatsh 2004;11:231–47.
30. Dey P, Bundred N, Gibbs A, Hopwood P, Baildam A, Boggis C, James M, Knox F, Leidecker V, Woodman C. Costs and benefits of a one stop clinic compared with a dedicated breast clinic: randomised controlled trial. BMJ 2002;324:507–11.
31. Gardner TF, Nnadozie MU Sr, Davis BA, Kirk S. Patient anxiety and patient satisfaction in hospital-based and freestanding ambulatory surgery centers. J Nurs Care Qual 2005;20:238–43.
32. Jenkins CD, Jono RT, Stanton BA. Predicting completeness of symptom relief after major heart surgery. Behav Med 1996;22:45–57.
33. Locker D, Shapiro D, Liddell A. Overlap between dental anxiety and blood-injury fears: psychological characteristics and response to dental treatment. Behav Res Ther 1997;35:583–90.
34. Novak A, Burgess ES, Clark M, Zvolensky MJ, Brown RA. Anxiety sensitivity, self-reported motives for alcohol and nicotine use, and level of consumption. J Anxiety Disord 2003;17:165–80.
35. Spielberger CD. Theory and research on anxiety. In: Spielberger C, ed. Anxiety and Behavior. New York: Academic Press; 1966:3–20.
36. Arntz A, van Eck M, Heijmans M. Predictions of dental pain: the fear of any expected evil, is worse than the evil itself. Behav Res Ther 1990;28:29–41.
37. Dawson ME, Schell AM, Filion DL. The electrodermal system. In: Cacioppo JT, Tassinary LG, Berntson GG, eds. Handbook of Psychophysiology, 2nd ed. Cambridge, UK: Cambridge University Press; 2000:200–23.
38. Marteau TM, Bekker H. The development of a six-item short-form of the state scale of the Spielberger State-Trait Anxiety Inventory (STAI). Br J Clin Psychol 1992;31(Pt 3):301–6.
39. Gardner MJ, Altman DG. Confidence intervals rather than P values: estimation rather than hypothesis testing. Br Med J (Clin Res Ed) 1986;292:746–50.
40. Dailey YM, Humphris GM, Lennon MA. Reducing patients’ state anxiety in general dental practice: a randomized controlled trial. J Dent Res 2002;81:319–22.
41. Floyd MR, Lang F, McCord RS, Keener M. Patients with worry: presentation of concerns and expectations for response. Patient Educ Couns 2005;57:211–6.
42. Lazare A. Shame and humiliation in the medical encounter. Arch Intern Med 1987;147:1653–8.
43. Holt CS, Heimberg RG, Hope DA, Liebowitz MR. Situational domains of social phobia. J Anxiety Disord 1992;6:63–77.
44. Schlenker BR, Leary MR. Social anxiety and self-presentation: a conceptualization and model. Psychol Bull 1982;92:641–69.
45. Harrington J, Noble LM, Newman SP. Improving patients’ communication with doctors: a systematic review of intervention studies. Patient Educ Couns 2004;52:7–16.
46. Meryn S. Improving doctor-patient communication. Not an option, but a necessity. BMJ 1998;316:1922.
47. Ong LM, de Haes JC, Hoos AM, Lammes FB. Doctor-patient communication: a review of the literature. Soc Sci Med 1995;40:903–18.
48. Stewart MA. Effective physician-patient communication and health outcomes: a review. CMAJ 1995;152:1423–33.
49. Ben-Zeev T, Fein S, Inzlicht M. Arousal and stereotype threat. J Exp Soc Psychol 2005;41:174–81.
50. Yerkes RM, Dodson JD. The relation of strength of stimulus to rapidity of habit-formation. J Comp Neurol Psychol 1908;18:459–82.
51. Kupst MJ, Dresser K, Schulman JL, Paul MH. Evaluation of methods to improve communication in the physician-patient relationship. Am J Orthopsychiatry 1975;45:420–9.
52. Ley P. Memory for medical information. Br J Soc Clin Psychol 1979;18:245–55.
53. Ley P, Whitworth MA, Skilbeck CE, Woodward R, Pinsent RJ, Pike LA, Clarkson ME, Clark PB. Improving doctor-patient communication in general practice. J R Coll Gen Pract 1976;26:720–4.
54. Edelmann RJ. Anxiety: Theory, Research and Intervention in Clinical and Health Psychology. Chichester, NY: Wiley; 1992.
55. Bennett ES, Stulc S, Bassi CJ, Schnider CM, Morgan BW, Henry VA, Henderson B, Roskam S. Effect of patient personality profile and verbal presentation on successful rigid contact lens adaptation, satisfaction and compliance. Optom Vis Sci 1998;75:500–5.
56. Morgan P. Trends in UK contact lens prescribing. Optician 2007;233:16–7.
57. Humphris GM, Clarke HM, Freeman R. Does completing a dental anxiety questionnaire increase anxiety? A randomised controlled trial with adults in general dental practice. Br Dent J 2006;201:33–5.