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Pilot Study of Contact Lens Practitioner Risk-Taking Propensity

Carnt, Nicole*; Keay, Lisa; Willcox, Mark D. P.; Evans, Vicki; Stapleton, Fiona

doi: 10.1097/OPX.0b013e31821ddd9c
Original Article

Purpose. To determine risk-taking propensity of optometrists and the association with the volume of contact lens practice and prescribing profile. Other factors associated with high practitioner risk taking and larger volume contact lens practices were also investigated.

Methods. Sixty-four practitioners were recruited through Australian professional associations. Practitioners completed a risk-taking propensity survey and rated the importance of risk factors for contact lens-related microbial keratitis on prescribing decisions and wearer advice (prescribing profile). Demographics and the number of contact lens wearers seen per week were documented. Risk-taking propensity was estimated after adjusting for item difficulty using Rasch analysis, then scaled 0 to 100. Prescribing profile, practice type, practitioner age, and gender were tested for association with risk-taking propensity. Risk-taking propensity, practitioner age, personal contact lens wear, and the socioeconomic status of the practice location were investigated for association with the volume of contact lens patients with regression.

Results. Rasch analysis of the risk-taking questionnaire indicated good person separation and reliability (2.44, 0.86) but some item redundancy (1.69, 0.74). Risk taking (mean 35, range 0 to 71) was associated with increasing number of contact lens patients (p = 0.02). The perceived importance of risk factors (p = 0.9) and likelihood of discussing them with patients (p = 0.7) were not associated with risk-taking propensity. Risk taking (p = 0.02) and socioeconomic status of the practice location (p = 0.03) were predictors of higher volume contact lens practices.

Conclusions. Practitioners who see a higher volume of contact lens patients tend to have higher risk-taking personalities. However, increased risk taking did not affect the perceived importance and type of advice given to contact lens wearers. Higher socioeconomic status of the practice location is also associated with larger volume of contact lens patients. This information gives insight into what drives higher volume contact lens practice within Australia and may have applications to the contact lens and wider optical industry.


*BOptom, FAAO



Brien Holden Vision Institute, Sydney, New South Wales, Australia (NC, MDPW, FS), School of Optometry and Vision Science, University of New South Wales, New South Wales, Australia (NC, LK, MDPW, VE, FS), and The George Institute for Global Health, University of Sydney, New South Wales, Australia (LK).

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (

This work was supported by the Brien Holden Vision Institute and the British Contact Lens Association Dallos Award 2010.

Received November 30, 2010; accepted March 21, 2011.

Nicole Carnt, Brien Holden Vision Institute, Level 3, Rupert Myers Building, North Wing, Gate 14, Barker Street, University of New South Wales, Sydney, New South Wales 2052, Australia, e-mail:

Contact lenses in Australia, and many countries around the world, are generally only available on prescription from a registered practitioner. Prescriptions are usually issued with an expiration date requiring review from a practitioner before a further supply can be purchased. Practitioners have a legal duty of care to check the fit and prescribe lenses that are adequate for the visual and physiological needs of the wearer1 and the majority of wearers report receiving advice about how to care and handle contact lenses from practitioners.2

Contact lenses and solutions are packaged with instructions but in many cases, reference to “in accordance with your practitioner's advice” is made. Recent studies have highlighted the need for consistent guidelines for practitioners3 and attempts have been made by several bodies including the U.S. Food and Drug Administration4, but these guidelines are not universally endorsed or adopted.

The safety and complications rates with contact lens products may be influenced by how they are marketed, prescribed, and the types of people who wear lenses. When a frequent replacement modality was first introduced into the contact lens market in the 1980s, the relative risk of microbial keratitis was significantly higher when compared with similar lenses replaced less frequently.5,6 Over time, as frequent replacement lenses became the lens of first choice, this excess risk disappeared.7 This initial excess risk has been attributed to the use of new technology as a problem solving modality or to either the wearers or practitioners being early adopters of new technology.7,8 Risk taking has been associated with a need to experience novel stimuli9 and a market dominated by wearers prescribed by “early adopter” practitioners, prone to take more risks, may have artificially inflated the risk of microbial keratitis with this new technology when first introduced.

Contact lens wearers with higher risk-taking propensity have been shown to be less compliant than those that take fewer risks.10 High risk-taking propensity is associated with a decreased perception of the danger of situations.11 Higher risk-taking practitioners may believe severe complications are less common and/or the consequences are not as severe as more conservative colleagues. These thought processes are relevant to the Health Belief Model that indicates that the susceptibility and severity of a condition need to be acknowledged for compliance to occur.12,13 High risk-taking practitioners may therefore, be less inclined to follow generally accepted best practice advice to strongly educate wearers on adequate hygiene and lens care.

We hypothesize that practitioners with high risk-taking personalities have larger contact lens practices and do not place as much importance on the behavioral risk factors for microbial keratitis in information given to wearers or in consideration of the non-modifiable risk factors when prescribing contact lenses compared with those who are prone to take fewer risks. This study aimed to determine the attributes of contact lens practitioners and mode of practice that are associated with high risk-taking personality styles.

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In this study, we assessed the relationship between the risk-taking personality style of practitioners, the volume of contact lens practice, the way they interacted with current and potential contact lens wearers, and their demographic status. The relationship between risk taking and the volume of contact lens practices was explored adjusting for demographics of the practice and practitioner.

Practitioners were invited to participate in the study via two sources; the first group was verbally invited to participate at a Continuing Education seminar hosted by the Optometrists Association of Australia (OAA), NSW Division in June 2009; the second group, members of the Cornea and Contact Lens Association of Australia (CCLSA), were sent an email invitation. Both groups completed a validated questionnaire assessing risk-taking propensity,11 prescribing profile and volume of wearers was self-reported either on paper or on-line. The study was approved by the local ethics committee and followed the Tenets of the Declaration of Helsinki, 2000.

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Risk-Taking Propensity Survey

A 20-item instrument11 scored on a 5-point Likert scale was used to determine risk-taking propensity (Appendix available at All questions were positively phrased. However, according to the scoring system, a higher score indicated lower risk taking. Before analysis, scores were reversed so that a high number corresponds with high risk-taking propensity. Discriminating ability and reliability of the survey items and respondents were investigated with the Rasch model (Ministeps, Chicago, IL).14 Raw scores for the 20 items were converted to an interval estimate of risk-taking propensity using Rasch analysis15 and then scaled to 0 to 100.

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Prescribing Profile

Supplementary Digital Content 1 also details the prescribing profile survey. Practitioners self-reported the average number of contact lens wearers they saw per week in six categories. They were asked to rate on a 1 to 4 scale how important they thought it was to discuss with wearers specified modifiable potential risk factors for microbial keratitis and how non-modifiable intrinsic risk factors influence how they prescribe contact lenses to individuals. These factors were expanded from a previous survey of practitioners that was used to assess knowledge and application of research evidence in contact lens practice.16

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Demographic and Population Data

Practitioners were asked their gender, date of birth, whether they wore contact lenses themselves, the type of practice, and the postal code of their primary practice location. Socioeconomic status of the region of the practice location was determined by the Socio-Economic Indexes for Areas (SEIFA) Index of Education and Occupation (IEO)17 decile corresponding to the postal code of the primary practice. The IEO is calculated from information gathered at the 2006 Australian Census and is derived from variables such as the proportion of people with tertiary qualifications or employed in skilled occupations in the designated area compared with other regions in Australia.18

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A previous analysis of risk-taking propensity of contact lens wearers using the same survey,10 indicated a sample of 52 subjects was sufficient to show a 15-point difference in risk taking score (0 to 100) with 80% power at a significance of 5%. Demographics and risk-taking propensity of the OAA and CCLSA recruited optometrists were compared with the t test and chi-square test. In univariate analyses, the association between risk taking and practitioner profile and age was assessed using correlation, risk taking and volume of contact lens practice and type of practice, with analysis of variance, and risk taking and sex using a t test. Risk taking, age, IEO, and whether practitioners wore contact lenses were considered in a nominal logistic regression to determine predictors of the volume of contact lens practice. Nominal logistic regression, as opposed to linear regression, was performed as the volume of wearers was collected in categories. The categories for volume of contact lens wearers and IEO were collapsed for analysis because of the small sample size in some of the categories. Analysis was conducted with SPSS statistical software Version 16.0 (SPSS, Chicago, IL). Statistical significance of p < 0.05 was set.

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Sixty-four optometrists completed the survey, 43 from the OAA workshop and 21 from the CCLSA. The demographics of the practitioners are shown in Table 1. The majority of practitioners worked in independent practices, and there were a similar number of male and female optometrists participating. There was no difference between the practitioners recruited from the OAA workshop compared with CCLSA in terms of age (p = 0.6), gender (p = 0.5), practice type (p = 0.4), whether they wore contact lenses themselves (p = 0.9), or in their risk scores (p = 0.3). As expected, the members of the CCLSA fitted a higher volume of wearers that the OAA workshop group (p = 0.003).



The mean risk score of all practitioners was 35 with an SD of 16, and ranged from 0 to 71, when scaled 0 to 100. Fig. 1 shows a modified Wright plot19 of the relationship between the individual scores (in logits) and the item difficulty. Although item separation and reliability were slightly lower than ideal (1.69, 0.74), person separation and reliability were within accepted limits (2.44, 0.86).



Table 2 illustrates the distribution of the number of wearers seen on average per week per practitioner. For analysis, the categories were collapsed into three groups, low volume, ≤1; mid volume 2 to 10; and high volume, >10 wearers per week because there was a low sample size in some of the categories. The majority of practitioners saw between 2 and 10 wearers per week. The distribution of the IEO deciles is shown in Table 3, which indicates that the majority of practice locations were in higher socioeconomic areas. As for the volume of wearers, IEO was collapsed into three groups, low deciles 1 to 5, mid deciles 6 to 8, and high deciles 9 to 10. The proportions of practitioners who rated the discussion of key modifiable risk factors with wearers and rated intrinsic factors in lens prescribing as “very important” is shown in Fig. 2. High importance was attached to modifiable risk factors, such as washing hands but less to intrinsic risk factors such as youth and gender.







A higher risk-taking score was associated with an increasing number of wearers seen per week (p = 0.03) but not with information conveyed to wearers about modifiable risk factors, how intrinsic traits influence contact lens prescribing, age of the practitioner, gender (p = 0.7), or the type of practice (independent; multiple/franchise; locum; p = 0.7; Table 4).



Regression analysis of the factors predicting the number of wearers seen per week indicated that risk taking (p = 0.02) and IEO (deciles collapsed to three categories low 0 to 5; mid 6 to 8; high 9 to 10; p = 0.03) were significant factors. Parameter estimates, shown in Table 5, indicate that risk taking was significant when the low volume practitioners were compared with the mid- and high-volume practices, whereas IEO was only significant between the low- and high-volume practices.



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Practitioners with higher risk-taking propensity saw more wearers per week indicating that they may be more inclined to see opportunities for contact lens wear compared with low risk takers. This relationship was able to discriminate more closely than socioeconomic status of the practice region, which was also predictive of contact lens practice. To our knowledge, this is the first time personality characteristics of optometrists have been examined and compared with the options used for refractive correction.

When optometrists practice in higher educated, more skilled workforce regions, the potential for a higher volume of contact lens patients is also increased. This is not surprising because contact lenses are more expensive than spectacles and more available to wealthier individuals.20,21 It was expected that the CCLSA members would see a higher volume of wearers per week compared with the OAA workshop group. It is interesting that there was no difference in the risk taking propensity of the two recruitment groups; however, we would expect that if we had a larger sample of CCLSA members, we would have seen similar factors predicting success if this group alone was analyzed.

Another factor that is likely to influence the success of contact lens prescribing is the communication skills of the practitioner. Studies of non-verbal cues that are involved with social persuasion have indicated that an authoritative but approachable manner is advantageous,22,23 and these characteristics are likely to be relevant to contact lens practice. In addition, well-developed clinical skills and early career exposure to contact lens fitting may increase confidence and render practitioners more likely to suggest contact lenses to potential wearers. It would be interesting to measure and incorporate these factors into future models that predict high volume contact lens dispensing.

Although risk-taking contact lens wearers tend to be more non-compliant,10 high risk-taking practitioners did not appear in this survey to offer different advice or prescribe lenses based on different criteria compared with low risk takers. It is likely that clear evidence/advice about risks for contact lens complications exists and most practitioners recognize the importance of these issues. Our findings suggest that increased infection rates with frequent replacement lenses close to market launch7 in the 1980s were probably not explained by risk-taking personality of new adopter practitioners giving less stringent advice to wearers than low risk takers. It may be more likely to be related to the type of wearer that was fitted, such as wearers who had previous adverse events, or high risk-taking propensity of those new adopter wearers themselves, and/or a tendency to take more risks with the lenses because they had a perceived increased level of safety.

In this group of contact lens practitioners, younger age and male gender were not associated with higher risk taking, as in other populations such as motor vehicle drivers.24 Younger age and male gender are established independent risk factors for developing microbial keratitis.25 Adolescents and young adults have been shown to have a higher risk-taking propensity thought, in part, because of the way they view the world,26,27 and physiological differences in their brains.27 However, in this study, we were not able to explore the effect of age as most practitioners were >30 years of age. It is interesting that male practitioners were not higher risk-takers than females, which may indicate that optometrists are a homogenous group with no differences by gender.

In medicine, risk-taking personalities of practitioners have been investigated in relation to patient care. Higher risk-taking practitioners have been found to admit less emergency patients with chest pain to hospital,28 make less referrals,29,30 prescribe less antibiotics,30 and order fewer laboratory diagnostic tests.31 It would be interesting to explore the relationship between risk taking and patient care in optometry, particularly for prescribing different types of contact lenses but also in the area of prescribing therapeutic drugs for anterior eye conditions and referral rates.

Practitioners have a unique position in counseling wearers about the safety of lenses as well as prescribing lenses that fit and provide good vision and long-term physiological health. Supply of contact lens solutions through pharmacy and supermarket chains and supply of lenses by internet traders is likely to diminish the level of care optometrists can provide to wearers as point of sale advice on product use and aftercare schedule is probably not provided by these other retailers. A recent epidemiological study showed that internet/mail order purchasing is an independent risk factor for microbial keratitis.32 Internet contact lens purchasers have been shown to be more time pressured and less likely to follow Food and Drug Administration instructions for lens care.33 The proportion of wearers obtaining lenses via internet or mail order has increased recently21 and is likely to continue to expand which could pose a public health issue. Increasing awareness of the risks of contact lens wear of this group will be an ongoing challenge.

Several studies have not shown an increase in contact lens compliance following intervention strategies. One study looked at self-analysis among a population of young university students34 and it is likely that this group is among the most difficult in which to increase compliance. In another study, an enhanced education program was not more effective than standard instruction on contact lens compliance35; however, this may be because the standard instruction was beneficial in itself. Although it must be acknowledged that there is likely to be a level of non-compliance with most wearers that will fluctuate depending on life and time stresses, and that manufacturers and regulatory bodies need to acknowledge that lenses and solutions will have a level of “user error” that should be factored into testing regimes, a certain level of compliance is expected. It is imperative, however, for responsible practitioners, to always reinforce hygiene and compliance.

The findings of this study give direction for the marketing of contact lenses. Optometrists are in a unique position of being the gatekeeper of new optical products in the marketplace and the contact lens industry works through practitioners to market contact lenses and new products. A previous study has found that high risk takers accurately assess health risks but low risk takers tend to overestimate risks.36 Industry often uses practitioners who have high volume practices or peer leaders to test new products and introduce them into markets. It is possible that high risk-taking propensity in peer leaders encourages exploration of new products in the market. It would have been interesting in this study to ask if people try new products as soon as they are released to explore this hypothesis and this will be followed up in subsequent studies.

Although the sample size of this study is relatively small and represents only ∼2% of the estimated 3,719 Australian optometrists in clinical practice in 2009, it is sufficient for analysis, and represented a reasonable spread of risk-taking personalities. However, the proportion of independent practitioners in this cohort is likely to be higher than in the overall population of Australian practitioners and this may limit the generalizability of this study. Recruitment of additional non-independent practitioners in Australia and practitioners from other regions may have produced a wider spread of risk taking personalities and would be expected to strengthen the conclusions of this study. In addition, inclusion of sufficient numbers of practitioners in different modes of practice and from different regions may provide insights into the practitioners attracted to certain styles of practice. A strength of this study is that it was conducted with optometrists practicing in the community. These practitioners are more difficult to access than those working in industry or academia, but the responses are much more likely to reflect actual patient care.

Practitioners with higher risk-taking propensity prescribe more contact lenses than those who are prone to take fewer risks. However, high risk-takers report giving similar advice to contact lens wearers as their lower risk-taking colleagues. Non-modifiable intrinsic factors play the same role in prescribing contact lenses to potential wearers. In addition to risk-taking personality of the practitioner, the socio-economic status of the region in which they practiced was a predictor of higher volume contact lens practice. This information sheds light on what factors drive high use of contact lenses in optometric practice in Australia and has important implications for the contact lens and possibly wider optical industry.

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We thank the practitioners who took part in this study and acknowledge the logistical support of the Optometrists Association of Australia and the Cornea and Contact Lens Society of Australia. We also thank Christopher Brady and Andrea Villanti for assistance with the modified Wright plot.

Nicole Carnt

Brien Holden Vision Institute

Level 3, Rupert Myers Building, North Wing

Gate 14, Barker Street

University of New South Wales

Sydney, New South Wales 2052



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The appendix (risk-taking and prescribing profile surveys) is available at

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practitioner; optometrist; risk taking; compliance; practice; contact lens; socioeconomic status

© 2011 American Academy of Optometry