Optometrists' attitudes toward using OCT angiography lag behind other retinal imaging types

While optometrists' attitudes toward established retinal imaging types are generally positive, they are unknown for optical coherence tomography angiography (OCTA). We performed a cross‐sectional survey to estimate attitudes toward OCTA and identify clinician and/or practice characteristics that influence them.

and the accuracy of diagnoses. 7,9 Retinal imaging uptake in primary eye care practices is increasing [10][11][12][13] and reflects recommendations by expert consensus groups and peak professional bodies to integrate ocular imaging into standard clinical care. [14][15][16][17][18][19] Retinal imaging has continued to evolve, and new imaging modalities have become available for commercial use. 20,21 Unlike established retinal imaging, their acceptance is difficult to judge using self-reported practice patterns, self-rated confidence 10,22 or competency, 23 as most optometrists have limited initial exposure to these procedures in primary eye care practices. Understanding attitudes toward new retinal imaging and factors likely to promote or reduce their acceptance may guide efforts to increase implementation and consequently the translation of clinical benefits of this new technology to community care settings. 24 Dabasia et al. reported that 40%-55% of optometrists endorsed statements that specialist equipment such as retinal imaging enhances clinical assessment, management, decision-making, enables increased involvement in co-management arrangements and confers financial or reputational benefits to the practice. 11 However, these attitudes pertained to a limited number of retinal imaging types relative to the range of devices currently available.
We conducted a cross-sectional survey to estimate attitudes toward using state-of-the-art retinal imaging in primary eye care practices throughout Australia, with the secondary purpose to identify individual clinician or practice-level characteristics that influenced these attitudes. State-of-the-art retinal imaging was defined using the example of optical coherence tomography angiography (OCTA), which first became commercially available in 2014. 25 OCTA provides visual representations of retinal vascular networks by comparing decorrelations between repeated OCT B-scans 25 and demonstrates superior ability in detecting sight-threatening neovascular lesions across a range of retinal diseases. [26][27][28] Despite these advantages, recent estimates suggest that OCTA is only available in 10.5%-18.6% of clinical settings. 12,29 As part of the survey, a clinical scenario where OCTA had just become available in the respondent's practice if they did not already have access to the technology was presented. Previous work shows that further clinical training 10,30 and greater exposure to other technology in the workplace is linked with a more positive attitude toward new technology. 29 Thus, we hypothesised that overall attitudes toward OCTA would be positive and that higher education and a greater number of ophthalmic devices used at the current workplace would positively affect attitudes.

METHODS
Researchers at the Centre for Eye Health (University of New South Wales, Sydney) designed and conducted a crosssectional mail-out survey of randomly selected practicing optometrists with general registration across Australia. The research protocol was approved by a University of New South Wales Human Research Ethics Advisory Committee (HC220118; April 2022).

Survey instrument design
A comprehensive review of the literature was performed to identify previously published surveys evaluating clinician attitudes toward new technology in clinical practice by searching PubMed using the following terms: surveys and questionnaires, diagnostic equipment, optometry and ophthalmology. Reference lists were hand-searched to obtain additional articles. Relevant articles were retrieved and reviewed to identify themes, topic areas and items from previous questionnaires. Items included in the survey were primarily based on a recently published survey evaluating attitudes of optometrists toward artificial intelligence 29 and the Unified Theory of Acceptance and Use of Technology 2 (UTAUT2).
The UTAUT2 questionnaire evaluates constructs that are considered significant determinants of user acceptance and usage of new technology including, but not limited to: performance expectancy (degree that technology will increase job performance), effort expectancy (ease of use), social influence (belief that other important people think that they should use the technology), facilitating conditions (belief that there is organisational and technical infrastructure to support technology use) and hedonic motivation (fun or pleasure obtained from using technology). 31 A draft instrument was pilot-tested by three research students who were also registered optometrists. The feedback was mostly related to improving the consistency of terminology between items, changing ambiguous wording, adding clarifying statements and subheadings and changing the order of items to improve the flow of the survey. Appropriate modifications were made to address these comments while maintaining the integrity of item formats derived from original sources. The final eight-page self-administered survey ( Figure S1) was structured into four sections:

Key points
• The usage and availability of optical coherence tomography angiography is lower than other commercially available types of retinal imaging. • Optometrists are undecided regarding the usefulness of optical coherence tomography angiography, and less confident that they have the knowledge to interpret it compared with other types of retinal imaging. • Further work is needed to communicate the benefits of optical coherence tomography angiography usage in primary eye care. A free response section was provided at the end of the survey for any additional comments. Multiple choice questions in section 2 included the following options: never (score 1), once a month (score 2), 2-3 times per week (score 3), 4-5 times per week (score 4), daily (score 5), many times per day (score 6) or not available at my workplace (score 0). In sections 3 and 4, agreement to statements was ranked on a 5-point Likert scale: strongly disagree (score 1), disagree (score 2), neither agree nor disagree (score 3), agree (score 4), and strongly agree (score 5). As Likert scales represent ranked categorical levels of strength of agreement or disagreement on an ordinal scale, 32 overall item responses were mapped to appropriate descriptive statements by rounding the mean of all item responses (e.g., a mean score of 3.5 out of 5 was mapped to overall agreement).

Survey administration
A modified version of Dillman's Total Design method was used to administer the survey to minimise response burden and maximise response rates. 33 Survey packs comprising a booklet-type questionnaire, introductory letter and prenumbered reply-paid (stamped) return envelope were mailed to each potential participant in May 2022. When the surveys were returned, the assigned number was recorded and the corresponding participant contact details were removed from the mailing list. Non-respondents were sent additional reminder survey packs from June to October following the same procedures as the initial mail-out. Participants were not offered any financial incentives for completing the survey and confidentiality and anonymity were maintained throughout data collection, analysis and interpretation.

Sampling frame
Practising optometrists registered with Optometry Australia, a professional body of optometrists that represents 85% of all registered optometrists in Australia, were eligible for the study. 34 In accordance with sample size requirements, 252 postcodes were randomly selected from a complete list of Australian postcodes. 35 Participants were then identified by inputting the postcodes in the 'Find an optometrist' function provided on the Optometry Australia website. 36 The number of postcodes selected per state was stratified according to the proportion of Australian optometrists practising in each state. 34

Sample size estimate
As there are 6083 practising optometrists in Australia who hold general registration, 34 a sample size of 126 participants was needed to provide 95% certainty around a 10% margin of error on the primary outcome question probing attitudes toward OCTA. 37 The expected response rate from the literature is at least 50%; 37-40 thus, 252 potential participants were invited to participate in the study.

Statistical analysis
Responses were recorded in Microsoft Excel (Micro soft.com) and transposed to SPSS (version 25; IBM, ibm.com) for data analysis. Categorical variables were described by frequencies and continuous data and the results of centred and balanced Likert scales were described by means and standard deviations (SD). 41 Univariable and multivariable linear regression was used to explore relationships between independent variables in section 1 and the primary outcome question probing attitudes toward using new retinal imaging in primary eye care practice, that is, 'I believe OCTA is useful in daily practice', which gauges performance expectancy. 31 Twosided 5% significance levels were used to identify statistically significant results. Differences >0.5SD between Likert scales were accepted as clinically meaningful. 42 All statistical analyses were conducted using SPSS.

Response rate
The survey was sent to the sample population in five consecutive mail-out rounds between 9th May and 10th October. After the initial mail-out, 49 of 252 (19%) surveys were returned; an additional 35 surveys were returned after the second mail-out, 18 after the third mail-out, 10 after the fourth mail-out and 6 after the final mail-out. Data collection ended 10 weeks (December 5th) after the final mail-out and an overall response rate of 47% (118/252) was achieved. Response rates were calculated using the standard definitions established by the American Association for Public Opinion Research (AAPOR) with surveys missing more than 50% of responses excluded from analysis (n = 0). 43 The individual question completion rate ranged from 78% (92/118) to 100% with most non-responses occurring in section 2 (usage frequency).
Two participants failed to complete the first 12 items of the survey, resulting in consecutive missing responses to participant characteristic questions. Some respondents also selected multiple options for items soliciting main workplace location (n = 2), work setting (n = 1) and type of record keeping system (n = 4), despite instructions to provide only one response, which were treated as invalid meaning that an individual response for that item was not included. One respondent indicated that they saw 10 patients with retinal disease on an average day at their main workplace, exceeding the two in total that they saw. Thus, both responses to items 1.10 and 1.11 were similarly treated as invalid in this case. Complete details of respondent characteristics can be found in Table 1 and Table S1.
Clinician practices mainly used electronic record systems (87.3%, 103/118) for record-keeping, although a small proportion reported using paper-based records (11.9%, 14/118). The mean number of computerised T A B L E 1 Key respondent characteristics.

Age (years)
Mean (SD) 44 systems used in practices was 3.6 (1.6) and external, contracted IT service providers were most frequently used to oversee IT systems (61.9%, 73/118). Complete details of respondent and workplace characteristics can be found in Table 1 and Table S1.

Retinal imaging device usage
Optometrists frequently reported using fundus cameras and OCT 'many times a day' ( Respondent attitudes toward the application of retinal imaging in primary eye care were also generally positive. There was strong agreement for both statements 'I use retinal imaging to aid the diagnosis of retinal disease' (mean score 4.7 [0.6]) and 'I believe there is an overall need for retinal imaging in primary eye care' (mean score 4.7 [0.7]). Respondents also agreed that they used retinal imaging as a learning tool to improve their own diagnostic abilities with a mean score of 4.4 (0.8).
Optometrists agreed with all statements pertaining to the operational aspects of using retinal imaging devices. Agreement was greatest for the statement 'I find retinal imaging easy to use' with a mean score of 4.4 (0.8), followed by 'I find retinal imaging enjoyable to use' (4.2 [0.9]) and 'I use retinal imaging to save time' (3.6 [1.3]). Similarly, there was overall agreement toward statements exploring motivations to use retinal imaging due to peer influence: 'People who influence my work behaviour think I should use retinal imaging' (mean score 3.9 [0.9]) and 'People whose opinions that I value prefer that I use retinal imaging' (mean score 4.0 [0.9]) ( Table 3).
For items exploring the facilitating conditions of retinal imaging use, respondents strongly agreed with the statements 'Retinal imaging fits into my clinical workflow' and 'I have the knowledge to use retinal imaging equipment' for which the mean scores were 4.5 (0.7). There was also overall agreement that they had the knowledge to interpret retinal imaging results (mean score 4.4 [0.7]), and that retinal imaging is compatible with other technology used in the workplace (mean score 4.2 [1.0]). The statement attributed with the lowest score was 'I can get help from others when I have difficulty using retinal imaging' (3.7 [1.2]). The mean scores and distribution of responses for all statements are provided in Table S2.

Attitudes toward OCTA
To determine respondents' attitudes toward newer retinal imaging, key items from the UTAUT2 questionnaire included in section 3 were adapted to probe attitudes toward OCTA. As recent surveys indicate that OCTA is not widely available, 12 respondents were asked to consider a hypothetical scenario where the technology had just become available at their practice if they did not already have access to it.
While respondents were previously neutral toward the key statement 'I believe OCTA is useful in daily practice' (3.4 [0.8]), establishing its availability at their current workplace/s created a significant shift in attitudes toward agreement with the corresponding item 'I believe OCTA will be useful in daily practice' (3.6 [0.8]). However, as the mean difference in scores (0.22 with a 95% CI around the difference of 0.08-0.37) was less than half a standard deviation (0.78), this does not represent a clinically meaningful change.

Variable Results
Computerised systems (may have reported <1), % (n/N) Other items adapted for the final section of the survey originally referred to retinal imaging rather than OCTA. Thus, the difference in mean scores between corresponding items was designed to represent differences in attitudes toward older versus newer retinal imaging. A clinically significant difference in mean scores was observed between corresponding items measuring hedonic motivation (fun or pleasure obtained from using new technology) (p < 0.001, 0.68 [0.92]), peer influence (p < 0.001, 0.84 [1.14]) and facilitating factors (p < 0.001, 1.48 [1.09]), shown in Table 4. Overall, respondents felt less positive about using OCTA than retinal imaging, indicating neither agreement or disagreement to the statements: 'people who influence my work behaviour think I should use OCTA' (mean score 3.0 [0.9]) and 'I have the knowledge necessary to interpret OCTA' (mean score 2.9 [1.1]). Although there was also a negative shift in attitudes regarding hedonic motivation, respondents agreed that both retinal imaging (mean score 4.2 [0.9]) and OCTA (mean score 3.5 [0.8]) would be enjoyable to use.

Factors influencing attitudes toward OCTA
Of all respondent characteristics, the number of optometrists working per day at the main workplace (p = 0.03) was the only variable significantly associated with a weaker positive belief in the usefulness of OCTA in daily practice (multivariate p = 0.02). Univariate analysis revealed that performance expectancy attitudes toward OCTA did not vary by clinician or practice characteristics including age (p = 0.24), gender (p = 0.94), primary eye care experience (p = 0.28), work setting (p = 0.68), total (p = 0.85) or retinal disease (p = 0.94). Patients seen per day, state (p = 0.69) or location (p = 0.79) of the respondents' main workplace. Attitudes on the usefulness of OCTA did not differ significantly based on the accessibility of ophthalmology services (p = 0.15), degree to which respondents felt involved in decision-making to acquire (p = 0.84) or perform (p = 0.15) retinal imaging, the number of computerised (p = 0.85) systems or parties used to oversee IT systems (p = 0.49) and responsibility for IT systems at work (p = 0.30). Complete details are summarised in Table S3. General respondent comments regarding use of retinal imaging provided at the end of the survey are listed in Table S4.

DISCUSSION
We conducted a mail-out survey of practising optometrists in Australia to estimate their attitudes toward using T A B L E 2 Usage frequency of retinal imaging devices.

Retinal imaging
A variety of retinal imaging types are commercially available to diagnose and monitor retinal diseases. The adoption of new retinal imaging methodologies into clinical practice improves standards of care by enhancing visualisation of disease features that assist with clinical diagnosis and management. For example, OCT imaging visualises fluid associated with neovascular AMD 44 and polypoidal choroidal neovascularisation 45 with greater sensitivity than fundus photography, and has become essential in determining treatment indication and monitoring the effectiveness of anti-angiogenic therapy. 46 Similarly, infrared reflectance is superior to other imaging modalities for identifying reticular pseudodrusen, 47 an important risk factor for progression to late AMD. 48 The consistency of disease feature interpretation can also be improved by utilising different types of retinal imaging. In late AMD, fundus autofluorescence is superior to digital fundus photography for documenting the size of atrophic areas, 49 and interobserver agreement of diabetic retinopathy grades is higher for ultra-wide field than digital fundus imaging. 50,51 Thus, the adoption of new types of retinal imaging is beneficial for retinal disease screening, diagnosis and management. However, the availability and usage of different imaging modalities varies among primary eye care practices and optometrists in high-income countries. 11,12 Recent surveys estimate that fundus photography and OCT is available to over 75% of Australian optometrists, yet only 42% have access to ultrawide-field imaging. 12 Similarly, over 90% of optometrists use digital retinal imaging to care for patients, but only 30%-40% utilise ultrawide field or fundus autofluorescence imaging. 23 Thus, it would be useful to predict factors influencing the acceptance and use of new, state-of-the-art retinal imaging types, particularly where availability is initially low, such as OCTA, which is available to <20% of Australian optometrists. 12 Potential barriers to implementing new retinal imaging in primary eye care can be explored by assessing the attitudes of clinicians toward them, as attitudes influence the use of new technology. 31 The advantage of this approach is that attitudes can be identified irrespective of whether retinal imaging types are available, whereas measuring usage is restricted by availability. This study is the first to explore clinician attitudes toward retinal imaging types that are commercially available and to determine whether practice or clinician characteristics influence attitudes toward new technology, represented by OCTA.

Attitudes toward retinal imaging in clinical practice
Previous works describing optometrists' attitudes toward retinal imaging are limited to specific disease-contexts and focus on retinal imaging types that are relevant to them. However, the findings suggest that optometrists believe there is adequate organisational and technical infrastructure to support technology use, that is, facilitating factors. For example, Jamous et al. reported that most optometrists felt confident or very confident using standard (62.0%) or stereoscopic optic nerve head photography (66.1%) and OCT with optic nerve head and retinal nerve fibre layer analysis (71.9%) for glaucoma assessment. 22 Ly et al. also found that 77% of optometrists rated their competency as above average or excellent for colour fundus photography, while this proportion was reduced for OCT (43%) and fundus autofluorescence imaging (21%) when using retinal imaging to manage AMD. 23 Similarly, our results showed that most optometrists believe they have the knowledge necessary to T A B L E 4 Comparison of attitudes toward retinal imaging between sections 3 and 4.

Corresponding question number and statement in section 3
Ranked score, mean (SD) use and interpret retinal imaging, with 93.2%-94.1%, indicating agreement or strong agreement toward these statements represented by mean scores of 4.4 (0.7) to 4.5 (0.7) out of 5. In our study, optometrists also expressed agreement or strong agreement toward other facilitating factors such as the suitability of retinal imaging for their workflow, compatibility with other technologies and the ability to obtain assistance using them. Together, these findings show that facilitating factors promote retinal imaging technology use in primary eye care practices, although the degree of this effect may differ between retinal imaging types and the disease for which the imaging is being applied.
Existing work also suggests that optometrists hold positive attitudes toward the application of retinal imaging. Ly et al. probed optometrists' views on retinal imaging (modified retinal photography, fundus autofluorescence and OCT) in AMD and found that more than 95% agreed with the relevance of these techniques to their practice. 23 Our results support these findings as 86.4%-94.1% of respondents agreed or strongly agreed that retinal imaging aids the diagnosis of disease and improves their diagnostic abilities and there is an overall need for the technology in primary eye care, represented by the mean scores of 4.4 (0.7) to 4.7 (0.7) out of 5. Moreover, the findings indicate that optometrists not only hold positive attitudes toward the application of retinal imaging for AMD, but also for general examinations in primary eye care practices.

Optical coherence tomography angiography as a state-of-the-art technology
The primary advantage of OCTA over existing types of retinal imaging used in primary eye care practice is the ability to reveal microvascular impairments and neovascularisation of the vascular plexuses at different depths from the choroid to the inner limiting membrane non-invasively. 52 Its utility in identifying and monitoring the progression of quiescent choroidal neovascular lesions is well documented across retinal disease. OCTA reveals a higher incidence of choroidal neovascularisation in pachychoroid spectrum diseased eyes with shallow pigment epithelial detachments 53 and is superior to dye angiography for detecting type 1 lesions. 54 In AMD, OCTA can also be used to monitor for quiescent neovascular lesion enlargement, 55 a risk factor for exudation, 56 and thus guide review intervals. OCTA can also detect retinal microvascular abnormalities in diabetic patients without retinopathy, 57 which are associated with dyslipidaemia, high-, low-density lipoprotein cholesterol and hypertension 58 and may prompt recommendations for earlier systemic review.
Despite these advantages, the benefits of OCTA are yet to translate into primary eye care practices, and its availability and usage remains low. 12 At present, clinician attitudes toward OCTA are also unknown and as such, the reasons for poor uptake are elusive. Our results show that the attitudes of Australian optometrists toward OCTA are less positive than for established retinal imaging types, and these views did not change significantly when OCTA availability was established as part of a hypothetical scenario. This suggests that it is not only low availability, but attitudes toward OCTA which are impacting usage rates. Indeed, optometrists felt neutral about the usefulness of OCTA in daily practice, while expressing agreement or strong agreement toward the usefulness of other types of retinal imaging. Compared to other retinal imaging types used in primary eye care practices, optometrists perceived OCTA to be less enjoyable to use, less endorsed by people influencing their work behaviours and felt less confident that they had the knowledge to interpret the results.
Optical coherence tomography angiography is often described as a useful alternative to fluorescein angiography for retinal vasculature assessment due to its non-invasive administration. [59][60][61] It is possible that optometrists' attitudes toward OCTA were less positive compared to other retinal imaging types due to the belief that it is better suited to ophthalmology practices and outside the scope of optometric practice. Such views were not identified in comments provided in the free response section where most participants expressed concern about the facilitating and operational aspects of using OCTA, cost of acquiring the technology or indicated that they did not consider OCTA useful as they work in paediatric eye care. However, it may be worthwhile investigating the perceived application of OCTA in primary eye care in future studies to understand why optometrist attitudes toward OCTA were less positive compared to other retinal imaging types.

Factors influencing attitudes toward OCTA
Previous studies have found that further training positively influences optometrists' attitudes toward new devices. For example, optometrists with training in pachymetry believed it to be more useful, 30 and those who are therapeutically endorsed are more likely to perform OCT than their non-endorsed counterparts. 10 Greater exposure to computerised systems in the workplace has also been associated with more positive attitudes toward new artificial intelligence diagnostic tools among primary eye care clinicians. At a time when OCT was only utilised by 15% of optometrists in the United Kingdom, optometrists working in independent practices were more likely to use the technology than those working in multiple or group practices. Utilisation of other specialist equipment such as gonioscopy and corneal topography was also positively associated with OCT usage. 11 In contrast, our study found that higher qualifications, the number of computerised systems, practice type or the number of retinal imaging devices used at the current workplace did not significantly influence performance expectancy attitudes toward OCTA. Only the number of optometrists working per day had a weak, negative effect on this outcome (p = 0.02). Optometrists may be less willing to use OCTA if their clinical workflow is potentially impacted by having to share retinal imaging resources with other optometrists or interrupt colleagues to use equipment in their consulting room. Both factors may contribute to longer appointments and negatively affect clinical efficiency and workflow. 62,63

Strengths and limitations
The present study is the first to comprehensively examine optometrists' attitudes toward established and state-ofthe-art retinal imaging and clinician or practice characteristics that potentially influence the implementation of new imaging technology in primary eye care. Although the target sample size was not achieved, the gender and state distribution of participating optometrists closely reflects numbers reported by the Optometry Australia board 34 and the Australian Health Practitioner Regulation Agency. 64 Optometrists who are not members of Optometry Australia were also excluded from our sampling frame; however, it is unlikely that this will affect the generalisability of results to the target population as 85% of optometrists hold membership. Furthermore, we used random sampling and rigorous methods to optimise our response rate. 33 Therefore, it is likely that our results are representative of practising optometrists in Australia.
A limitation of the study was that 66.9% of optometrists nominated independent practices as their main workplace although approximately half of optical outlets in Australia are owned by corporate companies. 65,66 Our findings mirror results from other surveys administered via Optometry Australia which also reported higher than expected proportions of optometrists working in independent practices (58%-64.7%). 10,12,29 It is possible that surveys concerning scope of practice, practice patterns and new diagnostic tools may be perceived as more relevant to optometrists working in independent practices as they have greater freedom to enforce changes to clinical scope and workflow. Indeed, 90% of independent optometrists in this study indicated that they were able to influence or have a major role in decisions to acquire retinal imaging, whereas only 35% of corporate optometrists indicated the same.
The item non-response rate also exceeded 10% for three items pertaining to the usage frequency of OCTA, ultrawide-field imaging and fundus autofluorescence. The response burden of this section was increased as there were seven options per item instead of five, which may have contributed to the large number of skipped items; 67 however, the missing data does not affect the primary outcome results.

CONCLUSION
Understanding optometrist attitudes toward retinal imaging is essential for identifying potential barriers to usage, particularly for newer imaging types. These results show that Australian optometrists have a positive outlook on using established retinal imaging types. However, they are unsure that OCTA provides the same benefits to clinical performance or integrates into their practice. Further work is needed to advocate the benefits of using OCTA across all primary eye care clinicians.

AC K N O W L E D G E M E N T S
The authors thank the Centre for Eye Health clinical reception staff for facilitating survey pack distribution during the project. Open access publishing facilitated by University of New South Wales, as part of the Wiley -University of New South Wales agreement via the Council of Australian University Librarians.

FU N D I N G I N FO R M AT I O N
This work was supported by the Australian Research Training Program scholarship and the Small Grants Funding Scheme from the Australian Human Rights Institute to authors AL and RC and the Centre for Eye Health, Guide Dogs NSW/ACT.