Introduction

Worldwide, ophthalmology is experiencing a reduction in its time allocation within medical school curricula [1], an issue which has been recognised for almost a century [2]. What teaching time is available needs to be utilised effectively, in educating students on the relevant theory, as well as procedural skills of ophthalmology. In the UK currently, ophthalmology training has been cited as not providing medical students with enough training in the skill of direct ophthalmoscopy [3] and in the wider world this is a diminishing, or perhaps absent component of the medical curricula [4]. It has also been suggested that it is perhaps unrealistic to expect students to become competent in direct ophthalmoscopy in the short time frame allotted within UK curricula [5]. Modern ophthalmoscopes are tailored to the skilled specialist, with many features untouched by the inexperienced user [6], therefore few students are able to use the ophthalmoscope effectively [7].

The direct ophthalmoscopy examination is clearly an important clinical skill, yet the procedure is difficult to teach and equally as problematic to assess [8]. Thus the complexities of ophthalmoscopy are twofold [9]. Not only can the ophthalmoscope be difficult to use correctly, the examiner must also be able to interpret what they see.

Although ophthalmoscopy is challenging at first, success and proficiency can be gained in time [10]. It is a skill all students must be introduced to [11], and that every doctor should be conversant with, not just the trained ophthalmologist [10, 12]. The Royal College of Ophthalmologists has produced a curriculum for Undergraduate and Foundation Doctors, and states the undergraduate would be able to:

  • “Perform a competent clinical examination of an eye with a pen torch and direct ophthalmoscope.

  • Describe the appearance of the optic disc and important retinal landmarks, as well as their orientation and dimensions with ophthalmoscope.

  • Demonstrate the red reflex” [13].

Although alternative methods of fundoscopy have been introduced, which allow for the ability to recognise retinal pathology without requiring the skill of ophthalmoscopy [7], they do not allow for examination of the anterior eye. In addition, these devices require the patient to be alert and cooperative, consequently making them irreplaceable by the direct ophthalmoscope in certain conditions, or situations, such as critical care [14].

One alternative to the traditional ophthalmoscope (TO) is the Arclight ophthalmoscope (Arclight Medical, UK, http://arclightscope.com), see Supplementary Images 1 and 2. This is a new, affordable, lightweight ophthalmoscope, which has been created primarily for use in developing countries. Furthermore, UK sales contribute to the provision of devices and education in developing countries [15]. This study explored the possibility that this device could be used as an alternative to the TO as a means for introducing medical students to the technique of ophthalmoscopy and investigated its effect on skills acquisition.

Materials and methods

Forty University of Dundee medical students took part in a cross-over trial comparing the Arclight to the TO, following approval by the local Research and Ethics Committee. Participants were recruited voluntarily by e-mail, and were included if they were in their 1st or 2nd year of studies, prior to sitting their ophthalmology placement. They were excluded if they had prior experience with either ophthalmoscope model or of any ophthalmoscopy training. Written consent was obtained from every individual.

The cross-over trial was split into two periods. In period one, 23 participants were taught how to use the TO first (Group A), and 17 learned how to use the Arclight ophthalmoscope (Group B). Groups were then assessed on the initial device. There was a 2-week washout period between sessions before they were taught the second device. They did not have access to either ophthalmoscope in this period for practice. In period two, Group A (n = 23) was then reassessed using the Arclight, and Group B (n = 17) was reassessed on the TO. Sessions were randomised based on participant availability and hosted on different days so no conferring could occur. Students were not told which device they would be taught first.

A video tutorial was created to teach students the basics of ophthalmoscopy with each ophthalmoscope, and the different regions of the fundus to assess during the examination.

A normal fundus photograph was “photoshopped” with six different, randomly assigned letters, placed in the key areas of the eye that would be examined when using an ophthalmoscope: superonasal, superotemporal, inferonasal, inferotemporal, optic disc, and macula [10, 16]. This image was then made into a slide, which could be placed into a prosthetic eye on a mannequin head, and examined during the ophthalmoscopy procedure.

Two separate sets of fundus slides were created: set one was used when assessing the TO, and set two for the Arclight, reducing the risk of cross-contamination. Each set of slides had four different font sizes: 8, 6, 4 and 2 pt with distinctive letters on each slide. Both sets used different letters so no conferring or recall could occur. The letters were written in white, capital, Arial bold font, to provide a contrast to the red fundus.

Students were assessed using a mock objective, structured, clinical, examination (OSCE). Teaching and assessment sessions were consistent, with no bias or influence imposed on the students [17]. The use of the OSCE effectively provided objective assessment of the skill, allowing for comparison between groups [11].

Four mannequin heads were set up in order of largest to smallest fundus font sizes. Both left and right eyes in the same mannequin had identical font sizes. For each fundus slide, the subjects were allowed 1 min to assess, the end point of the examination being locating all six letters on the slide, or the time limit running out. Students worked from the largest font size downwards each time. Students were given an answer sheet which the examiner filled in as they called out the letter and corresponding region. Due to the nature of the prosthetic eyes, only the posterior eye was examined.

The primary outcome of the study was to calculate the total number of letters identified by each device, with a total of 48 letters attainable. The correct number of letters examined in each of the core areas of the fundus was compared in both the TO and Arclight in a binary fashion; 1 point was given if students identified the right letter in the correct corresponding region, and 0 point if they did not achieve this.

A questionnaire was then distributed following completion of the study. This allowed qualitative data on the students’ perceptions of each device to be collected. Students were asked which device they preferred, which device they would use for future practice, which device they felt gave them the clearest view of the fundus, and which device was more user friendly. In addition, students were asked to rate both devices in terms of simplicity of use and quickness of learning on a seven point Likert scale, and asked why they gave this rating. This was then analysed using inductive thematic analysis.

The results from a previous study [18] were used for a one-sided power calculation, with an estimated mean difference in effect size of 4.15 and standard deviation of 8.90. With an alpha = 0.05 and power = 0.80, the projected sample size was 36. A one-sided test was used to detect if the Arclight would be more effective than the TO, thus determining if it could be used in clinical practice.

Statistical analysis was carried out using SPSS version 22 (SPSS, Inc, Chicago, Illinois, USA). Variables are presented as the mean ± standard deviation. Comparisons of baseline results of each device were calculated using Student’s t tests. Statistical significance was considered when p < 0.05.

Results

Forty medical students between the ages of 17 and 29 took part. In Group A, there were 12 females and 11 males. In Group B, there were eight females and nine males. There were 2 1st-year students and 21 2nd-year students in Group A, and 11 1st-year students and 6 2nd-year students in Group B. Training and assessment was completed by all subjects.

Overall, students who learned the TO first performed better on second assessment using the Arclight in 100% of cases (Group A). Of students who were taught the Arclight ophthalmoscope first, only 11.8% of students improved on second performance with the TO (Group B). Regardless of group, 92.5% of students performed better with the Arclight ophthalmoscope. Students were assessed comparing four different font sizes. Comparison of the different font sizes showed the greatest discrepancy between font size 2 pt. These results can be seen in Figs. 1 and 2.

Fig. 1: Mean number of letters identified in period one.
figure 1

Total number of participants = 40. Traditional ophthalmoscope (TO) n = 23, Arclight ophthalmoscope n = 17. Four different font sizes 8, 6, 4, 2 pt were used per prosthetic eye. Total number of letters per slide = 6; total number of slides = 8; therefore, the total number of letters which could be identified = 48 letters. Results are broken down to show the result of each device per slide. Mean score for TO (n = 23) = 23.70/48 letters (49.3%), SD: 9.20; mean score for Arclight (n = 17) = 40.47/48 letters (84.3%), SD: 6.88. The total difference in means was 16.77, 95% CI: 11.63–21.93. A two-sample T-test showed p < 0.0001.

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Fig. 2: Mean number of letters identified in period two.
figure 2

Total number of participants = 40. Arclight n = 23; TO n = 17. Four different font sizes 8, 6, 4, 2 pt were used per prosthetic eye. Total number of letters per slide = 6; total number of slides = 8; therefore, the total number of letters which could be identified = 48 letters. Results are broken down to show the results of each device per slide. Mean score for Arclight (n = 23) was 44.26/48 letters (92.2%), SD: 2.77. Mean score of the TO (n = 17) was 36.24/48 letters (75.5%), SD: 6.81. The total difference in means for the second period was 8.02, 95% CI: 4.52–11.52. A two-sample T-test showed p < 0.0001.

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First period of the cross-over trial

In the first period of the cross-over trial, the mean score using the TO (n = 23) was 23.70/48 (49.3%) (SD: 9.20), and the mean score using the Arclight ophthalmoscope (n = 17) was 40.47/48 (84.3%) (SD: 6.88). The difference in results between both instruments, with the Arclight scoring highest, was 16.77, 95% CI: 11.63–21.93. A two-sample T-test showed T = 6.32, p < 0.0001. Results are shown as per each letter identified in Fig. 1.

Second period of the cross-over trial

In the second period of the cross-over trial, the mean score using the Arclight ophthalmoscope (n = 23) was 44.26/48 (92.2%) (SD: 2.77), and the mean score of the TO (n = 17) was 36.24/48 (75.5%) (SD: 6.81). The difference in results between both instruments for the second period, with the Arclight scoring highest, was 8.02, 95% CI: 4.52–11.52. A two-sample T-test showed T = 4.60, p < 0.0001. Results are broken down per prosthetic eye slide in Fig. 2.

Comparing the two periods of the cross-over trial there was evidence of period-by-treatment interaction. The difference between the instruments reduced by 8.75, 95% CI: 1.41–16.08.

The overall results are shown in Fig. 3.

Fig. 3: Mean results in both periods of cross-over trial.
figure 3

Period one: TO n = 23 (23.70/48 letters); Arclight n = 17 (40.47/48 letters). Period two: Arclight n = 23 (44.26/48 letters); TO n = 17 (36.24/48 letters).

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Performance of the TO improved by 52.9% from being used as the device of first exposure, to performance following Arclight exposure. Using the Arclight ophthalmoscope following exposure to the TO showed performance improvement by 9.4%, compared with when just using the Arclight alone.

In Group A, there was a 100% improvement rate from the TO to the Arclight ophthalmoscope. In Group B, there was an 11.8% improvement rate from the Arclight to the TO. Results can be shown in Figs. 4 and 5.

Fig. 4: Group A results.
figure 4

Students were taught how to use the traditional ophthalmoscope followed by Arclight ophthalmoscope. Performance increased by 100%.

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Fig. 5: Group B results.
figure 5

Students were taught how to use the Arclight ophthalmoscope followed by traditional ophthalmoscope. There was an 11.8% improvement rate in Group B.

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Questionnaire

The questionnaire results were split into three main sections: binary responses where students chose either the Arclight or the TO; students’ rationale of choices; and students’ perceptions on the teaching they received. There was a 100% response rate from the questionnaire.

Binary responses showed that 82.5% of students preferred the Arclight ophthalmoscope, and 82.5% of students said they would pick the Arclight as the preferred future ophthalmoscope. In all, 77.5% said the Arclight gave a clearer view of the back of the eye, and 80% selected the Arclight as the more user friendly device. The students also thought the Arclight was simpler to use and felt it was quicker to learn.

Students’ responses as to why they found each device user friendly and which instrument they would pick for future practice were themed using inductive thematic analysis.

Students’ results were collated, and three main themes emerged: “device and functionality” and “visualising the back of the eye” were discussed for both devices, and “ease of use” was only mentioned for the Arclight. Participants felt that the Arclight was lightweight, easier to hold, had fewer settings so was less complex to use, and was more manoeuvrable. Some students, however, did feel the TO was easier to look through as there was only one piece of visualising apparatus, and others felt the settings were easier to manipulate.

“Ease of use” and “Device and functionality” were the main reasons the Arclight was selected as the preferred future device. Due to its small nature, it was “easier to operate and handle”, and “easy to get close to the eyes”. The questionnaire concluded that participants agreed that the design established a more portable and lightweight model than the TO [16].

The TO, however, still had its benefits. Some students found the “controls were more conveniently placed”, hence making it “more easy to zoom/adjust”. The TO has the dials on the side of the device, which students could adjust whilst examining the eye. In addition, it has only “one place to look through”, when compared with the magnifying loupe and sight hole of the Arclight, which have potential to cause confusion.

The final aspect to the questionnaire explored students’ opinions of the teaching method utilised. All students felt that a video tutorial was an appropriate method of teaching such a skill. The majority of students, however, felt that additional teaching instructions in the form of a checklist or similar would be desirable, due to the complexity of both devices.

Discussion

Use of the traditional direct ophthalmoscope is well established in ophthalmic practice, however, medical students should be trained in the most effective way possible. Overall, there was a clear indication that students performed more successfully with the Arclight. This study confirms that the introduction to the smaller, more portable Arclight enhances students’ performance at ophthalmoscopy, when compared with the traditional device. Results also illustrate that the average performance using the TO improved by 52.9% following exposure to Arclight, than when used alone. Acquiring the skill of ophthalmoscopy using the Arclight was overall easier than with the TO, no matter which device was learned first. This may indeed have considerable implications for medical school teaching if chosen as the device of first exposure. Introducing the Arclight to the curriculum for initial learning could have beneficial effects when students are introduced to the TO in later clinical placements.

These results also suggest that the Arclight could not only be used as an introduction to the TO, but as a replacement for learning ophthalmoscopy within the medical curricula.

The smallest font size provided the greatest discrepancy between the devices. Students’ scores using the Arclight were significantly higher. This correlated with questionnaire results, where 77.5% of students admitted having a clearer view of the back of the eye with the Arclight. “Visualising the back of the eye” was a common theme that emerged from the inductive thematic analysis, both for the Arclight being more user friendly and for reasons why it was picked as the preferred device for future practice. Identification of the smallest font size with such clarity, and in as timely a manner, could predict greater identification of ocular pathology from the Arclight.

Previous studies have introduced the concept that it is unrealistic to expect students to become competent in direct ophthalmoscopy in the short curriculum time frame [5]. This study, however, has shown that students can be taught how to use the Arclight, and use it accurately, in an even shorter time interval than that dictated by the syllabus.

Although many different medical subspecialties vigorously compete for time in the curriculum, an adequate amount must be allotted for learning ophthalmology. This, however, would require taking time from another specialty. The ease, and promptness of learning of the Arclight when compared with a TO, points to it being a reasonable solution to the teaching burden of ophthalmoscopy [1].

The majority of research studies avoid the teaching component of ophthalmoscopy, by assessing already experienced final year medical students or physicians. This study took an alternative perspective, creating a teaching experience for the novice medical student, and an assessment of subsequent performance.

Several limitations have to be taken into account in the research study. Due to the period × treatment interaction, in the presence of a carryover it is useful to look solely, and base analysis, on the first period [19], as if it were a parallel group trial. The design of the cross over, however, assumes minimal carryover effect of a treatment/skill into the next period. Consequently, one could argue that the trial should have proceeded as if there were no carryover, as opposed to testing for it [20]. A washout period was considered in the trial, to leave enough time between each device, as both skills are very similar. Due to the time constraints of the study, however, only a maximum of 2 weeks was permitted between teaching sessions. Students did not have access to either device during the washout period, and subjectively informed us that they had not practiced either ophthalmoscope.

Overall, the Arclight achieved better results in every domain assessed. It was the preferred device, better performed device, more user friendly, and in students’ opinion, gave a clearer view of the back of the eye. Students also found it easier to learn, and simpler to use than the TO. In addition, the Arclight was considered to be smaller, more manoeuvrable and the settings easier to manipulate. The majority of participants picked the Arclight as the device they would use for future practice.

Although ophthalmology teaching in the UK [21] and wider world may be diminishing [4], the Arclight could be the answer for training our junior doctors, making ophthalmoscopy an easier skill to acquire. It is clear that the Arclight ophthalmoscope has a place not just in the developing world, but also within our medical curricula, and this may take a number of forms. Whether this be as a replacement for the TO currently used for teaching, as an introduction to ophthalmoscopy prior to training with the traditional direct ophthalmoscope, or as a revision tool, the authors support its ongoing development, research and implementation.

Summary

What was known before

  • Whilst variable, time allocated to ophthalmology within medical school curricula is diminishing.

  • Skills acquisition within such time constraints can be challenging.

  • Direct ophthalmoscopy represents a particular difficulty.

What this study adds

  • Students were found to perform better, and prefer, the Arclight.

  • Performance using the traditional ophthalmoscope was improved following prior exposure to the Arclight.

  • The Arclight may be an effective alternative to the direct ophthalmoscope for teaching around the world.