Comparative evaluation of a novel solar powered low-cost ophthalmoscope (Arclight) by eye healthcare workers in Malawi ====================================================================================================================== * Rebecca Blundell * David Roberts * Evridiki Fioratou * Carl Abraham * Joseph Msosa * Tamara Chirambo * Andrew Blaikie ## Abstract This study compared a novel low-cost solar powered direct ophthalmoscope called the Arclight with a traditional direct ophthalmoscope (TDO). After appropriate training, 25 Malawian eye healthcare workers were asked to examine 12 retinal images placed in a teaching manikin head with both the Arclight ophthalmoscope and a traditional direct ophthalmoscope (Keeler Professional V.2.8). Participants were scored on their ability to identify clinical signs, to make a diagnosis and how long they took to make a diagnosis. They were also asked to score each ophthalmoscope for ‘ease of use’. Statistically significant differences were found in favour of the Arclight in the number of clinical signs identified, correct diagnoses made and ease of use. The ophthalmoscopes were equally effective as a screening tool for diabetic retinopathy, and there was no statistically difference in time to diagnosis. The authors conclude that the Arclight offers an easy to use, low cost alternative to the traditional direct ophthalmoscope to meet the demands for screening and diagnosis of visually impairing eye disorders in low-income and middle-income countries. * ophthalmoscopes * blindness * diabetic retinopathy * optic nerve diseases * culturally appropriate technology ## Introduction Over 285 million people worldwide suffer from significant visual impairment of which approximately 60%–70% is considered to be preventable and treatable.1 2 The majority of cases reside in low-income and middle-income countries (LMICs)1 where access to diagnostic tools is least.3 4 Early identification and treatment, particularly of those conditions affecting the retina and optic nerve, relies on tools such as the traditional direct ophthalmoscope (TDO). Although the TDO has traditionally been one of the main ophthalmic screening and diagnostic tools, it has limitations of high initial cost of purchase, requirement for regular maintenance (bulbs and batteries) and perceived difficulty of use.5 6 Consequently, the ‘functional’ availability of this important device in LMICs is limited. The Vision 2020 Right to Sight initiative is a global strategy, launched in 1999, with the aim to eliminate avoidable blindness by 2020.7 The initiative has three main aims: disease control, human resource development and infrastructure strengthening including relevant technology development for eye care delivery.8 Along with the Lancet Commission,9 recommendations have emphasised the development of ‘frugal’ and culturally appropriate technology for users in LMICs. In response to these challenges, a novel low-cost multipurpose diagnostic device has been developed by Arclight Medical10 employing a number of innovative and unique design features (figure 1). ![Figure 1](http://innovations.bmj.com/https://innovations.bmj.com/content/bmjinnov/4/2/98/F1.medium.gif) [Figure 1](http://innovations.bmj.com/content/4/2/98/F1) Figure 1 The Arclight with selected features highlighted. The key patented feature of the device is to employ a Light Emitting Diode (LED), which can be charged by an integrated photovoltaic (solar) panel. This novel design eliminates the need for bulky, hard to source and expensive replacement filament bulbs and batteries and mains electricity charging. The LED is small enough to be placed directly below the viewing hole, facing the patient, creating a near axial light source (figure 2), avoiding using a mirror to redirect light from below as is traditionally done. These design changes create a slim (110 mm long×26 mm wide×9 mm thick) and light device (18 g). ![Figure 2](http://innovations.bmj.com/https://innovations.bmj.com/content/bmjinnov/4/2/98/F2.medium.gif) [Figure 2](http://innovations.bmj.com/content/4/2/98/F2) Figure 2 The Arclight illumination uses a light emitting diode placed directly below the viewing hole, facing the patient, creating a near-axial light source unlike the traditional direct ophthalmoscope, which uses a mirror to redirect light into an axial path. Additionally, the Arclight has an integrated magnifying loupe and otoscope broadening its diagnostic potential. As it is available at only £5.00 to low-income users when sold in bulk,11 it is potentially an economically and practical alternative to TDOs in LMICs. As yet, however, no studies have evaluated the effectiveness of the Arclight in diagnosing retinal disorders (including diabetic retinopathy) among eye care providers in a LMIC. ### The aim of this study The aim of the study is to compare how the Arclight device performs in comparison to a TDO when used by Malawian eye healthcare professionals examining the fundi of simulated eyes. ## Materials and methods Appropriate ethical approval was obtained. Twenty-five eye healthcare professionals and optometry students were recruited with fully informed consent. Participants were recruited from two hospital eye departments and one school of optometry. The participants were already familiar with using a TDO. An introductory ‘refresher’ session was provided on direct ophthalmoscopy and the examiners had a brief training session with the Arclight to familiarise themselves with the practicalities of how the device works. ### Clinical signs, diagnosis and ease of use (EOU) scores Participants were asked to examine 12 retinal pathology slides placed in an Adam-Rouilly teaching manikin head (figure 3). Slides included background retinopathy and diabetic maculopathy, preproliferative retinopathy, advanced proliferative retinopathy, diabetic maculopathy, pan laser photocoagulation, normal fundus, glaucomatous disc, papilloedema/swollen disc, toxoplasmosis scar/optic atrophy, cytomegalovirus, central retinal vein occlusion and central retinal artery occlusion. A cross-over design was utilised with 12 participants using the Arclight first (group 1) and the TDO second and 13 participants the converse (group 2). The TDO used in this study was a Keeler Professional V.2.8. The order of the slides was randomised before ‘crossing over’. ![Figure 3](http://innovations.bmj.com/https://innovations.bmj.com/content/bmjinnov/4/2/98/F3.medium.gif) [Figure 3](http://innovations.bmj.com/content/4/2/98/F3) Figure 3 The Arclight being used with teaching slides in a manikin head. The participants were asked to describe the clinical signs they saw on the slide and to provide a diagnosis. Every clinical sign correctly identified received one mark. The time taken to reach a diagnosis was also recorded. Correct diagnoses, recognition of clinical signs and time taken to diagnose were normally distributed and a paired t-test was used to assess statistical significance. Participants were additionally asked to rate the EOU as described below: 1. Could not use this ophthalmoscope to see the red reflex. 2. Could see the red reflex. 3. Could not focus the fundus. 4. Could see vessels but not optic disc. 5. Could see the disc and retinal fields but it was not in focus. 6. Could see the disc and retinal fields in focus with high level of difficulty. 7. Could see disc and retinal fields in focus with medium level of difficulty. 8. Could see disc and retinal fields in focus with low level of difficulty. For descriptive statistics, an EOU score greater than 7 was defined as ‘easy’ and less than 6 (