Enabling Community Ophthalmology with the Smartphone Slit Lamp

We describe a novel universal smartphone adaptor (MIDAS) designed to provide high quality images of the anterior segment of the human eye. The device allows image capture of the anterior segment in multiple forms, including diffuse macro illumination, slit beam illumination, and cobalt blue filter illumination. Special effort is made to produce a design that is ergonomically efficient, yet has a simple learning curve. When used by a trained operator, this device allows the diagnosis of anterior segment conditions of the eye, and real time communication with an ophthalmic specialist in the primary care setting.

The device consists of two parts, an illumination part and a mobile phone fixture part. These two parts are joined by strong magnets to make it easy to use and adjust. This device is compatible with different models of Android smartphones and iPhones. It can be powered with either using the smartphone battery or an external power source.

MIDAS is designed for use by healthcare professionals (including for medical education). When used by a trained operator, it allows the complete assessment of the anterior chamber of the eye. This aids in the assessment and diagnosis of the following: Assessment of anterior chamber depth Slit beam optical section of anterior chamber structures including the cornea, anterior chamber, iris, lens Slit beam optical section of conjunctival, episcleral and scleral structures Slit beam assessment of tear film height Diffuse beam high magnification assessment of ocular adnexa including lid margins, Meibomian glands, and tear film Cobalt blue filter assessment of corneal pathologies (with the aid of fluorescein dye, separately provided) MIDAS thus provides additional diagnostic capabilities for anterior segment diseases in the primary care setting by leveraging on the imaging capabilities of the ubiquitous smartphone. This can allow real-time diagnosis of anterior segment conditions through tele-ophthalmology, and also be the basis for automated diagnoses for selected conditions when standardized images are used.

Teleophthalmology is a rapidly expanding field of interest, with different types of services ranging from speciality ophthalmology (glaucoma, diabetic retinopathy, age-related macular degeneration, retinopathy of prematurity) to comprehensive ophthalmology and emergency ophthalmology. There are also various strategies for teleophthalmology practice, including store-and-forward and real-time interactive service. Together, these initiatives have shown great patient satisfaction (Ophthalmology 2017;124:539-546). However, a big limitation of these services is the requirement of specialized equipment either in the form of an immobile clinic or a mobile van, which physically moves to more remote parts where ophthalmology service is not readily available - the standard slit-lamp instrument is bulky, immobile and costs in the region of S$20,000. Therein lies the big difference between most other teleophthalmology products and ours – the ability to incorporate affordable, mobile, and easy-to-use interfaces to the primary care physician, without the need for specialized training or specialized technicians to acquire “standardized’’ images. Specifically, our smartphone anterior segment camera is designed to capture standardised slit-lamp images using the smartphone. The slit image is critical in the diagnosis of many conditions, including but not limited to uveitis, scleritis, corneal edema, corneal perforation, angle closure glaucoma. Through an integrated application, this could provide the means for increased diagnostic capabilities in the primary care setting through direct communication with the tertiary care service.