A novel auxiliary method combining a smartphone with a handheld slit-lamp for ocular image documentation of cataracts and diabetic retinopathy in remote regions

Vision impairment is an important public health problem in China. With the acceleration of population aging, the incidence of ocular diseases such as cataracts and diabetic retinopathy (DR), which carry a high risk of blindness, is gradually increasing and placing a huge burden on public health screening in China. However, traditional screening tools such as desktop slit-lamp and fundus photography are bulky and expensive, making them unavailable in remote regions. Their limitations restrict the scope and frequency of screening. Therefore, we have proposed an accessible, low-cost and simple method to assist in the screening process. It can acquire and save screening images, which can be used for remote communication and referral decisions to address the shortage of equipment and personnel in remote areas and alleviate the burden on public health systems. In this paper, we aim to investigate the preliminary technical feasibility of this novel auxiliary method that combines a smartphone and a handheld slitlamp, by describing the characteristics of cataracts and DR, serving as an auxiliary tool for low-resource clinical innovation in the screening of blinding diseases in remote and economically underdeveloped areas. We combine a smartphone and a handheld slit-lamp using a simple adapter that connects the smartphone to the eyepiece, so that the images observed through the slit-lamp can be displayed on the smartphone screen. This simple combination is easy to carry and allows for immediate access to and storage of ocular images. We have captured and documented characteristic features of cataracts and DR. These images may serve as a triage support and referral decisions when abnormal findings are suspected. We have successfully used this method to capture clear images of cataracts, including three different types: cortical, nuclear and posterior subcapsular opacity. The characteristic features of DR also have been captured for a preliminary disease staging. We have even captured a few other ocular surface and fundus diseases. All images can be saved and used for remote consultation with ophthalmologists. All these results demonstrate the preliminary technical feasibility of this method, which may serve as a practical auxiliary tool for preliminary ocular image acquisition and documentation in remote and low-resource settings, enabling ophthalmic review of disease, teleconsultation by ophthalmic professionals, and referral support, thereby alleviating the public health burden associated with screening.