Fundoscopic examination using a smartphone camera: a review of effectiveness and feasibility in detecting hypertensive retinopathy in hypertensive crisis patients

Introduction: In patients presented with hypertensive crises, a fundoscopic assessment is necessary because once hypertensive retinopathy is discovered, a hypertensive emergency is diagnosed, and intravenous antihypertensive medication is recommended. However, direct ophthalmoscopy is relatively underutilized, especially under the social distance regulation, which may result in delayed diagnosis and treatment. The novel method, namely, smartphone-based fundoscopy offers longer working distance and shorter doctor-patient contact time, however, there is limited data regarding its feasibility and effectiveness. Objective: We aimed to gather scientific evidence on the smartphone-based fundoscopy in terms of its effectiveness, accessibility, and trainability in detecting hypertensive retinopathy among hypertensive crisis patients in emergency room settings. Methods: A literature search was conducted on PubMed, Google Scholar, and the Cochrane Library for papers published from January 2010 to November 2021. Keywords including hypertensive crisis, hypertensive retinopathy, target organ damage, fundoscopic optic examination, direct ophthalmoscope, fundus images, smartphone fundoscopy, digital fundus camera, and COVID-19 were used. Full papers published in English and abstracts of non-English publications were all reviewed. Results: Eight studies out of 34 fulfilled our search criteria. Five observational studies confirmed the effectiveness of smartphone-based fundoscopy in obtaining fundus images adequate for interpretation compared with those from commercially available fundus cameras. Also, smartphone-based fundoscopy offers time-saving properties as it allows fundus examination to be effectively completed within 74 seconds compared to 130 seconds with a traditional direct ophthalmoscope. Two studies investigated the accessibility of smartphone-based fundoscopy and discovered that fundus images can be obtained by using 20 diopter condensing lenses with the video mode of the smartphone camera, which can be easily provided even at a primary level hospital due to their low cost. Another study reviewed the trainability of the smartphone-based fundoscopy in 137 undergraduate medical students which concluded that 75% of these students can identify the optic nerve within 20–25 minutes of face-to-face demonstration. Conclusion: With a greater diagnostic capability, accessibility, and trainability of smartphone-based fundoscopy makes it a potentially game-changing technique for detecting hypertensive retinopathy in hypertensive emergency patients, especially during the current COVID-19 pandemic, in which longer working distance and shorter doctor-patient contact time are both required.