Teleophthalmology is a branch of telemedicine that delivers eye care through digital medical equipment and telecommunications technology. Today, applications of teleophthalmology encompass access to eye specialists for patients in remote areas, ophthalmic disease screening, diagnosis and monitoring; as well as distant learning.
Teleophthalmology enables health professionals to take ocular images and attend to patients who have limited access to ocular health care. These images allow the ophthalmologist or optometrist, health care professionals and researchers to carry out the aforementioned applications. The required equipment includes a camera that can take ocular images and a computer terminal with network capabilities, which can transfer the images. There has been a significant increase in teleophthalmology research over the past decade. However, differences in health information exchange standards, data security, liability issues, and cost of equipment are other major challenges in teleophthalmology.
Implementation
Although ocular photography has been present since the early 1980s, the transfer of digital images from one location to another for assessment is a relatively recent phenomenon. The rise of digital imaging in the early 1990s allowed ophthalmologists and optometrists to capture images and store them on computers for future assessment. The advent of the Internet allowed for the digital transfer of these ocular images from one location to another.
Current teleophthalmological solutions are generally focused on a particular eye problem, such as diabetic retinopathy, retinopathy of prematurity, macular degeneration, strabismus and adnexal eye diseases. Less common conditions that can be revealed using retinal images are arterial and vein occlusions, chorioretinitis, congenital anomalies, and tapetoretinal abitrophy. Several population-based studies have used retinal imaging to relate ophthalmic abnormalities to general conditions, including hypertension, renal dysfunction, cardiovascular mortality, subclinical and clinical stroke, and cognitive impairment.
Mobile applications are widely available in ophthalmology and optometry as tools for eye tests (visual acuity, colour test, and viewing eye images) and for educational purposes. Technological advancements in digital ocular imaging devices are perceived by many as key drivers for teleophthalmology. Recently, emerging retinal imaging modalities such as optical coherence tomography are capable of producing digital images of the retina with a micrometer resolution, which can be transmitted for research or diagnostic purposes. Along with systems designed for health care professionals, patient-centred systems such as Eye-File for use by the general public are emerging.
Process
Fundus photography is performed by a fundus camera, which basically consists of a specialized low power microscope with an attached camera.
Teleophthalmology services can be provided primarily in two ways synchronously or asynchronously:
Synchronous teleophthalmology enables real-time interaction between participants (using standard telemedicine technologies e.g. video-conferencing), synchronous to supervise the removal of corneal foreign bodies and for consultations. Asynchronous teleophthalmology in a "store-and-forward" method, where data is captured and transmitted for review at a later time.
Images of the eye can be captured non-invasively through various methods, generally by a technician or non-physician health care professional. External eye: standard digital stills or video camera Anterior segment: slit lamp connected to a camera Posterior segment or retina: fundus camera Mydriasis (pupil dilation, e.g. using tropicamide) may be required to obtain an image of sufficient quality. Stereoscopy may be used to detect retinal thickening. The image can then be transferred, over the Internet or dedicated network to a physician for immediate examination, or for storage and later review. Ideally, the image is encrypted or anonymized for transmission, to protect patient confidentiality. Between image capture and viewing, image processing may be done, including compression, enhancement and edge-detection. Image evaluation, to detect various pathologies in the case of asynchronous evaluation, is often done by an ophthalmologist, optometrist or primary care physician, though it is also performed by specially trained staff. Image evaluation may also be automated to provide pathology detection or grading.