Cellular Diagnostics of the Retina

Diseases of the retina and the optic nerve are the leading causes of blindness and visual impairment worldwide. Maculopathy, diabetic retinopathy, and glaucoma alone account for over 200 million patients with severe vision loss, most of which is caused by late diagnosis and treatment.

Many retinal diseases arise from dysfunctions in the retinal pigment epithelium (RPE) cells, which are essential for the survival of photoreceptors (cones and rods), the cells responsible for vision. Since these dysfunctions affect cellular morphology, the ability to detect even the most subtle changes in the appearance of RPE cells during the earliest stages of the degenerative process would allow the disease to be identified and the most appropriate therapeutic strategy to be implemented at the earliest stages of the disease—before clear clinical signs and symptoms appear and before irreversible damage occurs to the photoreceptors and, consequently, to vision.

Today, a precise and accurate analysis of the ocular fundus cannot do without retinal imaging exams performed using instruments with increasingly sophisticated technologies, in particular OCT (Optical Coherence Tomography). This technique provides ultra-high-resolution scans of the retina. However, although the image quality is excellent for photoreceptors, there are significant limitations when observing other structures—especially RPE cells and optic nerve fibers. The limitations of OCT are due, on the one hand, to the transparency of retinal cells, which does not allow good contrast in the images, and on the other, to artifacts caused by patients’ eye movements. Furthermore, the type of lighting used by the device (transpupillary illumination) means that once the light enters the pupil, it is partly absorbed and partly reflected by the segments of the photoreceptors, disrupting the weak backscattered signal from the RPE cells and reducing the signal-to-noise ratio.

To overcome the limitations of OCT and obtain better visualization of the structures behind the photoreceptors—particularly the RPE cells—a new technology has been developed, known as Adaptive Optics Transscleral Phase Imaging (AO-TFI). By combining adaptive optics with a different type of fundus illumination (oblique transscleral illumination), this method enhances contrast between retinal cells and provides ultra-high-resolution images (at the cellular level) of the portion of retina between the retinal pigment epithelium and the nerve fiber layer that makes up the optic nerve head.

From the innovative AO-TFI technology comes a new instrument called Cellularis, capable of visualizing individual retinal cells in detail—like a microscope, but in vivo. Cellularis allows for both qualitative (morphological) and quantitative (numerical) analysis of retinal cells, representing a true revolution in the field of retinal imaging diagnostics. The examination with Cellularis is non-invasive, lasts only a few seconds, and does not require pupil dilation in the patient. The device is also equipped with artificial intelligence software capable of analyzing patients’ retinal images and detecting the possible presence of pathological markers.

Cellularis has not yet entered clinical practice. However, Rome Vision Clinic has decided to equip itself with this state-of-the-art device in order to participate in international clinical studies whose results—along with those from very recent research—may confirm Cellularis’s ability to detect qualitative and quantitative alterations in RPE cells and optic nerve fibers that would otherwise be invisible with other instruments. Monitoring the retina at the cellular level should allow not only for early diagnosis—with the possibility of optimizing therapeutic effectiveness—but also for detailed tracking of the pathological process and observation of treatment effects, enabling the acquisition of new data and insights into these processes.