Structure-function of retinal photoreceptors in glaucoma

• Applicant: Dr. Juliane Matlach
• Subject Area: Ophthalmology
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 387007305

The Eye as a Window to Imaging Living CellsGlaucoma is a worldwide leading cause of irreversible blindness characterized by damage to the optic nerve. As a degenerative ocular disease, glaucoma mainly affects retinal ganglion cells and their axons. It is controversial whether photoreceptors respective cones and rods which convert light into a signal that is transmitted (via interconnections) to ganglion cells are lost in glaucoma as a result of a retrograde degeneration in a progressing disease. As retinal cones are bigger than rods and densely packed in the central retina, it is possible to image single cones in the living eye using high-resolution imaging of the retina. Cones are particularly interesting to study because it is these cells that underlie vision.With the development of advanced imaging technologies, in vivo imaging of retinal structures at cellular level has become possible allowing for diagnosing and monitoring of ocular diseases. By narrowing the scan angle of a standard commercially available confocal scanning-laser-ophthalmoscope (cSLO) or using a small-field objective add-on lens (SFO) with a standard optical coherence tomography (OCT) device which are both routinely used for patients with various ocular diseases, retinal microstructures can be imaged noninvasively in a patient-friendly clinical setting. So far, histological and clinical studies on morphologic and functional cone loss in glaucoma have yielded conflicting results. Loss of cones has been reported in some studies investigating cone density using high-resolution imaging or cone function measured by electrophysiology. This however could not be confirmed by other studies.The aim of our project is to study the involvement of retinal photoreceptors in the disease progression of glaucoma. We wish to determine if a quantitative reduction of cone numbers captured using the small-angle cSLO and SFO add-on lens with OCT and a qualitative cone loss measured with electrophysiology is seen in glaucoma in corresponding areas of visual field loss. If we can find structural and functional loss of photoreceptors in glaucoma, this would revise pathognomonic characteristics of glaucoma as a retinal ganglion cell disease and utilises a new diagnostic tool to image cones for diagnosing glaucoma. Furthermore, there may be a better understanding of recurring visual hallucinations as reported by some glaucoma patients.

• DFG Programme: Research Grants