Retinal Laser Microsurgery guided by OCT and adaptive optics – CLOVIS3D

Retinal laser photocoagulation is commonly used in ophtalmology to treat the macular edema. Macular edemas may result from various pathologies, the first of which is diabetic retinopathy, affecting one to two million people in France alone. The usual treatment for macular edema is a photocoagulation at the center of the retina. The interest of this treatment has been recently confirmed by several studies. However, the way this treatment is administered remains highly empirical. Increasing its precision should help one improve its efficiency while reducing undesirable side effects.

The therapeutic target of the laser can be twofold: retinal pigment epithelium (RPE) or retinal vessels. Whatever the aimed target, it is impossible with current lasers to prevent some degree of damage to healthy neighbouring tissues, which can entail a permanent degradation of visual acuity. This is due to a lack of control of the localisation of the laser impact; indeed, current systems do not include a real-time visualization of the volume of tissues being photocoagulated, and the laser focusing quality is degraded by unintentional eye movements and by optical defects of the eye. Moreover, the laser treatment dose titration is currently performed empirically, with a mere visual control. Improving the accuracy of the procedure should therefore increase its efficiency and reduce collateral damages. This implies a better control of the laser impact and a better control of its effect.

Retinal imaging has been revolutionized in the past ten years by the use of Optical Coherence Tomography (OCT) and adaptive optics (AO). OCT provides a real-time high precision 3D image, and AO corrects in real-time the eye's aberrations and movements. AO is currently applied to laser beam focusing in metallurgy, to optical telecommunications, and to high-power lasers used in Physics experiments. OCT thus provides a robust imaging solution for visualizing the retina, and AO brings a sound and proven solution for focusing laser beams.

The aim of this project is to build an ophthalmological laser system that integrates a real-time 3D visualization and an AO system in order to better control the laser delivery. Such a system will allow the surgeon to choose on the OCT image the impact point of the laser; the latter will be locked in real-time so that the laser impact is better defined in space, in the three dimensions. This revolution of the surgical procedure will bring considerable gains both in efficiency and time. This project will be carried all the way to the clinical evaluation of a mockup on a few patients.

This particularly ambitious objective can only be met by relying on a proven and efficient partnership, which gathers the French leaders of the three technical fields involved: ONERA, leading French player of adaptive optics, internationally recognized in laser focusing applications and imaging of the human retina; Quantel Medical, world's third manufacturer of laser photocoagulation systems; CIC 1423 of the Quinze-Vingts Hospital, French national reference centre for retinal diseases.

The ability to produce a genuine "3D laser bistoury" for a cost close to that of current photocoagulation systems will bring a decisive competitive advantage, thus opening a world market of several hundred units per year.