The LITE path, a new dimension for diagnostic imaging
The Institut de la Màcula and the Institute of Photonic Sciences (ICFO) undertake all the technological and clinical validation phases of the Development of Advanced Laser Imaging Techniques for the anterior and posterior Eye (LITE) project. The programme also involves Italy’s Construzione Strumenti Oftalmici (CSO), Istituto Nazionale di Ottica (INO) e Istituto di Fisica Applicata "Nello Carrara" (IFAC). Co-funded by the Catalan Agency for Business Competitiveness (ACCIÓ) and the European Union through the Seventh Framework Programme for Research and Technological Development as part of the BiophotonicsPlus initiative, it aims to promote R&D in the field of photonics and feed into applications that offer excellence for patient diagnosis and monitoring.
The project has completed all its phases and has now arrived at the construction of a multifunctional prototype that acquires and integrates the images of the eye’s anterior and posterior segments, with high spatial resolution and label-free modality.
Initial phases: AOSLO and SHG
The project’s Catalan team developed, tested and validated all the hardware that came together finally in LITE. Firstly, an adaptive optics scanning laser ophthalmoscope (AOSLO) was chosen. This enabled the retinal images of patients and healthy individuals to be obtained successfully.
The researchers then created a corneal imaging system with second harmonic generation (SHG), developed by the project’s Italian partners. This had a flexible design that combines the obtaining of clinically relevant results (bottom detection) with the possibility of researching clinical tissue from complementary perspectives (simultaneous detection of anterior and posterior segments). In addition, more functionalities were added to it, including the possibility of polarised analyses that provide the option of controlling the formation and alignment of fibrillary components. Both methods can share the same laser scanning module, a considerable advantage with regard to its costs and size.
Using these systems, 22 patients were studied and classified. Sixteen of these were selected: five with Retinitis Pigmentosa, six with Stargardt disease and five who had no eye complaints. These techniques enabled the construction of complex and retinal images and microperimetries, allowing clear observation of the state of the eye fundus. The images facilitate improved analyses and knowledge of each patient’s specific lesions and the progression of their diseases.
Construction and validation of LITE
Once the benefits and functionalities of the application of AOSLO and SHG have been assessed separately in the diagnostic tests, the team of experts addressed the integration of both systems into a single one. This involves the hybrid system that lends its name to the project, and that captures images that provide a deeper knowledge of certain retinal and corneal characteristics. It enables observation of the ocular anatomy with a precision and detail unknown up to now: for the retina, it provides a diagnosis of degenerative blindness-causing eye diseases that is better tailored to cellular scale. It also offers new, more precise effectiveness assessment parameters. This responds to the emerging experimental therapies, such as regenerative medicine treatments with stem cell implantation.
The use of LITE enables the diagnoses and therapeutic monitoring of retinal pathologies to enter a new therapeutic dimension: the teams of the Institut de la Màcula and the ICFO will continue to perform scans on the patients participating in the programme until November 2016.
Laser ophthalmoscopy: method for examining the eye. It uses the technique of confocal laser scanning microscopy to create diagnostic imaging of the retina or the cornea.
Adaptive optics scanning laser ophthalmoscopy (AOSLO): technique used to measure living retinal cells. It utilises adaptive optics to remove the optical aberrations obtained from laser ophthalmoscopy.
Second harmonic generation (SHG): non-lineal optical process in which photons with the same frequency interacting with a non-lineal material are effectively combined to generate new photons with twice the energy and half the wavelength of the initial photons.