Thesis Natàlia Ramírez Cano - June 12

Next June 12, 2026 at 11:00 a.m., the public defense of the doctoral thesis by Natàlia Ramírez, titled Medida morfológica de la tortuosidad de los vasos retinianos mediante análisis digital de imagen, will take place. The event will be held at the Auditorium of the University Vision Center (CUV) of the Faculty of Optics and Optometry of Terrassa (Passeig del Vint-i-dos de Juliol, 660. 08222 Terrassa) and can also be followed online via the link: meet.google.com/sti-qkko-ihk

The research has been supervised by Dr. Maria Sagrario Millán García Varela and is part of the doctoral program in Optical Engineering of the Department of Optics and Optometry at UPC.

Medida morfológica de la tortuosidad de los vasos retinianos mediante análisis digital de imagen.

The importance of the retinal vascular network

• Direct and non-invasive biomarker: The tortuosity of retinal vessels allows early detection of ocular, vascular, and systemic diseases.

• High sensitivity: Being a fine structure, it reacts quickly to changes in blood pressure and hemodynamic factors.

• Morphological changes: Alterations result in visible modifications in thickness, curvature, deviation, and the level of vessel tortuosity.

How is it currently analyzed?

Quantitative analysis is performed by processing digital retinographies using algorithms that calculate two types of indices:

• Local: They evaluate specific vessel segments (without bifurcations).

• Global: They synthesize the information of the entire vascular network.

The current problem is that the calculation of these indices is limited by technical factors such as image resolution, framing type (centering on the macula or the optic disc), and the mathematical criteria used to weight global indices.

Objectives and structure of the thesis

The doctoral thesis is presented as a compendium of three scientific publications and directly addresses these challenges through three lines of study:

• Impact of the framing type (macular or papillary) on local indices.
• Influence of image resolution on the robustness of local measurements.
• Proposal of a mathematical validation framework to objectively connect local and global indices.

Conclusions and clinical contribution

Criteria are established for choosing reliable local indices, the limitations of image capture are demonstrated, and a methodological bridge is created between local and global measurements.

The thesis contributes to the standardization of retinal tortuosity analysis to improve its actual clinical use in medical diagnosis.

Members of the committee

The evaluation committee will consist of:

• President: Dr. Justo Arines Piferrer,  Professor at the University of Santiago de Compostela

• Secretary: Dr. Xavier Molinero Albareda,  Professor, Polytechnic University of Catalonia

• Member: Dr. Olga María Conde Portilla,  Professor, University of Cantabria

Additional information

For more information about this thesis and other scheduled defenses in the Optical Engineering program, you can consult the UPC Doctoral School website.