RT info:eu-repo/semantics/doctoralThesis
T1 Aplicación de la medida del DEFF en la adaptación de lentes multifocales personalizados
A1 García Espinilla, Óscar
A2 Universidad de Valladolid. Escuela de Doctorado
K1 Optometría
K1 Presbyopia
K1 Presbicia
K1 Multifocal ophthalmic lenses
K1 Lentes oftálmicas multifocales
K1 Foveal fixation axis
K1 Eje de fijación foveal
K1 2209 Óptica
AB Presbyopia refers to the gradual loss of the lens ability to accommodate, resulting in reduced visual acuity for near tasks. Multifocal ophthalmic lenses are the primary solution for correcting presbyopia. These lenses are characterized by having power for distance vision in their upper part and power for near vision in their lower part. These zones are connected by a gradual transition corridor, allowing clear vision at all distances. However, achieving multifocality introduces optical aberrations (primarily astigmatism) in the lens lateral areas. These aberrations can impact user adaptation and even lead to lens abandonment. To mitigate this, precise facial measurements are essential to align the lens with the user’s gaze and minimize the impact of lateral aberrations. Nevertheless, the traditional method of measuring these distances, which involves using a frame ruler to measure the nasopupillary distance (NPD) and interpupillary distance (IPD), has limitations. The main limitation is that using the pupil centre as a reference in NPD and IPD does not guarantee proper lens centration with the user’s gaze, because typically, the pupil centre does not align precisely with the fixation axis (difference known as the kappa angle). In this doctoral thesis, a new measurement paradigm has been evaluated to measure the distance between foveal fixation axes (FFA) and validate its application in the process of adapting and customizing multifocal ophthalmic lenses for presbyopia correction. The FFA is defined as the direct line connecting the fixation point to the fovea. Until now, there have been no devices available for its measurement in professional practice. This doctoral thesis demonstrates that FFA measurement is repeatable for clinical use and allows satisfactory adaptation of presbyopic users to multifocal ophthalmic lenses centred with FFA as the reference.
YR 2024
FD 2024
LK https://uvadoc.uva.es/handle/10324/71385
UL https://uvadoc.uva.es/handle/10324/71385
LA spa
NO Escuela de Doctorado
DS UVaDOC
RD 22-nov-2024