Publicação
The retinal response to dynamic changes in image spatial and temporal properties using selective experimental stimulation and myopia control devices
| Resumo: | The scientific community’s interest in understanding the retinal mechanisms of defocus has increased as myopia has become a hot research topic in vision research. The retina’s electrical activity can be recorded through different clinical electrophysiological techniques. Several methods for compensation and management of myopia progression have shown promising results in decreasing the rate of eye growth in children. Contact lenses with positive peripheral power or alternating power changes are used for myopia management. However, the mechanisms by which the retina detects, processes and responds to the defocus imposed by those devices are not yet well understood. The main objective of the series of experiments conducted in this thesis was to evaluate the retinal response to changes in the spatial and temporal characteristics of the image, such as defocus and optical quality. All procedures were carried out at CEORLab (University of Minho). The results showed that the electrophysiology apparatus and the different methodologies for assessing the retina’s electrical activity are sensitive to distinct characteristics of the image, such as spatial frequency, stimulus orientation, changes in defocus and optical quality. In eyes with keratoconus, using a scleral lens to mask the corneal irregularities helps to rule out the optical distortion produced by the ectasia as a confounding factor for evaluating the retinal health of those patients. The blind spot stimulation with blue light of a specific wavelength produced an increase in the retinal response of myopic eyes, and a possible retrograde feedback mechanism from the inner to the outer retinal layers is hypothesized; this increase was dependent on the temporal dose of blind spot stimulation. Different contact lenses for myopia management changed the retinal response in different ways and in different retinal layers and geographical locations. The parafovea seems to play an important role in detecting and processing myopic peripheral defocus induced by those contact lenses. In the last part of the study, it is suggested that, similar to blue light stimulation of the optic nerve, there might be a retrograde feedback mechanism of the retina in response to the defocus produced by the contact lenses of radial power gradient designed for myopia management. It is also proposed that there should be a relationship between the retinal function and the structural changes in the choroid produced by defocus induction. Electrophysiological techniques are suitable to advance further in this potential connection. |
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| Autores principais: | Sousa, Ana Isabel Carvalho Amorim |
| Assunto: | Contact lenses Electrophysiology of vision Myopia management Peripheral defocus Retina Controlo da miopia Desfocado periférico Electrofisiologia da visão Lentes de contacto |
| Ano: | 2023 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The scientific community’s interest in understanding the retinal mechanisms of defocus has increased as myopia has become a hot research topic in vision research. The retina’s electrical activity can be recorded through different clinical electrophysiological techniques. Several methods for compensation and management of myopia progression have shown promising results in decreasing the rate of eye growth in children. Contact lenses with positive peripheral power or alternating power changes are used for myopia management. However, the mechanisms by which the retina detects, processes and responds to the defocus imposed by those devices are not yet well understood. The main objective of the series of experiments conducted in this thesis was to evaluate the retinal response to changes in the spatial and temporal characteristics of the image, such as defocus and optical quality. All procedures were carried out at CEORLab (University of Minho). The results showed that the electrophysiology apparatus and the different methodologies for assessing the retina’s electrical activity are sensitive to distinct characteristics of the image, such as spatial frequency, stimulus orientation, changes in defocus and optical quality. In eyes with keratoconus, using a scleral lens to mask the corneal irregularities helps to rule out the optical distortion produced by the ectasia as a confounding factor for evaluating the retinal health of those patients. The blind spot stimulation with blue light of a specific wavelength produced an increase in the retinal response of myopic eyes, and a possible retrograde feedback mechanism from the inner to the outer retinal layers is hypothesized; this increase was dependent on the temporal dose of blind spot stimulation. Different contact lenses for myopia management changed the retinal response in different ways and in different retinal layers and geographical locations. The parafovea seems to play an important role in detecting and processing myopic peripheral defocus induced by those contact lenses. In the last part of the study, it is suggested that, similar to blue light stimulation of the optic nerve, there might be a retrograde feedback mechanism of the retina in response to the defocus produced by the contact lenses of radial power gradient designed for myopia management. It is also proposed that there should be a relationship between the retinal function and the structural changes in the choroid produced by defocus induction. Electrophysiological techniques are suitable to advance further in this potential connection. |
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