Myopia is the most common ocular disorder worldwide and the leading cause of visual impairment in children. Its progression affects the normal retinal development, increasing the risk of suffering severe ocular pathologies that lead to irreversible blindness. Although the mechanism for myopia progression is not completely elucidated yet, it is suggested that the quality of the peripheral retinal images may play a role. This produced an enormous interest in using spectacle lenses with different focusing properties for foveal and peripheral vision as a treatment to slow myopia progression. In this work, we developed a novel instrument to optically characterise spectacle lenses designed for myopia control under realistic viewing conditions. First, the testing beam impinges the spectacle under test with different eccentricities. For each eccentricity, a steering mirror guides the beam towards a liquid crystal spatial light modulator (SLM). The SLM allows for reproducing several pupil sizes, shaping the pupil according to the eccentricity, reproducing ocular aberrations for different levels of myopia, and acquiring the through-focus point spread functions (PSFs). An electrically tunable liquid lens, conjugated to the SLM, compensates the base power of the tested lens and focuses the beam into a camera’s sensor. Three spectacle lenses were tested, and different optical metrics were calculated from the PSF and the modulation transfer function.
Cataracts is a common ocular pathology that increases the amount of intraocular scattering. It degrades the quality of vision by both blur and contrast reduction of the retinal images. In this work, we propose a non-invasive method, based on wavefront shaping (WS), to minimize cataract effects. For the experimental demonstration of the method, a liquid crystal on silicon (LCoS) spatial light modulator was used for both reproduction and reduction of the realistic cataracts effects. The LCoS area was separated in two halves conjugated with the eye’s pupil by a telescope with unitary magnification. Thus, while the phase maps that induced programmable amounts of intraocular scattering (related to cataract severity) were displayed in a one half of the LCoS, sequentially testing wavefronts were displayed in the second one. Results of the imaging improvements were visually evaluated by subjects with no known ocular pathology seeing through the instrument. The diffracted intensity of exit pupil is analyzed for the feedback of the implemented algorithms in search for the optimum wavefront. Numerical and experimental results of the imaging improvements are presented and discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.