AOSLO retinal imaging - psychophysics
AOSLO imaging - Modelling
MPhys (Hons) PhD
Career Development Lecturer
- Departmental Lecturer, Pembroke College
The image formed on the retina is often blurred by optical distortions that are inherent in all eyes. Our ability to extract useful visual information from the environment is dependent on the quality of the retinal image and its sampling by the photoreceptors, using optimal eye movements.
I study the effects that certain types of optical distortion (e.g. a focus error, such as myopia, or a more complicated higher-order aberration) have on the retinal image and the knock-on effects for visual tasks, such as reading text. Complex patterns of blur, produced even in normal eyes, can affect the neural mechanisms underlying such tasks and can have far-reaching effects on higher-level processes such as word recognition. With knowledge of the impact that these optical distortions have on these tasks we can better model and predict visual performance with low vision.
Sampling of the retinal image by the light-sensitive cells of the retina is not a static process; our eyes are constantly in motion, even when we fixate on an object (e.g a word printed on a page). As a consequence of this motion, the light captured by an individual cell changes over time. To study sampling effects we have developed an adaptive optics scanning laser ophthalmoscope (AOSLO), in collaboration with the Centre for Advanced Instrumentation at Durham University, to capture images of the retina at a cellular scale. Using this system we can track the miniature eye movements made during fixation. From these measurements we can infer the spatio-temporal sampling of an image formed on the retina and relate it to psychophysical measures of visual performance.
In collaboration with the Ophthalmology Department we are using the AOSLO to study inherited retinal diseases at a cellular scale. We are searching for early-stage changes in the retina that could lead to a better understanding of disease progression and to closer monitoring of potential treatments.
AOSLO retinal imaging - clinical
Recording fixational eye movements with a new AOSLO: simulation, measurement and evaluation
Young LK. et al, (2017), Journal of Vision, 17, 34 - 34
Vision science and adaptive optics, the state of the field.
Marcos S. et al, (2017), Vision Res, 132, 3 - 33
Critical band masking reveals the effects of optical distortions on the channel mediating letter identification.
Young LK. and Smithson HE., (2014), Front Psychol, 5
Accounting for the phase, spatial frequency and orientation demands of the task improves metrics based on the visual Strehl ratio.
Young LK. et al, (2013), Vision Res, 90, 57 - 67
Different aberrations raise contrast thresholds for single-letter identification in line with their effect on cross-correlationbased confusability
Young LK. et al, (2013), Journal of Vision, 13
Different aberrations raise contrast thresholds for single-letter identification in line with their effect on cross-correlation-based confusability.
Young LK. et al, (2013), J Vis, 13
How feasible is it to capture the functional consequences of the optical distortions of the eye in a single metric?
Young LK. et al, (2012), PERCEPTION, 41, 1273 - 1273
Not all aberrations are equal: reading impairment depends on aberration type and magnitude.
Young LK. et al, (2011), J Vis, 11