Amblyopia Research
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Stereopsis in Amblyopic Eyes
To evaluate the ability of children with amblyopia to process different kinds of stereoscopic information. |
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Motion Perception in Amblyopia
To use behavioural and functional magnetic imaging (fMRI) techniques to examine motion processing in the amblyopic and fellow eyes of children diagnosed with strabismic, anisometropic, or combined amblyopia. 3D Vision and Strabismus Asare AK, Meier K, Chang EC, Mulholland C, Lyons C, Wilcox LM, Giaschi D. (2022). Coarse stereopsis prior to strabismus surgery is associated with post-surgical ocular alignment in children. The Association for Research in Vision & Ophthalmology 2022 Annual Meeting. Denver, Colorado Depth information can be extracted from small retinal disparities (fine stereopsis) and from large disparities that give rise to diplopia (coarse stereopsis). Previously, we showed retrospectively that some children with strabismus have intact coarse stereopsis when fine stereopsis is disrupted, and these children have better ocular alignment after strabismus surgery. Here we describe a prospective study to assess three pre-surgical measures that may predict ocular alignment after strabismus surgery: fine stereopsis, coarse stereopsis, and global motion thresholds, all of which have been shown to be sensitive to disruption of binocular vision. Our preliminary findings suggest that coarse, but not fine, stereoscopic performance may be useful for predicting ocular alignment outcomes after strabismus surgery. Binocular Treatment for Amblyopia Asare A, Ho C, Im HY, Giaschi D (2023) Evaluation of motion perception and binocular vision following dichoptic treatment for amblyopia. 23rd Annual Meeting of the Vision Sciences Society, Tampa, Florida Poor monocular visual acuity and binocular vision, including stereopsis, are characteristic of amblyopia. Motion perception is also often disrupted in both amblyopic and fellow eyes. Occlusion therapy is the gold-standard treatment for amblyopia, but it is often not successful at restoring visual acuity, stereopsis or motion perception. In this study, we evaluated the effectiveness of a recently developed video game-based dichoptic treatment for restoring these aspects of vision in amblyopia |
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Select Completed Projects
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Birch, E., Kelly, K., Giaschi, D. (2019). Fellow Eye Deficits in Amblyopia. Journal of binocular vision and ocular motility, 69(3), 116-125. Amblyopia is a neurodevelopmental disorder of the visual system, as a result of discordant visual experience during infancy or early childhood. Because amblyopia is typically defined as monocularly reduced visual acuity accompanied by one or more known amblyogenic factors, it is often assumed that the fellow eye is normal and sufficient for tasks like reading and eye-hand coordination. Recent scientific evidence of ocular motor, visual, and visuomotor deficits that are present with fellow eye monocular viewing and with binocular viewing calls this assumption into question. This clinical update reviews the research that has revealed fellow ocular motor and visual deficits and the effect that these deficits have on an amblyopic child's visuomotor and visuocognitive skills. We need to understand how to prevent and rehabilitate the effects of amblyopia not only on the nonpreferred eye but also on the fellow eye. |
Kugathasan, L., Partanen, M., Chu, V., Lyons, C., & Giaschi, D. (2019). Reading ability of children treated for amblyopia. Vision research, 156, 28-38. https://www.sciencedirect.com/science/article/pii/S0042698919300045 |
Meier, K., & Giaschi, D. (2017). Unilateral amblyopia affects two eyes: Fellow eye deficits in amblyopia. Investigative Ophthalmology & Vision Science, 58, 1779-1800. https://iovs.arvojournals.org/article.aspx?articleid=2614682 |
Meier, K., Sum, B., & Giaschi, D. (2016). Global motion perception in children with amblyopia as a function of spatial and temporal stimulus parameters. Vision Research, 127, 18-27. https://www.sciencedirect.com/science/article/pii/S0042698916300724 |
Giaschi, D., Chapman, C., Meier, K., Narasimhan, S., Regan, D. (2015). The effect of occlusion therapy on motion perception deficits in amblyopia.Vision Research, 114, 122-134. https://www.sciencedirect.com/science/article/pii/S0042698915002175?via%3Dihub |
Giaschi, D., Lo, R., Narasimhan, S., Lyons, C. & Wilcox, L.M. (2013) Sparing of coarse stereopsis in stereo deficient children with a history of amblyopia. Journal of Vision, 13(10):17,1-15. |
Narasimhan S, Harrison ER, Giaschi DE (2012) Quantitative measurement of interocular suppression in children with amblyopia. Vision Research, 66, 1-10. https://www.sciencedirect.com/science/article/pii/S0042698912001782?via%3Dihub |
Ho CS, Giaschi DE. (2007) Stereopsis-dependent deficits in maximum motion displacement in strabismic and anisometropic amblyopia.. Vision Research, 47, 2778-2785. https://www.sciencedirect.com/science/article/pii/S0042698907003069 |
Wang J, Ho C, Giaschi D. (2007) Deficient motion-defined and texture-defined figure-ground segregation in amblyopic children. Journal of Pediatric Ophthalmology and Strabismus, 44 (6), 363-371. Purpose: Motion-defined (MD) form deficits have been reported in the fellow eye and the amblyopic eye of children with amblyopia. These findings implicate possible direction-selective motion processing and/or static figure-ground segregation deficits. Recent evidence suggests that deficient MD form perception in the fellow eye of amblyopic children may not be fully accounted for by a general motion processing deficit. This study investigates the contribution of figure-ground segregation deficits to the MD form perception deficits in amblyopia. Methods: Performance in 6 amblyopic children (5 anisometropic, 1 aniso-strabismic) and 32 control children with normal vision were assessed on MD form, texture-defined (TD) form and global motion tasks. Results: Group performance on MD and TD form tasks were significantly worse in amblyopic children than in control children. Group performance on global motion was not significantly different between the two groups. Conclusions: Our present findings suggest faulty figure-ground segregation mechanisms are likely responsible for the observed MD form perception deficits in amblyopia. |
Ho C, Paul P, Asirvatham A, Cavanagh P, Cline R, Giaschi D. (2006) Abnormal spatial selection and tracking in children with amblyopia. Vision Research, 46, 3274-3283. https://www.sciencedirect.com/science/article/pii/S0042698906002136?via%3Dihub |
Ho C, Giaschi D, Boden C, Dougherty R, Cline R, Lyons C. (2005) Deficient motion perception in the fellow eye of amblyopic children. Vision Research 45, 1615-1627. https://www.sciencedirect.com/science/article/pii/S0042698905000283?via%3Dihub |
Ho C, Giaschi D (2005) Low-level and high-level maximum motion displacement deficits in amblyopic children. Journal of Vision 5(8):292a. https://www.sciencedirect.com/science/article/pii/S0042698909003447?via%3Dihub |