Associate Professor Sieu Khuu

Associate Professor Sieu Khuu

Associate Professor
Medicine & Health
School of Optometry and Vision Science


My research program is primarily focused in the discipline of visual perception with emphases on cognitive and visual neuroscience. This research seeks to understand the computational rules underlying the extraction and processing of visual information and how this information is used by the visual system to aid visually guided behaviour. This research focuses on the following areas: 1) To contribute to the understanding of visual perception with emphasis on the computational processes that underlies the perception of 3D motion and form. 2) To understand how the visual system detects image contrast, and how efficient and focused measures of this visual function can be applied to vision screening and the diagnosis of visual dysfunction.



  • Bachelor of Science hons (UWA, 1999)
  • Doctor of Philosophy, (UWA, 2003)


Research Goals 

  • To understand the computational rules that is applied to extract and process local and global form and motion information by the human visual system. 
  • To understand how three-dimensional representations of object/global form and motion are obtained from the two-dimensional retinal image, and how binocular and monocular cues (e.g., shadows and shading) interact to enable a three-dimensional representation.
  • To develop and adapt psychophysical tasks for application in clinical settings for use in the diagnosis and remediation of visual deficits, particularly in new visual field technology and deficits arising from neurotoxicity.


Research in Detail

My research primarily focuses on using visual psychophysics to characterize and quantifying human perception. Particularly this research seeks to measure how sensitive is the visual system in detecting visual attributes and characterizing the factors that affect this process. This work is experimental in nature and cross-disciplinary with emphasis on neuroscience, psychology and optometry.

A major theme of my research is to understand how the visual system is able to detect and recognize the form and motion of objects in the three-dimensional environment.  This is not a simple operation as the brain must first extract local/feature components of the image and then combine them for object recognition. At present our understanding of the computation underlying this process is limited and my research seeks to infer from behaviour what these computational rules are. This involves first measuring the detectability of motion and form information and second determining how might form and motion perception changes when other visual attributes are manipulated.  Understanding the conditions under which perception changes, allows for inferences to be made about the specificity and specialization of the visual system in the processing of form and motion which can be related to neurophysiological studies that explore where and how vision is processed in the brain. Current projects in my laboratory investigate the mechanism by which local and global form and motion estimates are derived, and what role visual awareness plays in this process.

Recently, I have sought to develop and adapt appropriate psychophysical tests/tasks for clinical assessment and use to detect and contribute to the diagnosis of eye disease. For example, recent projects have sought to characterize global motion and form loss in dry cleaners who have exposed to organic solvents. Exposure to organic solvents leads to neurotoxicity, which causes changes in visual function. Behavioural measures of global form and motion have been applied to characterize loss in dry cleaners. Current student projects continue this theme by investigating the development of more functional tests of colour perception, and in the characterization of music sight reading in expert and novice musicians.

In collaboration with the Centre for Eye Health research has been conducted to investigate the influence of spatial and temporal summation in the detection of contrast in perimetric technologies. Here research is focused on devising the most appropriate spatial and temporal stimulus properties that might lead to better detection and diagnosis of eye diseases.


Research Grants

  • La Salle University Research grant awarded to: Jimenez, I., Garzon, J., Rodriguez, M.F., & Khuu S.K. AUD 78,000, 2014. Grant entitled: Visual and ocular neurotoxicity in workers exposed to organic solvents.
  • National Health and Medical Research Council (NHMRC), Project Grant, awarded to: Kalloniatis, M., Mitchell, P., Hayen, A., Healy, P., Coroneo, M., Stapleton, F., Khuu, S.K., AU $1,099,710, AAP1033224, 2012-2016. Grant entitled: “Systematic glaucoma screening and diagnostic effectiveness: improving patient outcomes through early detection.”
  • The Australian Research Council, Discovery Project Grant (Australian Government) awarded to S.K. Khuu & A. Hayes, AU$110,000, DP110104713, 2011-2013. Grant entitled: “ Detection and identification by the human visual system of curved contour structure in natural images: A computational and psychophysical analysis.”
  • Research Grants Council of Hong Kong, Competitive Earmarked Research Grant (Hong Kong government) awarded to: L. Li & S.K. Khuu. HK$554,435, HKU7478/08H, 2008-2010. Grant entitled: “An investigation on the influence of concurrent head movement on human visual perception of object motion”
  • Research Grants Council of Hong Kong, Competitive Earmarked Research Grant (Hong Kong government) awarded to:  S.K. Khuu. HK$489,294, HKU7409/06H, 2006-2008. Grant entitled: “Human perception of image speed derived from the simultaneous extraction and analysis of visual information in two- and three-dimensional space.”
  • The University of Hong Kong Competitive Earmarked Research Grant Merit award, HK$50,000 2005.
  • Research Grants Council of Hong Kong, Competitive Earmarked Research Grant (Hong Kong government) awarded to: A. Hayes & S.K. Khuu. HK$402,000, HKU7426/05H, 2005-2008.  Grant entitled: “Human perception of global form and global motion in both the image plane (fronto-parallel) and the stereo-depth plane, using random dipole patterns ('Glass patterns') and random dot kinematograms.”


Current Students Projects (PhD and Honours) and Supervision Opportunities

My research laboratory offers opportunities to undertake supervised research in a variety of projects that seeks to understand the functional basis of visual behaviour, and the development of appropriate psychophysical tests to detect and characterize eye function. Current topics are:

  • Understanding the role of visual awareness in the integration and perception of global form and motion.
  • The perception of three-dimensional structure inferred from both monocular and binocular cues. In particular the role of cast and attached shadows in the perception of three-dimensional structure and depth position.
  • The development of contrast sensitivity test by which to characterize visual function across the visual field. In particular, a major focus of this research is to understand spatial and temporal summation in the detection of contrast and how these stimulus properties can be adapted to improve the detection of eye disease.


Current students:

Post Graduate Research 

  • New perimetric technologies in the detection and diagnosis of Glaucoma. Dr. Jack Phu, 2014 – present. Co-supervisor with Professor Michael Kalloniatis.
  • The role of visual awareness in the integration of global form and motion information.  – Mr Eric Chung, 2013 – present
  • Characterising eye movement patterns and expertise in novice and expert music sight readers. Ms. Patricia Arthur – 2011 – present
  • The development of functional tests for colour perception. Ms Vanessa Honson 2013 – present. 
  • Ms. Noha Alsaleem, 2012 – present. Research area: Improved psychophysical measures of contrast detection in glaucoma

5th year research projects (Optometry) and Vision Science Honours

  •   Optical defocus in the periphery: Implications for behavioural measurements of contrast detection, vernier and visual acuity. Ms Taibia Shafaie 2014.
  • Putting the pieces together: Role of asynchronous presentation in perception of global form. Miss Sarah Boneham & Miss Emilie Ross, 2014.
  • Influences of peripheral optical defocus on perimetry. Mr David Kim & Ms Shereen Kassir, 2014 (Co-Supervisor)
  • The effect of image size on the efficiency of eye movements when reading text. Mr Alexander Du & Mr Alex Luong, 2014, (Co-Supervisor).
  • Does controversy concerning typographical inter- sentence spacing boil down to visual crowding? Mr Vincent Khou & Miss Vivien Chen, 2014.  (Co-Supervisor)


Teaching and Outreach

 My teaching specialization is in Vision Science and falls into two areas: the biological basis of behaviour, with a strong emphasis on neuroscience and cognitive neuropsychology, and sensory perception, incorporating research methods such as psychophysics.

 The courses I currently teach to Optometry and Vision Science students inform about the psychology and neuroscience of visual and sensory perception, as well as the research techniques employed by research practice in these areas.

I am the course coordinator for:

  • VISN2211: Organisation and Function of the Visual System
  • VISN3211: New Development in Vision Science


Professional affiliations and service positions 

  • Undergraduate Coordinator, School of Optometry and Vision Science
  • Member of the Executive Committee in School of Optometry and Vision Science
  • Member of the Faculty of Science Education Committee
  • Convenor of Vision Science Honours in the School of Optometry and Vision Science.


Awards and Achievements 

  • Finalist, UNSW innovation award 2013. New inventions staff category: “Visual field testing: equating temporal and spatial summation” M. Kalloniatis, S.K. Khuu & N. Al Saleem.
  • UNSW, Faculty of Science ARC Silver Star Award, AUD $35,000, 2013.
  • The University of Hong Kong Competitive Earmarked Research Grant Merit award, HK$50,000 2007.
  • The University of Hong Kong Competitive Earmarked Research Grant Merit award, HK$50,000 2005.
  • “Methods and systems for diagnosis of ocular disease”. Inventors: Kalloniatis, M. Khuu, S.K., & Alsaleem, N. (2012). Patent: WO/2014/094035


Research Groups

Research Topics

  • Blue light blocking lenses, effects on visual and non-visual systems
  • Surface and Material Perception
  • Visual electrophysiology, visual psychophysics, detection of brain abnormalities
  • Visual Processing
+61 2 9385 4620
School of Optometry and Vision Science Level 3, Room 3.028 North Wing, Rupert Myers Building