# Fine-scale eye-movement differences in psychosis and their contribution to abnormal vision

> **NIH NIH R21** · UNIVERSITY OF ROCHESTER · 2024 · $192,500

## Abstract

Project summary/abstract
Eye movement abnormalities in schizophrenia (SZ) have been documented for over 100 years, yet it remains
unknown whether fine-scale eye movements differ in this population. This is unfortunate because the neural
structures underlying oculomotor control are well-documented, implying that group differences could shed light
on the underlying illness pathophysiology. Moreover, establishing fine-scale eye movement differences could in
principle provide a distinguishing biobehavioral marker, which in turn could be used for differential diagnosis or
clinical prediction. Additionally, fine-scale eye movements contribute to everyday activities, such as recognizing
facial expressions at a distance, reading, and discriminating fine spatial stimuli. Therefore, it is conceivable that
abnormal micro- eye movements could be associated with—and even causally related to—impairments of these
visual functions in psychosis. Thus, a major goal of the research described in this proposal is to establish that
fine-scale eye movements do indeed differ among those with psychosis (Aim 1). These differences will be
assessed in people with a psychotic disorder and in well-matched healthy adults during steady fixation and in
the presence of complex foveal stimuli. In contrast to possibly all prior psychosis studies, we will use a high-
precision digital Dual Purkinje Image Eye-Tracker (1 arcmin resolution) with a head-stabilizing helmet to minimize
small head motions, and frequent re-calibrations throughout data collection. Additionally, a custom-made system
for gaze contingent display control, will enable the implementation of a state-of-the-art calibration procedure,
which effectively reduces the gaze localization error to less than 5 arcmin. Since visual acuity and reading are
often impaired among psychosis patients and may even portend a future psychotic disorder, we will attempt to
generate group differences with tasks that probe these same processes. Moreover, to establish a reference
baseline for fine oculomotor behavior and to consider hitherto unnoticed problems in fixational stability, we will
assess small eye movement differences during steady fixation without an active task. Aside from assessing
whether micro- eye movement differences characterize psychosis, we will also assess their relationship to visual
perceptual deficits (Aim 2). In particular, we will probe for correlations between microsaccade characteristics
and the magnitude of visual acuity and reading deficits. We will also consider whether trials with a higher rate
of microsaccades are related to impaired reading or impaired visual acuity compared to trials without such eye
movements, and whether image stabilization on the retina (which removes the benefits of microsaccades)
worsens acuity more for controls than for patients. Findings will inform our understanding of how eye movement
differences in psychosis are related to perception at the micro-scale, which in turn can sugges...

## Key facts

- **NIH application ID:** 10849936
- **Project number:** 5R21EY035001-02
- **Recipient organization:** UNIVERSITY OF ROCHESTER
- **Principal Investigator:** Brian Patrick Keane
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $192,500
- **Award type:** 5
- **Project period:** 2023-06-01 → 2026-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10849936

## Citation

> US National Institutes of Health, RePORTER application 10849936, Fine-scale eye-movement differences in psychosis and their contribution to abnormal vision (5R21EY035001-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10849936. Licensed CC0.

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