Factors in Learning And Plasticity: Healthy Vision

NCT05439759 | Active Not Recruiting

• 1 other identifier: 300006197 (Study 1)
• Study Type: interventional
• Target: 120
• Locations: 1 country
• Sites: 2

Brief Summary

A greater understanding of plasticity after central vision loss can inform new therapies for treating low vision and has the potential to benefit millions of individuals suffering from low vision. The treatment of low vision is particularly relevant to the mission of the National Eye Institute (NEI) to support research on visual disorders, mechanisms of visual function, and preservation of sight. The comparison of different training and outcome factors is in line with the National Institute of Mental Health (NIMH) Research Domain Criteria (RDOC) framework and studies in an aging population are consistent with the mission of the National Institute on Aging (NIA).

Conditions

Macular Degeneration; Central Visual Impairment

Keywords

plasticity; central vision loss; perceptual learning

Outcome Measures

Primary Outcomes (3)

• Change from Baseline Radial Bias from the Crowding Task after completion of Training at approximately 7 weeks

  The ratio of the crowding threshold along the axis connected to the fovea vs. along the orthogonal axis.

  Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average

• Change from Baseline Saccadic Precision after Completion of Training at approximately 7 weeks

  Consistency across trials in placement of the first saccade calculated by the distribution across trials (bivariate contour ellipse area) of the landing point of the first fixation of each trial.

  Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average

• Change from Baseline Fixation Stability after Completion of Training at approximately 7 weeks

  Normalizing fixations in the PRL to the first fixation to that region and calculating the distribution of all fixation locations in this normalized space (measured as a bivariate contour ellipse area).

  Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average

Other Outcomes (18)

• Change from Baseline Acuity after Completion of Training at approximately 7 weeks

  Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average

• Change from Baseline Contrast Sensitivity after Completion of Training at approximately 7 weeks

  Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average

• Change from Baseline Minimal print size from the MNREAD task after Completion of Training at approximately 7 weeks

  Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average

Study Arms (4)

Condition 1: Training visual sensitivity

EXPERIMENTAL

A standard Perceptual Learning approach to train early visual processes of discriminating the orientation of Gabor patches presented at threshold- level contrast. Preliminary data, using this method, in normally seeing and MD participants show both feasibility and preliminary evidence that this training gives rise to improvements in acuity.

Behavioral: Condition 1: Training visual sensitivity

Condition 2: Training spatial integration

EXPERIMENTAL

Most visual tasks involve integrating features to discriminate objects, therefore requiring brain areas that can integrate features from multiple receptive fields from early visual areas. Thus spatial integration involves what investigators refer to as mid-level vision. Spatial integration is a particular concern in developing a PRL since an area of the visual periphery that is best suited to discriminate a simple visual feature may not be appropriate to integrate information across objects, such as in reading or recognizing facial identity or expression. Investigators address this issue with a targeted spatial integration training approach developed by MPI Seitz and based on contour integration tasks used in previous PL studies to train mid-level visual processes. Target stimuli consist of contours formed by spaced Gabors. Difficulty of detecting the target is manipulated by varying orientation jitter of Gabors making up the target.

Behavioral: Condition 2: Training spatial integration

Condition 3: Training spatial attention

EXPERIMENTAL

A key attribute of most real-world visual tasks is that individuals alternate shifting and holding attention and eye movements to different objects in the visual field while searching for and discriminating possible sources of visual information. To train this, investigators will implement a task structure that requires participants to alternate between holding and switching attention and making targeted eye movements. The basic task is to press a key whenever a red circle appears in a series of other colored circles, with a target presented every 2 to 4s. Participants must maintain vigilance for relatively long periods, detect objects in the near periphery, switch attention based upon exogenous and endogenous cues, and make eye- movements to move areas of spared vision to those locations. These are aspects of attention and eye movements not incorporated in Conditions 1 and 2.

Behavioral: Condition 3: Training spatial attention

Condition 4: Combination training

EXPERIMENTAL

In Condition 4, investigators combine the elements of Conditions 1-3. The investigators test the extent to which a combined training gives rise to the joint benefits of each training individually, or integrative benefits potentially surpass the benefits of the individual training alone. The visual sensitivity task from Condition 1 will alternate across blocks with the spatial integration task from Condition 2, using the timing of targets and location switches from Condition 3; Gabors or contours are used as targets instead of the red- circle in Condition 3 and a fixation point is presented instead of distractors to maintain a similar stimulus configuration as Conditions 1 and 2.

Behavioral: Condition 4: Combination training

Interventions

Condition 2: Training spatial integration BEHAVIORAL

Spatial integration involves what the investigators refer to as mid-level vision. Spatial integration is a concern in developing a PRL since an area of the visual periphery that is best suited to discriminate a simple visual feature may not be appropriate to integrate information across objects, such as in reading or recognizing facial identity or expression. The investigators address this issue with a targeted spatial integration training approach developed by MPI Seitz and based on contour integration tasks used in previous PL studies to train mid-level visual processes. Target stimuli consist of contours formed by spaced Gabors. The difficulty is manipulated by varying orientation jitter of Gabors. Several optotypes will be included to promote generalization, including shapes and facial expressions.

Condition 2: Training spatial integration

Condition 3: Training spatial attention BEHAVIORAL

The investigators will implement a task structure that requires participants to alternate between holding and switching attention and making targeted eye movements. The basic task is to press a key whenever a red-circle appears in a series of other colored-circles, with a target presented every 2 to 4s. Participants must maintain vigilance for relatively long periods, detect objects in the near periphery, switch attention based upon exogenous and endogenous cues, and make eye- movements to move areas of spared vision to those locations. These are aspects of attention and eye movements not incorporated in Conditions 1 and 2.

Condition 3: Training spatial attention

Condition 4: Combination training BEHAVIORAL

Daily tasks involve a combination of being sensitive to basic visual features, being able to integrate these features, and directing attention and eye movements to better evaluate the information of potential interest. To address this integrative nature of real-world vision,Condition 4 combines the elements of Conditions 1-3.

Condition 4: Combination training

Condition 1: Training visual sensitivity BEHAVIORAL

Investigators adopt a standard PL approach to train early visual processes of discriminating the orientation of Gabor patches presented at threshold contrast. Across training blocks, Gabors will range in spatial frequency, where contrast is adapted with a 3/1 staircase. Whenever a specific contrast threshold is reached, spatial frequency will increase by 2 cycles per degree and contrast will be reset. Preliminary data from this method in normally seeing and MD participants show both feasibility and tentative evidence that this training gives rise to improvements in acuity.

Condition 1: Training visual sensitivity

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Aged 18-30
• Corrected vision (20/40 or better)
• No reported incidence of retinal pathology.

You may not qualify if:

• Pacemaker or any ferromagnetic metal implanted in their body
• Metal of any type implanted in their head (limited dental work is acceptable)
• Claustrophobia
• Needing non-standard glasses (other than the simple MR-compatible glasses that can be supplied) for best-corrected distance vision
• Being hearing-impaired
• Weight over 300 pounds
• Maximum body girth over 60 inches
• Previous serious head injury
• Presence of hallucinations or delusions
• Excessive old, or colorful tattoos, especially near the head
• Pregnancy
• Braces/permanent retainer

Sponsors & Collaborators

• University of California, Riverside: collaborator
• University of Alabama at Birmingham: lead

Study Sites (2)

UAB

Birmingham, Alabama, 35294, United States

Location

University of California, Riverside

Riverside, California, 92521, United States

Location

MeSH Terms

Conditions

Blindness, Cortical; Macular Degeneration; Scotoma

Condition Hierarchy (Ancestors)

Blindness; Vision Disorders; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Eye Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Retinal Degeneration; Retinal Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: June 7, 2022
• First Posted: June 30, 2022
• Study Start: October 24, 2022
• Primary Completion (Estimated): November 1, 2026
• Study Completion (Estimated): November 1, 2026
• Last Updated: February 9, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, ICF, ANALYTIC CODE
• Time Frame: Within one year of the final participant completing data collection.

Locations

US (2)