Adaptive Optics Scanning Light Ophthalmoscopy (AOSLO) and Microperimetry (MP) Sub-study
Structure and Function in the Progression of Atrophic AMD: Validation of Photoreceptor Damage Observed With OCT Using AOSLO (Adaptive Optics Scanning Light Ophthalmoscopy and Microperimetry
Study Overview
Status
Conditions
Detailed Description
Age-related macular degeneration (AMD) is a leading cause of blindness worldwide, with geographic atrophy (GA) representing the advanced, untreatable form of the disease. GA leads to progressive degeneration of retinal cells critical for vision, resulting in irreversible vision loss and a significant impact on patients' quality of life. Despite the prevalence of GA, treatment options remain limited. Current therapeutic strategies focus on slowing the enlargement of atrophic regions, but clinical trials have faced challenges in demonstrating clear patient benefits.
In clinical practice, GA progression is often evaluated by measuring the area of atrophy on retinal imaging, such as fundus autofluorescence (FAF) and, more recently, optical coherence tomography (OCT). These structural biomarkers are used in clinical trials to assess the efficacy of new drugs, with the FDA accepting a reduction in the rate of GA enlargement as a successful outcome. However, these structural metrics often fail to correlate with functional vision loss, leaving patients and physicians disappointed by treatments that may stabilize GA progression without improving their visual outcomes.
The ellipsoid zone (EZ), a hyperreflective layer visualized on OCT, represents the structural integrity of photoreceptors-cells responsible for converting light into visual signals. In patients with one or more GA lesions, OCT imaging shows that the EZ is typically absent within the GA, while the EZ in the perilesional zone may be attenuated or damaged. Perilesional EZ loss is thought to represent the area at highest risk for future vision loss. With the FDA approval of photoreceptor preservation as an endpoint for GA trials, there has been significant interest in measuring EZ loss from OCT scans. Drug approval will now focus on the prevention of EZ loss in the perilesional areas rather than GA area expansion. However, it is important to establish whether the absence of the EZ truly indicates photoreceptor damage and whether there is a functional correlation between EZ loss and visual sensitivity. Adaptive Optics and microperimetry are two modalities that can help address this.
This sub-study is a pilot comparative imaging study. In addition to the imaging procedures collected for the main COCO GA study [NCT05961332], participants will have the following study images obtained:
- Spectralis OCT (if applicable),
- visual acuity,
- ocular biometry, which is a non-invasive eye test using a machine called an IOL master,
- microperimetry, and
- Adaptive Optics Scanning Light Ophthalmoscopy (AOSLO)
Study Type
Enrollment (Estimated)
Phase
- Not Applicable
Contacts and Locations
Study Locations
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Wisconsin
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Madison, Wisconsin, United States, 53792
- University of Wisconsin
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Participation Criteria
Eligibility Criteria
Ages Eligible for Study
- Adult
- Older Adult
Accepts Healthy Volunteers
Description
Inclusion Criteria (from the main study):
- 50 years or older and may be either male or female and may be of any race
- Established diagnosis of geographic atrophy (GA) due to age-related macular degeneration (AMD)
- GA characteristics: GA area of between 1.25 mm² and 23 mm², with seventy percent of eyes having GA area ranging from 2.5 mm² to 17.5 mm². GA may be unifocal or multifocal. GA may be subfoveal or extrafoveal, with twenty-five percent of eyes having subfoveal GA. The presence of concurrent peripapillary atrophy will not exclude participants from participation
- Willing to participate as evidenced by signing the written informed consent
Additional Sub-study Inclusion Criteria:
Early-stage GA defined as
- GA area of between 1.25 mm2 and 23 mm2
- GA may be unifocal or multifocal
- GA may be subfoveal or extrafoveal
- Concurrent peripapillary atrophy will not exclude participant from participation
- Phakic and pseudophakic participants are eligible for enrollment, with phakic participants prioritized when feasible.
Exclusion Criteria (from the main study):
- Unable to tolerate ophthalmic imaging
- Presence of neovascular AMD on optical coherence tomography (OCT) as confirmed by an ophthalmologist
- Presence of significant media opacity preventing adequate retinal imaging
- Presence of concurrent retinal disease which may confound assessment
Additional Sub-study Exclusion Criteria:
- Ocular media opacity or other condition(s) that, in the opinion of the investigators, may preclude imaging.
- Individuals who, in the opinion of the investigator, are unable to tolerate study procedures or comply with study requirements.
- Prior or current treatment with intraocular injections for geographic atrophy (e.g., pegcetacoplan [Syfovre] or similar therapies) is not permitted.
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Diagnostic
- Allocation: N/A
- Interventional Model: Single Group Assignment
- Masking: None (Open Label)
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
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Experimental: Microperimetry, Optical Coherence Tomography, Adaptive Optics
Imaging procedures may be completed during a single study visit or across two study visits based on participant availability and operational workflow.
When procedures occur across two visits, OCT imaging will be performed first to allow WRC review prior to scheduling microperimetry and AOSLO imaging.
If all procedures are completed during a single visit, the total visit time is approximately 5-6 hours.
If a second study visit is needed, only the remaining study procedures will be completed, so the second visit will be shorter since the initial ophthalmic procedures have already been performed.
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AOSLO imaging offers unprecedented resolution by correcting optical distortions, enabling direct visualization of individual photoreceptors.
The procedure takes 60 minutes.
Other Names:
Microperimetry measures retinal sensitivity at specific retinal locations while tracking eye movements, enabling precise correlation with structural changes.
The procedure takes up to 45 minutes.
OCT will be performed using the Heidelberg Spectralis system with a high-resolution scanning protocol.
This is a repeat procedure, the first image was obtained in the main study.
The procedure takes 5 minutes.
Other Names:
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Incidence of Photoreceptors in EZ absent regions
Time Frame: up to 6 hours total during one or two study visits
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The aim is to validate the use of AOSLO imaging for OCT-based EZ classifications, directly visualizing photoreceptor mosaics and correlating EZ loss with photoreceptor structure. Semi-automated machine learning algorithms will be used to segment the EZ layer on OCT images and generate en face maps. All algorithm outputs will be reviewed and verified by trained human graders. AOSLO imaging will validate these maps by providing photoreceptor cell counts and qualitative assessments in the same region |
up to 6 hours total during one or two study visits
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Area of EZ absent regions on AOSLO vs OCT imaging
Time Frame: up to 6 hours total during one or two study visits
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The aim is to validate the use of AOSLO imaging for OCT-based EZ classifications, directly visualizing photoreceptor mosaics and correlating EZ loss with photoreceptor structure. Semi-automated machine learning algorithms will be used to segment the EZ layer on OCT images and generate en face maps. All algorithm outputs will be reviewed and verified by trained human graders. Graders will independently measure area of EZ loss from images of each device. The measurements (in mm²) will be compared between the two devices. |
up to 6 hours total during one or two study visits
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Correlation of Retinal Sensitivity Data with EZ Status
Time Frame: up to 6 hours total during one or two study visits
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The aim is to correlate structural metrics (EZ status from OCT and AOSLO) with functional data (microperimetry), establishing EZ loss as a reliable biomarker for vision loss.
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up to 6 hours total during one or two study visits
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Collaborators and Investigators
Sponsor
Investigators
- Principal Investigator: Amitha Domalpally, MD, PhD, University of Wisconsin, Madison
Publications and helpful links
Study record dates
Study Major Dates
Study Start (Estimated)
Primary Completion (Estimated)
Study Completion (Estimated)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Additional Relevant MeSH Terms
Other Study ID Numbers
- 2023-0958 Sub-study
- SMPH/OPHTHAL&VIS SCI/FPRC (Other Identifier: UW Madison)
- Protocol Version 4/20/2026 (Other Identifier: UW Madison)
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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