Geographic Atrophy
Conditions
Brief summary
This research sub-study is to evaluate if combining images from Optical Coherence Tomography (OCT) scans with Adaptive Optics Scanning Light Ophthalmoscopy (AOSLO) and Microperimetry (MP) could show a link between structural changes in the back of the eye and vision. 10 participants that were enrolled in the COmparison of Clarus and Optos Ultrawide Field Imaging Systems for Geographic Atrophy study \[NCT05961332\] will be approached to enroll. Participants may complete OCT imaging and initial assessments during an initial visit and may return for additional procedures, including microperimetry and AOSLO imaging, within a window of up to 4 weeks.
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)
Interventions
DEVICEAdaptive Optics Scanning Light Ophthalmoscopy
AOSLO imaging offers unprecedented resolution by correcting optical distortions, enabling direct visualization of individual photoreceptors. The procedure takes 60 minutes.
DEVICEMicroperimetry
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.
DEVICEOptical Coherence Tomography
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.
Sponsors
University of Wisconsin, Madison
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
50 Years to No maximum
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of Photoreceptors in EZ absent regions | up to 6 hours total during one or two study visits | 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 |
| Area of EZ absent regions on AOSLO vs OCT imaging | up to 6 hours total during one or two study visits | 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. |
| Correlation of Retinal Sensitivity Data with EZ Status | up to 6 hours total during one or two study visits | 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. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORAmitha Domalpally, MD, PhD
University of Wisconsin, Madison
Outcome results
None listed