Choroidal and Retinal Features in PACD and POAG on OCT and OCTA

Glaucoma is a group of irreversible, progressive optic neuropathies that can lead to severe visual field defects and even blindness, affecting nearly 95 million people worldwide. Based on anterior chamber angle structure, glaucoma is classified into primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG). Although POAG is more common, PACG is more severe and more likely to cause blindness if not managed appropriately. Globally, PACG accounts for approximately 25% of all glaucoma cases but is responsible for roughly 50% of glaucoma-related blindness. Generally, the term "glaucoma" implies optic nerve damage; however, glaucomatous optic neuropathy may be absent in subacute and acute angle-closure glaucoma. Therefore, according to international consensus, primary angle-closure disease is categorized as PACD-encompassing primary angle-closure suspect (PACS), primary angle closure (PAC), and PACG-based on the extent of angle closure, intraocular pressure elevation, and optic nerve damage. With advances in ophthalmic imaging, an increasing array of diagnostic modalities has been applied to glaucoma diagnosis. Optical coherence tomography (OCT), which utilizes low-coherence light to display cross-sectional images of the retina in vivo, represents a rapid, non-invasive, and continuously evolving imaging method. Building upon OCT, OCTA has emerged as a novel imaging technique that allows non-invasive visualization and assessment of blood flow in individual retinal layers [5]. Existing OCT and OCTA research on glaucoma primarily focuses on the optic disc and macula of glaucoma patients, providing evidence of changes in the retinal nerve fiber layer, macular ganglion cell thickness, optic nerve head structure, and peripapillary and macular vasculature. Other studies have examined choroidal vascular architecture and thickness in glaucoma; previous findings from our research group also indicate that choroidal vascular density is significantly lower in eyes with POAG and PACG compared to normal eyes, while choroidal stromal area is significantly greater in PACG than in POAG eyes and normal controls. Further investigation into choroidal and retinal alterations in glaucoma is warranted. Consequently, the OCT and OCTA fundus characteristics of patients with PACD and POAG remain an area with unexplored unknowns. This study utilizes OCT and OCTA to observe the choroidal and retinal tissue structure and vascular hemodynamics in patients with PACD and POAG, aiming to comprehensively investigate structural changes in the glaucomatous fundus, broaden new research directions, and explore and supplement the understanding of glaucoma pathogenesis.

Study Overview

• Status: Recruiting
• Conditions: Glaucoma; Choroid; OCTA

• Study Type: Observational
• Enrollment (Estimated): 132

Contacts and Locations

• Study Contact: Name: Yuheng Tan; Phone Number: +02066615461; Email: tanyuhesper@163.com

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China, 510060
      • Recruiting
      • Zhongshan Ophthalmic Center, Sun Yat-sen University
      • Contact: Yuheng Tan; Phone Number: +02066615461; Email: tanyuhesper@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

This study includes an observation cohort of adults diagnosed with POAG or PACD and a control cohort of healthy adults without glaucoma. Eligible participants range in age from 18 to 90 years and have no history of confounding retinal or neurological diseases that would interfere with OCT/OCTA imaging assessment.

Description

Inclusion Criteria:

• Control group: Healthy individuals with no history of ocular surgery, IOP < 21 mmHg, and CDR < 0.5 bilaterally without asymmetry
• Observation group: Glaucoma specialist-confirmed diagnosis of POAG or PACD (per ISGEO staging: PACS/PAC/PACG)

Exclusion Criteria:

• History of retinal or macular disease (e.g., AMD, DR, RVO, ERM)
• Non-glaucomatous optic neuropathy (e.g., MS, NMO)
• Poor OCT/OCTA image quality
• Refusal to sign informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Control Group; Inclusion Criteria: Individuals undergoing routine physical examination, generally in good health, with no history of prior surgery.; No use of glaucoma medications, no evidence of elevated intraocular pressure (IOP < 21 mmHg), no significant optic nerve head (ONH) asymmetry (cup-to-disc ratio difference < 0.2), and cup-to-disc ratio (CDR) < 0.5 in both eyes.; Age between 18 and 90 years, inclusive; any gender. Exclusion Criteria: Known history of retinal disease, including any condition involving macular degeneration (e.g., age-related macular degeneration, diabetic retinopathy, retinal vein occlusion, viral retinitis, or epiretinal membrane).; Optic nerve abnormalities other than glaucoma, such as those associated with neurological complications (e.g., Multiple Sclerosis, Neuromyelitis Optica).; Poor quality of OCT or OCTA images obtained post-examination.; Refusal to sign the informed consent form.
Observation Group; Inclusion Criteria: Confirmed diagnosis of Primary Open-Angle Glaucoma (POAG) or Primary Angle-Closure Disease (PACD) by a glaucoma specialist. The diagnosis of POAG is based on standard clinical criteria, specifically: presence of an open angle, glaucomatous optic neuropathy, current or past elevation of intraocular pressure, and visual field defects [10]. PACD cases are diagnosed and enrolled according to the clinical staging system of PACS, PAC, and PACG as established by the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) .; Age between 18 and 90 years, inclusive; any gender. Exclusion Criteria: Known history of retinal disease, including any condition involving macular degeneration (e.g., age-related macular degeneration, diabetic retinopathy, retinal vein occlusion, viral retinitis, or epiretinal membrane).; Optic nerve abnormalities other than glaucoma, such as those observed in patients with neurological com

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Subfoveal choroidal thickness (μm)	Subfoveal choroidal thickness (SFCT) is defined as the vertical distance between the outer border of the retinal pigment epithelium (RPE)/Bruch's membrane complex and the choroid-scleral junction directly beneath the fovea centralis. This measurement is obtained using a widefield swept-source OCT device, which enables enhanced depth imaging and high-resolution visualization of the choroid.The assessment is subsequently conducted by a masked, experienced grader using the integrated caliper tool. SFCT serves as a quantitative biomarker for choroidal structural changes associated with primary angle-closure disease (PACD) and primary open-angle glaucoma (POAG).	Day 1
Deviation of the horizontal watershed zone	The deviation of the horizontal watershed zone (HWZ) is assessed by determining whether the HWZ is displaced superiorly or inferiorly relative to the fovea centralis. This evaluation is performed using 24 × 20 mm en face OCTA images acquired with a widefield swept-source OCTA device. All measurements are carried out with the device's built-in caliper tool by a masked, experienced grader. The HWZ deviation serves as a quantitative indicator reflecting alterations in choroidal venous outflow patterns.	Day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Choroidal vascularity index (%)	Choroidal vascularity index (CVI) is defined as the ratio of choroidal vascular volume to total choroidal volume within a designated region, expressed as a percentage, with higher values indicating greater vascular density. The measurement was performed on images acquired with a widefield swept-source OCTA deviceand assessed by a masked, experienced grader.	Day 1

Collaborators and Investigators

• Sponsor: Zhongshan Ophthalmic Center, Sun Yat-sen University

Study record dates

Study Major Dates

• Study Start (Actual): July 16, 2024
• Primary Completion (Estimated): April 20, 2027
• Study Completion (Estimated): April 20, 2027

Study Registration Dates

• First Submitted: April 16, 2026
• First Submitted That Met QC Criteria: May 6, 2026
• First Posted (Actual): May 12, 2026

Study Record Updates

• Last Update Posted (Actual): May 12, 2026
• Last Update Submitted That Met QC Criteria: May 6, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Eye Diseases; Ocular Hypertension; Glaucoma
• Other Study ID Numbers: 2024KYPJ067

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No