Biomarker Sampling for Glaucoma Detection

(AH-Tears Trial)

Not currently recruiting at 1 trial location

Overseen By Dominique Geoffrion, B.Sc.

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Centre hospitalier de l'Université de Montréal (CHUM)

Disqualifiers: Other ocular diseases

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 7

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to discover new methods for detecting glaucoma earlier in individuals with corneal transplants, especially those with Boston keratoprosthesis. Researchers seek to determine if certain substances in the eye's fluid (aqueous humor) and tears can indicate the onset or worsening of glaucoma. The trial will collect samples from various participant groups, including those undergoing cataract surgery, glaucoma surgery, or intraocular surgery post-transplant. Ideal candidates are those requiring these specific surgeries and who have had a corneal transplant. The goal is to identify early warning signs that could aid in future treatments to prevent vision loss. As an unphased trial, this study offers participants the opportunity to contribute to groundbreaking research that may lead to earlier detection and improved prevention of vision loss.

Do I need to stop my current medications for the trial?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that this biomarker sampling method is safe for glaucoma detection?

Research has shown that collecting samples of the clear fluid in the eye, known as aqueous humor (AH), and tears is generally safe for patients. Aqueous humor, the clear liquid inside the eye, is commonly sampled during eye exams and is usually well-tolerated, with no major safety concerns reported.

Tear sampling is non-invasive, as it does not involve surgery or cutting into the body. Research indicates that collecting tears is safe and aids in understanding changes related to glaucoma, a condition that damages the eye's optic nerve. For instance, studies have analyzed tear samples from individuals with glaucoma to identify proteins linked to the disease's progression, with no significant safety issues noted.

Overall, both AH and tear sampling have been studied for their safety and are considered low-risk procedures. This information may reassure those considering participation in a clinical trial about these specific procedures. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the trial because it explores innovative ways to detect glaucoma earlier and more accurately by analyzing biomarkers in the eye's aqueous humor and tears. Unlike traditional methods that rely on assessing optic nerve damage or measuring eye pressure, this approach could identify glaucoma by detecting specific biological markers, potentially leading to earlier intervention. By sampling these fluids during various eye surgeries, researchers aim to understand how glaucoma develops and progresses, which could revolutionize how this condition is diagnosed and treated in the future.

What evidence suggests that this trial's sampling methods could be effective for detecting glaucoma?

Research has shown that analyzing the fluid in the eye (aqueous humor) and tears can help identify signs of glaucoma, a disease that can lead to vision loss. In this trial, participants will undergo various surgical procedures, during which samples of aqueous humor and tears will be collected for analysis. Studies have found that certain proteins and changes in eye fluid are linked to glaucoma. For instance, higher levels of specific proteins and substances called AGEs (advanced glycation end-products) appear in people with glaucoma. Tear fluid also plays a crucial role; changes in tear protein levels and markers like IL-6 are associated with glaucoma. These findings suggest that monitoring these indicators may help detect glaucoma early and guide treatment to prevent further vision damage. ^{6 7 8 9 10}

Who Is on the Research Team?

Younes Agoumi, MD FRCSC

Principal Investigator

Centre hospitalier de l'Université de Montréal (CHUM)

Mona Harissi-Dagher, MD

Principal Investigator

Centre hospitalier de l'Université de Montréal (CHUM)

Are You a Good Fit for This Trial?

This trial is for adults over 18 who can be monitored throughout the study. It's suitable for those needing corneal transplants, with or without glaucoma, and those requiring glaucoma surgery, with prior corneal transplants. Participants must have specific eye conditions and give informed consent. Those under 18 or unable to consent, or with other eye diseases are excluded.

Inclusion Criteria

I do not have glaucoma or any systemic diseases.

You understand and agree to participate in the study after being provided with all the necessary information.

I have the eye condition specified for my group.

Exclusion Criteria

I am under 18 years old.

I am unable to understand and give consent for treatment.

I have eye conditions not being studied in this trial.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Corneal Transplantation

Participants undergo corneal transplantation (penetrating keratoplasty or Boston keratoprosthesis) and samples are collected at baseline

Baseline

1 visit (in-person)

Intraocular Surgery

Participants undergo intraocular surgery (cataract, retina, or glaucoma) following corneal transplantation, with sample collection for analysis

3-12 months

Multiple visits (in-person) at 3, 6, and 12 months

Follow-up

Participants are monitored for safety and effectiveness after treatment, including evaluation of intraocular pressure and structural changes

12 months

Regular visits (in-person) at 3, 6, and 12 months

What Are the Treatments Tested in This Trial?

Interventions

• Sampling of aqueous humor
• Sampling of tears

Trial Overview The study investigates if certain inflammatory substances in the fluid (aqueous humor) inside the eye and tears can predict glaucoma after a corneal transplant. Researchers will collect samples of this fluid and tears from participants to identify potential biomarkers.

How Is the Trial Designed?

Group I: Intraocular surgery following corneal transplantation Experimental Treatment 2 Interventions

Participants needing intraocular surgery (cataract, retina or glaucoma), with prior corneal transplantation (penetrating keratoplasty or Boston keratoprosthesis). This allows analyzing samples during the potential development or progression of glaucoma in participants who have previously undergone corneal transplantation.

Group II: Glaucoma surgery following corneal transplantation Experimental Treatment 2 Interventions

Participants needing glaucoma filtration surgery, with prior corneal transplantation (penetrating keratoplasty or Boston keratoprosthesis). This allows analyzing samples once glaucoma is confirmed in participants who have previously undergone corneal transplantation.

Group III: Corneal transplantation Experimental Treatment 2 Interventions

Participants needing corneal transplantation (penetrating keratoplasty or Boston keratoprosthesis), with or without glaucoma. This allows analyzing samples at baseline (time 0), at the time of the corneal transplantation procedure.

Group IV: Cataract surgery only Placebo Group 2 Interventions

Participants needing cataract surgery, without glaucoma or any other corneal diseases.

Group V: Glaucoma surgery only Placebo Group 2 Interventions

Participants needing glaucoma filtration surgery, without any prior corneal transplantation.

Who Is Running the Clinical Trial?

Centre hospitalier de l'Université de Montréal (CHUM)

Lead Sponsor

Trials

389

Recruited

143,000+

Published Research Related to This Trial

The study developed a novel method using three-dimensional synchronous fluorescence spectroscopy (3D-SFS) to analyze tear fluid, which can help distinguish between healthy individuals and those with primary open-angle glaucoma (POAG).

By processing synchronous excitation spectra and utilizing second derivative analysis, the researchers identified key parameters that improve the diagnostic accuracy for early-stage glaucoma, suggesting potential for machine learning applications in automated diagnosis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Derivative Three-Dimensional Synchronous Fluorescence Analysis of Tear Fluid and Their Processing for the Diagnosis of Glaucoma. Dubayová, K., Krajčíková, K., Mareková, M., et al.[2022]

In a study of 33 young adults, significant changes in eye aberrations were observed during the 10 seconds after blinking, indicating that the tear film's stability can affect visual quality.

The research found that individuals with shorter tear film break-up times (TFBUTs) exhibited greater wavefront aberrations, suggesting that tear quality may play a crucial role in eye health and vision, highlighting the need for personalized assessments in clinical settings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dynamic changes in ocular Zernike aberrations and tear menisci measured with a wavefront sensor and an anterior segment OCT. Xu, J., Bao, J., Deng, J., et al.[2019]

Tear fluid analysis is a promising method for identifying new biomarkers for early diagnosis of glaucoma, which is crucial since the disease often progresses without symptoms until advanced stages.

Identifying specific and sensitive biomarkers in tear fluid could help in understanding the underlying mechanisms of glaucoma and differentiate between its various types, potentially leading to better diagnostic and treatment strategies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Tear Film-specific Biomarkers in Glaucoma Patients. Fomo, KN., Schmelter, C., Pfeiffer, N., et al.[2022]

A study involving 52 glaucoma patients and 55 control subjects identified eight biomarkers in the aqueous humor that can distinguish glaucoma from non-glaucoma controls with 90% sensitivity and 87% specificity, highlighting the potential for early diagnosis.

One significant biomarker, transthyretin, was found to be upregulated in glaucoma patients and may contribute to the disease by forming amyloid deposits that could obstruct fluid outflow and increase intraocular pressure.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Transthyretin and complex protein pattern in aqueous humor of patients with primary open-angle glaucoma. Grus, FH., Joachim, SC., Sandmann, S., et al.[2021]

In a clinical trial evaluating three topical ophthalmic medications, 957 volunteers were recruited, but only 320 were enrolled due to strict eligibility criteria, primarily related to abnormal tear production as measured by the Schirmer test.

The study found that 22% of screened subjects had abnormal Schirmer test results, with decreased tear production being the most common issue, highlighting the importance of screening in clinical trial design for ophthalmic studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Recruitment and screening experience for a clinical trial involving tear concentrations of a new drug. D'Antonio, JA., Baker, KS., Berkebile, CE., et al.[2019]

The Schirmer tear test (STT) shows a rapid initial uptake of tears followed by a steady state, allowing for a more detailed understanding of tear production over time, which is crucial for diagnosing conditions like keratoconjunctivitis sicca (KCS).

In normal dogs, the initial tear uptake rate was significantly higher (29.3 mm/min) compared to dogs with KCS (1.9 mm/min), indicating that the STT can effectively differentiate between normal tear production and abnormalities in tear film.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Analysis of tear uptake by the Schirmer tear test strip in the canine eye. Williams, DL.[2018]

In patients with glaucoma undergoing chronic topical treatments, there is a significant increase in pro-inflammatory cytokines in their tears, indicating an inflammatory response to the medication.

The study found that both Th1 and Th2 type cytokines were elevated, with Th1 cytokines showing the most marked increase, suggesting that these treatments may provoke an immune response that could affect ocular surface health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Measurement of inflammatory cytokines by multicytokine assay in tears of patients with glaucoma topically treated with chronic drugs. Malvitte, L., Montange, T., Vejux, A., et al.[2018]

The newly designed tear collection apparatus allows for the collection of larger volumes of tears quickly and safely, minimizing the risk of damaging the eye, which enhances the reliability of tear chemistry research.

This method not only preserves the chemical composition of the tear samples but also reduces irritation for subjects, making it easier to gather larger participant groups for studies on eye diseases.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

An improved technique for collection of human tears. Webster, HJ., Kairys, DJ.[2018]

A novel technique using phenol red threads for collecting human tear samples has been shown to be as effective, if not more so, than traditional methods like glass capillaries and Schirmer's paper strips for proteomic analysis.

This method is low-invasive and causes minimal discomfort to patients, making it a promising option for collecting tear samples to identify biomarkers and monitor treatment effectiveness in eye and systemic diseases.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

An Extensive Study of Phenol Red Thread as a Novel Non-Invasive Tear Sampling Technique for Proteomics Studies: Comparison with Two Commonly Used Methods. Kecskeméti, G., Tóth-Molnár, E., Janáky, T., et al.[2022]

Biomarkers are valuable tools for understanding ocular diseases, aiding in diagnosis, treatment monitoring, and predicting clinical responses, thanks to their ability to provide measurable indicators of disease processes.

The review highlights the use of easily accessible ocular matrices like tears and aqueous humor for biomarker evaluation, which allows for repeat sampling and objective measures of treatment effectiveness in clinical settings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Review of Biomarkers in Ocular Matrices: Challenges and Opportunities. Tamhane, M., Cabrera-Ghayouri, S., Abelian, G., et al.[2020]

A new method for quantifying tear protein concentration was developed, allowing for sensitive measurement in small tear sample volumes (as low as 3 microL) from healthy subjects, with a mean protein concentration of 4.11 mg/mL.

The assay demonstrated consistent results across samples from 33 healthy individuals, indicating its reliability and potential for use in clinical settings to assess tear protein levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A protein dye-binding assay on cellulose membranes for tear protein quantification: use of conventional schirmer strips. López-Cisternas, J., Castillo-Díaz, J., Traipe-Castro, L., et al.[2015]

In a study involving 15 subjects, different tear collection methods were compared, revealing that Schirmer's strip collection provided the highest concentration of MUC5AC, while basal tear collection yielded the highest concentration of MUC16.

The findings suggest that the choice of tear collection method should be based on the specific mucin being analyzed, as each method has distinct advantages for capturing different mucins in human tear fluid.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Concentrations of MUC16 and MUC5AC using three tear collection methods. Ablamowicz, AF., Nichols, JJ.[2022]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12110543/

Metabolomic Profiling of Aqueous Humor From Glaucoma ... Our results revealed significant metabolic alterations in POAG that affect key cellular functions. Agmatine and thiamine could be potential ...

2. sciencedirect.com sciencedirect.com/science/article/pii/S2352340925006055

Comprehensive characterization of human aqueous humor ... This study aims to establish a comprehensive aqueous humor proteomics database for research on primary open-angle glaucoma (POAG), encompassing ...

3. nature.com nature.com/articles/s41598-025-03781-3

Identifying diagnostic biomarkers for glaucoma based on ... This study employed Mendelian randomization (MR) and bioinformatics approaches to identify potential biomarkers for glaucoma.

4. frontiersin.org frontiersin.org/journals/molecular-neuroscience/articles/10.3389/fnmol.2024.1397461/full

Advances in aqueous humor proteomics for biomarker ... This review summarizes current advances in AH proteome investigation and their relevance to primary open angle glaucoma (POAG), as well as introduces relevant ...

5. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8389649/

Candidate Glaucoma Biomarkers: From Proteins to ... ELISA-based quantification showed aqueous humor and blood levels of protein carbonyls and AGEs to be significantly higher in glaucomatous samples, which may be ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11179400/

Using Electronic Health Record Data to Determine the ... Aqueous humor samples are routinely collected at the slit lamp in clinic mainly for diagnostic purposes and previous comparatively small studies have shown this ...

7. tvst.arvojournals.org tvst.arvojournals.org/article.aspx?articleid=2802630

Evaluation of Serum and Aqueous Humor Neurofilament Light ... In this study, we collected AH and serum samples from patients with glaucoma undergoing ocular surgery as part of their routine care to determine whether there ...

8. cell.com cell.com/heliyon/fulltext/S2405-8440(24)10021-7

Trends and hot spots in research related to aqueous humor ... This study unveiled present patterns of global collaboration, emerging frontiers, fundamental knowledge, research hotspots and current trends in AH.

9. nature.com nature.com/articles/s43856-025-00862-2

Proteomics approach identifies aqueous humor biomarkers ... Our research shows that analyzing aqueous humor can provide valuable insights into the biology of retinal diseases such as GA.

10. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11076703/

Advances in aqueous humor proteomics for biomarker ... This review summarizes current advances in AH proteome investigation and their relevance to primary open angle glaucoma (POAG), as well as introduces relevant ...