Biomarker Sampling for Glaucoma Detection
(AH-Tears Trial)
Recruiting in Palo Alto (17 mi)
Age: 18+
Sex: Any
Travel: May Be Covered
Time Reimbursement: Varies
Trial Phase: Academic
Recruiting
Sponsor: Centre hospitalier de l'Université de Montréal (CHUM)
Disqualifiers: Other ocular diseases
No Placebo Group
Trial Summary
What is the purpose of this trial?
Glaucoma is the most common threat to vision rehabilitation in patients with Boston keratoprosthesis type 1 (KPro) implantation. High intraocular pressure (IOP) is the most important risk factor for glaucoma and may lead to irreversible retinal and optic nerve damage. Glaucoma drainage device (GDD) surgery is used to divert aqueous humor (AH) from the anterior chamber to an external reservoir to regulate flow and decrease the IOP. The AH is in direct communication with any corneal damage or surgery undertaken in the anterior chamber and can serve as a source of potential biomarkers to detect early inflammatory or glaucomatous changes. Tears are also one of the most accessible and non-invasive source of biomarkers, especially in Kpro eyes where the central optic allows communication between aqueous humor and the tears at the surface of the eye. The investigators propose to test the hypothesis that distinct inflammatory mediators in the AH and tears can serve as biomarkers for glaucoma development and progression after CT, making them specifically amenable to targeted treatment strategies to minimize 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 data supports the effectiveness of the treatment involving sampling of aqueous humor and tears for glaucoma detection?
Is tear sampling safe for humans?
Tear sampling methods, such as using phenol red threads and polyethylene tubes, are considered low in invasiveness and discomfort, making them safe for human use. These methods do not significantly alter the chemical composition of the tears, ensuring reliable research results without causing harm to the eye.678910
How does this treatment for glaucoma differ from others?
Eligibility Criteria
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
You understand and agree to participate in the study after being provided with all the necessary information.
I do not have glaucoma or any systemic diseases.
I have the eye condition specified for my group.
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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.
Trial Timeline
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
Treatment Details
Interventions
- Sampling of aqueous humor (Procedure)
- Sampling of tears (Procedure)
Trial OverviewThe 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.
Participant Groups
5Treatment groups
Experimental Treatment
Placebo Group
Group I: Intraocular surgery following corneal transplantationExperimental Treatment2 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 transplantationExperimental Treatment2 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 transplantationExperimental Treatment2 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 onlyPlacebo Group2 Interventions
Participants needing cataract surgery, without glaucoma or any other corneal diseases.
Group V: Glaucoma surgery onlyPlacebo Group2 Interventions
Participants needing glaucoma filtration surgery, without any prior corneal transplantation.
Find a Clinic Near You
Research Locations NearbySelect from list below to view details:
Centre Hospitalier de l'Université de Montréal (CHUM)Montréal, Canada
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Who Is Running the Clinical Trial?
Centre hospitalier de l'Université de Montréal (CHUM)Lead Sponsor
References
Tear Film-specific Biomarkers in Glaucoma Patients. [2022]Glaucoma is a group of chronic eye diseases that lead to degeneration of retinal ganglion cells (RGCs) and their axons followed by irreversible loss of vision in the patient. Glaucoma is a disease that initially evolves asymptomatically with the first symptoms appearing only at an advanced stage of this eye disease. For this reason, it is always necessary to develop state-of-the-art technologies and methods for the identification and characterization of new, specific biomarkers for the early diagnosis of glaucoma. Therefore, the analysis of biological fluids, as in this case the tear fluid of patients, represents an attractive source to identify new specific as well as sensitive biomarkers in glaucoma. These biomarkers could be involved in the pathophysiological processes of glaucoma or possibly serve for diagnostic differentiation of various types of glaucoma.
Derivative Three-Dimensional Synchronous Fluorescence Analysis of Tear Fluid and Their Processing for the Diagnosis of Glaucoma. [2022]Sensitive and rapid diagnosis of the early stages of glaucoma from tear fluid is a great challenge for researchers.
Measurement of inflammatory cytokines by multicytokine assay in tears of patients with glaucoma topically treated with chronic drugs. [2018]To investigate the ocular surface inflammatory response to chronic topical treatments in patients with glaucoma by measuring the cytokine level in tears using multiplex bead analysis.
Review of Biomarkers in Ocular Matrices: Challenges and Opportunities. [2020]Biomarkers provide a powerful and dynamic approach to improve our understanding of the mechanisms underlying ocular diseases with applications in diagnosis, disease modulation or for predicting and monitoring of clinical response to treatment. Defined as measurable indicator of normal or pathological processes, biomarker evaluation has been used extensively in drug development within clinical settings to better comprehend effectiveness of treatment in ocular diseases. Biomarkers in the eye have the advantage of access to multiple ocular matrices via minimally invasive methods. Repeat sampling for biomarker assessment has enabled reproducible objective measures of disease process or biological responses to a drug treatment. This review describes the usage of biomarkers with respect to four commonly sampled ocular matrices in clinic: tears, conjunctiva, aqueous humor and vitreous. Issues that affect the evaluation of biomarkers are discussed along with opportunities to leverage biomarkers such that ultimately, they can be used for customized targeted therapy.
Dynamic changes in ocular Zernike aberrations and tear menisci measured with a wavefront sensor and an anterior segment OCT. [2019]To measure dynamic change characteristics of spatial and temporal variations in the post-blink tear film of normal eyes.
Concentrations of MUC16 and MUC5AC using three tear collection methods. [2022]To determine the optimal tear collection method for analysis of ocular surface mucins MUC5AC and MUC16.
An improved technique for collection of human tears. [2018]While pursuing a study of lysozyme levels in human tears, the authors were dissatisfied with collection systems previously used. We therefore constructed a new, improved apparatus for tear collection using a thin, flexible polyethylene tube attached to a standard 25-gauge 1.0 cc tuberculin syringe. This system is superior to previously-designed apparati in that it permits the collection of a relatively large volume of tears in a short time without risking damage to delicate ocular structures. This promises to enhance the reliability of tear chemistry research without significantly adulterating the chemical composition of the samples. Typical results for total protein, levels of IgA and lysozyme, and Minimum-Inhibitory-Concentration bioassay of tears are presented to support the authors' position that standard chemical assays are not altered. An additional bonus inherent in this technique is the potential for obtaining larger populations of experimental subjects due to the low level of irritation that subjects experience when tears are sampled. This apparatus is easily amenable to clinical and medical diagnostic studies of tear chemistry in patients suffering from various eye diseases.
Recruitment and screening experience for a clinical trial involving tear concentrations of a new drug. [2019]The process of recruitment and screening of volunteers for clinical research studies has not been thoroughly evaluated in the ophthalmic literature. The data for the current report were derived from a double-masked randomized clinical trial designed to evaluate and compare the effective tear level concentrations of three topical ophthalmic medications. Subjects were recruited from the general population and were healthy volunteers on no medications. Tear volume was measured by the Schirmer test with anesthesia; acceptable results were in the range of 10-25 mm/5 min. Study enrollment was limited to 32 subjects per week, with a total sample size goal of 320. The study population, 18-45 years of age, consisted primarily of white male college students. Nine hundred fifty-seven volunteers were recruited. Of the 498 of these subjects that reported for screening (52%), 459 (48%) were actually screened, and 320 (33%) were enrolled. The overall prevalence of an abnormal Schirmer test ( 25 mm/5 min in either eye) in the screened population was 22%. The frequency of decreased tear production (13%) was slightly greater than that of increased tear production (9%). An abnormal Schirmer test was the primary reason for ineligibility. The completion rate for those enrolled was 96%. This type of information is valuable when designing a clinical trial, especially with regard to budgetary, time table, and sample size estimations.
Analysis of tear uptake by the Schirmer tear test strip in the canine eye. [2018]To analyze the uptake of tears in a Schirmer tear test (STT) in vitro and in vitro.
An Extensive Study of Phenol Red Thread as a Novel Non-Invasive Tear Sampling Technique for Proteomics Studies: Comparison with Two Commonly Used Methods. [2022]Tear samples are considered in recent publications as easily, noninvasively collectible information sources for precision medicine. Their complex composition may aid the identification of biomarkers and the monitoring of the effectiveness of treatments for the eye and systemic diseases. Sample collection and processing are key steps in any analytical method, especially if subtle personal differences need to be detected. In this work, we evaluate the usability of a novel sample collection technique for human tear samples using phenol red threads (cotton thread treated with the pH indicator phenol red), which are efficiently used to measure tear volume in clinical diagnosis. The low invasiveness and low discomfort to the patients have already been demonstrated, but their applicability for proteomic sample collection has not yet been compared to other methods. We have shown, using various statistical approaches, the qualitative and quantitative differences in proteomic samples collected with this novel and two traditional methods using either glass capillaries or Schirmer's paper strips. In all parameters studied, the phenol red threads proved to be equally or even more suitable than traditional methods. Based on detectability using different sampling methods, we have classified proteins in tear samples.
A protein dye-binding assay on cellulose membranes for tear protein quantification: use of conventional schirmer strips. [2015]To develop a method to quantify tear protein concentration with the sensitivity to measure this variable in the restricted volumes of single human tear samples.
Transthyretin and complex protein pattern in aqueous humor of patients with primary open-angle glaucoma. [2021]To analyze protein patterns in the aqueous humor of glaucoma patients in comparison to control subject using two different methods.