Proteomic Profiles in Trabeculectomy Patients

Long-term Observation of Tear Proteomic Profiles and Ocular Surface in Trabeculectomy Patients Before and After Surgery

Approximately 70 million people world-wide are affected with glaucoma, of whom 6.7 million have bilateral blindness.5 Elevated intro-ocular pressure is the major modifiable risk factor in glaucoma, and reducing intraocular pressure to a consistently low level can delay disease progression and therefore, blindness.6 Topical intraocular pressure -lowering medication remains the first-line treatment for glaucoma, with surgical intervention playing a secondary role in cases suboptimally controlled with medication alone.

In this study, we plan to assess the change in tear proteins in trabeculectomy patients before and after operations. It is hoped that this study could help us gain more understanding of the possible mechanism accounting for the development of dry eye disease in glaucoma patients, which could help us develop better screening modalities and therapeutic agents for glaucoma patients at risk to prevent the development of dry eye disease.

Study Overview

• Status: Completed
• Conditions: Glaucoma

Detailed Description

Study Objectives and Purpose

There are two primary aims in this study:

1. To assess changes in the tear proteomic profiles in pre-trabeculectomy and post-trabeculectomy patients
2. To assess the changes in clinical signs of the eye and tear film as well as dry eye symptoms.

Study Material Human Tears will be collected from patients in SNEC clinic

Study Design:

120 patients will be recruited for this study (details as described below). Schirmers I test, Tear Osmolarity, Tear Break Up Time (TBUT), Anterior segment optical coherence tomography (ASOCT) and Impression cytology will be done during the study visits. Subjective symptom and severity of dry eye disease will be assessed through Visual Analog Scale (VAS).

No. of visits:

There will be 4 visits in this study. Visit 1: Pre-trabeculectomy operation Visit 2: 6 month after trabeculectomy surgery Visit 3: 1 year after trabeculectomy surgery Visit 4: 3 years after trabeculectomy surgery

Selection and Withdrawal of Subjects Recruitment Criteria

1. 120 patients will be recruited from glaucoma clinics in SNEC
2. Patients age ≥ 21 years old
3. Patients who require trabeculectomy operation

Treatment of subjects

Study Procedures:

1. Fluorescein staining will be used to visualize patient eyes.

2. Schirmer's test will be used to measure the amount of tear production

   1. A small strip of filter paper will be inserted inside the lower eyelid
   2. A topical aneasthetic is placed into the eye before the filter paper to prevent tearing due to the irritation from the paper
   3. The eyes are closed for 5 minutes.
   4. The paper is then removed and the amount of moisture is measured

3. Impression cytology will be performed to collect the superficial conjunctival cells for analysis

   1. While the eye is still anaesthetized from Schirmer's test, one end of a filter paper will be impressed upon the temporal conjunctiva whilst the other hand is grasped in place with a blunt smooth edged forceps.
   2. The filter paper is removed from the conjunctiva with a peeling motion after 2-3 seconds.
   3. The paper is placed into an eppendorf tube for future analysis.

4. Tear osmolarity, Tear Break Up Time (TBUT) will be measured in all patients

   a) Tear osmolarity will be measured using the osmolarity chip, 3 chips per eye

5. Anterior segment optical coherence tomography will be performed to assess the tear meniscus and image for any conjunctivochalasis

   a) The patient will be asked to look at a target in the instrument while blinking normally. The instrument will scan the lower eyelid margin for imaging of the tear meniscus and conjunctivochalasis

6. Symptoms and severity of dry eye disease will be assessed through the Visual Analog Scale (VAS) system

Assessment of efficacy Outcome Measures

1. Symptoms and severity of dry eye disease will be quantified based on the Visual Analog Scale (VAS)11
2. Amount of moisture of the filter paper will be measured in Schirmer's test
3. Clinical assessment of dry eye disease through Tear break up time (TBUT) and Tear Osmolarity measurements
4. Tear meniscus height and area in the images obtained with optical coherence tomography

Target sample size 120 subjects will be enrolled in the study.

• Study Type: Observational
• Enrollment (Actual): 36

Contacts and Locations

Study Locations

• Singapore
  • Singapore, Singapore, 168751
    • Singapore National Eye Centre/ Singapore Eye Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

120 patients will be recruited for this study

Description

Inclusion Criteria:

1. 120 patients will be recruited from glaucoma clinics in SNEC
2. Patients age ≥ 21 years old
3. Patients who require trabeculectomy operation

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change from baseline in the tear protein profiles in trabeculectomy patients at 3 years	Baseline and 3 years

Secondary Outcome Measures

Outcome Measure	Time Frame
Symptoms and severity of dry eye disease	Baseline and 3 years
Amount of tears will be measured	Baseline and 3 years
Tear Osmolarity will be measured	Baseline and 3 years
Tear meniscus height will be measured	Baseline and 3 years

Collaborators and Investigators

• Sponsor: Singapore National Eye Centre

Study record dates

Study Major Dates

• Study Start: November 1, 2013
• Primary Completion (Actual): October 1, 2018
• Study Completion (Actual): October 1, 2018

Study Registration Dates

• First Submitted: April 19, 2013
• First Submitted That Met QC Criteria: April 25, 2013
• First Posted (Estimate): April 26, 2013

Study Record Updates

• Last Update Posted (Actual): October 31, 2018
• Last Update Submitted That Met QC Criteria: October 29, 2018
• Last Verified: October 1, 2018

More Information

Terms related to this study

• Keywords: Longitudinal; Trabeculectomy; Ocular surface damage; Tear proteins profiles
• Additional Relevant MeSH Terms: Eye Diseases; Ocular Hypertension; Glaucoma
• Other Study ID Numbers: R980/89/2012; 2013/020/A (Other Identifier: Singhealth Centralised Institutional Review Board)