Proteomic Profiles in Trabeculectomy Patients
Condition: Glaucoma
MeSH terms: Glaucoma
Study type: Observational

Summary: 
      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.
    

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.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        120 patients will be recruited for this study
      
Keywords: Tear proteins profiles; Longitudinal; Ocular surface damage; Trabeculectomy