Tear Layer Lipid Thickness in Pterygium Patient Before and After Surgery

October 20, 2020 updated by: Louis Tong, Singapore National Eye Centre

The Assessment of Tear Layer and Tear Layer Lipid Distribution Pre and 1 Month Post Pterygium Surgery Using a LipiView Ocular Surface Interferometer (LipiView)

The investigators study aims to capture the objective effects of pterygium surgery on tear layer lipid thickness and the tear layer.

Previous objective studies of the tear film has been limited to corneal staining grading, tear break up time and Schirmer's test which have been shown to poor to moderate repeatability. The effect of pterygiums on tear layer lipid thickness (LLT) has not previously been explored. With the LipiView Ocular Surface Interferometer, the investigators have the ability to assess the optical coherence interference pattern produced by light reflected off the tear film in a safe and non-invasive manner. Software analysis of the image then measures the tear LLT which can be used to objectively quantify the diagnosis of lipid-deficient dry eye.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

Pterygium is a condition characterized by abnormal conjunctival growth on the cornea and is particularly prevalent in tropical climates. In severe circumstances, it may lead to visual loss by obscuration of the visual axis and inducing corneal astigmatism (1). It is often also associated with dry eye symptoms and studies have previously shown some correlation with shortened tear break up time (TBUT)(2) but not Schirmer's Test (3).

Schirmer's Test, corneal staining and TBUT are often used to investigate symptoms of dry eyes but the diagnosis and assessment is often difficult due to the poor repeatability of the tests(4). Treatments for dry eyes often rely on patient's subjective symptomatic improvements as a measure of outcome although no literature has been published of subjective symptoms for pterygium patients. The effects of pterygium surgery and tear lipid layer thickness has also not been studied.

The LipiView Ocular Surface Interferometer is a HSA-approved imaging device that allows clinicians evaluate the characteristics and thickness of the tear lipid layer thickness (LLT) in a safe and non-invasive manner. The device utilizes white light from a LED source that is directed at the tear film over the inferior corneal region. Reflected light is captured by a high resolution camera and the optical inference pattern is evaluated by software to determine the LLT (5). It also was found to correlate with other dry eye diagnostic tests, such as tear film break-up time (TBUT), Schirmer's test and corneal staining(6,7). LLT is also reported to better correlate with symptoms than other objective dry eye tests(5).

LipiView was also capable of detecting a significant change in longitudinal lipid thickness in 10 patients one month after blepharoplasty. A similar result may be obtained from the investigators patients post pterygium surgery.

This current study aims to investigate the effects of pterygium surgery on tear lipid layer thickness with LipiView. The results will be compared with the effects of pterygium surgery on TBUT, and corneal staining. The subjective improvement in dry eye symptoms post pterygium surgery will also be studied.

Clinical importance This study can provide further data to support pterygium surgery as a role in dry eyes management in an objective and reproducible manner. New data on pterygium and tear lipid layer thickness as well as subjective dry eye symptoms will also be explored.

Study Objectives and Purpose The Assesssment of Dry Eye Symptoms, Tear Layer and Tear Layer Lipid Thickness Pre and 1month Post Pterygium Surgery using a LipiView Ocular Surface Interferometer (LipiView)

Study design:

Prospective study

Rationale:

Methods:

Participants and target sample size Target sample size: 80 40 patients who will be undergoing pterygium surgery will be recruited for this study. Another 40 patients will be recruited from the general ophthalmology (ECS) clinic. These patients are cleared to have no lid disturbances in terms of function or anatomy, and will serve as the "control" group.

Permission will be sought from the junior ophthalmologists and the supervising ophthalmologist (in the event of a training list) or from the senior ophthalmologist if he is performing the surgery himself. These patients would have been diagnosed with pterygium and opted for surgical excision and conjunctival autograft. Pre operatively they will complete a simple questionnaire to evaluate any dry eye symptoms. Participants will be examined under the slit lamp for fluorescein dye corneal staining and fluorescein dye tear break up time. The patients will then undergo a LipiView Ocular Surface Interferometer Measurement of Tear lipid layer thickness.

Visit schedules Two/Three visits is required for paticipants who are undergoing pterygium surgery.

Only one visit is required for normal controls who are recruited from general ophthalmology (ECS) clinic.

Duration of study:

10 months.

Procedures:

  1. Assessment of Dry Eye Symptoms (SANDE) Participants will be asked to score and fill up a dry eye questionnaire that assesses the symptomatic severity and frequency of dry eyes symptoms.

    • SANDE Questionnaire Consists of 3 questions on frequency and severity. VAS will be applied to evaluate dry eye symptoms as described by Schaumberg et al. (Schaumberg, Gulati et al. 2007). The scores will be recorded separately for frequency and severity of dry eye symptoms. Patients will be asked to mark "X" on a 100mm line that corresponds to the degree of the symptom. A global score will be calculated by multiplying the frequency score by the severity score and taking the square root of the result (to transform back to the original scale).

    Basic biodata such as age, race, gender will also be recorded.

  2. LipiView Ocular Surface Interferometer Measurement of Tear lipid Layer Thickness

    Prior measuring the tear lipid layer thickness, participants are advised not to:

    i. instill any eye ointment for at least 24 hours, or ii. instill eye drops or wear contact lenses for 4 hours, or iii. swim in a chlorinated pool, rub their eyes or put on eye cosmetics on the day of the measurement.

    During the measurement of each eye, the participants place their chins on a chin rest and look at a single white light source for 30 seconds. During this period, participants are encouraged to blink freely at a comfortable rate which the assessor measures the LLT.

    Similar steps would be taken for the other eye as a control eye.

    Assessment of fluorescein tear break up time and corneal staining will be conducted only after LipiView LLT measurement.

  3. Fluorescein Dye Tear Break-up Time (TBUT) Fluorescein dye is introduced onto the lower eyelid by a wetted fluorescein strip. The tear film will then be observed with blue light using a slit lamp to the point where it breaks. The time from the previous blink to the breaking of the tear film will be recorded to the nearest second.
  4. Fluorescein Dye Corneal Staining After fluorescein dye is introduced, the cornea will be examined for green stains indicating epithelial erosion, a sign of damage due to dryness. The number of green stains and their location on the cornea (superior, central, inferior, temporal, nasal fields) will be recorded.
  5. Patient will undergo pterygium excision and conjunctival autograft on the prearranged surgery date.
  6. Steps 1-4 will be repeated 1 month post operatively.

Outcomes:

Primary outcome:

An increase in tear lipid layer thickness 1 month post pterygium surgery in the operated eye.

Statistics:

There will be no interim analysis. Analysis will be performed after all the subjects have completed the required visits or have withdrawn from the study.

Data will be analysed for sample mean of pre and post-operative questionnaire score, tear break up time, corneal staining and tear lipid layer thickness in both the operated and un-operated eye. The confidence intervals of the pre and post-operative in both the operated and un-operated will be calculated with T-test analysis.

Expected outcomes:

There should be decreased dry eye symptoms in the operated pterygium eye with a improvement in tear break up time, decreased corneal staining and increase tear lipid layer thickness when compared to pre operative.

Potential problems No potential problems are expected for this study.

Inclusion Criteria

1. Normal controls or patients with pterygium who have consented for pterygium surgery and are willing to participate in this study

Exclusion Criteria

  1. Active ocular surface conditions such as infections.
  2. Any other specified reason as determined by clinical investigator.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
76

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Singapore
    • Singapore.
      • Singapore, Singapore., Singapore, 168751
        • Singapore Eye Research Institute

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

21 years to 99 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Healthy normal volunteers and Pterygium patients undergoing surgery to remove Pterygium

Description

Inclusion Criteria:

  • Normal controls or patients with pterygium who have consented for pterygium surgery and are willing to participate in this study

Exclusion Criteria:

  • Active ocular surface conditions such as infections.
  • Any other specified reason as determined by clinical investigator.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
tear lipid layer thickness
Time Frame: 1 month
An increase in tear lipid layer thickness 1 month post pterygium surgery in the operated eye
1 month

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Singapore National Eye Centre

Study record dates

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Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2013

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 1, 2020

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2020

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 9, 2014

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 10, 2014

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 11, 2014

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 22, 2020

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 20, 2020

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2020

More Information

Terms related to this study

Keywords

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Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • R1075/90/2013
  • 2013/851/A (Other Identifier: SingHealth Centralised Institutional Review Board)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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