Ocular Surface Microbiome in Dry Eye Patients

NCT02161341 | Completed

• 2 other identifiers: R1146/48/20142014/520/A
• Study Type: observational
• Target: 82
• Locations: 1 country
• Sites: 1

Brief Summary

The ocular surface is the first line of defence of the eye, it is therefore where external threats are sensed, and potential insults neutralised. Over the course of evolution, various microbes, especially bacteriae, have come to colonise the ocular surface as commensals. The commensals have a role to maintain the homeostasis of the ocular surface. 1 The innate immunity of the ocular surface is very active, and consists of active mechanisms to suppress inflammation 2. For example, there exist macrophages, dendritic cells, suppressor cells, regulatory cells, B cells, IgA, lysozyme, anti-microbial peptides and barriers against external agents. The normal commensals of the ocular surface maintain a basal level of activation of innate defence by stimulating the pattern recognition receptors on ocular surface epithelial cells. This normal composition of microbes is important since inflammation and infection will result if there is introduction of a pathogenic strain that overcomes the flora, or if a dominant strain secretes excessively immunogenic products, such as the exotoxin A of Staphylococcus which triggers marginal keratitis, a form of type IV hypersensitivity. The flora load of microbiome could also influence tear function as a higher flora load was found to be associated with increased mucin degradation 3 and reduced globet cell densitiy 4. Previous studies \[I'm not sure which studies these are\] at SERI/SNEC also point to the importance of microbes. For example, in dry eye patients, there is increased lysophospholipids in the tear, and this may contribute to inflammatory mediators such as arachidonic acid and other metabolites. The lysophospholipids are formed by phospholipase A2 reactions, and the latter may be microbial in origin. Since dry eye is a known inflammatory disease of the ocular surface, this is one way that microbes can contribute to the pathology.

Conditions

Dry Eye

Keywords

Bacterial microbiome; Gene expression

Outcome Measures

Primary Outcomes (1)

• bacterial microbiome

  Determine the composition of the bacterial microbiome of the human ocular surface in normal volunteers and dry eye patients

  1 day

Secondary Outcomes (2)

• Gene expression

  1 day

• Clinical characteristic

  1 day

Eligibility Criteria

• Age: 21 Years - 85 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Dry eye patients and healthy normal volunteers

You may qualify if:

• Subjects must be 21 years or older
• Willing to perform all the eye examinations in this study

You may not qualify if:

• Known history of thyroid disorders (diagnosed by physician).
• Known history of Sjogren syndrome or rheumatoid arthritis (diagnosed by physician).
• No ocular surgery within the last 3 months and LASIK within 1 year.
• Ocular surface diseases such as pterygium, or obvious lid/orbital disease with lagophthalmos.
• Any other specified reason as determined by clinical investigator.

Sponsors & Collaborators

• Singapore National Eye Centre: lead

Study Sites (1)

Singapore Eye Research Institute

Singapore, 168751, Singapore

Location

Biospecimen

Retention: SAMPLES WITHOUT DNA

Microbiome swab will be collected from the inferior fornix of the lower eyelids to determine composition of the bacterial microbiome of the human ocular surface in normal volunteers and dry eye patients

MeSH Terms

Conditions

Dry Eye Syndromes

Condition Hierarchy (Ancestors)

Lacrimal Apparatus Diseases; Eye Diseases

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Clinician-Scientist, Senior Consultant

Study Record Dates

• First Submitted: June 9, 2014
• First Posted: June 11, 2014
• Study Start: June 1, 2014
• Primary Completion: October 1, 2018
• Study Completion: October 1, 2018
• Last Updated: October 31, 2018

Record last verified: 2018-10

Locations

SG (1)