Optimization of Sampling and Processing of Samples for Molecular Microbial Research on Ocular Surface Samples

Study Overview
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Brief Summary
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The use of anesthetics and the processing of the retrieved samples are major confounding factors that influence the results of microbiome research.

Detailed Description
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The use of anesthetics is subject of discussion in ocular surface microbiome research. One publication showed a significant lower alpha diversity when using an anesthetic. However, the diluting effect of the anesthetic drop itself was not accounted for. On the other hand, using anesthetics will enable patients to tolerate sampling better and this might allow better sampling. To analyze the effect of anesthetic drops on the composition of the ocular surface microbiome, we sampled volunteers undergoing general anesthesia. By using artificial tears as a control, we aimed at accounting for the diluting effect of the anesthetic. By using volunteers under general anesthesia, we wanted to assure similar pressure with or without topical anesthesia since the executor was not influenced by the patient's reaction. Furthermore, the effect of different extraction protocols on sequencing results will be assessed by sampling different volunteers in both eyes on non consecutive days.

Official Title
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Optimization of Sampling for Molecular Microbial Research on Ocular Surface Samples and Building a Framework for Comparing Current Sequencing Results Using Different Extraction Protocols.

Conditions
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Microbiota, Ocular Surface

Intervention / Treatment
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* Diagnostic Test: Conjunctival swab
* Drug: Oxybuprocaine Hydrochloride 0.4% Eye Drops
* Drug: artificial tears


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Willing to undergo sampling of the conjunctiva Fluent in written and verbal Dutch Capable of giving informed consent Exclusion Criteria: Allergy to oxybuprocaine Medication usage in one eye only

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: When the patient is under general anesthesia for another reason, he or she receives a drop of artificial tears in one eye and a drop of anesthetic in the other eye in a randomized way.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Drop of artificial tears<br>A drop op Thealoz duo | Diagnostic Test: Conjunctival swab<br>* Swab of the conjunctival fornices of both eyes<br>Drug: artificial tears<br>* One drop of artificial tears in the other eye<br>* Other names: Thealoz duo;|
| Active Comparator: Drop op anesthetic<br>A drop of oxybuprocaïne | Diagnostic Test: Conjunctival swab<br>* Swab of the conjunctival fornices of both eyes<br>Drug: Oxybuprocaine Hydrochloride 0.4% Eye Drops<br>* One drop of topical anesthesia in one eye<br>* Other names: anesthetic;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in richness of the microbial flora measured as operational taxonomic units | The difference in richness and evenness of distribution of the microbial flora of samples retrieved after a drop of topical anesthesia versus samples retrieved after a drop of artificial tears. | 5 minutes per sampling session | 
| Difference in evenness of distribution of the microbial flora measured as operational taxonomic units | The effect of the different microbial DNA extraction protocols on the richness and evenness of distribution of the microbial flora of the ocular surface will be compared. | 5 minutes per sampling session | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ocular surface microbiome, Anesthesia, Extraction protocol