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

Not Applicable

Completed

• Conditions: Microbiota; Ocular Surface
• Interventions: Diagnostic Test: Conjunctival swab; Drug: Oxybuprocaine Hydrochloride 0.4% Eye Drops; Drug: artificial tears

• Registration Number: NCT04193774
• Lead Sponsor: Universitaire Ziekenhuizen KU Leuven

Brief Summary

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

Detailed Description

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.

Study Timeline

• Study Start: 2019-08-19
• Study First Submitted: 2019-12-04
• Study First Submitted QC: 2019-12-06
• Study First Posted: 2019-12-10
• Primary Completion: 2021-12-31
• Study Completion: 2021-12-31
• Status Verified: 2022-06
• Last Update Submitted: 2022-07-18
• Last Update Posted: 2022-07-22

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 24

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Drop op anesthetic	Oxybuprocaine Hydrochloride 0.4% Eye Drops	A drop of oxybuprocaïne
Drop of artificial tears	Conjunctival swab	A drop op Thealoz duo
Drop of artificial tears	artificial tears	A drop op Thealoz duo
Drop op anesthetic	Conjunctival swab	A drop of oxybuprocaïne

Primary Outcome Measures

Name	Time	Method
Difference in richness of the microbial flora measured as operational taxonomic units	5 minutes per sampling session	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.
Difference in evenness of distribution of the microbial flora measured as operational taxonomic units	5 minutes per sampling session	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.

Trial Locations

Locations (1)

University Hospitals Leuven, Department of Ophthalmology; 🇧🇪 Leuven, Belgium