Ocular Surface Microbiota Alterations Following FS-LASIK and Their Association With Postoperative Dry Eye

Area of Science:

• Ophthalmology
• Microbiology
• Genomics

Background:

• Limited evidence exists on ocular surface microbiota (OSM) alterations post-femtosecond laser-assisted in situ keratomileusis (FS-LASIK).
• The relationship between OSM changes and postoperative dry eye (DE) requires further investigation.
• Understanding these changes can aid in early DE detection and targeted treatment strategies.

Purpose of the Study:

• To compare the OSM profiles of patients who develop DE versus those who do not after FS-LASIK.
• To identify specific microbial signatures associated with postoperative DE.
• To establish a foundation for predicting and managing DE following refractive surgery.

Main Methods:

• Patients undergoing FS-LASIK were assessed 3 months postoperatively.
• Participants were classified into DE and non-DE groups based on OSDI, TBUT, and Schirmer I test results.
• Corneal nerve morphology was evaluated using IVCM, and conjunctival sac samples were analyzed for OSM via 16S rRNA sequencing.

Main Results:

• The DE group exhibited higher OSM alpha-diversity, with decreased Proteobacteria and increased Bacteroidetes.
• Key genus-level shifts included enrichment of Veillonella, Streptococcus, and Aggregatibacter, and depletion of Pseudomonas and Lactobacillus in the DE group.
• Staphylococcus abundance correlated positively with OSDI scores and negatively with corneal nerve parameters, while Lactobacillus showed positive associations with Schirmer test values and corneal nerve density.

Conclusions:

• Dysbiosis between Staphylococcus and Lactobacillus genera may serve as a biomarker for DE susceptibility.
• These microbial imbalances present potential therapeutic targets for managing postoperative DE.
• Preoperative microbial composition might influence postoperative outcomes and the risk of developing DE.