Ocular Surface Dysbiosis Associated With Allergic Conjunctival Diseases, Tacrolimus

Allergy and conjunctivitis
Researchers cannot conclusively determine whether allergic conjunctival disease or tacrolimus treatmentents play a more significant role in ocular surface dysbiosis.

Ocular surface microbiota tend to be dysbiotic in patients with severe refractory allergic conjunctival disease (ACD) compared with patients who had mild ACD and control participants, according to a study in Cornea.

Researchers analyzed ocular surface microbiota dysbiosis in 27 patients; 13 with vernal keratoconjunctivitis (VKC), 8 with atopic keratoconjunctivitis (AKC), and 6 healthy control group participants. All participants with ACD (n=21) were actively treated with topical tacrolimus. They were further split into mild (n=11) or severe (n=10) subgroups based on clinical scores obtained via cluster analysis, as well as expression of specific cytokines on the ocular surface. Researchers utilized the Schirmer test to collect tear specimens from all participants, and microbial composition was determined through next-generation 16S rRNA sequencing analysis.

Researchers found that patients with ACDs experienced significantly decreased ocular surface microbiota diversity compared with healthy controls. In all groups, the ocular surface microbiota found were mainly members of the phylum Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria

“The relative abundance of ocular surface microbiota in patients with ACDs was increased for phylum Firmicutes and decreased for phylum Proteobacteria,” according to the investigators. “The genera Blautia (vs mild ACD group) and Morganella (vs control group) exhibited significantly increased abundance only in the severe ACD group.”

Study limitations include a lack of analysis on the microbiota of untreated patients with VKC and AKC and a failure to account for age or seasonal variations.

Disclosure: This research was supported by Takanashi Milk Products Co., Ltd. Multiple study authors declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 


Inada N, Shoji J, Harata G, et al. Dysbiosis of ocular surface microbiota in patients with refractive allergic conjunctival diseases. Cornea. Published online December 8, 2021. doi: 10.1097/ICO.0000000000002940