Effects Of Ocular Demodex Infection On The Morphology And Biomechanics Of Keratoconus

To assess the impact of demodex mite infection on corneal morphology, biomechanics, and epithelial thickness in patients with Keratoconus(KC).

This case-control study included 122 patients with KC who visited Wuhan Aier Hankou Eye Hospital from December 2022 to December 2023.

All KC patient's upper eyelid was examined using in vivo laser confocal microscopy to assess demodex mite infection. Patients with a mite count of four or more mites per eye were categorized into the KC Demodex + group (study group), comprising 60 individuals and a total of 120 eyes. Conversely, those with a mite count of less than four mites per eye were placed in the KC Demodex - group (control group), which included 62 individuals with a total of 124 eyes. Both groups underwent corneal topography, biomechanical analysis, and anterior segment optical coherence tomography (OCT) examination, along with evaluations of eye rubbing and itchiness scores.

The eye itch and eye rubbing scores in the KC Demodex+ group were significantly higher than those in the Demodex - group, with all differences having statistical significance (z=-6.231, -9.482，all P<0.001). Additionally, the eye itch and eye rubbing scores in the Demodex+ group were positively correlated with the number of mites present (r=0.355 ,0.359 ,all P<0.001). In terms of corneal measurements, Front Kmean, Back Kmean and A2 Velocity were all greater in the Demodex+ group compared to the Demodex- group (t=2.029,-2.701,-2.917,all P<0.05). Moreover, the corneal SSI was lower in the Demodex+ group (P=0.020).