A new approach of ocular nebulization with vitamin B12 versus oxytocin for the treatment of dry eye disease: an in vivo confocal microscopy study.

To present a new ocular nebulization therapy for the treatment of dry eye disease (DED) and investigate the efficacy of vitamin B12 (VB12) and oxytocin (OXT) nebulization with clinical parameters and in vivo confocal microscopy (IVCM). Thirty-eight patients with DED were enrolled, with 19 receiving VB12 nebulization and 19 receiving OXT nebulization twice weekly for 3 months. Clinical signs and symptoms including Ocular Surface Disease Index, self-assessment of light sensitivity and dryness, tear meniscus height, tear break-up time (BUT), and corneal staining, along with IVCM data of basal epithelial cell density, sub-basal dendritic cell (DC) density, nerve density, and nerve tortuosity were acquired at baseline, 1 month, and 3 months after starting treatment. Patients treated with VB12 improved significantly in all signs and symptoms except for nerve tortuosity during the three-month treatment, while OXT demonstrated similar effects apart from BUT and nerve tortuosity. VB12 group revealed a higher BUT at 1 month and 3 months with a higher basal epithelial cell density at 3 months compared with OXT group, and a lower DC density was observed in OXT group at 1 month. Change of basal epithelial cell density was more significant at 3 months in VB12 group, with OXT group showing a significantly higher DC reduction at 1 month. The nebulization therapy delivering VB12 and OXT appears to be effective in improving the symptoms and signs of dry eye, with a relatively stronger effect of BUT elevation and epithelial repair in VB12 and anti-inflammation in OXT nebulization.