Aims The physiopathology of rosacea and the correlation between ocular and cutaneous rosacea remains unclear. This study analysed ocular and cutaneous rosacea with in vivo confocal microscopy (IVCM).

Methods Thirty-four eyes of 34 patients with confirmed rosacea-associated meibomian gland dysfunction-related evaporative dry eye were enrolled in the study. The ophthalmological investigations included dry eye ocular surface disease index (OSDI), the Schirmer test, tear osmolarity, tear break up time, the Oxford score, infrared meibography for meibomian gland (MG) analysis and IVCM investigation for cornea, MG and skin analysis (cheek, hand). Presences of Demodex in the MG and in the cheek were also investigated. We established scores for quantifying the MG alterations in the MG (IVCM-MG) and cheek (IVCM-Cheek), and scores for Demodex quantification in the MG and cheek (IVCM-MG-Dex and IVCM-Cheek-Dex).

Results IVCM was relevant for analysing the cornea and MG structures and was also suitable for cutaneous analysis. Exposed skin explorations presented the epidermal and dermal layers clearly. In patients with rosacea, the IVCM-MG alteration scores were correlated with IVCM-Cheek (R²=0.27 and p=0.0006) and IVCM-MG-Dex was correlated with IVCM-Cheek-Dex (R²=0.70 and p<0.0001). However, no correlation was found between the IVCM-MG or IVCM-Cheek and the break up time, Schirmer, Oxford and osmolarity evaluations.

Conclusions IVCM could be a safe, effective and reliable tool to quantify alterations of the cornea, MG and cheek glands in patients with rosacea combined with quantification of Demodex infections. As a valuable tool for investigating the pathophysiology of the disease, it could be used to assess the effectiveness of therapy.