Clinical characteristics of patients with refractory meibomian gland dysfunction unresponsive to intense pulsed light treatment

Purpose: To investigate the clinical characteristics of patients with meibomian gland dysfunction (MGD) who are unresponsive to additional intense pulsed light (IPL) therapy and to identify the risk factors for poor treatment response. Methods: Patients with moderate-to-severe MGD who had previously undergone four sessions of IPL treatment with a 590 nm filter at another clinic, received an additional four sessions of IPL therapy. A total of 66 eyes were analyzed. Patients' subjective assessments before and after the additional IPL treatments were scored on a scale from 0 to 4, where 0=moderate improvement, 1=mild improvement, 2=no change, and 3=aggravated MGD. Patients who scored 0 or 1 were classified as Group 1 (Responsive group), while those who scored 2 or 3 were classified as Group 2 (Refractory group). Results: After the additional IPL treatment, significant differences were observed between the groups in the Oxford and Sjögren’s International Clinical Collaborative Alliance (SICCA) staining scores (all P<0.001). Significant differences were found between the groups with regard to both upper and lower lid meibum quality and meibum consistency (all P<0.001). Group 2 had a significantly higher meibomian gland grade compared to Group 1 (P<0.001). Changes in the Oxford staining score (P=0.032), SICCA staining score (P=0.003), meibum quality (P<0.001), meibum consistency (P<0.001), and meibomian gland grade (P<0.001), before and after the additional treatment, were significantly greater in Group 1 than in Group 2. Logistic regression analysis identified higher Oxford staining scores (P=0.029; odds ratio 12.69) and elevated metalloproteinase-9 (MMP-9) levels (P=0.021; odds ratio 3.88) as significant risk factors for refractory MGD. Conclusions: Patients with refractory MGD, who did not respond to additional IPL treatment, exhibited poor ocular staining scores before treatment. High tear MMP-9 levels and elevated Oxford staining scores were identified as significant risk factors for poor treatment outcomes.