Methods
itching, HL, telangiectasias, inflammation, obstructions of the MG, photophobia
INFLAMMATION
This prospective, randomized paired-eye study was conducted with the approval of the Institutional Review Board of the Asan Medical Center and the University of Ulsan College of Medicine, Seoul, South Korea (2021–0815). The study adhered to the tenets of the Declaration of Helsinki and followed good clinical practice guidelines. Signed informed consent was obtained from all participants before enrollment. The inclusion criteria were as follows: healthy adult patients aged between 19 to 85 years with moderate-to-severe MGD and a moderate OSDI score of > 23. Diagnosis of moderate to severe MGD was confirmed when patients exhibited moderate to severe symptoms, including ocular discomfort, itching, or photophobia at least 3 months before enrollment and clinical signs of moderate to severe degree MGD. One or more of the following three clinical signs in moderate to severe MGD were necessary: decreased meibum secretion with MG expressor or cloudy/toothpaste-like secretion with MG expressor; > 2 definite telangiectasias in the lid margin; and > 2 obstructions of the MG orificeAll patients underwent four sessions of IPL (M22; Lumenis, Yokneam, Israel) with meibomian gland expression (MGX) performed by one trained physician (HL) with a 2-week interval between each IPL session. Before the treatment sessions, every patient underwent Fitzpatrick skin typing, and adjustment of the IPL system was performed for a specific setting. All patients enrolled had Fitzpatrick skin type 3In addition, tear osmolarity, Schirmer’s test I without topical anesthesia, and tear matrix metalloproteinase (MMP)-9 expression were measured. MMP-9 level measurement was performed using the InflammaDry immunoassay (Rapid Pathogen Screening, Inc., Sarasota, FL). One blue line in the control zone with one red line in the result zone indicated a positive test result, whereas one blue line without a red line indicated a negative test result. A red line in the result zone correlated to a concentration of MMP-9 (strong positive, positive, or weak positive). Throughout the grading scale, we could apply semi-quantitative interpretations regarding ocular surface inflammation severity. Because of proportional increases in MMP-9 concentration with signal strength, a more vivid color in the red zone indicates higher MMP-9 levels (0 = none; 1 = trace; 2 = weak positive; 3 = positive; and 4 = strong positive)MG expressibility is a key baseline characteristic that correlates with ocular surface parameters and cytokines