Effects and Prognostic Factors of Intensive Pulse Light Treatment for Meibomian Gland Dysfunction

The investigators are going to Investigate the comparative efficacy of intense pulsed light therapy alone with that of intense pulsed light plus meibomian gland expression for meibomian gland dysfunction.

Enrolled patients are going to be randomly assigned to two groups. All of the patients will undergo four treatment sessions in total, which are two weeks apart. Group 1 will undergo two sessions of intense pulsed light therapy with meibomian gland expression, as well as two sessions of intense pulsed light alone. Group 2 will receive two sessions of intense pulsed light therapy alone, and two sessions of intense pulsed light therapy with meibomian gland expression. The following parameters will be measured at baseline, 2 weeks after the second treatment session, and 2 weeks after the fourth treatment session: tearfilm break-up time, Oxford grade for corneal staining, meibomian gland expressibility, meibum quality, and ocular surface disease index.

IPL therapy will be performed with the M22® (Lumenis, Dreieich, Germany). IPL treatment is going to be administered to the skin below the lower eyelid. Before treatment, the eyes will be protected with opaque goggles. Ultrasound gel is going to be applied to the patient's face from tragus to tragus including the nose in order to conduct the light, help to spread the energy evenly, and provide a degree of protection. The intensity of the IPL treatment will range from 9.8J/cm2 to 13J/cm2 according to Fitzpatrick Skin Type Grading.

IPL therapy will be performed with the M22® (Lumenis, Dreieich, Germany). IPL treatment is going to be administered to the skin below the lower eyelid. Before treatment, the eyes will be protected with opaque goggles. Ultrasound gel is going to be applied to the patient's face from tragus to tragus including the nose in order to conduct the light, help to spread the energy evenly, and provide a degree of protection. The intensity of the IPL treatment will range from 9.8J/cm2 to 13J/cm2 according to Fitzpatrick Skin Type Grading.

Oxford grade for staining was assessed on a scale of 0 to 5. It was scaled according to the degree of corneal staining as follow: 0 (absent), 1 (minimal), 2 (mild), 3 (moderate), 4 (marked), and 5 (severe)

Change from baseline meibomian gland expressibility score at 2 weeks after the last treatment session

The meibomian gland expressibility was assessed on a scale of 0 to 3 in five glands on the central lower lid. It was scaled according to the number of glands expressible, as follows: 0 (all glands), 1 (three to four glands), 2 (one to two glands) and 3 (no glands)

The meibum quality score were divided into the following four degrees: 0 (clear), 1 (cloudy), 2 (granular), and 3 (toothpaste)

The ocular surface diseases index score range from 0 to 100 based on the result of standardized ocular surface disease index questionnaire. Higher value represent worse subjective symptom.

Inclusion Criteria: - Clinical diagnosis of meibomian gland dysfunction Exclusion Criteria: Medical conditions in which IPL is contraindicated (pregnancy, breastfeeding, lupus, and any major uncontrolled health problem). Contact lens wearer Previous ocular surgery Previous thermal treatment for dry eye disease (e.g. LipiFlow)