الفهرس 
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Abstract
This study aims to assess the efficacy and the effect of intense pulsed light (IPL) therapy on tears proteins and lipids of normal rabbits and patients with Meibomian gland dysfunction (MGD). Intense pulsed light application on rabbits eyes: In this study, thirty- five male albino rabbits weighing 2.5-3 kg were divided into two groups as following: The control group: composed of 5 rabbits (n = 10 eyes). IPL exposed groups: Thirty rabbits received 5 overlapping IPL flashes applied to the skin of the lower eyelid of each eye from Xenon flash lamp emitting wavelengths of light ranging from 565nm to near infrared 1400 nm. The IPL device voltage was 100 - 240 V, frequency 50 - 60 Hz, input was 16-Watt, optical exposure range was 2.5 - 6.5 J/cm2, maximum optical energy was 23J, pulse duration was < 2.0 ms and repetition time was 1-3.5 s. Tears samples were collected from control rabbits’ eyes , after 1 day, one week and 2 weeks. The rabbits were sacrificed respectively after the estimated periods and eye lids were dissected for histological examination. Intense pulsed light for patients with MGD: Tear samples (25-100µl) were collected from: (1) control subjects; (2) 12 patients with MGD before IPL session; (3) 12 patients with MGD treated with IPL with the same parameter used for rabbits. The following measurements for both rabbits and Patients with MGD were applied: Estimation of total protein concentration Sodium dodecyl sulfate polyacrylamide gel lectrophoresis (SDS- PAGE) for tears protein. Measurement of lipid profile: total lipid, cholesterol, triglycerides and phospholipids. Thin layer chromatography for phospholipids determination (TLC). Histopathological examination for rabbits’ Meibomian glands. Results were summarized as follows: Firstly: in rabbits After one day of exposure to IPL, the total protein content in rabbits’ tears was increased (P>0.01) and was followed by an obvious decrease after one week (P>0.05) and two weeks (P< 0.05) respectively. The SDS-PAGE profile showed considerable increase in the intensities of lysozyme and Lactoferrin, 108 KDa and 150 KDa after 1 day of exposure to IPL compared with the control pattern. In addition, the electrophoretic pattern of rabbits’ tears showed gradual improvement in all protein fractions after one and two weeks of exposure to IPL. The percntage change in total lipids concentration as compared with the control group were, 6.22٪ (P<0.05), 27.25٪ (P>0.01), 6.07٪ (P<0.05) after 1 day, 1 week and 2 weeks, respectively.The percentage change in tears colesterol as compared with the control were, 30.9٪ (P> 0.01), 31.4 ٪ (P> 0.01) and 0.16٪ after 1 day, 1 week and two weeks, respectively. Ttriglycerides concentration showed very high significant increase 50٪ (P> 0.001), 83٪ (P> 0.001) 36.5٪ (P> 0.01) after one day, one week and two weeks, respectively. The phospholipids content in the rabbits tears was significantly increased from 2.69±0.14 mg/ml for the control to 3.74±0.07 mg/ml, 3.29±0.15 mg/ml, 2.82±0.09 mg/ml with percentage change of 39.26 ٪ (P> 0.001), 22.6 ٪ (P>0.01), 5.13٪ (P> 0.001) after 1 day, 1 week and two weeks of exposure to IPL, respectively. The percentage changes in phosphatidylserine concentration after1 day, 1 week and 2 weeks were 13.38 ٪ (P> 0.01), 7.04 ٪ (P> 0.05) and 1.29٪ (P> 0.05) compared with the control group. Phosphatidylinositol concentration showed significant increase 10.9٪ (P> 0.01) followed by gradual decrease after one week and two weeks with percentage changes of 5.04٪ (P> 0.05) and 0.7٪ (P< 0.05). Phosphatidylethanolamine concentration was changed 12.9٪ (P> 0.01), 9.6 ٪ (P> 0.05), 4.4 ٪ (P< 0.05). Phosphatidylcholine showed significant increase (15٪, P> 0.01) followed by gradual improvement after 1 week and two weeks with percentage change of 6.8٪, P>0.05) and 0.15٪, P< 0.05), respectively. Moreover, histologic analysis of the Meibomian gland of the exposed rabbits revealed the presence of slight dilatation in the central duct without any change in the ductal epithelium after one day only and did not exhibit any changes throughout the next experimental periods. Secondly: in patients with MGD Significant improvements were observed in patients tears protein concentration and molecular weight after treatment with IPL. The most pronounced effect was in the molecular weight of tears lysozyme, lactoferrin and albumin. Tears lipid showed improvement in total lipids, triglycerides, cholesterol, and phospholipids concentration. In Thin layer chromatography (TLC), the tears of Patients with MGD had significantly lower amounts of anionic phosphatidylethanolamine,phosphatidylinositol, phosphati- dylserine but not the zwitterionic neutral phospholipid phosphatidylcholine. These anionic phospholipids showed obvious recovery after receiving IPL treatment. Conclusion: Intense pulsed light (IPL) therapy is an efficient treatment in MGD eyes. It induced improvement in tears protein and lipids content and composition. The anionic phospholipids were the most vulnerable after IPL treatment than the other zwitterionic phospholipids.