Department of Ophthalmology, University of Texas Southwestern Medical Center at Dallas, TX 75390-9057, USA.
Cornea. 2011 Aug;30(8):843-7. doi: 10.1097/ICO.0b013e31820cd291.
To evaluate the effect of excess meibum on tear evaporation rate in patients with and without dry eye.
Eleven healthy subjects and 16 patients with dry eye were tested. The dry eye group was divided into 2 subgroups: classic keratoconjunctivitis sicca (KCS) with clear and easily expressed meibum and KCS with meibomian gland dysfunction (MGD) with turbid secretions and difficult-to-express meibum. Evaporative measurements were performed at baseline and after digital expression of meibomian glands at 12, 24, 36, and 48 minutes. Two ranges of relative humidity were used, 25% to 35% and 35% to 45%. The data were expressed as microliters per square centimeter per minute.
An increase in the evaporation rate of the tear film was noted for all measurements at both relative humidities in the classic KCS and KCS with MGD groups compared with healthy subjects (P < 0.05). The average evaporation rates at relative humidities of 25% to 35% and 35% to 45% were 0.056 ± 0.016 and 0.040 ± 0.008 for the classic KCS group; 0.055 ± 0.026 and 0.037 ± 0.019 for the KCS with MGD group and 0.033 ± 0.012 and 0.023 ± 0.008 for the healthy group. Also, a decrease in the evaporation rate was observed in the healthy and KCS with MGD groups between baseline and the first measurement after digital expression for both relative humidities (P < 0.05). The classic KCS group did not show any changes after expression.
Classic KCS and KCS with MGD groups showed an increase in tear evaporation rates compared with the healthy group. Aqueous tear evaporation diminished in the healthy and KCS with MGD groups after expression of meibomian glands. However, this effect was transient and negligible after the second measurement.
评估有和无干眼症患者过量油脂对泪液蒸发率的影响。
对 11 名健康受试者和 16 名干眼症患者进行了测试。干眼症组分为 2 个亚组：经典干燥性角结膜炎（KCS），其油脂清晰且易于表达，以及睑板腺功能障碍（MGD）所致的 KCS，其油脂浑浊且难以表达。在基线时以及 12、24、36 和 48 分钟时行睑板腺的数字式挤压后进行蒸发测量。使用了 2 个相对湿度范围，分别为 25%至 35%和 35%至 45%。数据以每平方厘米每分钟微升表示。
在经典 KCS 和 KCS 伴 MGD 组中，与健康受试者相比，所有测量值在两种相对湿度下均观察到泪膜蒸发率增加（P <0.05）。在相对湿度为 25%至 35%和 35%至 45%时，经典 KCS 组的平均蒸发率分别为 0.056±0.016 和 0.040±0.008；KCS 伴 MGD 组分别为 0.055±0.026 和 0.037±0.019；健康组分别为 0.033±0.012 和 0.023±0.008。此外，在两种相对湿度下，健康组和 KCS 伴 MGD 组在基线与数字式挤压后的第一次测量之间，蒸发率均下降（P<0.05）。经典 KCS 组在挤压后无任何变化。
与健康组相比，经典 KCS 和 KCS 伴 MGD 组的泪液蒸发率增加。在挤压睑板腺后，健康组和 KCS 伴 MGD 组的水样泪液蒸发减少。然而，在第二次测量后，这种影响是短暂的且可以忽略不计。
