Mathers W D
Department of Ophthalmology, University of Iowa Hospitals, Iowa City 52242.
Ophthalmology. 1993 Mar;100(3):347-51. doi: 10.1016/s0161-6420(93)31643-x.
Secretions from the meibomian gland are believed to be important in reducing ocular surface water evaporation and preventing dry eye. Patients with blepharitis frequently have meibomian gland dysfunction with loss of meibomian glands (drop out). The authors hypothesized that dry eye that often occurs in patients with chronic blepharitis is secondary to increased evaporation associated with gland loss.
The authors measured the ocular surface water evaporation and tear osmolarity of patients with meibomian gland drop out and patients with gland drop out with a low Schirmer test. These findings were compared with those of a control group.
The authors found that eyes with meibomian gland drop out and those with drop out and a low Schirmer test had a significantly higher evaporative rate at 30% relative humidity (average, 49.9 +/- 21 x 10(-7) g/cm2/second, or 0.49 +/- 0.29 microliters/minute evaporative loss per eye, and 59.1 +/- 28 x 10(-7) g/cm2/second, or 0.58 +/- 0.23 microliters/minute, respectively) when compared with those in the control group (average, 14.8 +/- 6 x 10(-7) g/cm2/second, or 0.15 +/- 0.07 microliters/minute [P < 0.05]). There was a significant correlation between evaporative rate and gland drop out (r = 0.522).
Patients with meibomian gland drop out, and especially those with low tear production by Schirmer test, have an increased risk of dry eye developing through increased evaporation.
睑板腺分泌物被认为在减少眼表水分蒸发和预防干眼方面具有重要作用。睑缘炎患者常伴有睑板腺功能障碍及睑板腺缺失（萎缩）。作者推测，慢性睑缘炎患者中经常出现的干眼是由与腺体缺失相关的蒸发增加所致。
作者测量了睑板腺萎缩患者以及泪液分泌试验（Schirmer试验）结果较低的腺体萎缩患者的眼表水分蒸发和泪液渗透压。将这些结果与对照组进行比较。
作者发现，睑板腺萎缩的眼睛以及泪液分泌试验结果较低的萎缩眼睛在相对湿度为30%时的蒸发率显著更高（平均分别为49.9±21×10⁻⁷克/平方厘米/秒，即每只眼睛每分钟蒸发损失0.49±0.29微升，以及59.1±28×10⁻⁷克/平方厘米/秒，即0.58±0.23微升/分钟），而对照组的平均蒸发率为14.8±6×10⁻⁷克/平方厘米/秒，即0.15±0.07微升/分钟（P<0.05）。蒸发率与腺体萎缩之间存在显著相关性（r = 0.522）。
睑板腺萎缩的患者，尤其是泪液分泌试验结果较低的患者，因蒸发增加而发生干眼的风险增加。
