Eye Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
Cornea. 2010 Oct;29(10):1125-30. doi: 10.1097/ICO.0b013e3181d25cbd.
It is important to accurately measure intraocular pressure (IOP) in eyes with corneal endothelial dysfunction both before and after Descemet stripping with automated endothelial keratoplasty (DSAEK). Glaucoma is a common comorbidity in this population, and IOP elevation can worsen corneal edema. Additionally, preexisting glaucoma and steroid-responsive ocular hypertension are significant risk factors for graft rejection after DSAEK. Accurate tonometry is limited by variations in central corneal thickness (CCT) and corneal hydration that may affect corneal biomechanical properties. We analyzed CCT and IOP in eyes before and after DSAEK to determine whether changes in corneal biomechanics because of edema, grafted tissue, and subsequent stromal deturgescence affect IOP measurement.
A retrospective chart review was performed on 32 eyes from 31 patients with corneal edema secondary to Fuchs endothelial dystrophy, bullous keratopathy, or prior graft failure, or rejection that received uncomplicated DSAEK with no evidence of persistent corneal edema or steroid-induced ocular hypertension. IOP was measured by Tono-Pen XL, and CCT was measured by ultrasound pachymetry before and approximately 3 months after surgery. We used paired t tests to evaluate changes in CCT and IOP after DSAEK and linear regression to determine the relationship between CCT and IOP before and after surgery.
CCT significantly decreased from 703 ± 82 to 650 ± 52 μm after DSAEK (P = 0.0026), but there was no significant change in measured IOP (16.7 ± 3.4 mm Hg preoperatively and 16.3 ± 4.1 mm Hg postoperatively; P = 0.61). There was no significant relationship between CCT and IOP before (slope = 0.10 ± 0.07 mm Hg/10 μm; r = 0.062; P = 0.17) or after (slope = 0.21 ± 0.14 mm Hg/10 μm; r = 0.072; P = 0.14) DSAEK.
CCT is significantly reduced by DSAEK but remains well above the normal range. IOP remains near the preoperative level 3 months after DSAEK. Furthermore, no correction is required for Tono-Pen measurements of IOP in corneas thickened by edema secondary to endothelial dysfunction or by DSAEK.
在进行 Descemet 撕囊与自动化内皮角膜移植术（DSAEK）之前和之后，准确测量角膜内皮功能障碍眼的眼内压（IOP）非常重要。该人群中常见的合并症是青光眼，IOP 升高会加重角膜水肿。此外，DSAEK 后，青光眼和类固醇反应性眼高压是移植物排斥的重要危险因素。眼压的准确测量受到中央角膜厚度（CCT）和角膜水化的变化的限制，这些变化可能会影响角膜生物力学特性。我们分析了 DSAEK 前后的 CCT 和 IOP，以确定水肿、移植组织和随后的基质去水肿引起的角膜生物力学变化是否会影响 IOP 测量。
对 31 例因 Fuchs 内皮营养不良、大疱性角膜病变或先前移植失败或排斥而导致角膜水肿的 32 只眼进行回顾性图表审查，这些患者接受了无明显持续性角膜水肿或类固醇诱导性眼高压的单纯 DSAEK。术前和术后约 3 个月，使用 Tono-Pen XL 测量 IOP，使用超声角膜测厚仪测量 CCT。我们使用配对 t 检验评估 DSAEK 后 CCT 和 IOP 的变化，并使用线性回归分析确定手术前后 CCT 和 IOP 之间的关系。
DSAEK 后 CCT 从 703±82µm 显著下降至 650±52µm（P=0.0026），但测量的 IOP 无明显变化（术前 16.7±3.4mmHg，术后 16.3±4.1mmHg；P=0.61）。术前（斜率=0.10±0.07mmHg/10µm；r=0.062；P=0.17）或术后（斜率=0.21±0.14mmHg/10µm；r=0.072；P=0.14）CCT 与 IOP 之间无显著关系。
DSAEK 可显著降低 CCT，但仍远高于正常范围。DSAEK 后 3 个月，IOP 仍接近术前水平。此外，对于由内皮功能障碍或 DSAEK 引起的水肿增厚的角膜，无需对 Tono-Pen 测量的 IOP 进行校正。
