Center for Ophthalmic Optics and Lasers, Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
Cornea. 2012 Feb;31(2):145-9. doi: 10.1097/ICO.0b013e318221cef8.
To evaluate optical coherence tomography (OCT) in the measurement of donor corneas in preparation for endothelial keratoplasty.
Donor corneas were imaged by OCT while immersed in preservation medium. Central corneal thickness (CCT) was measured by OCT from the Bowman layer to the endothelium. The corneas were then mounted on an artificial anterior chamber, and the epithelium was removed. Ultrasound pachymetry (USP) was used to measure CCT just before sectioning with a microkeratome. The central graft thickness (CGT) was measured by USP. The graft was then returned to the medium and imaged by OCT.
The study included 154 donor corneas. The average CCT measured by OCT (550 ± 63 μm) was thicker (P < 0.001) than that measured by USP (507 ± 54 μm). Similarly, the CGT measured by OCT (158 ± 41 μm) was thicker (P = 0.0005) than that measured by USP (153 ± 38 μm). The predictability of cut depth, as assessed by pooled standard deviation (SD), was better (P = 0.023) for USP (41 μm) compared with OCT (48 μm). The graft was thicker (P < 0.001) peripherally than centrally in OCT images. The predictability of cut depth by OCT was better (P < 0.001) for corneas thinner than 600 μm (SD = 45.6 μm) compared with those thicker than 600 μm (SD = 86.9 μm).
The donor corneal measurements by OCT were not as predictable as those by USP. The predictability of graft thickness, however, could be optimized using OCT to select for corneas thinner than 600 μm and then using immediate precut USP to set the microkeratome depth. A graft thickness profile measured by OCT could be useful to the surgeon.
评估光学相干断层扫描（OCT）在准备内皮角膜移植术中对供体角膜的测量。
将 OCT 用于对浸泡在保存介质中的供体角膜进行成像。OCT 从 Bowman 层测量角膜中央厚度（CCT）到内皮。然后将角膜安装在人工前房中，去除上皮。超声角膜测厚仪（USP）用于在使用微型角膜刀切片前测量 CCT。使用 USP 测量中央移植物厚度（CGT）。然后将移植物放回介质中并由 OCT 成像。
本研究纳入了 154 个供体角膜。OCT 测量的平均 CCT（550±63μm）比 USP 测量的 CCT（507±54μm）更厚（P<0.001）。同样，OCT 测量的 CGT（158±41μm）比 USP 测量的 CGT（153±38μm）更厚（P=0.0005）。OCT 的预测性（通过 pooled standard deviation [SD] 评估）优于 USP（41μm 比 48μm，P=0.023）。在 OCT 图像中，移植物周边比中央更厚（P<0.001）。对于厚度小于 600μm 的角膜（SD=45.6μm），OCT 预测切深的准确性优于厚度大于 600μm 的角膜（SD=86.9μm，P<0.001）。
OCT 测量供体角膜的结果不如 USP 测量的结果可预测。然而，通过 OCT 选择厚度小于 600μm 的角膜，然后使用即时预切 USP 设定微型角膜刀的深度，可以优化移植物厚度的预测性。OCT 测量的移植物厚度谱可能对外科医生有用。
