Koçluk Yusuf, Yalniz-Akkaya Zuleyha, Burcu Ayse, Örnek Firdevs
Ophthalmology Clinic, Ministry of Health Ankara Training and Research Hospital, Ankara, Turkey.
Ophthalmic Res. 2015;53(1):21-7. doi: 10.1159/000365518. Epub 2014 Dec 6.
To determine and compare various quantitative parameters of pellucid marginal degeneration (PMD) and keratoconus with against-the-rule astigmatism (KC-ARA) obtained by elevation-based Scheimpflug imaging and to identify characteristics that can be used to discriminate PMD from KC-ARA.
Ophthalmology Clinic, Ministry of Health Ankara Training and Research Hospital, Ankara, Turkey.
Retrospective case-control study.
Patients with ARA, a butterfly or crab claw pattern in the curvature maps, a kissing bird pattern in the elevation maps and the bell sign in the pachymetric maps were identified, and 60 eyes of 40 patients were chosen for the evaluation. The patients were divided into two groups: the PMD group (29 eyes of 18 patients) and the KC-ARA group (31 eyes of 22 patients). By moving the cursor manually, the pachymetric maps and Scheimpflug images were searched for a thinner location than the automatically identified thinnest location. The coordinates and thickness of this manually identified location were evaluated.
In the PMD group, 7 (24.1%) eyes did not have any thinner location than the automatically identified thinnest location on the pachymetric maps and the Scheimpflug images, and in 22 (75.8%) eyes, a thinner location, which was located more peripherally, was found by manual evaluation of the pachymetric maps or Scheimpflug images. In 9 (31.0%) eyes of these 22, the manually identified thinnest locations were visible on pachymetric maps, and in 13 (44.8%) eyes the more peripheral thinnest locations were not visible on pachymetric maps but on Scheimpflug images. In the KC group, no patients had thinner locations than the automatically identified thinnest points on the pachymetric maps and the Scheimpflug images.
A more peripheral thinner location than the automatically identified thinnest location exists in most of the eyes with PMD. In KC-ARA eyes, a thinner location than the automatically found thinnest point does not exist. Accordingly, a more peripheral thinner point than the identified thinnest point is a very strong indication for PMD.
通过基于高度的Scheimpflug成像技术，确定并比较透明边缘变性（PMD）和伴有逆规散光的圆锥角膜（KC-ARA）的各种定量参数，并识别可用于区分PMD和KC-ARA的特征。
土耳其安卡拉卫生部安卡拉培训与研究医院眼科诊所。
回顾性病例对照研究。
识别出曲率图呈蝴蝶或蟹爪样、高度图呈亲吻鸟样且测厚图呈钟形的ARA患者，选取40例患者的60只眼进行评估。将患者分为两组：PMD组（18例患者的29只眼）和KC-ARA组（22例患者的31只眼）。通过手动移动光标，在测厚图和Scheimpflug图像中寻找比自动识别出的最薄位置更薄的位置。评估该手动识别位置的坐标和厚度。
在PMD组中，7只眼（24.1%）在测厚图和Scheimpflug图像上没有比自动识别出的最薄位置更薄的位置，22只眼（75.8%）通过对测厚图或Scheimpflug图像的手动评估发现了更薄的位置，且该位置更靠周边。在这22只眼中，9只眼（31.0%）手动识别出的最薄位置在测厚图上可见，13只眼（44.8%）更靠周边的最薄位置在测厚图上不可见，但在Scheimpflug图像上可见。在KC组中，没有患者在测厚图和Scheimpflug图像上有比自动识别出的最薄点更薄的位置。
大多数PMD眼存在比自动识别出的最薄位置更靠周边的更薄位置。在KC-ARA眼中，不存在比自动发现的最薄点更薄的位置。因此，比识别出的最薄点更靠周边的更薄点是PMD的一个非常有力的指征。
