Geneva University Hospitals, Geneva, Switzerland.
Cornea. 2011 Aug;30(8):917-9. doi: 10.1097/ICO.0b013e31820143d1.
We report a case of failure of corneal collagen cross-linking (CXL) for progressive keratoconus after preoperative stromal swelling with hypoosmolar riboflavin solution in an extremely thin cornea.
CXL was performed using the protocol established for the treatment of thin corneas. Preoperative minimal thickness after abrasion was 268 μm and increased to 406 μm after swelling with hypoosmolar riboflavin solution.
Despite CXL, a distinct progression of up to 1.9 diopters was observed at 3 months after the procedure on the anterior corneal surface. At 6 months after CXL, progression had increased to 2.3 diopters. Although swelling with hypoosmolar riboflavin solution was effective and led to a preoperative thickness of more than 400 μm, the increase in biomechanical resistance was not sufficient to arrest the progression of the disease.
Little is known about the minimal stromal thickness required for effective CXL to occur. Although swelling with hypoosmolar riboflavin solution over 400 μm and safety of the procedure can be achieved in even thinner corneas, the outcome of this case suggests that a minimal preoperative stromal thickness of 330 μm needs to be respected for a successful CXL procedure.
我们报告了一例在极薄角膜中使用低渗核黄素溶液进行术前基质肿胀后，角膜交联（CXL）治疗进行性圆锥角膜失败的病例。
使用为薄角膜治疗建立的方案进行 CXL。术前经研磨后最小厚度为 268μm，用低渗核黄素溶液肿胀后增加至 406μm。
尽管进行了 CXL，但在术后 3 个月，在前角膜表面仍明显进展了 1.9 屈光度。在 CXL 后 6 个月，进展增加到 2.3 屈光度。尽管低渗核黄素溶液肿胀有效，并导致术前厚度超过 400μm，但生物力学阻力的增加不足以阻止疾病的进展。
对于有效发生 CXL 所需的最小基质厚度知之甚少。尽管在甚至更薄的角膜中可以实现超过 400μm 的低渗核黄素溶液肿胀和手术安全性，但该病例的结果表明，成功的 CXL 手术需要最小术前基质厚度为 330μm。
