Misson G P, Landini G, Murray P I
Academic Unit of Ophthalmology, University of Birmingham, UK.
Curr Eye Res. 1993 Nov;12(11):957-61. doi: 10.3109/02713689309029221.
Dendritic ulcers, the commonest manifestation of herpes simplex epithelial keratitis (HSEK) are fractals. It is likely that their fractal properties alter if they progress to a geographic appearance. This study investigates the relationship of maximum ulcer diameter (Feret's diameter) to area (Dm) and perimeter fractal dimensions (Ds), parameters of the complexity of their areas and outlines respectively. For dendritic ulcers in the size range of 1.6-3.2 mm, Dm = 1.41 +/- 0.06 and Ds = 1.40 +/- 0.04 (mean +/- SD). With increasing ulcer size, a progressive divergence of the values of Dm and Ds occurred, such that values of 1.75 and 1.22 respectively were found at a maximum diameter of 8.4 mm. These results imply that as ulcers enlarge, their outlines become less irregular and they fill more of a 2-dimensional plane. Dm and Ds are useful parameters in quantifying the progression of HSEK from dendritic to amoeboid morphology and could have a role in the assessment of ulcer response to pharmacological intervention. A knowledge of the fractal properties of HSEK may increase understanding of the mechanisms of ulcer formation and viral spread.
树枝状溃疡是单纯疱疹性上皮性角膜炎（HSEK）最常见的表现形式，属于分形结构。如果它们发展为地图状外观，其分形特性可能会改变。本研究调查了最大溃疡直径（费雷特直径）与面积（Dm）和周长分形维数（Ds）之间的关系，这两个参数分别表示溃疡面积和轮廓的复杂程度。对于直径在1.6 - 3.2毫米范围内的树枝状溃疡，Dm = 1.41 +/- 0.06，Ds = 1.40 +/- 0.04（平均值 +/- 标准差）。随着溃疡尺寸的增加，Dm和Ds的值逐渐出现差异，在最大直径为8.4毫米时，分别发现其值为1.75和1.22。这些结果表明，随着溃疡扩大，其轮廓变得不那么不规则，并且它们占据的二维平面更多。Dm和Ds是量化HSEK从树枝状形态向阿米巴样形态进展的有用参数，并且在评估溃疡对药物干预的反应中可能发挥作用。了解HSEK的分形特性可能会增进对溃疡形成机制和病毒传播的理解。
