Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom.
Cont Lens Anterior Eye. 2010 Jun;33(3):128-35. doi: 10.1016/j.clae.2009.11.004. Epub 2010 Jan 6.
To determine if a clinically comparable contact lens could be designed for patients with keratoconus utilising a corneal topographer and its contact lens design software.
A total of 30 patients with keratoconus were recruited for this randomized, double-masked prospective study. Corneal topography was performed on each patient using the Orbscan II (Bausch & Lomb, NY, USA) topographer. The topographers' Fitscan RGP fitting software was used to derive a tri-curve rigid contact lens specification. This was manufactured, and then compared by three experienced clinicians with the patients' conventionally fitted (habitual) lens. Each aspect of contact lens fitting was graded, and each grade was weighted for kappa analysis to determine if there was any significant difference between the Fitscan-derived lens and the patients' habitual lens.
Percentage agreement levels between the two fitting techniques were between 74% and 100%. Kappa values varied from below 0 to 0.60, indicating poor to moderate agreement. A slight bias towards flatter apical fitting in the Fitscan design was found in some cases of advanced keratoconus. There was no systematic bias for either fitting technique when comparing visual performance and lens comfort. A higher percentage of Fitscan-derived lenses were deemed suitable to dispense to patients, either directly or after minor parameter modification.
This study demonstrates that a satisfactory lens design for keratoconic patients can be produced utilising a topography-based system, when compared to a patients' conventionally fitted lens. The potential advantages of this system include simplified lens selection and reduced trial lens usage, with a reduction in patient discomfort, clinical chair-time and costs.
利用角膜地形图及其隐形眼镜设计软件，为圆锥角膜患者设计一种临床可比的接触镜。
本研究为随机、双盲前瞻性研究，共招募了 30 名圆锥角膜患者。每位患者均使用 Orbscan II（美国纽约州巴恩斯-洛厄尔公司）角膜地形图仪进行角膜地形图检查。使用 Topographers' Fitscan RGP 适配软件得出三曲线硬性隐形眼镜规格。制造出这种隐形眼镜，然后由三位经验丰富的临床医生与患者的常规适配（习惯）隐形眼镜进行比较。对隐形眼镜适配的各个方面进行评分，并对每个等级进行kappa 分析，以确定 Fitscan 衍生镜片与患者习惯镜片之间是否存在显著差异。
两种配镜技术之间的一致性百分比在 74%至 100%之间。kappa 值从 0 到 0.60 不等，表明一致性较差或中等。在某些晚期圆锥角膜病例中，Fitscan 设计中发现了轻微的偏向于更平坦的顶点拟合的趋势。在比较视觉效果和镜片舒适度时，两种适配技术都没有系统偏差。与传统适配的镜片相比，更高比例的 Fitscan 衍生镜片适合直接或稍作参数修改后配给患者。
与患者的常规适配镜片相比，这项研究表明，利用基于地形图的系统可以为圆锥角膜患者设计出令人满意的镜片。该系统的潜在优势包括简化镜片选择和减少试用镜片的使用，从而减轻患者的不适、减少临床椅旁时间和成本。
