Author Affiliations
Abstract
1 Research and Development, SCHWIND Eye-Tech-Solutions, 63801 Kleinostheim, Germany
2 Interdisciplinary Center for Scientific Computing (IWR), Universität Heidelberg, 69117 Heidelberg, Germany
3 Mannheim Institute for Intelligent Systems in Medicine (MIISM), Universität Heidelberg, 69117 Heidelberg, Germany
4 Central Institute for Computer Engineering (ZITI), Universität Heidelberg, 69117 Heidelberg, Germany
5 CZS Heidelberg Center for Model-Based AI, Universität Heidelberg, 69117 Heidelberg, Germany
Purpose: Despite theoretical models for achieving laser-based ablation smoothness, methods do not yet exist for assessing the impact of residual roughness after corneal ablation, on retinal polychromatic vision. We developed a method and performed an exploratory study to qualitatively and quantitatively analyze the impact of varying degree of corneal roughness simulated through white and filtered noise, on the retinal image. Methods: A preliminary version of the Indiana Retinal Image Simulator (IRIS) [Jaskulski M., Thibos L., Bradley A., Kollbaum P., et al. (2019) IRIS – Indiana Retinal Image Simulator. https://blogs.iu.edu/corl/iris] was used to simulate the polychromatic retinal image. Using patient-specific Zernike coefficients and pupil diameter, the impact of different levels of chromatic aberrations was calculated. Corneal roughness was modeled via both random and filtered noise [(2013) Biomed. Opt. Express4, 220–229], using distinct pre-calculated higher order Zernike coefficient terms. The outcome measures for the simulation were simulated retinal image, Strehl Ratio and Visual Strehl Ratio computed in frequency domain (VSOTF). The impact of varying degree of roughness (with and without refractive error), spatial frequency of the roughness, and pupil dilation was analyzed on these outcome measures. Standard simulation settings were pupil size = 6 mm, Defocus Z[2, 0] = 2 μm (−1.54D), and Spherical Aberrations Z[4, 0] = 0.15 μm. The signal included the 2–4th Zernike orders, while noise used 7–8th Zernike orders. Noise was scaled to predetermined RMS values. All the terms in 5th and 6th Zernike order were set to 0, to avoid overlapping of signal and noise. Results: In case of a constant roughness term, reducing the pupil size resulted in improved outcome measures and simulated retinal image (Strehl = 0.005 for pupil size = 6 mm to Strehl = 0.06 for pupil size = 3 mm). The calculated image quality metrics deteriorated dramatically with increasing roughness (Strehl = 0. 3 for no noise; Strehl = 0.03 for random noise of 0.25 μm at 6 mm diameter; Strehl = 0.005 for random noise of 0.65 μm at 6 mm diameter). Clear distinction was observed in outcome measures for corneal roughness simulated as random noise compared to filtered noise, further influenced by the spatial frequency of filtered noise. Conclusion: The proposed method enables quantifying the impact of residual roughness in corneal ablation processes at relatively low cost. Since normally laser ablation is an integral process divided on a defined grid, the impact of spatially characterized noise represents a more realistic simulation condition. This method can help comparing different refractive laser platforms in terms of their associated roughness in ablation, indirectly improving the quality of results after Laser vision correction surgery.
Residual roughness Cornea ablation Random and filtered noise Polychromatic vision Ablation smoothness 
Journal of the European Optical Society-Rapid Publications
2023, 19(1): 2023013
作者单位
摘要
南京航空航天大学 机电学院,南京 210016
为提高准分子激光屈光矫正手术的精确性和安全性,建立了单纯近视和复性近视散光、单纯远视和复性远视散光的角膜切削量模型,并在此模型基础上给出了准分子激光切削角膜的叠加“飞点扫描”算法,该模型和算法用于临床指导眼屈光手术。根据术后的跟踪调查,89只眼睛(88只近视和复性近视散光眼,1只复性远视散光眼)在手术后球镜镜度、柱镜镜度减退了,裸眼视力也明显提高了,术后80.7%的眼睛裸眼视力≥0.8。调查结果表明,该模型和算法具有很高的精确性和安全性,手术效果令人满意。
激光技术 飞点扫描 准分子激光 角膜切削 laser technique flying-spot scanning excimer laser cornea ablation 
激光技术
2006, 30(6): 0631
作者单位
摘要
南京航空航天大学机电学院,中国江苏,南京,210016
本文在分析国内外研究人眼角膜的数学模型的基础上,提出了能够用于进行近视、远视、散光等屈光手术的数学模型,并就准分子激光的切削原理和"飞点扫描"技术进行了研究,本文的研究成果直接用于准分子激光眼科治疗机,取得了满意的手术效果.
准分子激光 数学模型 飞点扫描 角膜切削 excim er laser mathem atical model flying- spot scanning cornea ablation 
激光生物学报
2003, 12(1): 1
作者单位
摘要
南京航空航天大学机电学院,南京,210016
本文研究了准分子激光屈光手术的原理、切削机理、角膜切削方式的选择、准分子激光切削量与能量密度的关系、"飞点扫描"技术.并在此基础上研制了准分子激光眼科治疗机,经过临床应用,取得了满意的手术效果.
准分子激光 飞点扫描 角膜切削 Excimer Laser flying - spot Scanning cornea ablation 
应用激光
2003, 23(1): 41

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