Influence of spatial and temporal spot distribution on the ocular surface quality and maximum ablation depth after photoablation with a 1050 Hz excimer laser system

Mrochen, Michael; Schelling, Urs; Wuellner, Christian; Donitzky, Christof

doi:10.1016/j.jcrs.2008.10.053

Cited by 22 publications

(24 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…18,19 Critical asymmetric heating of the cornea can be avoided by optimum distribution of the laser spots. In a study by Mrochen et al, 19 the highest mean temperature increase using this 1000 Hz excimer laser was 10.11 K. Therefore, the 11 C limit Bende et al 15 recommend for corneal heating during ablation was not exceeded.…”

Section: Discussionmentioning

confidence: 99%

First clinical results of epithelial laser in situ keratomileusis with a 1000 Hz excimer laser

Mohrenfels

Khoramnia

Wüllner

et al. 2010

Journal of Cataract and Refractive Surgery

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

First clinical results of epithelial laser in situ keratomileusis with a 1000 Hz excimer laser

Mohrenfels

Khoramnia

Wüllner

et al. 2010

Journal of Cataract and Refractive Surgery

Self Cite

View full text Add to dashboard Cite

show abstract

“…19 The flying spot technique was first proposed and patented by Lin,20,21 followed by their pioneering work regarding beam smoothness and ablation quality. In a study by Mrochen et al, 22 bovine corneas and PMMA plates were photoablated using a 1050-Hz excimer laser prototype for corneal laser surgery. Four temporal and spatial spot distributions (scan sequences) with different temporal overlapping factors were created for three myopic, three hyperopic, and three PTK ablation profiles.…”

Section: System Calibration and Ablation Roughnessmentioning

confidence: 99%

Review of technological advancements in calibration systems for laser vision correction

Arba-Mosquera

Vinciguerra²,

Verma

2018

J. Biomed. Opt.

View full text Add to dashboard Cite

Abstract. Using PubMed and our internal database, we extensively reviewed the literature on the technological advancements in calibration systems, with a motive to present an account of the development history, and latest developments in calibration systems used in refractive surgery laser systems. As a second motive, we explored the clinical impact of the error introduced due to the roughness in ablation and its corresponding effect on system calibration. The inclusion criterion for this review was strict relevance to the clinical questions under research. The existing calibration methods, including various plastic models, are highly affected by various factors involved in refractive surgery, such as temperature, airflow, and hydration. Surface roughness plays an important role in accurate measurement of ablation performance on calibration materials. The ratio of ablation efficiency between the human cornea and calibration material is very critical and highly dependent on the laser beam characteristics and test conditions. Objective evaluation of the calibration data and corresponding adjustment of the laser systems at regular intervals are essential for the continuing success and further improvements in outcomes of laser vision correction procedures.

show abstract

“…9,10 Furthermore, higher refractive settings correlate with decreasing surface smoothness. These results have been reproduced in PMMA by O'Donnell et al, 11 showing an increase of 25 nm roughness per micron of ablation in PMMA.…”

mentioning

confidence: 99%

Optimum Laser Beam Characteristics for Achieving Smoother Ablations in Laser Vision Correction

Verma

Hesser

Arba-Mosquera

2017

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

PURPOSE. Controversial opinions exist regarding optimum laser beam characteristics for achieving smoother ablations in laser-based vision correction. The purpose of the study was to outline a rigorous simulation model for simulating shot-by-shot ablation process. The impact of laser beam characteristics like super Gaussian order, truncation radius, spot geometry, spot overlap, and lattice geometry were tested on ablation smoothness. METHODS.Given the super Gaussian order, the theoretical beam profile was determined following Lambert-Beer model. The intensity beam profile originating from an excimer laser was measured with a beam profiler camera. For both, the measured and theoretical beam profiles, two spot geometries (round and square spots) were considered, and two types of lattices (reticular and triangular) were simulated with varying spot overlaps and ablated material (cornea or polymethylmethacrylate [PMMA]). The roughness in ablation was determined by the root-mean-square per square root of layer depth. RESULTS.Truncating the beam profile increases the roughness in ablation, Gaussian profiles theoretically result in smoother ablations, round spot geometries produce lower roughness in ablation compared to square geometry, triangular lattices theoretically produce lower roughness in ablation compared to the reticular lattice, theoretically modeled beam profiles show lower roughness in ablation compared to the measured beam profile, and the simulated roughness in ablation on PMMA tends to be lower than on human cornea. For given input parameters, proper optimum parameters for minimizing the roughness have been found. CONCLUSIONS.Theoretically, the proposed model can be used for achieving smoothness with laser systems used for ablation processes at relatively low cost. This model may improve the quality of results and could be directly applied for improving postoperative surface quality.

show abstract

Influence of spatial and temporal spot distribution on the ocular surface quality and maximum ablation depth after photoablation with a 1050 Hz excimer laser system

Cited by 22 publications

References 35 publications

First clinical results of epithelial laser in situ keratomileusis with a 1000 Hz excimer laser

First clinical results of epithelial laser in situ keratomileusis with a 1000 Hz excimer laser

Review of technological advancements in calibration systems for laser vision correction

Optimum Laser Beam Characteristics for Achieving Smoother Ablations in Laser Vision Correction

Contact Info

Product

Resources

About