Critical review on refractive surgical lasers

Lin, J. T.

doi:10.1117/12.199376

Cited by 32 publications

(28 citation statements)

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“…Equations (1) and (2) are equal for Q 1 = Q 2 = 0, as expected. For both equations the number of diopters to correct, D, is related to the pre-surgical and post-surgical radius (R 1 and R 2 , respectively) as follows [18,19]:…”

Section: Methodsmentioning

confidence: 99%

“…The ablation depth for the hyperopic correction, s(y), provided by the Munnerlyn formula (which considers the anterior cornea as a sphere) is given by [18,19,29]:…”

Section: Methodsmentioning

confidence: 99%

“…The Munnerlyn formula [18,19] has been replaced by algorithms such as wavefront-guided [20], wavefront-optimized [12] and Q-optimized [21][22][23] (with fixed post-operative corneal asphericity Q) that provide better results on visual quality.…”

Section: Introductionmentioning

confidence: 99%

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Hyperopic Q-optimized algorithms: a theoretical study on factors influencing optical quality

Jiménez

Alarcón

Anera

et al. 2017

Biomed. Opt. Express

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Abstract:In this work, we analyze the way in which pupil size, optical zone, and initial hyperopic level influence optical quality for hyperopic Q-optimized corneal refractive surgery. Different Q-optimized algorithms and the Munnerlyn formula were tested to analyze the optical quality of the final retinal image for initial hyperopic errors from 1D to 5D. Three optical zones (5.5, 6, and 6.5 mm) and two pupil diameters (5 and 7 mm) were considered. To evaluate optical quality, we computed the modulation transfer function (MTF) and the area under MTF (MTFa). Q-optimized values at around Q = −0.18 were found to provide the best optical quality for most of the conditions tested. This optimum final asphericity for hyperopic ablation was not depending on the degree of hyperopia corrected, the optical zone or the pupil size being this information important for clinical practice.

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Section: Methodsmentioning

confidence: 99%

“…The ablation depth for the hyperopic correction, s(y), provided by the Munnerlyn formula (which considers the anterior cornea as a sphere) is given by [18,19,29]:…”

Section: Methodsmentioning

confidence: 99%

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Hyperopic Q-optimized algorithms: a theoretical study on factors influencing optical quality

Jiménez

Alarcón

Anera

et al. 2017

Biomed. Opt. Express

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“…Although algorithms based on a customized corneal ablation are currently being proposed [1,2], to date most ablation algorithms, though proprietary, rely on the parabolic approximation of Munnerlyn [3]. According to this equation, the ablation depth, s(y), is given by sðyÞ ¼ 4Dy…”

Section: Introductionmentioning

confidence: 99%

Optimum corneal asphericity of myopic eyes for refractive surgery

Díaz¹,

Anera²,

Jiménez³

et al. 2003

Journal of Modern Optics

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Abstract.In this work, an improvement to the Munnerlyn formula used in refractive surgery is proposed by selecting the final corneal asphericity. A theoretical optical analysis has been performed by adopting the RMS (root mean square) spot size as a merit function. Two different sets of myopes having refractive errors ranging up to À7D have been tested. The results show that a corneal asphericity of around Q ¼ À0.61, with the radius provided by the emmetropization formula based on thin lens theory, may improve image quality after surgery. This value could be used in practical surgery because it is easy to implement in the ablation algorithm and it requires no additional data from other clinical surgery instrumentation.

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“…18 The spot positioning algorithm has a major influence on the resulting ablation smoothness, with the scanning excimer lasers based on flying spot technology rendering smoother ablations compared to older technologies. 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.…”

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.

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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.

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Critical review on refractive surgical lasers

Cited by 32 publications

References 0 publications

Hyperopic Q-optimized algorithms: a theoretical study on factors influencing optical quality

Hyperopic Q-optimized algorithms: a theoretical study on factors influencing optical quality

Optimum corneal asphericity of myopic eyes for refractive surgery

Review of technological advancements in calibration systems for laser vision correction

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