Introduction
In this day and age, a comprehensive range of tools is available to tailor treatments to the unique needs of each patient. CustomEyes® combined with the SCHWIND AMARIS® system (SCHWIND eye-tech-solutions) provides the highest level of personalization in laser vision correction, utilizing advanced total and corneal wavefront technology. This approach accounts for factors such as biomechanical properties, stromal haze, remodelling effects, and various treatment strategies, ensuring a truly customized solution for optimal outcomes.
Preoperative Investigation
For patients with subtle visual imperfections, a customized excimer laser treatment—commonly referred to as wavefront-guided treatment—utilizes data from advanced imaging technologies to enhance precision. High-resolution diagnostic devices like the SCHWIND PERAMIS ocular aberrometer and MS-39 (SCHWIND eye-tech-solutions) anterior segment-OCT (AS-OCT) generate detailed maps of curvature, elevation, pachymetry, power, and wavefront errors of the eye. This information allows modern excimer laser platforms to deliver highly personalized treatments tailored to the patient’s specific needs.
Wavefront-guided treatments, which account for posterior curvature and the entire optical system, often preserve more tissue compared to purely topography-based approaches.1 Additionally, AS-OCT provides valuable tomographic insights into corneal structure, such as pachymetry and the thickness of individual layers, including the epithelium and Bowman’s layer.
Recently, there has been increased focus on different healing modalities. The epithelial layer, with its remarkable regenerative capacity, has become a key factor in treatment planning thanks to advancements in AS-OCT technology, allowing precise measurement and inclusion of epithelial characteristics. Previous studies using high-frequency ultrasonic devices have shed light on the epithelial healing response after refractive procedures.2 However, it is crucial to consider biomechanical changes, such as corneal weakening and curvature gradient shifts,3 which can affect the overall shape of the cornea and, in turn, impact visual outcomes.
A promising development is the visualization of expected outcomes based on individualized treatment planning, adding another powerful tool to this comprehensive treatment approach.
Planning
The AMARIS® system is programmed using precise, individualized measurements of each patient’s eye, encompassing both the cornea and the entire ocular system. With this diagnostic information, the SCHWIND treatment planning software enables truly personalized customization for optimal vision correction, so-called CustomEyes® (Figure 1). The software takes total (corneal) wavefront data into account and allows for the refraction to be fine-tuned, maximizing tissue preservation within certain limits, or even to the fullest extent possible. The goal is to maintain high corneal stability and to optimize the corneal shape according to patient individual needs, while aiming for emmetropia and best possible uncorrected distance visual acuity (UDVA).
Figure 1. The AMARIS® system automatically detects the most tissue-saving refraction, while taking given constraints into consideration. This allows for personalized customization for optimal vision correction.
In the minority of cases, the primary focus of customized treatments is to alleviate symptoms and enhance the patient’s quality of life by cornea regularization, rather than striving for vision perfection without glasses.
Furthermore, CustomEyes® automatically identifies the high-order aberrations that need to be corrected, ensuring minimal tissue removal with the aim to increase UDVA, CDVA, and visual quality (Figure 2).
Figure 2. The ablation volume consists of low-order aberrations and high- order aberrations which is expressed in one ablation profile following a sophisticated aspheric approach.
Treatment
CustomEyes® with SCHWIND AMARIS® can be performed in different ways: intrastromal ablation, which is almost painless and allows for more rapid visual recovery,4 or as a premium surface treatment that takes individual epithelial thickness information and stromal irregularities for increased precision into account. The epithelium, with its masking effect,5 compensates for stromal irregularities. In cases of highly aberrated eyes with an irregular corneal surface, a transepithelial ablation (SmartSurfACE) is especially beneficial due to its smoothing effect.6 This can even be followed by sequential PTK with masking fluid for additional polishing of the cornea, a well-established option.7
The SCHWIND AMARIS® excimer laser provides the ideal technology platform to execute true customization with high precision and safety. It features a latency-free, seven-dimensional eye tracker combined with a fine 0.54-mm Super-Gaussian spot profile (full width at half maximum). It also features a unique algorithm of thermal control (ITEC) at cornea level—even at highest laser frequency —and incorporates dual energy levels for enhanced speed and accuracy.
Conclusion
It is essential to include high-quality diagnostic images from advanced, high-resolution devices like the SCHWIND PERAMIS and MS-39 to ensure precise and tailored treatment planning followed by safe lasering with leading SCHWIND AMARIS® technology.
The broad spectrum of high-resolution diagnostic possibilities, combined with a variety of treatment methods, allows for maximally personalized approaches to meet each patient’s individual need with CustomEyes®.
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2. Reinstein D, Archer T, Gobbe M, et al. Epithelial thickness in the normal cornea: three-dimensional display with artemis very high-frequency digital ultrasound. J Refract Surg. 2008;24:571-581.
3. Vinciguerra P, Roberts CJ, Albé E, et al. Corneal curvature gradient map: a new corneal topography map to predict the corneal healing process. J Refract Surg. 2014;30(3):202-207.
4. Zhang J, Feng Q, Ding W, Peng Y, Long K. Comparison of clinical results between trans-PRK and femtosecond LASIK for correction of high myopia. BCM Ophthalmology (2020) 20:243
5. Lin D, Holland S, Verma S, Hogden J, Arba-Mosquera S. Immediate and short term visual recovery after SmartSurfACE photorefractive keratectomy. J of Optometry Volume 12, Issue 4, 2019, Pages 240-247.
6. Vinciguerra P, Camesasca Fl, Vinciguerra R, et al. Advanced surface ablation with a new software for the reduction of ablatin irregularities. J Refract Surg. 2017;33:89-95.
7. Vinciguerra P, Lippera M. Sequential customized therapeutic keratectomy. CRST Global. January 2022.
