Effects of Eye Registration on the Astigmatism Correction in the Surface Laser Ablation

2010 ◽  
Vol 51 (6) ◽  
pp. 809
Author(s):  
Deoksun Cha ◽  
Sang Kyoon Kim ◽  
Gyeoung Hwan Roh ◽  
Hyo Myung Kim ◽  
Jong Suk Song
Keyword(s):  
Laser Ablation ◽  
Astigmatism Correction ◽  
Surface Laser

scholarly journals Role of Optical Coherence Tomography on Corneal Surface Laser Ablation

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Bruna V. Ventura ◽  
Haroldo V. Moraes ◽  
Newton Kara-Junior ◽  
Marcony R. Santhiago
Keyword(s):  
Optical Coherence Tomography ◽  
Laser Ablation ◽  
Imaging Modality ◽  
Corneal Thickness ◽  
Optical Coherence ◽  
Corneal Surface ◽  
Cross Sectional ◽  
Surface Laser ◽  
The Time Domain

This paper focuses on reviewing the roles of optical coherence tomography (OCT) on corneal surface laser ablation procedures. OCT is an optical imaging modality that uses low-coherence interferometry to provide noninvasive cross-sectional imaging of tissue microstructurein vivo.There are two types of OCTs, each with transverse and axial spatial resolutions of a few micrometers: the time-domain and the fourier-domain OCTs. Both have been increasingly used by refractive surgeons and have specific advantages. Which of the current imaging instruments is a better choice depends on the specific application. In laserin situkeratomileusis (LASIK) and in excimer laser phototherapeutic keratectomy (PTK), OCT can be used to assess corneal characteristics and guide treatment decisions. OCT accurately measures central corneal thickness, evaluates the regularity of LASIK flaps, and quantifies flap and residual stromal bed thickness. When evaluating the ablation depth accuracy by subtracting preoperative from postoperative measurements, OCT pachymetry correlates well with laser ablation settings. In addition, OCT can be used to provide precise information on the morphology and depth of corneal pathologic abnormalities, such as corneal degenerations, dystrophies, and opacities, correlating with histopathologic findings.

scholarly journals Efficacy and safety of single-step transepithelial photorefractive keratectomy with the all-surface laser ablation SCHWIND platform without mitomycin-C for high myopia: A retrospective study of 69 eyes

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259993
Author(s):  
Jean Baptiste Giral ◽  
Florian Bloch ◽  
Maxime Sot ◽  
Yinka Zevering ◽  
Arpine El Nar ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Laser Ablation ◽  
Mitomycin C ◽  
High Myopia ◽  
Photorefractive Keratectomy ◽  
Efficacy Rate ◽  
Care Hospital ◽  
Case Series Study ◽  
Surface Laser ◽  
Rate Frequency

Background Studies suggest that transepithelial photorefractive keratectomy (TransPRK) with the all-surface laser ablation (ASLA)-SCHWIND platform is effective and safe for both low-moderate myopia and high myopia. In most studies, mitomycin-C is administered immediately after surgery to prevent corneal opacification (haze), which is a significant complication of photorefractive keratectomy in general. However, there is evidence that adjuvant mitomycin-C induces endothelial cytotoxicity. Moreover, a recent study showed that omitting adjuvant mitomycin-C did not increase haze in low-moderate myopia. The present case-series study examined the efficacy, safety, and haze rates of eyes with high myopia that underwent ASLA-SCHWIND TransPRK without adjuvant mitomycin-C. Methods All consecutive eyes with high myopia (≤-6 D) that were treated in 2018–2020 with the SCHWIND Amaris 500E® TransPRK excimer laser without adjuvant mitomycin-C in a tertiary-care hospital (France) and were followed up for 6 months were identified. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and spherical equivalent (SE) were recorded before and after surgery. Postoperative haze was graded using the 4-grade Fantes scale. Efficacy rate (frequency of eyes with 6-month UCVA ≤0.1 logMAR), safety rate (frequency of eyes that lost <2 BSCVA lines), predictability (frequency of eyes with 6-month SE equal to target SE±0.5 D), efficacy index (mean UCVA at 6 months/preoperative BSCVA), and safety index (BSCVA at 6 months/preoperative BSCVA) were computed. Results Sixty-nine eyes (38 patients) were included. Mean preoperative and 6-month SE were -7.44 and -0.05 D, respectively. Mean 6-month UCVA and BSCVA were 0.00 and -0.02 logMAR, respectively. Efficacy rate and index were 95.7% and 1.08, respectively. Safety rate and index were 95.7% and 1.13, respectively. Predictability was 85.5%. Grade 3–4 haze never arose. At 6 months, the haze rate was zero. Conclusions ASLA-SCHWIND TransPRK without mitomycin-C appears to be safe as well as effective and accurate for high myopia.

scholarly journals Effect of Pulsed Laser Ablation on the Increase of Adhesion of CRN Coating-Substrate

2018 ◽  
Vol 26 (43) ◽  
pp. 61-70
Author(s):  
Paulína Zacková ◽  
Lucia Števlíková ◽  
Ľubomír Čaplovič ◽  
Martin Sahul ◽  
Vitali Podgurski
Keyword(s):  
Laser Ablation ◽  
Residual Stresses ◽  
High Speed ◽  
Substrate Surface ◽  
Base Material ◽  
High Speed Steel ◽  
Cobalt Content ◽  
Deposition Process ◽  
Adhesion Behavior ◽  
Surface Laser

Abstract The contribution deals with analysis of the influence of the substrate surface laser ablation before deposition process to improve the adhesion of coating-substrate system. The coatings were applied to the high-speed steel 6-5-2-5 (STN 19 852) and WC-Co cemented carbide with cobalt content of 10 wt%. LAteral Rotating Cathodes (LARC®) process was chosen for evaporation of individual CrN layers. Influence of laser ablation on the substrate morphology, structure, roughness, presence of residual stresses inside the substrates and layers and their adhesion behavior between the layers and the base material was studied. Scanning electron microscopy fitted with energy dispersive spectroscopy was utilized to investigate morphology and fracture areas of substrates with CrN layers. X-ray diffraction analysis was employed to detect the residual stresses measurements. Adhesion between the coatings and substrate was analyzed using “Mercedes” testing.

All Surface Laser Ablation and Crosslinking

2021 ◽  
pp. 177-186
Author(s):  
Miguel Rechichi ◽  
Marco Ferrise ◽  
Samuel Arba Mosquera
Keyword(s):  
Laser Ablation ◽  
Surface Laser

scholarly journals Effect of D-Panthenol on Corneal Epithelial Healing after Surface Laser Ablation

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Islam Mahmoud Hamdi
Keyword(s):  
Laser Ablation ◽  
Laser Surface ◽  
Corneal Epithelial ◽  
Epithelial Regeneration ◽  
Covered Area ◽  
Statistical Relevance ◽  
Surface Laser ◽  
Larger Sample ◽  
Subjective Sensation ◽  
Epithelial Healing

Purpose. To study the effect of D-panthenol (provitamin B5) on corneal epithelial healing, in cases of surface laser ablation. Patients and Methods: 45 eyes, of 45 patients undergoing laser surface ablation, received D-panthenol 2% in one eye and artificial tear drops of similar composition not containing D-panthenol in the other eye, postoperatively, for 2 months. Patients were examined daily for 3 days after the procedure. They were then examined weekly for 1 month. An additional examination was made after 2 months. Visual acuity (Log MAR) was assessed at every visit. Rate of healing (% of covered area) and subjective sensation of discomfort (scale 0–5) were assessed in the 1st 3 visits. Residual manifest cylinder (D) (as a parameter of corneal irregularity) and corneal clarity (epithelial and stromal haze) were assessed from week 1 to month 2. Results. During the first 3 days, both groups showed statistically nonsignificant ( P > 0.05 ) results. From week 1 to month 2, eyes receiving D-panthenol showed better vision and less residual cylinder ( P < 0.05 ) at week 1. For all other parameters, and at different examinations, both groups showed a statistically nonsignificant ( P > 0.05 ) difference. Still, eyes receiving D-panthenol showed better values at the majority of the parameters tested. Conclusion. D-Panthenol effect on corneal epithelial regeneration is of minimal clinical relevance. A different dosage and a larger sample of patients might reveal a statistical relevance. This trial is registered with https://doi.org/10.1186/ISRCTN81441126.

scholarly journals Clinical Outcomes of Aberration-Free All Surface Laser Ablation (ASLA) vs. Aberration-Free ASLA Assisted by Smart Pulse Technology in High Myopia: A One-Year Follow-Up Study

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
XiaoHao Du ◽  
Jia Zhang ◽  
Meng Su ◽  
WenJia Cao ◽  
Shuang Zeng ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Laser Ablation ◽  
High Myopia ◽  
Healing Time ◽  
Spherical Equivalent ◽  
Surface Laser ◽  
Epithelial Healing ◽  
Better Than ◽  
Pulse Technology

Purpose. To compare the clinical outcomes of aberration-free all surface laser ablation (ASLA) with and without the use of smart pulse technology (SPT) in high myopia. Methods. This study retrospectively analyzed 138 eyes (138 patients, only the right eye was selected) treated for high myopia (spherical equivalent ≥−6.00 diopters) using aberration-free ASLA (non-SPT group; 85 eyes) and aberration-free ASLA assisted by SPT (SPT group; 53 eyes). Examinations such as visual acuity, refraction, and haze were performed before the 12-month follow-up. Corneal epithelial healing time was assessed in the first postoperative day. Visual acuity and refraction examination were performed at 7 days and 1, 3, 6, and 12 months postoperatively. Corneal haze was evaluated in 1, 3, 6, and 12 months. Safety, efficacy, and corneal wavefront aberrations were assessed 12 months after the treatment. Results. At 12 months postoperatively, 60% versus 40% of eyes achieved 20/16 Snellen lines or better, and 92% versus 82% of eyes achieved 20/20 Snellen lines or better visual acuity in the SPT and the non-SPT groups, respectively. The average postoperative epithelial healing time was 3.75 ± 1.00 days in the SPT group and 3.73 ± 1.30 days in the non-SPT group ( P ≥ 0.05 ). The safety and the efficacy index of the SPT group were better than those of the non-SPT group in the follow-ups. The attempted spherical equivalent before the surgery and the achieved spherical equivalent at 12 months were comparable between the two groups. Regarding the aberrations, the results of Coma 90° in the SPT group were better than those in the non-SPT group ( P ≤ 0.05 ), but the increase of RMS HOAs (root mean square higher order aberrations), Coma 0°, and spherical aberration postoperatively had no statistical difference between the two groups ( P ≥ 0.05 ). Conclusions: Both aberration-free ASLA with and without SPT showed favorable safety, effectiveness, and predictability within 12 months for high myopia. And, ASLA using SPT might have potential advantages in the long-term visual quality.

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