scholarly journals Excimer Laser and Femtosecond Laser in Ophthalmology

10.5772/64238 ◽  
2016 ◽  
Author(s):  
Liang Hu ◽  
Yiqing Huang ◽  
Meng Lin
Keyword(s):  
Femtosecond Laser ◽  
Excimer Laser

scholarly journals Excimer versus Femtosecond Laser Assisted Penetrating Keratoplasty in Keratoconus and Fuchs Dystrophy: Intraoperative Pitfalls

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Moatasem El-Husseiny ◽  
Berthold Seitz ◽  
Achim Langenbucher ◽  
Elena Akhmedova ◽  
Nora Szentmary ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Excimer Laser ◽  
Outcome Measures ◽  
Penetrating Keratoplasty ◽  
Positive Pressure ◽  
Group Iii ◽  
Fuchs Dystrophy

Purpose. To assess the intraoperative results comparing two non-mechanical laser assisted penetrating keratoplasty approaches in keratoconus and Fuchs dystrophy.Patients and Methods. 68 patients (age 18 to 87 years) with keratoconus or Fuchs dystrophy were randomly distributed to 4 groups. 35 eyes with keratoconus and 33 eyes with Fuchs dystrophy were treated with either excimer laser ([Exc] groups I and II) or femtosecond laser-assisted ([FLAK] groups III and IV) penetrating keratoplasty. Main intraoperative outcome measures included intraoperative decentration, need for additional interrupted sutures, alignment of orientation markers, and intraocular positive pressure (vis a tergo).Results. Intraoperative recipient decentration occurred in 4 eyes of groups III/IV but in none of groups I/II. Additional interrupted sutures were not necessary in groups I/II but in 5 eyes of groups III/IV. Orientation markers were all aligned in groups I/II but were partly misaligned in 8 eyes of groups III/IV. Intraocular positive pressure grade was recognized in 12 eyes of groups I/II and in 19 eyes of groups III/IV. In particular, in group III, severe vis a tergo occurred in 8 eyes.Conclusions. Intraoperative decentration, misalignment of the donor in the recipient bed, and need for additional interrupted sutures as well as high percentage of severe intraocular positive pressure were predominantly present in the femtosecond laser in keratoconus eyes.

scholarly journals Outcomes of LASIK for Myopia or Myopic Astigmatism Correction with the FS200 Femtosecond Laser and EX500 Excimer Laser Platform

2018 ◽  
Vol 12 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Muanploy Niparugs ◽  
Napaporn Tananuvat ◽  
Winai Chaidaroon ◽  
Chulaluck Tangmonkongvoragul ◽  
Somsanguan Ausayakhun
Keyword(s):  
Visual Acuity ◽  
Femtosecond Laser ◽  
Excimer Laser ◽  
Clinical Results ◽  
Laser In Situ Keratomileusis ◽  
Distance Visual Acuity ◽  
Astigmatism Correction ◽  
Full Correction ◽  
One Year ◽  
Myopic Astigmatism

Purpose: To evaluate the efficacy, predictability, stability and safety of laser in situ keratomileusis (LASIK) using the FS200 femtosecond laser and EX500 excimer laser platform. Methods: The outcomes of 254 eyes of 129 consecutive patients with myopia or myopic astigmatism who underwent full correction femtosecond laser-assisted LASIK at CMU LASIK Center were assessed. Pre-operative and post-operative parameters including manifest refraction, Uncorrected Distance Visual Acuity (UDVA), Best Corrected Distance Visual Acuity (BDVA), corneal topography and tomography were analyzed. The results between low to moderate myopia and high myopia were compared up to 12 months. Results: Mean pre-operative Spherical Equivalent (SE) was -5.15±2.41 Diopters (D) (range -0.50 to -11.50 D) and -0.13±0.28 D, -0.13±0.27 D, -0.13±0.28 D and -0.14±0.30 D at 1, 3, 6, and 12 months, post-operatively. At 12 months, the propor¬tion of eyes achieving UDVA ≥ 20/20 was 90.0% and ≥20/40 was 98.8%. The proportion of eyes achieving post-operative mean SE ±0.5 D, and ±1 D was 91.3%, and 98.5%. No eyes lost more than two lines of BDVA. The low to moderate myopic group had a statistically significant better UDVA at one (p=0.017) and three months (p=0.014) but no difference at six (p=0.061) and 12 months (p=0.091). The mean post-operative SE was better in low to moderate myopic group at every follow-up visit (p=0.001, 0.007, <0.001 and <0.001). Conclusion: One-year clinical results of LASIK with the FS200 femtosecond laser and EX500 excimer laser showed high efficacy, predictability, stability and safety.

scholarly journals Prophylactic Corneal Cross-Linking in Myopic Femtosecond Laser-Assisted In Situ Keratomileusis: Long-Term Visual and Refractive Outcomes

Optics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 55-62
Author(s):  
Federico Alonso-Aliste ◽  
Jonatan Amián-Cordero ◽  
Rahul Rachwani-Anil ◽  
Concepción De-Hita-Cantalejo ◽  
Davide Borroni ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Femtosecond Laser ◽  
Excimer Laser ◽  
Cross Linking ◽  
Spherical Equivalent ◽  
Refractive Outcomes ◽  
Safety Effectiveness

The purpose of our study was to evaluate the safety, effectiveness, predictability, and stability of myopic and astigmatic laser-assisted in situ keratomileusis (LASIK) with simultaneous prophylactic corneal cross-linking (CXL) in thin corneas. In total, 100 eyes from 50 patients who were subjected to myopic and astigmatism femtosecond LASIK with simultaneous prophylactic CXL were included. The design of the study was retrospective, longitudinal, and observational. All patients had a 48-month follow-up. The MEL 80 excimer laser was utilized with the Aberration Smart Ablation platform. CXL treatment was applied when the predicted stromal thickness was less than 330 µm. Patients’ mean age was 30.22 ± 5.97 years. Previous mean spherical equivalent was −5.50 ± 1.65 (−9.50 to −1.13) diopters (D). Postoperative mean spherical equivalent was −0.24 ± 0.29 (−0.85 to +0.50) D. Visual acuity (VA) of 20/20 or better was observed in 87% of the eyes and no eyes experienced VA loss. Spherical equivalent within ±0.50 D was observed in 93% of eyes, and 4% of eyes varied by 0.50 D or more between 3 and 48 months. Prophylactic corneal cross-linking with simultaneous femtosecond laser-assisted in situ keratomileusis in thin corneas proved to be effective, safe, and predictable. The results remained stable after 48 months of follow-up.

scholarly journals Effect of Femtosecond Lasik for Myopes on Corneal Hysteresis and Tonometry

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
S Z Mansour ◽  
T H Mohamed ◽  
H S Saadeldin ◽  
E M Awadallah
Keyword(s):  
Retinal Detachment ◽  
Femtosecond Laser ◽  
Prospective Study ◽  
Excimer Laser ◽  
Refractive Surgery ◽  
Fort Worth ◽  
The Mean ◽  
G Value ◽  
A Prospective Study ◽  
Flap Creation

Abstract Background Near-sightedness, also known as short-sightedness and myopia, is a condition of the eye where light focuses in front of, instead of on, the retina. This causes distant objects to be blurry while close objects appear normal. Other symptoms may include headaches and eye strain. Severe near-sightedness increases the risk of retinal detachment, cataracts, and glaucoma. Objectives The aim of the present study is to quantify the biomechanical effects of Femtosecond LASIK for myopes using the Ocular Response Analyzer. Patients and Methods This is a prospective study that was conducted on 30 eyes. 20 patients signed an informed written consent. The (30) eyes underwent refractive surgery using Femto-LASIK flap creation by (IntraLase iFS, Abbott Medica Optics, California, USA) and excimer laser by (WaveLight Allegretto, Alcon, Fort Worth, Texas, USA). Results The same parameters used in our study, 40 eyes of 20 patients who underwent LASIK for myopia treatment using a femtosecond laser were enrolled. IOP and the corneal biomechanical markers were measured preoperatively and 1 month after LASIK using ORA and GAT. The mean preoperative CCT was548.63 µm with SD ± 27.71, mean preoperative CH was 10.89 mmHg with SD ± 1.50and CRF was 10.47 mmHg with SD ± 1.64. The postoperative CCT, MRSE, CH &CRF were 493 µm with SD ± 30.84, -0.80 with SD ± 0. 14 (D), 8.41 mmHg with SD ± 1.19 &7.16 mmHg with SD ± 1.33 respectively. The values are significantly lower than preoperative.(p &lt;0.001). The mean preoperative IOPcc, IOPg, IOP by GAT was 14.31mmHg with SD ± 2.42,14.19 mmHg with SD ± 2.54, 13.42 mmHg with SD ± 2.19.respectively, while the mean postoperative IOPcc, IOPg and IOP by GAT was 13.64 ±2.09, 10.27± 2.26, 10.83± 2.83 respectively. Conclusion Myopic photorefractive surgery using Femto-LASIK flap creation causes reduction in CH and IOP; obvious change in the IOP-G value postoperatively, so it is more accurate to measure IOP-CC as it is a major factor to be taken into consideration.

scholarly journals Penetrating Keratoplasty for Keratoconus – Excimer Versus Femtosecond Laser Trephination

2017 ◽  
Vol 11 (1) ◽  
pp. 225-240 ◽  
Author(s):  
Berthold Seitz ◽  
Achim Langenbucher ◽  
Tobias Hager ◽  
Edgar Janunts ◽  
Moatasem El-Husseiny ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Femtosecond Laser ◽  
Excimer Laser ◽  
Penetrating Keratoplasty ◽  
Contact Lenses ◽  
Corneal Transplantation ◽  
Correction Method ◽  
Good Prognosis ◽  
Severe Stage ◽  
First Choice

Background: In case of keratoconus, rigid gas-permeable contact lenses as the correction method of first choice allow for a good visual acuity for quite some time. In a severe stage of the disease with major cone-shaped protrusion of the cornea, even specially designed keratoconus contact lenses are no more tolerated. In case of existing contraindications for intrastromal ring segments, corneal transplantation typically has a very good prognosis. Methods: In case of advanced keratoconus – especially after corneal hydrops due to rupture of Descemet’s membrane – penetrating keratoplasty (PKP) still is the surgical method of first choice. Noncontact excimer laser trephination seems to be especially beneficial for eyes with iatrogenic keratectasia after LASIK and those with repeat grafts in case of “keratoconus recurrences” due to small grafts with thin host cornea. For donor trephination from the epithelial side, an artificial chamber is used. Wound closure is achieved with a double running cross-stitch suture according to Hoffmann. Graft size is adapted individually depending on corneal size („as large as possible – as small as necessary“). Limbal centration will be preferred intraoperatively due to optical displacement of the pupil. During the last 10 years femtosecond laser trephination has been introduced from the USA as a potentially advantageous approach. Results: Prospective clinical studies have shown that the technique of non-contact excimer laser PKP improves donor and recipient centration, reduces “vertical tilt” and “horizontal torsion” of the graft in the recipient bed, thus resulting in significantly less “all-sutures-out” keratometric astigmatism (2.8 vs. 5.7 D), higher regularity of the topography (SRI 0.80 vs. 0.98) and better visual acuity (0.80 vs. 0.63) in contrast to the motor trephine. The stage of the disease does not influence functional outcome after excimer laser PKP. Refractive outcomes of femtosecond laser keratoplasty, however, resemble that of the motor trephine. Conclusions: In contrast to the undisputed clinical advantages of excimer laser keratoplasty with orientation teeth/notches in keratoconus, the major disadvantage of femtosecond laser application is still the necessity of suction and applanation of the cone during trephination with intraoperative pitfalls and high postoperative astigmatism.

scholarly journals Συγκριτική μελέτη διαθλαστικών επεμβάσεων Lasik με femtosecond laser και μηχανικό μικροκερατόμο

2014 ◽  
Author(s):  
Γεώργιος Δρανίδης
Keyword(s):  
Femtosecond Laser ◽  
Excimer Laser

ΠΕΡΙΛΗΨΗ Σκοπός Σκοπός της προοπτικής αυτής μελέτης είναι η σύγκριση των επεμβάσεων lasik με femtosecond laser και με μηχανικό μικροκερατόμο. ΥΛΙΚΟ ΚΑΙ ΜΕΘΟΔΟΣ. Μελετήθηκαν 200 οφθαλμοί ασθενών που υποβλήθηκαν σε διόρθωση μυωπίας ή υπερμετρωπίας και αστιγματισμού με lasik με μηχανικό μικροκερατόμο και αντίστοιχα 200 οφθαλμοί ασθενών που υποβλήθηκαν στην ίδια διαδικασία με lasik με femtosecond laser. Οι παράμετροι που μελετήθηκαν με μετρήσεις που έγιναν προεγχειρητικά, στον 1 και τους 3 μήνες ήταν: το πάχος του κερατοειδούς και ο αριθμός των ενδοθηλιακών του κυττάρων, η ενδοφθάλμιος πίεση με τονόμετρα Goldmann και Pascal, και η καταγραφή του πραγματικού flap που καταγράφηκε με τη βοήθεια της διεγχειρητικής παχυμετρίας του κερατοειδή μετά την άρση του flap και πριν την εφαρμογή του excimer laser. Επίσης μελετάται το τελικό διαθλαστικό αποτέλεσμα, η τελική αδιόρθωτη οπτική οξύτητα και η μεταβολή που παρατηρείται στη σφαιρική εκτροπή, με τη χρήση του wavefront aberrometer. ΑΠΟΤΕΛΕΣΜΑΤΑ 1) ΜΥΩΠΙΑ Σε διόρθωση της μυωπίας και μυωπικού αστιγματισμού με LASIK με μηχανικό μικροκερατόμο υποβλήθησαν 178 οφθαλμοί 89 ασθενών. Σε διόρθωση της μυωπίας και μυωπικού αστιγματισμού με femtosecond LASIK υποβλήθησαν 166 οφθαλμοί 83 ασθενών. Συνολικά στην επέμβαση υποβλήθησαν 344 οφθαλμοί. Σε όλα αυτά τα περιστατικά δεν παρατηρήθηκε στατιστικά σημαντική διαφορά (p >0,05). Μεγαλύτερη διαφορά υπήρχε στον τομέα του flap , όπου στην femtosecond LASIK το πραγματικό πάχος του flap ήταν πιο κοντά στο επιθυμητό και παρουσίασε μικρότερες διακυμάνσεις. Στην μόνη παράμετρο όπου παρατηρήθηκε στατιστικά σημαντική διαφορά ήταν στη μεταβολή της σφαιρικής εκτροπής όπου στην Lasik με μηχανικό μικροκερατόμο υπάρχει αύξηση τους ενώ στην femtosecond υπάρχει μια μικρή μείωση ( p < 0,05). 2)ΥΠΕΡΜΕΤΡΩΠΙΑ Σε διόρθωση της υπερμετρωπίας και αστιγματισμού με LASIK με μηχανικό μικροκερατόμο υποβλήθησαν 22 οφθαλμοί από 11 ασθενείς. Σε διόρθωση της υπερμετρωπίας και αστιγματισμού με femtosecond lasik υποβλήθησαν 36 οφθαλμοί από 18 ασθενείς. Συνολικά στην επέμβαση υποβλήθησαν 58 οφθαλμοί. Κι εδώ τα αποτελέσματα δείχνουν ακριβώς το ίδιο, δηλαδή σε όλες αυτές τις περιπτώσεις υπήρχε μια ελαφρά υπεροχή της lasik με femtosecond χωρίς όμως να παρατηρηθεί στατιστικά σημαντική διαφορά πουθενά (p >0,05). Επίσης σημαντική διαφορά υπήρχε στον τομέα του flap, όπου στην lasik με femtosecond το πραγματικό πάχος του flap ήταν πολύ πιο κοντά στο επιθυμητό κι επίσης παρουσίασε μικρότερες διακυμάνσεις, αλλά και πάλι δεν υπήρξε στατιστικά σημαντική διαφορά μεταξύ των δυο μεθόδων. Στην μόνη παράμετρο όπου παρατηρήθηκε στατιστικά σημαντική διαφορά ήταν στη μεταβολή της σφαιρικής εκτροπής όπου στο μηχανικό μικροκερατόμο υπήρξε αύξηση τους ενώ στην lasik με femtosecond υπήρξε μια μικρή μείωση ( p < 0,05).Συμπεράσματα : Με την εξαίρεση της σφαιρικής εκτροπής όπου υπάρχει σαφής υπεροχή της lasik με femtosecond και στατιστικά σημαντική διαφορά, σε όλες τις άλλες παραμέτρους που μελετήθηκαν και συγκρίθηκαν δεν υπήρξε τέτοια διαφορά παρά την μικρή συνολικά υπεροχή της.

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