الفهرس 
FSL PRINCIPLES AND MACHINES Principles of FSLOnly 14 pages are availabe for public view
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Abstract
Femtosecond laser is a relatively new laser technology becoming popular for use in refractive correction. The ultra short laser pulses focuses the laser beam to a spot size of several micrometers in diameter and does not exceed pulse energy of 1 µJ, is in the range of 100–200 fs pulse duration. Therefore There is a reduction in the thermal and mechanical damage to the surrounding tissues.
The laser vaporizes small volumes of tissue by photo disruption, producing plasma, shock wave, cavitations and gas (CO2 and H2O) bubbles.
There are several uses for the femtosecond laser in ophthalmology with the energy and firing pattern controlled by computer, Fs laser use appears to be both safe and effective.
The use of femtosecond laser in LASIK is effective and safe procedure with less corneal higher-order aberrations resulting in better uncorrected visual acuity and contrast sensitivity
Recently, INTRACOR procedures. In this technique, Technolas FSL (Technolas Perfect Vision GmbH, Munich, Germany) is used to deliver five consecutive circular intrastromal laser pulses around the visual axis. Multifocal shape.
Femtosecond laser can be also used to make channels for implantation of intracorneal rings (Intacs) in the treatment of keratoconus and pellucid marginal corneal degeneration.
Moreover, FSL also used for intrastromal pocket creation for instilling the riboflavin solution paracentrally within the cornea, with no epithelial surface disturbance
ReLEx for correction of myopia is gaining attention including FLEX and SMILE.
The use of femtosecond laser in keratoplasty has been shown to be effective in both penetrating and lamellar types. In penetrating keratoplasty (PKP) , it provides precise corneal dissection of donor and recipient corneas, even if significant opacities were present In lamellar keratoplasty, Femtosecond laser–assisted lamellar keratoplasty (FALK) it can be programmed to produce precise lamellar cuts at any depth especially in deep corneal opacity
Also preexisting astigmatism can be treated by astigmatic arcuate incisions and limbal relaxing incisions, done with high precision and accuracy with femtosecond laser than what can be done manually.
Using of femtosecond laser in cataract surgery has increase accuracy of the surgical procedure, decrease recovery time and improve visual results Three companies: OptiMedica, LenSx and LensAR are in different stages of developing femtosecond laser systems for cataract surgery. These systems will create the initial corneal incisions, anterior capsulotomy which twice as strong as and more than five times precise in size and shape than manual capsulorhexis, and fragment the lens which decrease the cataract hardness, reducing the overall energy needed to remove the cataract with minimal damage to corneal endothelium, Posterior capsulorhexis which is a main step in congenital posterior polar cataract is a very difficult step to be done manually
One of the most important applications is glaucoma surgery. Permanent drainage channel may be created to reduce the elevated intraocular pressure .
The FS laser can be used for obtaining diagnostic corneal biopsies (3-mm diameter and 120µ to 200 µm thickness) in suspected infectious keratitis
In 2010, the USA Food and Drug Administration (FDA) cleared femtosecond laser systems for cataract surgery; FSL represent an exciting new technology in ophthalmology. It is likely that further experience and refinement will make FSL the predominant method in refractive surgery and markedly affect the field of cataract surgery.