الفهرس 
History of Cataract SurgeryOnly 14 pages are availabe for public view
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Abstract
The use of lasers in the treatment of cataract has long
been desired by ophthalmologists to overcome risks of
phacoemulsification. These risks include endothelial trauma
and thermal burns at the wound due to heat generation.
Early attempts at the use of lasers involved Nd:YAG
laser systems which are categorized into direct and indirect
acting systems. The direct acting system (Photon laser
PhacoLysis) consists of Nd:YAG system coupled with a
conventional ultrasound phacoemulsification system.
The indirect acting system (Dodick photolysis), approved
for cataract extraction by the FDA, transfers the laser energy in
a Q-switched mode from the laser source to a laser probe. It
produces no significant heat and allows for smaller wound
sizes.
Er:YAG laser system has the advantages of lower energy
requirements and lack of heat production. It works by being
focused directly into the lens nucleus, and the subsequent
optical breakdown causes micro fractures of the lens material.
This laser is called the Phacolase MCL-29.
YAG laser systems have some limitations. They are
restricted in their treatment of dense cataracts. Also The use of lasers in the treatment of cataract has long
been desired by ophthalmologists to overcome risks of
phacoemulsification. These risks include endothelial trauma
and thermal burns at the wound due to heat generation.
Early attempts at the use of lasers involved Nd:YAG
laser systems which are categorized into direct and indirect
acting systems. The direct acting system (Photon laser
PhacoLysis) consists of Nd:YAG system coupled with a
conventional ultrasound phacoemulsification system.
The indirect acting system (Dodick photolysis), approved
for cataract extraction by the FDA, transfers the laser energy in
a Q-switched mode from the laser source to a laser probe. It
produces no significant heat and allows for smaller wound
sizes.
Er:YAG laser system has the advantages of lower energy
requirements and lack of heat production. It works by being
focused directly into the lens nucleus, and the subsequent
optical breakdown causes micro fractures of the lens material.
This laser is called the Phacolase MCL-29.
YAG laser systems have some limitations. They are
restricted in their treatment of dense cataracts. Also The use of lasers in the treatment of cataract has long
been desired by ophthalmologists to overcome risks of
phacoemulsification. These risks include endothelial trauma
and thermal burns at the wound due to heat generation.
Early attempts at the use of lasers involved Nd:YAG
laser systems which are categorized into direct and indirect
acting systems. The direct acting system (Photon laser
PhacoLysis) consists of Nd:YAG system coupled with a
conventional ultrasound phacoemulsification system.
The indirect acting system (Dodick photolysis), approved
for cataract extraction by the FDA, transfers the laser energy in
a Q-switched mode from the laser source to a laser probe. It
produces no significant heat and allows for smaller wound
sizes.
Er:YAG laser system has the advantages of lower energy
requirements and lack of heat production. It works by being
focused directly into the lens nucleus, and the subsequent
optical breakdown causes micro fractures of the lens material.
This laser is called the Phacolase MCL-29.
YAG laser systems have some limitations. They are
restricted in their treatment of dense cataracts. Also phacoemulsification time with the laser tends to be longer than
with ultrasound. The fibres used in Er:YAG laser systems have
toxic properties upon degradation in an aqueous environment
and, must be connected to a nontoxic tip. The fibre used in
Nd:YAG systems is quartz, which minimally attenuates the
energy, and must be replaced after every four to five surgeries.
Femtosecond laser is an infrared laser that works at
wavelength of 1052 nm; it emits ultrashort laser pulses with a
diameter of 0.001 mm, and use a shorter pulse time of 10-15 s. It
improves safety, efficiency, precision and speed of ophthalmic
surgeries.
Femtosecond lasers produce tissue interaction known as
photodisruption. The laser cuts tissue by essentially vaporizing
it. The tight focus of laser energy creates a plasma and then a
cavitation bubble that expands and collapses separating the
tissue.
Femtosecond laser cataract surgery companies are:
Alcon, Inc. (Hünenberg, Switzerland), which purchased LenSx
Lasers, Inc.; LensAR, Inc. (Winter Park, FL); OptiMedica
Corp. (Santa Clara, CA), and Technolas Perfect Vision GmbH
(Munich, Germany).
Use of the femtosecond laser has the potential to
revolutionize cataract surgery with the creation of a capsulotomy, lens fragmentation, limbal relaxing incisions and
clear corneal incisions. It has the potential advantages of
improved safety and increased precisions.
The major risk involved in the surgery is loss of suction
during the procedure and displacement of the laser pulses. The
major disadvantage is the increased cost. Complex cataract
cases, such as those with opaque nuclei, corneal opacity or
edema, conjunctival bleb due to previous filtration surgery, or
poor iris dilation, are contraindications for the procedure.
Nevertheless, in the long run improved results will drive the
acceptance (or rejection) of femtosecond laser cataract technology.