- LASIK -
Laser-assisted In Situ Keratomileusis, Laser assisted In Situ Keratomileusis
What is LASIK?, History, THE PROCEDURE OF THE SURGERY, COMPLICATIONS, CATERACT, EXTERNAL LINKS
LASIK, (an acronym) and laser eye surgery are the common terms for for Laser-assisted In Situ Keratomileusis. This a form of refractive laser eye surgery performed by ophthalmologists for vision correction. The procedure is a preferred alternative over PRK (or photorefractive keratectomy), since it requires less time for full recovery, and the patient normally experiences less pain.
History
LASIK was made made possible due to by Dr Jose Barraquer, in 1970 who developed
the first microkeratome, used to cut thin flaps in the cornea and alter the shape,
in a "procedure" called keratomileusis. LASIK surgery was developed
further in 1990 by Dr. Lucio Buratto from Italy and by Dr. Ioannis Pallikaris
a Greek, as a melding of two prior techniques, keratomileusis and photorefractive
keratectomy. The procedute became popular because of its greater precision and
lower frequency of complications compared with the older techniques.
In 1991, LASIK was performed for the first time in the USA by Doctors Stephen Brint and Stephen Slade. The same year, Drs. Thomas and Tobias Neuhann successfully treated the first German LASIK patients with an automated microkeratome.
The
procedure of the surgery
Pre-operative
Patients wearing soft contact
lenses are instructed to stop wearing them 7one week to 10 days before surgery.
Patients wearing hard contact lenses should not wear them for a minimum of six
weeks plus another six weeks for every three years the hard contacts had been
worn. Before surgery, the surfaces of the patient's corneas are examined with
a computer scanning device determining the exact shape. Using low power lasers,
it creates a topographic map of the eye's cornea. This process detects astigmatism
and other irregularities in the cornea's shape. Using the information, a surgeon
should be able calculate the amount and location of corneal tissue to be removed
during surgery. The patient typically is prescribed antibiotics to start taking
beforehand, to minimize infections risk.
Surgery
Operations are generally performed with the patient awake and mobile, but
the patient is typically given a mild sedative and anesthetic eye drops.
Lasik is performed in two steps.
1) create a flap of corneal tissue.
2) Use an excimer laser to remodel the corneal stroma.
Complications
due to LASIK have been classified as those that occur due to preoperative, intraoperative,
early postoperative, or late postoperative sources
A subconjunctival hemorrhage
is a common and minor LASIK complication.The incidence of refractive surgery patients
having unresolved complications six months after surgery has been estimated from
3% to 6%. The following are some of the more frequently reported complications
of LASIK: Dry eyes, Overcorrection or undercorrection, Visual acuity fluctuation,
Halos or starbursts around light sources at night, Light sensitivity, Ghosts or
double vision, Wrinkles in flap (striae), Decentered ablation, Debris or growth
under flap
Thin or buttonhole flap, Induced astigmatism, Epithelium erosion,
Posterior vitreous detachment, Macular hole
Endophthalmitis. An infection of the eye is a risk for those taking LASIK. This is an infection inside the eye.
Patients
with retinal detachments may notice a curtain moving across part or all of their
vision. Early symptoms of retinal detachment include flashes of light and dark
spots that floating, but these symptoms occur frequently during the normal recovery
from cataract surgery. Patients who notice flashes, floaters, or loss of part
of their visual field should contact their ophthalmologist immediately.
Posteriorly dislocated lens material. On rare occasions, fragments of cataractous lens fall into a vitreous cavity behind the thin membrane normally surrounding the lens. The ophthalmologist can recommend a vitrectomy to remove lens material and prevent inflammation.
Choroidal hemorrhage. The retina receives its blood supply from a delicate web of fine blood vessels referred to as the choroid. On rare occasions during cataract surgery, the choroid can bleed, a condition known as a choroidal hemorrhage. It is more likely to occur in elderly patients and those with glaucoma and high blood pressure, but it is unpredictable. If the hemorrhage is confined to a small area of the choroid, patients normally recover without significant visual loss. Yet for the most severe cases of choroidal hemorrhage, patients can have complete and permanent visual loss. In modern cataract surgery, use of small incisions has reduced severity of choroidal hemorrhages.
Reported
figures for safety and efficacy are interpretable in different ways. In 2003,
the Medical Defence Union (MDU), the largest insurer for doctors in Britain, reported
a 166% increase in claims involving laser eye surgery; however, the MDU averred
that these claims resulted primarily from patients' “unrealistic expectations”
of LASIK rather than “faulty surgery”. A 2003 study reported in the
medical journal Ophthalmology found 18% of treated patients and 12% of treated
eyes needed further treatment. The higher the initial corrections, astigmatism,
and older age are risk factors for LASIK retreatment.
Cataracts
Cataracts
are common in those over 60. About 60 percent of those more than 60 years and
70 percent of those more than 75 years have cataracts.
Causes of caterats
Age. Medical conditions such as Diabetes and other systemic diseases, glaucoma, and metabolic abnormalities can cause cataracts. Physical injuries referred to as traumatic cataracts. A blow to the eye, great heat or cold, chemical injury, exposure to radiation, and other injuries may lead to cataract formation. Long term exposure to sunlight. Some types of steroids, and smoking.
How an eye usually works
Light
passes through the cornea-the curved, clear front surface of an eye. Then passes
through the pupil and lens. The curved surface of the cornea and the lens inside
the eye bend light rays so images of distant objects are focused on the retina,
the layer of nerve cells in the back of the eye. Rays of light from near objects
must be bent more than rays of light from distant objects to focus them sharply
on the eye's retina. The lens inside the eye must change shape to maintain a sharp
image when looking from distant to near objects. The lens becomes more rigid with
age, which is why many older people need reading glasses or bifocals.
FDA
information page on LASIK
Clario: Refractive
corneal surgery database and lexicon
Council
for Refractive Surgery Quality Assurance - LASIK patient advocacy and LASIK surgeon
certification.
Lasik News
http://www.lasikinstitute.org/ Laser eye surgery education council
http://www.allaboutvision.com/lasik-surgeons/california.htm Surgeons performing LAZIK IN California
http://www.laservision-uk.com/
Provision UK
Vision Surgery Rehab
Network: Support site for people with complications from LASIK and other eye surgeries.
Visionsimulations.com: How
patients with refractive surgery complications see the world.
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