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by Gary Allen & Dona Do
1) Retina
2) Cones & Rods
3) Fovea Centralis
4) Macular Plaque
5) Optic Nerve
What is it? Who gets it? Why would you
want it? What are the risks? What are the
benefits? How expensive is
it?
Refractive surgery is the correcting of a refractive error by changing the shape of the cornea with surgery.
Objects at distance are blurry & difficult to see.
Objects at proximity more clearly defined.
Corrected by Convex lenses as shown on diagram C & D
Difficulty seeing clearly at close distances
Objects at a distance more easily discernable.
Corrected by Convex lenses as shown on diagram A & B
Irregular curvature of the eye (shaped more like football than basketball)
Light in different planes focuses at different points
Flattening the cornea decreases myopia Increasing the steepness of the cornea
decreases Hyperopia Making the cornea more spherical
decreases Astigmatism All of these are correctable to some greater
or lesser degree through refractive surgeries
There are three types of surgery available utilizing Laser, Incision procedures or intraocular implants
Laser: Incision LASIK RK & AK PRK Intraocular LTK IOL
A flap is cut in the anterior cornea A laser is applied to the stroma underneath The flap is then replaced Pro- can treat large refractive errors shorter
healing time than PRK Local anesthetic (out patient procedure) Con-cost price ranges from $2,500-$1,000
Central Epithelium is Removed Laser is applied to bowman’s membrane Local anesthetic used 30 seconds of laser exposure Pro- can treat large refractive errors Con- greater laser exposure longer healing
time than LASIK.
Less common procedure LTK treats mild far-sightedness and also
provides a means of treating presbyopia (age-induced farsightedness)
Uses heat to steepen cornea Pro- lower incidence of complications for
LTK than with LASIK, with less than 1% adverse events
Con- only used to treat mild presbyopia
RK= Radial keratotomy for myopia AK= Astigmatic keratotomy for astigmatism Incisions in cornea heal causing reshaping
of eye Pro-can be done in poorer countries Con- higher risk of complications, less
effective, obsolete
Phakic Intraocular lenses Implanted into eye without removing the
natural lens Refractive lens-ectomy Natural lens is removed from eye and
replaced with intraocular lens PRO- for high myopia and cataracts Con- cost upwards of $1500 per eye.
1) Must have had no vision changes for at least two years
2) No underlying corneal
abnormalities3) No use of
contact lenses prior to surgery
Some anti-inflammatory medications are required
Possibility of infection based on procedure
Sunglasses outside are recommended for the first two weeks
Eye rubbing can cause damage
Some problems with glare can be noticed
Vision can be improved to 20/20 or greater but there is no guarantee of perfect vision.
Over time the corneal shape can gradually change requiring the need of glasses for reading this usually happens to candidates over 40-50 years of age.
What is it?
Who gets it? Why would you want
it?
What are the risks?
What are the benefits?
How expensive is it?
The evolution in correction of vision
Any one who fits criteria & wants better vision
Very small 0.1-0.9% have some form of complications
Benefits include improved vision to greater or lesser degree.
Prices Range $1000-$2500 per eye