Refractive Surgery
Vision Correction:
Laser refractive surgery aims to improve vision and reduce or eliminate the need for glasses or contact lenses by permanently changing the shape of the cornea, the watch-glass, clear front window of the eye.
Astigmatism:
Astigmatism occurs when the cornea is more curved in one direction than the other. If astigmatism is significant, light passing through the cornea is scattered. Images reaching the retina are distorted and vision is blurred. When treating astigmatism, refractive surgery techniques selectively reshape portions of the cornea to make it symmetrical and smooth, so that images focus clearly on the retina.
Myopia:
When treating myopia, or nearsightedness, refractive surgery techniques reduce the curvature of the cornea to lessen the eye's focusing power. Images that are focused in front of the retina, due to an elongated eye or steep corneal curve, are pushed closer to or directly onto the retina.
Hyperopia:
When treating hyperopia, or farsightedness, refractive surgery techniques make the cornea steeper to increase the eye's focusing power. Images that are focused beyond the retina, due to a short eye or thin cornea, are pulled closer to or directly onto the retina.
Common refractive surgery procedures include:
LASIK Laser-assisted In-situ Keratomileusis
PRK Photorefractive Keratectomy
Customized treatment:
Current standard LASIK and PRK treatment has reached an impressive level of safety and accuracy. While in the days of radial keratotomy (diamond blade incisions in the cornea) approximately 80% of patients achieved driving distance vision after one procedure, the success rate with LASIK for 20/40 vision increases to 98.2% at the Reinstein Institute. These figures are based on treating each eye using average parameters for the population.
In order to treat an eye on an individualized basis, and not as an "average" eye, it is necessary to obtain a wealth of information particular to an individual eye. While corneal thickness, topography and pupil size are important parameters widely used today in planning surgery, individualized treatment will require an exact layer-by-layer mapping of the cornea, in order to best predict how that particular cornea will respond to the surgery.
To date, there is only one proven, patented technology capable of measuring the individual components of the cornea: the epithelium (surface skin of the cornea), the flap, and the residual bed (under the flap). The Artemis scanner, developed by Dr. Reinstein and colleagues at Cornell University, was recently approved by the FDA, and the first prototype of the device is used by Dr. Reinstein in his routine practice.
Within the next few years, it is believed by many that the standard of care in refractive surgery will involve use of VHF digital ultrasound scanning of all patients before and after surgery.
Important facts:
- While the American Academy of Ophthalmology reports that 95% of patients treated can pass a standard driver's license exam (that requires a visual acuity of at least 20/40 without glasses or contacts), a study involving 715 consecutive eyes treated by Dr. Reinstein for all levels of myopia and hyperopia showed that 98.2% of eyes treated achieved 20/40 with one procedure. In patients with lower levels of correction, such as myopia up to -3.00 D, 99.5% achieved 20/40 or better vision. See outcomes [link to efficacy report].
- Additional enhancement surgeries may be required to achieve your desired results. Dr. Reinstein's enhancement rate for all levels of correction combined was 1.8%.
- You may still need glasses or contact lenses to achieve your best vision even after refractive surgery because ther are limits to the amount of tissue that can be removed for corneal sculpting. Accurate corneal thickness mapping and direct measurement of the individual corneal layers after a first treatment can determine if it would be safe to perform further corrective surgery. The Artemis [link] is currently the only non-invasive method of determining the thickness of the bed after LASIK to determine if more treatment is safe to proceed with. Dr. Reinstein has published extensively in this area [link - certain publications below]
- Reading glasses may still be necessary for middle-aged and older adults. Refractive surgery does not alter the aging process of the eye and does not prevent presbyopia. In fact, you may need reading glasses at a younger age.
- If you have specific occupational goals, check with your prospective employer about regulations concerning refractive surgery.
- Like all eye surgery, there is a risk of damaging the vision such that neither glasses nor contact lenses will be able to fully sharpen the vision back to the pre-surgery state. The level of risk increases with the severity of the correction to be accomplished. For example, in myopia up to -6.99 D, Dr. Reinstein's recent outcomes showed that the probability of losing a small amount of clarity in the vision, not correctable with glasses (loss of 2 or more Snellen lines of best corrected vision) is 0.1% or about 1 in 1,000.
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