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Unstable Refractive Error
An appropriate refractive surgery patient needs at least two consecutive years with less than 0.25 diopters of change in eyeglass prescription. The refractive error at the time of surgery can be corrected by surgery, but unstable error will cause vision to degrade and additional surgery may be required. Also, an unstable refractive error in an adult may indicate a disease or malady that could be a contraindication for laser vision correction surgery.
Cause of Refractive Error
The reason for refractive error like myopia (nearsighted, shortsighted) and hyperopia (farsighted, longsighted) is commonly that the eye itself is too long (myopia) or too short (hyperopia). Light entering the eye is focused in front of the retina for a person who is myopic and focused behind the retina for a person who is hyperopic.
Astigmatism commonly means that the cornea is irregular. Instead of being spherical like the top of a ball, the cornea is ellipical like the back of a spoon. Laser assisted refractive surgery can resolve most astigmatism, but progressive astigmatism may be a sign of a serious problem.
Presbyopia is when the muscles around the natural lens within the eye are less able stretch or squeeze the lens to change
its focus. This natural change of the lens shape for close vision is called accommodation. Presbyopia is why most people need reading glasses or bifocals after age 40.
How Laser Vision Correction Works
Conventional
or custom wavefront Lasik, Bladeless Lasik, PRK, or other laser assisted refractive surgery procedures change the point of focus by changing the shape of the cornea. In a process that removes corneal tissue, the cornea shape is changed so the light entering the eye is focused more closely at the retina, not behind or in front.
Laser vision correction cannot cure presbyopia, however there are workarounds like monovision that can reduce the need for reading glasses.
Unstable Astigmatism
An unstable astigmatism is more critical than unstable myopia or hyperopia. Progressive astigmatism may indicate corneal disease such as keratoconus that would be a contraindication for laser vision correction.
Reading Glasses
The loss of accommodation is a natural part of the aging process usually starting in the fourth decade of life. The need for stronger reading glasses indicates progressive presbyopia and is normally not a concern for Lasik, PRK, LASEK, Epi-Lasik, etc.
Looking For Best Lasik Surgeon?
If you are ready to choose a doctor to be evaluated for conventional
or custom wavefront Lasik, Bladeless Lasik, PRK, or any refractive surgery procedure, we recommend you consider a doctor who has been evaluated and certified by the USAEyes nonprofit organization.
Locate a USAEyes Evaluated & Certified Lasik Doctor.
Personalized Answers
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