An Intro to Refractive Surgery Options

7:02 PM

In today’s world, there isn’t just one way to achieve clearer vision.  If you are ready to move on from glasses and contact lenses, current refractive surgery options are better than ever.  So what is the right surgical option for you?  Short answer:  it depends.  So many factors play into which surgery will be most successful for your individual eyes, and your doctor will help you make the right choice based on your own needs.  Here’s a brief overview of the most popular surgery choices on the market today, and some of the key factors that make certain surgeries more ideal for certain patients.

LASIK (Laser Assisted Stromal In-Situ Keratomileusis)

A flap of the cornea is removed during LASIK
that is reapplied to act as a natural bandage via
When we think refractive surgery, most of us think of LASIK.  Laser eye surgery has the benefit of being quick, relatively painless, and has a very quick recovery time.  Today’s most accurate version of LASIK uses the laser for the entire procedure, both to cut a flap in the cornea that will act as a natural bandage as your eye heals and to perform the thinning of the cornea that “zeros out” your prescription.  This is often called bladeless LASIK or LASEK, and with its advent we’ve seen significantly better vision correction for both high prescriptions and astigmatism.  Studies suggest that LASIKcan routinely correct as high as -9.00D of nearsightedness (myopia), up to+2.50D of farsightedness (hyperopia) and up to 3.50D of astigmatism.  Today's Intralase procedures can accomplish as much as 6.00D of astigmstism.  This power range is based on an average corneal thickness; if you have thinner corneas there won’t be enough tissue to remove to correct for higher prescription ranges.  Corneal thickness is a measurement that all doctors will take to make sure you are a good candidate for surgery, and depending on the results your doctor will be better able to advise you as to whether you would still need glasses after surgery, or if surgery would be safe for you at all.
Who can’t get LASIK?  People with thin or irregular corneas (conditions like keratoconus for example) are unable to get LASIK surgery due to the risks of thinning their cornea to a point of prolapse.  People with corneal dystrophies, corneal scarring or a history of keloid scarring are not good candidates – if the cornea scars, you won’t be able to see clearly through it.  Inflammatory conditions are also a relative contraindication; people with rheumatoid arthritis, sarcoidosis, a history of herpes infections, Sjogren’s Syndrome, or significant dry eye will all heal poorly after surgery. Nearly everyone has dryness for the first 6 months after surgery, but many people that had dry eye complaints before surgery have severe dry eye problems after the surgery, sometimes requiring lifelong treatment.  Many doctors will recommend treating even mild dry eye before doing a surgical treatment to maximize the possibility for success.
What kind of vision can I expect?  Studies show that 94% ofpatients will achieve 20/40 or better (legal driving vision) after LASIK. As you can see from those numbers, not everyone achieves 20/20 vision after LASIK. You’ll be hard pressed to find a doctor that would guarantee such.   Vision won’t necessarily be as good as it is right now with your glasses or contact lenses after surgery, and some people will still wear night driving glasses after surgery to achieve that crystal sharp 20/20 vision if they desire it.  Even if your prescription isn’t corrected to zero, it will be very close.  Studies of LASIK surgeries since 2000 show 88% of eyes are within 1.00D of zeroprescription (emmetropia) after surgery, and 92 percent of eyes are within2.00D of emmtropia.  After age 40, everyone that has LASIK surgery to fully correct distance vision will still need reading glasses as they go through the normal aging condition called presbyopia where our eyes naturally lose the ability to focus up close.  So LASIK doesn’t mean no glasses ever again, but it does mean for most people that you will be glasses free for at least the majority of your day.
PRK (Photorefractive Keratectomy)
PRK is an older surgical procedure to correct vision that does not utilize a laser or a corneal flap as a natural bandage after the procedure.  As such it is significantly more painful – expect to miss around a week from work as you recover.  But the pro of PRK is that without a flap, you are fully regrowing a new cornea as the tissue heals, meaning less risk of scar tissue for people with thinner corneas or mild corneal changes that would prohibit them from LASIK.   PRK is typically around the same cost as LASIK, and studies show that visually patients that underwent LASIK or PRK achieve similar post-surgical results.
Phakic IOL
What if your prescription is too high for LASIK or PRK?  Your better option is to opt for an intraocular implant (IOL) that fully corrects your prescription– almost like having a contact lens implanted internally.  An IOL can correct very high prescriptions, as high as -20.00D and up to -6.00D of astigmatism. The IOL is placed either in front of your iris or behind your iris and in front of the lens (phakic means that they leave your lens in place).  The true perk of phakic IOLs is that nearly any prescription is possible, and if for some reason there is an issue, it is also possible to have it removed, unlike LASIK or PRK where the cornea is permanently changed.   The downside to phakic IOLs is that they require a much more invasive operation.  The lens has to be inserted into the eye, and since it is being placed much more internally than a LASIK or PRK procedure that only treats the cornea, there is an increased risk of cataract formation, glaucoma, or even retinal breaks or detachments.   The risks of these side effects is very low; studies show 1% of patients with phakic IOL develop acataract after the surgery.

A phakic IOL sits in front of the cornea acting like an internal contact lens via
Take Home:
With so many options, the best way to select the right surgery for you is to talk with a doctor you trust.  Refractive surgeons are well-versed in the options available today, and based on your personal and family medical history, your prescription, and your eye’s anatomy, they’ll be able to recommend the best option for you.  Just remember, any refractive surgery may not be able to achieve perfect, 20/20 vision in all lighting conditions.   Today’s refractive surgery may not mean no glasses ever again for every patient, but it will definitely significantly reduce your dependence on corrective eyewear and the freedom to see clearly without the constant hassle of bulky frames or contact lenses.  And what’s more, the technology just keeps getting better.  Even people with high prescriptions can now enjoy refractive surgery, even if you’ve been told you weren’t a candidate for LASIK in the past.  Better versions of LASIK and now the mainstream use of phakic IOLs means that there is a surgery option for nearly everyone.  


This post also  appears on the CIA Medical Insights Blog as free content donation by Dr. L to help promote discussion of ocular health on their website

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1 comments

  1. Just like to share as i found these helpful as part of the low vision awarenes month, here are some good resources about eye surgery options:
    1. The Anatomy of the Eye and Lasik
    2. Heatlhy food for healthy eyes

    ReplyDelete