Nvision Blog

Which Is Better: PRK or LASIK and Why?

Posted on February 16, 2020

Would you prefer apples or oranges? When it's time for a breakfast beverage, do you choose coffee or tea? Some choices we make are benign and based on our personal preferences. But others concern our health, and they're best made with the help of a doctor.

When you're considering refractive surgery, you'll get the option to choose between photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK).

Actually, your doctor will help you decide. And the one that's right for you will depend on a combination of eye health and lifestyle factors.

What Happens During Surgery?

Both PRK and LASIK change the way light moves through your eye. The shape of your cornea is altered, so images come into focus on the most sensitive cells in the retina. Blurring and distortion fade when your retina has access to every bit of critical information coming into the eyes.

During PRK:

  • Your eye is numbed.
  • Your doctor uses a small instrument to wipe away your top layer of corneal cells.
  • A laser reshapes the eye and brushes away irregularities.

During LASIK:

  • Your eye is numbed.
  • Your doctor cuts a layer or two of cells and pushes them aside.
  • A laser reshapes your eye.
  • The cut cells are replaced.

How Are They Similar?

PRK and LASIK are very different surgeries that require specialized equipment and a skilled practitioner. But they do share several similarities.

Both LASIK and PRK:

  • Correct common vision problems. Both surgeries can be used to correct nearsightedness, farsightedness, and astigmatism.
  • Have a similar fee. They cost about the same, analysts say. You can expect to pay up to $5,000 for both eyes.
  • Can help you see clearly. Visual acuity scores don't shift when researchers compare the procedures. Both can help people with vision problems to see clearly and not wear glasses or contact lenses all the time.

Even though these two procedures share attributes, they are right for some people and wrong for others.

patient undergoing prk surgery

Why Choose LASIK?

Doctors say most of their patients request LASIK when they want to amend their vision. This is a well-known procedure that has the ability to restore vision with very little sacrifice.

Most people who have LASIK experience little, if any, discomfort. Your eyes might feel gritty or dry, and you might need eye drops for a few weeks as you heal. But you're likely to describe your discomfort as mild, even in the few days after surgery. That's not true of PRK.

Reporters document their experience, and they agree that LASIK isn't terribly uncomfortable. They say they felt anxious to get back into normal activities within a few days.

Reporters discussing PRK had a different experience. They discuss feeling pain for an extended period of time.

Why Choose PRK?

LASIK might be considered a superior surgical choice, as it tends to produce good results with little discomfort. But not all patients are eligible for this surgery, and some don't have a lifestyle that's right for this procedure.

During LASIK, doctors replace the tissue they cut. But it's not stitched into place. If you're hit hard enough or you jolt your body quickly enough, you can push that flap away. That's a medical emergency that could require surgery.

Experts say PRK is best for people at risk for flap displacement. You could fall into this group if you:

  • Play high-impact sports, such as football or basketball.
  • Skydive.
  • Are in the military.
  • Trim trees or otherwise participate in active gardening activities.

You might also choose PRK if you have thin corneas. Your surgeon removes less tissue with PRK, and the epithelium that's scraped away does come back. You might not be eligible for LASIK with thin corneas, but your doctor might think PRK would work just fine.

Which Is Right for You?

Your doctor can help you make a smart decision about which surgery is best for your eyes, given your health and your lifestyle. It's not a decision you can make on your own, as you don't have all the information you need without a thorough eye exam. But your doctor can help.



What's the Difference Between PRK and LASIK? Healthline.

Types of Laser Eye Surgery: Cost and Risks of PRK vs. LASIK vs. LASEK. Money Crashers.

LASIK or PRK: Know Which One Suits Your Patient. Collaborative Eye.

When Is PRK a Better Choice Than LASIK? (January 2014). Practice Update.

17 Helpful Tips for Anyone Getting LASIK or PRK Eye Surgery. (April 2018). BuzzFeed.

What Is Photorefractive Keratectomy (PRK)? (September 2017). American Academy of Ophthalmology.


Which Is Better for Patients With Dry Eye: LASIK or SMILE?

Posted on February 16, 2020

Tears do more than help you express sadness. This precious liquid whisks away irritants before they attack the eye's delicate surface. Each tear also contains substances crucial for healthy eye tissue.

When you're recovering from surgery, your eyes need more tears than ever. But some operations can enhance dry eye symptoms. And if you have severe dry eye, you might not be a candidate for the procedure you want.

woman with dry eyes

How Does Surgery Cause Dry Eye?

LASIK and SMILE surgeries reshape your eye, so light and images focus on the retina in the back of your eye. The incisions necessary for that reshaping could interfere with your body's ability to produce tears.

During LASIK, your doctor:

  • Numbs your eye.
  • Uses a laser or scalpel to cut a small flap in the cornea.
  • Folds up that bit of tissue.
  • Uses a laser to reshape the tissue below.
  • Unfolds the flap and settles it in place.

During SMILE, your doctor:

  • Numbs your eye.
  • Uses a laser to reshape layers of tissue within the cornea.
  • Removes excess cells with suction.

SMILE surgery involves no flap. That means, experts say, that fewer nerves within your eye get cut. That's crucial, as those nerves both tell your eye when it's dry and trigger ducts to pump out fluids. If they're intact after surgery they could, in theory, produce fewer episodes of post-op dry eye.

patient receiving cataract surgery

Which Surgery Works Best?

Each eye is different, and a surgery that works best for your eyes might be terrible for your friend or neighbor. That said, doctors have dug into the data about LASIK and SMILE, and a winner is beginning to emerge.

Dry eye after both LASIK and SMILE is transient, researchers say. Anyone who has surgery will have eye discomfort, including cells that may feel:

  • Gritty
  • Blurred
  • Swollen
  • Painful
  • Irritated

These symptoms are usually mild, and they should fade quickly. But studies suggest they sometimes go away faster after SMILE. In one study, researchers found that LASIK came with more dry-eye complaints than SMILE at six months. But both groups had similar experiences at the 12-month mark.

In a second study, researchers found that 80 percent of SMILE patients didn't use artificial tears six months after surgery. Among LASIK patients, 57 percent didn't need these eye drops.

If you have dry eyes now, some surgeries could make your symptoms worse. Your doctor might recommend SMILE as your surgical choice to further reduce your risk of discomfort after the procedure is through.

But this surgery is only recommended for people with nearsightedness. If you have another form of vision loss, you'll need LASIK. That's true even if you have dry eye.

Treating Dry Eye Before Surgery

The healthier your eyes are before the surgery begins, the quicker your recovery will be. If your doctor identifies dry eye during your presurgical screening exam, there are plenty of treatment options you can try together.

Experts say doctors can treat dry eyes with:

  • Prescription eye drops. These solutions encourage your glands to make more tears. Your doctor can also use drops to reduce eyelid or cornea swelling.
  • Tear duct plugs. A tiny silicone stopper can keep your tears from leaving your eyes.
  • Warm compresses. Blocked glands in your eyes keep tears from flowing. Heat combined with massage can open them again.
  • Light therapy. Your doctor can use tiny pulses of light to open up blocked ducts yet more.

Doctors say pre-surgery dry eye treatment is crucial. That's true whether you need LASIK or SMILE. Your eyes will be healthier, and they will heal faster.

And the treatments work. In the past, people with serious dry eye problems couldn't get surgery. Now, with these treatment options, they can.

Your doctor must watch your progress carefully and advise you on surgery options. If you don't make enough progress, you may need to postpone or even halt your surgery plans.  


Lenticule May Beat LASIK in the Dry Eye Arena. (February 2012). EyeWorld.

Dry Eye After Small Incision Lenticule Extraction (SMILE) Versus Femtosecond Laser-Assisted in Situ Keratomileusis (FS-LASIK) for Myopia: A Meta-Analysis. (November 2016). PLoS One.

Dry Eye Disease Following Refractive Surgery: A 12-Month Follow-Up of SMILE Versus FS-LASIK in High Myopia. (2015). Journal of Ophthalmology.

SMILE May Induce Less Dry Eye Than LASIK. (June 2015). American Academy of Ophthalmology.

Point-Counterpoint: SMILE vs. LASIK. (February 2019). Review of Ophthalmology.

Dry Eyes. (March 2019). Mayo Clinic.

Contact Lens Complications Compared to LASIK Complications

Posted on February 16, 2020

Are contact lenses safer for your eyes? Or should you opt for LASIK instead?

If these questions keep you up at night, you’re not alone. We all want to do what’s best for our eyes. And it’s sometimes hard to parse medical jargon and get at the truth.

It’s true that LASIK is a surgery, and all similar procedures come with at least some risk. But contact lens complications are more common than those seen with LASIK.

While your doctor can help to cut your LASIK complication risk, you’ll need to adjust your contact injury rate alone. That’s not always easy.

Orthokeratology contact lenses

Contacts and Complications

Contacts are medical devices, and they're tightly regulated by the U.S. Food and Drug Administration. That organization wouldn't automatically approve something that wasn't safe.

But to keep your risk of problems as low as possible, you need to follow detailed instructions carefully. Few people do that.

In a study of contact-lens wearers, a third had a lens problem that required a trip to the doctor. That means the majority of people who wear contacts will have some sort of complication.

Most of the time, experts say, problems stem from bacteria. In some cases, infections can cause blindness. They can develop quickly, and often, they start with an innocent decision.

You might choose to:

  • Expose your contacts to water. You might rinse them under the tap, or you might wear them while swimming or showering.
  • Skip a cleaning step. You know you should clean your contacts before storing them. But you're tired, and you don’t. Bacteria can grow in just one night.
  • Reuse solutions. The liquids you need to care for contacts are expensive. But reusing solutions instead of replacing them can be dangerous.
  • Hold on to cases. You should replace your case regularly. If you hold onto it for too long, bacteria can grow.

The type of lens you use plays a role in complication rates. In one study, for example, researchers found that 86.84 percent of people wearing extended-use lenses had a problem. Only 67.85 percent of those who chose daily wear versions had the same issue.

Your doctor plays a role in the lenses you choose, but all the other complication risk factors stem from your choices. And global problem rates remain consistent over time. People don’t seem to change the way they care for contacts, even as the risks of improper contact use become clear.

lasik eye

LASIK and Complications

Every surgery comes with risks. You could have a reaction to the anesthetic drops, or the machine your doctor uses could malfunction. When you're preparing for surgery, it's easy for your mind to dream up plenty of scenarios that end with long-lasting blindness. In reality, LASIK comes with very few complications.

Industry records suggest that the LASIK complication rate sits at below 1 percent. Some people experience transient issues, such as:

  • Blurred vision.
  • Trouble with night vision.
  • Light sensitivity.
  • Mild pain or discomfort.
  • Dry eyes.

But often, these problems go away when the eye heals. It's very rare for them to persist.

Experts say LASIK technology is improving to reduce side effects. When compared to older surgeries, newer versions tend to come with fewer patient complaints. That means we can expect complication rates to drop even more.

To ensure the best outcome, you'll need to choose your surgeon carefully and work with a partner with plenty of experience and skill. You'll also need to stick to the follow-up care instructions given by your doctor. Do that, and there's no reason to expect major problems.

What Should You Do Next?

It's good to understand the risks and benefits of any medical procedure you're considering. That's true whether you're thinking about contacts or surgery.

But remember that your eyes are unique and special, and what's right for you might be different than what's right for someone else. Talk with your doctor to get the best advice on what should work for your eyes. 


Complications of Contact Lenses. UpToDate.

Contact Lens Risks. (September 2018). U.S. Food and Drug Administration.

Prevalence of Contact Lens-Related Complications Among Wearers in Saudi Arabia. (2016). Sudanese Journal of Ophthalmology.

LASIK Complication Rate: The Latest Facts and Stats You Should Know. (October 2017). American Refractive Surgery Council.

Facts About LASIK Complications. (December 2018). American Academy of Ophthalmology.

What Is the SMILE Procedure?

Posted on November 18, 2019

You probably associate the word smile with orthodontia, not ophthalmology. But if you're nearsighted, this term could take on a whole new meaning for you.

SMILE, otherwise known as small-incision lenticule extraction, is a surgical procedure that could help you to reduce or eliminate your need for glasses or contact lenses.


How Does SMILE Work?

SMILE is a refractive surgery that involves reshaping your eye. After surgery, light should pass directly through the center of your eyeball and focus on the perfect spot on your retina. LASIK and other laser-based surgeries have the same goal, but they achieve it in a different way.

In a LASIK surgery, your doctor cuts a small flap in the front of your eye, and that gets lifted up. A laser moves in and corrects the exposed tissue, and the flap settles back into place when the work is done.

SMILE surgeries involve no flaps. Doctors use lasers to reshape layers within the cornea while leaving the surface untouched. Excess tissue is suctioned away.

Experts say the innovation is similar to one seen in general surgery. You could have:

  • Open surgery, in which doctors make big cuts to see the field and make revisions
  • Laparoscopic surgery, in which the cuts are smaller, but the surgical outcome is similar

SMILE fans say recovery times are quicker. And you might be less susceptible to injuries later.

People who go through LASIK retain that cornea flap for the rest of life. A hit to your eye (from an errant soccer ball or a flapping branch, for example) could theoretically push it out of place. That could require surgery. The chances of such a complication from LASIK are incredibly slim, but with no flap, you have no similar risk.

Research suggests SMILE is effective. In one study of 328 people, 99 percent had 20/40 or better vision six months after surgery. At the six-month mark, 88 percent of people had 20/20 vision.

Many refractive surgeries are designed to amend all sorts of vision problems. SMILE is different.

Experts say the FDA has approved this surgery for nearsightedness, but at this point, you can't use it for anything else. You'll also need to meet surgical requirements.

To sign up for SMILE, experts say, you'll need to demonstrate that you are:

  • 22 or older.
  • Living with a stable eye prescription that hasn't changed within the last year.
  • Holding a prescription measuring between -1 and -8 diopters.
  • Healthy, with acceptable corneas and no history of eye disease or eye surgery.


Preparing for Surgery

SMILE is a precise procedure, and doctors like to ensure their patients are good candidates long before the work begins. Expect to go through a thorough eye exam, and be prepared to pay for the procedure.

Your doctor will:

  • Perform an exam to check your vision, measure the size of your pupils, assess the thickness of your corneas, and more.
  • Discuss your options so you can make an informed choice about SMILE or another refractive surgery.
  • Address your recovery so you'll be prepared to care for your eyes and heal.
  • Outline the cost as SMILE isn't often covered by insurance. Expect to pay $2,000 or more per eye.

Recovering From SMILE

Your surgery will be over in minutes, and you won't feel a thing. Your eyes will be numb, and if you feel nervous, your doctor can use medications to soothe your nerves. But you'll need to take several steps at home to protect your vision.

You'll use eye drops to combat infection, reduce swelling, and ease pain. As reporters point out, you'll need to use them every few hours, even at night. So you might lose a bit of sleep while your tissues knit together.

You'll also wear goggles while you sleep and in the shower, to protect your eyes from water and pokes.

After surgery, you'll have plenty of eye appointments. Your doctor will check your healing and your vision. If you don't achieve a 20/20 score (or something you deem acceptable in consult with your doctor), you might need another correction.

Some doctors use LASIK to fine-tune vision after SMILE, but others choose another solution. Your doctor can explain your options to you if the need arises.


Small Incision Lenticule Extraction SMILE—The Future of Refractive Surgery is Here. (January 2018). Missouri Medicine.

SMILE Procedure Expands Laser Vision Correction Options. (May 2017). American Refractive Surgery Council.

What Is Small Incision Lenticule Extraction? (June 2019). American Academy of Ophthalmology.

Who Is a Good Candidate for SMILE? (June 2019). American Academy of Ophthalmology.

I Had Laser Eye Surgery, and Here's How It Went. (April 2019). Independent.

Skills and Know-How Necessary for Successful SMILE Outcomes. (March 2016). EyeWorld.

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