Answers to 12 Common Questions about Lasik Eye Surgery

by Jul 6, 2021

LASIK, one of the many types of refractive surgery, is the most popular way to surgically correct vision. But how does it work?


Eye Anatomy

Before understanding what LASIK does, it is best to have a basic understanding of the eye’s anatomy.

Refractive error (or the need for a glasses or contact lens prescription) can be due to problems in two major eye structures—the lens or the cornea.

The lens is the middlemost structure of the eye and is a flexible tissue used to help focus light rays onto the retina (that backmost structure of the eye responsible for detecting light and transmitting it to the brain for visual processing).

The lens can help focus light rays through a process called accommodation. When we are young, we have lots of accommodation, so the lens really does not play too much of a role in our glasses prescription. However, as we get older (typically 40-50 years of age), we will start to see a decrease in the amount of accommodation and will need reading glasses to see up close.

The cornea, on the other hand, is the structure primarily involved in determining our glasses prescription and is what is altered by LASIK surgery.

Refractive error is created when the cornea is misshapen, resulting in light being refracted too much (myopia) or too little (hyperopia). This means the light is not focused directly onto the retina, but instead in front of or behind the retina, resulting in blur.

In mopes, or near-sighted individuals, the cornea is too steep. This causes the light to come to a focus in front of the retina.

In hyperopes, or far-sighted individuals, the cornea is too flat. This causes the light to come to a focus behind the retina.

The third refractive condition is astigmatism. In astigmatism, the cornea is not equally curved. Instead, it has two meridians of different curvature, resulting in light being focused onto two separated points on the retina. (Think about an oval shaped cornea instead of a spherical shaped cornea).

The cornea is composed of 5 layers—the epithelium (outermost layer), Bowman’s layer, the stroma, Descemet’s membrane, and the endothelium (innermost layer).

The stroma is the thickest layer and is thus the layer targeted during LASIK.


How Does LASIK Eye Surgery Work?

LASIK stands for Laser Assisted In-Situ Keratomileusis.

An ophthalmologist will use an Argon or Excimer laser to alter the structure of the cornea.

The eye is numbed with topical anesthetic and a small incisional flap is created through the corneal epithelium and Bowman’s layer.

The flap is gently flipped open to reveal the corneal stroma.

If you have myopia, the laser will shave off part of the central stroma, thus flattening the cornea so that it properly refracts light to land directly on the retina.

If you have hyperopia, the laser will shave off part of the peripheral stroma, thus steepening the cornea so that it properly refracts light to land directly on the retina.

If you have astigmatism, the laser will shave off parts of the stroma depending on the meridian strengths to flatten or steepen the cornea 360 degrees, thus resulting in light being refracted onto one point in the retina rather than multiple points.

After the stroma has been reshaped to correct for your prescription, the epithelium/Bowman’s layer flap will be gently pulled back into place and left to heal closed.


12 Common LASIK Eye Questions

What prescriptions can be corrected by LASIK surgery?

Every year the technology for LASIK improves and more and more prescriptions become available to correct. Currently, LASIK can be used to correct prescriptions ranging from -12.00 diopters (myopic prescriptions) to +6.00 diopters (hyperopic prescriptions). It can also correct up to 6.00 diopters of astigmatism.

Does LASIK Surgery Hurt?

No! It sounds scary to have a laser “shaving off” parts of your eye, but the most you will feel is a little tickle.

Can the LASIK laser burn me?

No. The laser used in LASIK surgery is extremely precise, everything must be aligned just right to allow it to actually cut through anything. If the laser is focused too far forward or backward, it will not do anything.

Will I be awake during LASIK surgery?

Yes. During surgery we need the eyes to be open. However, the equipment used to do the surgery is very precise and tracks your eyes to ensure they are not moving around. If you sneeze, cough, fart, etc. the system will shut down until your eyes stabilize again prior to restarting the process.

How long does it take to get LASIK?

The actual surgery time is very short! For most prescriptions, the laser surgeries will only take about 60 seconds per eye.

Can my optometrist (OD) perform LASIK surgery?

No. At this time only licensed ophthalmologists (MD) are permitted to perform LASIK surgery.

How do I know if I am a candidate for LASIK?

You will need to get a consultation with the ophthalmologist planning on doing your surgery. He or she will do a variety of tests to ensure your eyes are a good match for the surgery including checking corneal thickness, mapping out the contour of your cornea, checking your eye’s axial length, and checking to ensure your eyes are healthy and free of any current infections.

Who cannot get LASIK?

Individuals under the age of 18, those who have current infections, and those with keratoconus are not candidates for LASIK surgery.

What are the adverse effects of LASIK surgery?

Dryness is the most common complaint post-LASIK. Typically, the dryness will improve by 3 months post-operation, however eyes will likely remain at least somewhat drier post-op than they were pre-op.

Light sensitivity, glare, and haloes around lights are also common side effects of LASIK.

Will I still need reading glasses later in life?

Yes. As mentioned earlier, the lens is what is primarily responsible for the need for reading glasses after the age of 40. LASIK surgery does not affect the lens, and therefore cannot prevent the need for reading glasses at a later date.

At this time, there is no current surgery for improving accommodation. There are implants that can be used to help eliminate the need for reading glasses, but there is no “cure” for presbyopia (loss of accommodation).

Will LASIK completely correct my vision to 20/20?

In some cases, yes. In others, no. LASIK technology has come a long way since its initial invention. Most people will see great after surgery, however some individuals may still need corrective lenses to see “perfectly”. It all depends on the individual.

Do I still need to see my eye doctor yearly after LASIK?

Yes! Many people believe that they only need to see their eye doctor if they have vision problems. This is not the case. LASIK thins the cornea, making it more prone to infections. It is important to visit your eye doctor, to at least have them check the health of your eyes, yearly.

Not only is the front of your eyes’ health important, but so it the back part (the retina). It is advised that you see your eye doctor yearly to monitor for any changes in ocular health, as many changes in eye health are painless but can have severe repercussions if not caught in the early stages.


Dr. Nathan Abraham and the staff of the Abraham Eye Center specializes in cataract surgery, LASIK, PRK, and various corneal surgeries.  Call our ophthalmologist in Valencia, CA today at 661-977-7377 or schedule an appointment online if you are interested in lasik eye surgery.  Our eye doctor provides only the highest quality eye care and surgical services amongst eye doctors in the Valencia California area.

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