What is LASIK?

As with many technologies, like cellphones and computers, technical advances in refractive surgery technology have been rapid. Due to blade-less surgery and more accurate lasers and software, the optical results after modern refractive surgery have dramatically improved. Today, the vast majority of refractive surgery patients have independent vision after surgery that is at least as good, or better, than it was before surgery using glasses and contact lenses. Just imagine running on the beach or enjoying water sport without struggling with glasses or contact lenses.

Why is Laser Refractive Surgery necessary?

A laser can be used to treat vision problems caused by refractive errors. You have a refractive error when your eye does not refract (bend) light properly. To see clearly, light rays must be refracted by your cornea and lens. The light focuses on the retina which turns light into signals that travel to your brain and become images. With refractive errors, the shape of your cornea or lens keeps light from bending properly.


(Nearsightedness) – Light rays focus in front of the retina


Light rays focus on more than one point


(Farsightedness) – Light rays focus behind the retina

After Lasik

Light rays focus on one point on the retina
Lasik reduces your need for glasses or contact lenses

What to expect with topoguided Lasik.

Your expectations of Lasik should be realistic. Lasik allows people to do most of their everyday tasks without corrective lenses. However, there is still a chance you might need to wear glasses for certain activities, such as reading or driving at night. Your ophthalmologist will thoroughly examine your eyes and make sure you are a candidate for Lasik. He will make sure that you do not have eye diseases. For example, if you have dry eyes, they may be worse after Lasik. He will also measure the size of your pupil. If your pupil is very large, you could see halos (rings of light) at night after Lasik.

1. Measure and map the surface of your cornea

Your ophthalmologist will check the thickness of your cornea and take a detailed scan of the cornea’s surface. Your eye surgeon uses these measurements to program the computer-based laser used during surgery. During the procedure your eye will be numbed with eye drops. Your eye surgeon will place an eyelid holder on your eye to keep you from blinking.

2. Making the flap

Your eye surgeon will place a suction ring on your eye to keep it from moving. You will feel pressure like a finger pressing firmly on your eyelid. At this point, your vision will go dim or black. Blade-less Lasik involves a femto-second laser that creates millions of micron-sized bubbles at pre-determined positions inside the cornea that gently separate the layers of corneal tissue.

3. Lifting the flap

After the laser has fashioned the flap with the desired depth, size, orientation and position, the eye surgeon lifts and folds the flap back. Like opening a book.

4. Reshaping the cornea

You will be asked to stare at a light so that your eye does not move. Accurately targeted excimer laser pulses permanently reshape the exposed area. Complex mathematical algorithms guide the laser to remove microscopic amounts of corneal tissue at pre-determined positions on the cornea to correct its overall curvature, and in turn correct the refractive error.

5. Replacing the flap

After reshaping the cornea, your ophthalmologist folds the flap back down into position and smoothens the edges. The flap attaches on its own in minutes, where it will heal in place. The ophthalmologist will place a see-through shield over your eye. You should plan to go home and take a nap or just relax after the surgery. For a few hours, your eyes may feel scratchy or feel like they are burning. You will be given special eye drops.

6. Vision after Lasik

Statistically about 9 out of 10 people (90%) who have Lasik end up with vision between 20/20 and 20/40-without glasses or contact lenses. It is important to know that Lasikcannot prevent presbyopia. This is the normal, age-related loss of close-up vision. With or without refractive surgery, almost everyone who has excellent distance vision will need reading glasses after around age 40. There are refractive surgery options for presbyopia.

What if I cannot have Lasik?

Unfortunately everyone is not a good candidate for Lasik surgery. To qualify for Lasik there are certain requirements.

– You should be 18 years or older
– Your eye prescription should not have changed in the last year
– You need to be nearsighted, farsighted, and/or have astigmatism.
– Be aware of the cost of the surgery, as your medical insurance does not necessarily cover the expense.

Some people are not candidates for Lasik. They include people with:
– an unstable (changing) refractive error
– extreme levels of myopia, hyperopia or astigmatism
– severe dry eye
– corneas that are too thin or corneal disease advanced glaucoma
– other eye disease affecting vision
– a history of having certain eye infections
– diabetes that is not controlled well
– pregnant or nursing women

Your ophthalmologist could suggest other refractive procedures if you do not qualify to have Lasik. Photo refractive keratectomy and secondary lens implantation are two other options.

What are the risks of Lasik?

Most patients have side effects after Lasik that usually go away over time. However, in rare cases, they may not go away. For example, almost everyone who has Lasik will have dry eyes and changing vision during the day. These symptoms usually fade within a month. For some people, though, they may take longer to disappear or they may remain.

Side effects that are usually temporary:
• eye pain or discomfort (usually for the first 12 hours after surgery)
• scratchy eye
• small pink or red patches of blood on the white of the eye that go away in about 10 days

Side effects that usually improve in the first 3 months but can be permanent to some degree:
• hazy, foggy or blurry vision that fluctuates
• glare
• halos (rings) or starbursts around lights
• being sensitive to light

Other rare risks include:
• Eye infection. Remember research tells us that contact lenses are not always a safer choice than Lasik surgery. Both contact lenses and Lasik are very safe, although there is a small risk of complications from both of them
• Worse vision than before Lasik, even with glasses or contacts (called loss of best-corrected vision). In a study at Casey eye institute over 10 years and 18000 procedures no patient lost more a small amount (2 lines) of vision

Also, with Lasik, your vision may end up being under-corrected or over-corrected. These problems often can be improved with top up Lasik, glasses or contact lenses. Many surgeons offer top up Lasik free of charge for their patients.

You may not want to have refractive surgery if you are happy wearing contacts or glasses. Together, you and your ophthalmologist can weigh the risks and benefits of Lasik.