LASIK is the most popular and successful method of laser eye surgery. The all-laser LASIK technique, performed at our state-of-the-art laser center in New Jersey, is our preferred laser vision correction treatment in patients with nearsightedness, farsightedness, or astigmatism.

Dr. Hersh has been performing LASIK for over 25 years and has treated thousands of extremely satisfied patients.

In fact, he was the lead author of the clinical trial that led to the first FDA approval of the excimer laser for vision correction surgery in 1995 (click the title below), so he has some of the longest and most extensive experience in LASIK in the U.S.

Dr. Steven Greenstein trained under Dr. Hersh to perform LASIK, PRK, and other types of refractive surgery.
Results of Phase III Excimer Laser Photorefractive Keratectomy (LASIK) for Myopia

The Optical Principle of LASIK:

LASIK works like a contact lens. However, instead of putting a contact on your eye, the laser removes a thin film of tissue from the surface of the cornea (the clear, front “watch crystal” of the eye).

So, rather than putting on a contact lens, in LASIK we are removing what can be thought of as a tissue contact lens. Just like a contact lens, this focuses your vision to give you clear sight.

LASIK Eye Surgery Procedure Diagram
Illustrated side view of an eye, referring to the cornea as a tissue contact lens

How is LASIK Done:

In LASIK, a pancake-like thin flap of the cornea is first prepared with a high-speed laser called Intralase. Here at the Cornea and Laser Eye Institute – Hersh Vision Group in New Jersey, we use the all-laser technique exclusively, whereas older technology involved using an actual blade to create the flap.

The LASIK flap acts to preserve the surface epithelial cells (which are like tiles on a floor) to promote quick healing and improvement in vision. Visual recovery is typically overnight (in fact, most patients can drive and return to work the day after LASIK).

Next, the Wavelight excimer laser, using a beam of invisible ultraviolet light energy, is used to remove a small amount of tissue from the corneal surface beneath the flap.

The actual laser application takes approximately 1 minute. During the procedure, an eye-tracking mechanism makes sure that all laser spots are placed in the proper location, even if your eye inadvertently moves.

The specifications of the laser application are determined by the computer of the laser which is pre-programmed with your individualized data as determined during our measurements examination. In the topography-guided Contoura technique, your actual corneal map is also programmed directly into the laser.

After corneal reshaping, the LASIK procedure is finished when the corneal flap is repositioned. When the flap is replaced, it lies in the bed of the laser-removed tissue, causing the surface to change shape. This provides the effect of decreasing nearsightedness, farsightedness, or astigmatism.

Illustrated diagram of the LASIK eye surgery procedure steps

The LASIK Procedure:

LASIK procedures are performed here at CLEI in our laser suites. The entire process takes approximately 3 hours. During the first hour, we take more tests to confirm our previous measurements.

The procedure is performed in two steps and is entirely comfortable. You will be given an eye drop anesthetic to numb the eye and also a mild sedative to relax you.

In the first step to create the LASIK flap, a lid retainer supports your lids to avoid blinking during the procedure. You will be looking up at a microscope light and the actual laser treatment will take around 1 minute. After a short break, the Wavelight laser will be used to reshape the cornea.

Your surgeon, Dr. Hersh or Dr. Greenstein, will move the LASIK flap into position and you will be asked to look at a green flashing light in the laser microscope. A video eye-tracking mechanism compensates for any eye movements for added safety. The actual laser application will again take around 1 minute.

At the end of the LASIK procedure, the LASIK flap is repositioned with fluid.  Eyedrops to avoid infection and control inflammation are applied and will be used for one week.

Photo of a woman's face as she receives LASIK surgery

You are generally comfortable after the LASIK procedure. There may be some stinging for a few hours afterward. Vision usually begins to improve by the next morning.

Most people can work the next day; however, you will be seen in the office for an examination on that day.

The Accuracy of LASIK:

In general, more than 95% of patients achieve clear vision as they had with their contact lenses and glasses. In approximately 1 in 20 patients, based on individual healing responses, the entire refractive error may not be corrected or that there might be some over-correction.

If under-corrected, your vision will be clearer without glasses, but less powerful glasses may still be necessary to fine-tune to your best vision. For patients who are over-corrected, especially those patients who are somewhat older, reading vision might be difficult without glasses.

In these cases where vision is not optimal, we typically will consider a touch-up treatment 3 months after the original LASIK procedure to further improve vision.

Side Effects and Complications of LASIK:

There are 2 generally seen side effects immediately after LASIK. First, your eyes may feel dry. Typically, these sensations are mild and are treated with artificial tear drops and resolve over several weeks.  However, dry eye sensations can last in some patients. Second, you will notice a glare/halo around lights at night early after the procedure.

These, too, tend to resolve over the first few days or weeks after the procedure. They can last in a few patients; normally these symptoms can be helped with re-treatment if necessary. Furthermore, older patients, 40 years and older, may require reading glasses after the procedure.

There are also more severe complications that can occur with LASIK, as with all eye surgeries. These will be discussed in depth before your procedure.

Rest assured, though, today’s LASIK procedures at the Cornea and Laser Eye Institute in New Jersey are very safe and we do everything to safeguard your outcome from preoperative analysis to meticulous surgery, to careful postoperative care.


Illustration of an eye undergoing LASIK surgeryWe will discuss the expectations for your personal outcome in particular, and what you may reasonably expect to achieve with your vision.

In general, most patients achieved an excellent outcome, although around 5% of patients will undergo a re-treatment enhancement procedure to further improve vision if it is not clear after 3 months.

In addition, other optical side effects include halos around lights and glare, especially at night. Typically, these are early symptoms and improve over time.

These side effects have been much improved with the new Wavelight LASIK procedure. The other group of relatively rare complications may be secondary to problems with the LASIK surgery itself, subsequent corneal healing, and infection. We will discuss these possibilities in detail.

Although most excimer laser treatments today are done with the LASIK technique, some people may be better off with the surface PRK/LASEK procedure. Our preoperative examination and measurements determine our recommendation of the procedure which would be best in your particular situation.

In general, possible benefits of LASIK as compared with LASEK/PRK:

  • Tissue removal beneath a flap rather than at the surface preserves the surface corneal cells (epithelium) with the advantage of faster visual recovery
  • Postoperative discomfort is reduced
  • Tissue removal beneath a flap may decrease the risk of haze or scarring
  • Retreatments are easier to perform

Some risks of LASIK as compared with LASEK/PRK include:

  • Surgical risks (these are rarer with surgeons experienced in LASIK)
  • Damage to the corneal flap
  • Difficulties with the flap postoperatively

The Cornea and Laser Eye Institute is located in our state-of-the-art facility in Teaneck, New Jersey, an easy commute from Paramus, Morristown, Bedminster, and Princeton, and is the preferred destination for LASIK patients across the bridge in Manhattan, New York City.

We are conveniently located 3 miles from the George Washington Bridge which makes it an easy commute from New York City.

Our NJ LASIK patients are encouraged to visit our office and have their questions answered personally. Complimentary consultations are available with Dr. Steven Greenstein so please visit our New Jersey office.  Convenient hotel accommodations are available for out-of-state and international patients.

LASIK: A Step-by-Step Surgical Approach (adapted from Dr. Hersh’s textbook Ophthalmic Surgical Procedures)


Surgical correction of natural myopia, hyperopia, and astigmatism
Select cases of postsurgical myopia, hyperopia, and astigmatism
Select cases of presbyopia management with a monovision goal


Keratoconus and forme fruste keratoconus
Collagen vascular diseases and inflammatory ocular diseases
?Herpes keratitis
Epithelial basement membrane dystrophy

Preoperative Procedure

  1. Discontinue soft contact lens wear at least 1–2 weeks and rigid contact lens wear 2–4 weeks preoperatively. Confirm the stability and regularity of corneal topography.
  2. Patients should not wear eye makeup on the day of the procedure.
  3. Treat preexisting dry eye and blepharitis. Consider nonpreserved lubricants, lid hygiene, punctual plugs, topical cyclosporine, and oral doxycycline for blepharitis.
  4. Ensure appropriate corneal thickness with an ultrasonic pachymeter.

Note: Corneal thickness minus flap thickness minus ablation depth should be > 250 μm to minimize the risk of corneal ectasia.


  • Lid speculum
  • Gentian violet marking pen (± 3 mm optical zone marker or Sinskey hook)
  • Cellulose sponges
  • Microkeratome or femtosecond laser
  • LASIK or cyclodialysis spatula
  • LASIK irrigating cannula

Operative Procedure

  1. For lasers requiring pupil dilation, administer tropicamide 1% ± phenylephrine 2.5%. Otherwise, no dilation.
  2. Prep and drape operative eye.
  3. Place lid speculum.
  4. Create a LASIK flap.

Postoperative Procedure

  1. Place protective shields or goggles until the patient is examined on postoperative day 1. Continue eye protection for 2 additional nights when sleeping.
  2. Corticosteroid drops 4 times per day for 1 week.
  3. Topical antibiotic 4 times per day for 1 week.
  4. Nonpreserved lubricants as needed.
  5. Continue dry eye/blepharitis management as needed.
  6. Explain postoperative management to patients.

Follow-up Schedule

  1. Postoperative day 1: General examination with attention to flap striae. If significant striae are present, reposition the flap in the operating room.
  2. Postoperative week 1: General examination with attention to flap, assess for any infection of diffuse lamellar keratitis
  3. Month 1
  4. Month 3 (full exam to assess the status and consider retreatment if necessary)
  5. Months 6, 12 as necessary

LASIK Complications

Intraoperative Flap Problems

  1. Short flap
  2. Thin flap
  3. Buttonhole in flap
  4. Free flap

Early Postoperative LASIK Complications

  1. Slipped flap or flap macrostriae
  2. Epithelial defects or sloughing
  3. Iris tuck by the intraocular lens

Intermediate-Term LASIK Complications

  1. Diffuse lamellar keratitis (DLK)
  2. Microbial keratitis
  3. Microstriae
  4. Epithelial ingrowth

Late-Term LASIK Complications

  1. Over- and under corrections
  2. Induced astigmatism
  3. Induced topography irregularities
  4. Corneal ectasia and keratoconus

Frequently Asked LASIK Questions

1. How should someone choose a LASIK surgeon?

First, find a doctor by getting a referral from another doctor or a patient who has had laser vision correction. Remember, you should choose a doctor, not a laser center or particular equipment (most, but not all, laser systems are equally good today).

Focus your attention on just who will be performing your surgery. In evaluating a surgeon, some important things to look for are:

  • Education and training. Look for specialty fellowship training in corneal surgery. This is an additional formal education after a doctor’s ophthalmology residency program.
  • Experience. Choose a surgeon who has done at least 1000 LASIK surgeries in his/her career, does more than 500 procedures each year, and has been doing LASIK for more than 5 years.
  • Specialization. Choose a surgeon who specializes exclusively in this type of surgery.
  • Technology. Choose a surgeon who offers a complete range of technologies including Intralase and Custom Wavefront procedures.
  • Comfort. Make sure that you are comfortable with the surgeon and staff no matter where you go for your surgery.

2. What will my vision be after the LASIK procedure?

This varies among patients depending on the degree of nearsightedness, farsightedness, and astigmatism. Most patients no longer require glasses or contact lenses after LASIK.

However, as with any surgery, each patient may get a slightly different result depending on individual factors. No surgeon can guarantee 20/20 vision.

Studies in which we have participated show that, after one procedure, 95 percent of patients, in general, achieve 20/40 or better vision (that needed to pass the driver’s test) and about 80% achieve 20/20 or better.

At CLEI, for patients with 5 diopters or less of nearsightedness, well over 90% ultimately achieve 20/20 visual acuity. In the case where vision is not as clear as you want, an enhancement procedure will be suggested.

We will discuss the anticipated outcome for your specific situation as well as your possible need for a second treatment during your LASIK measurement session.

3. Will I need glasses or contact lenses after the procedure?

Usually not. However, LASIK is designed to decrease your dependency on glasses and contact lenses, not necessarily eliminate them for all tasks. For instance, some patients may need glasses for reading, night driving, or other specific tasks. Most patients find that they can do most things without glasses or contacts after the procedure.

4. What are the possible side effects?

Possible side effects and complications will be discussed in detail with you by the doctor. As in any kind of eye surgery, there is no guarantee of success.

In general, there are four possible side effects important to consider (although, of course, others are possible). They include:

  • Undercorrections and overcorrections. Because patients respond and heal differently, it is possible that the entire refractive error may not be corrected. If you are undercorrected, your vision will be clearer without glasses, but less powerful glasses may still be necessary to fine-tune to your best vision. Some patients are overcorrected. For them, up-close vision also might be difficult without glasses.
  • Reading glasses. Some patients, especially those more than 40 years old, may need reading glasses after the procedure.
  • Glare/halo/double vision. In some instances, especially at night, a patient may notice glare from lights or “ghost” images. In some cases, the risk of this has been minimized with the Custom Cornea Wavefront technique but still may occur.
  • Haze and surface irregularity. In LASIK, cells may grow beneath the flap or there may be problems with the flap such as wrinkling. Some patients may need to undergo treatment again.

5. There seem to be a number of different procedures. What is the difference?

There are 2 portions of the procedure to think about. First, how is the eye prepared for the laser? Here there are 2 general techniques: LASIK with a corneal flap and LASEK/PRK without a flap (see FAQ #6 below). For LASIK procedures, the flap can either be prepared with the Intralase laser or with a microkeratome.

Second, how is the laser computer programmed for the treatment? Here, again, there are 2 techniques: Programming using numbers similar to an eyeglass prescription or programming using the custom wavefront measurement.

Whether the nearsighted/astigmatism input or the custom wavefront input is used, either the LASIK or LASEK/PRK procedure can be done.

The exact technique of eye preparation and laser treatment will be determined by the surgeon based on the results of your examination. Some techniques are safer with better results for some patients, whereas other techniques will be better for other patients. No procedure is the “best” for everybody.

6. What is the difference between LASIK and LASEK/PRK?

First, remember that the 2 procedures are essentially the same. There is no difference in laser used, the principles of the vision correction, or in outcomes in general.

The difference is the first step in preparing the eye for laser treatment. In LASIK, a thin flap or pancake of corneal tissue is first prepared. The laser treatment is applied beneath this flap and the flap is reapplied.

In LASEK/PRK, the surface epithelial cells are first slid to the side and the laser treatment is applied to the cornea surface directly under the cells. Sometimes the cells are preserved as a sheet and sometimes they are removed depending on your individual case.

The cells regrow and smooth in about 5 days. LASEK/PRK generally is suggested in patients with thinner corneas or other problems where we think that it will be a safer technique.

Item LASEK / PRK Eye Surgery Traditional LASIK
Pre-procedure examination Similar Similar
Procedural difference Surface epithelium removed Corneal flap prepared
Excimer laser procedure Similar Similar
Postoperative discomfort Variable Usually minimal
Visual recovery Fluctuates over 1-2 weeks Starts improving at 1 day
Possible side effects Glare/halo/ghosting Corneal haze Glare/halo/ghosting Corneal flap problems

7. Is the procedure painful?

The procedure itself is done using topical numbing drops and is not painful. There may be some scratchiness and discomfort after the procedure when the anesthesia wears off. Medications are given to minimize this discomfort.

8. How much time must I take off from work following the procedure?

This depends on your job. In general, LASIK patients can return to work either the day after the procedure or they take one day off. For those jobs in which good visual acuity in both eyes is critical, it may take several days for vision to return to a level in which you can perform your job properly.

9. How often do I return for follow-up examinations after the procedure?

In general, there are short checkups one day and around 10 days after the procedure. We then examine you at three months, and six months and one year if necessary. The examination schedule is tailored to your specific situation.

10. How long does the procedure take?

Expect to be at the center for about three hours the day of the procedure. You will be in the actual laser room for about 30 minutes.

11. How soon will I notice an improvement in my vision after the treatment?

After LASIK, visual improvement is usually noted the day after the procedure and continues for a few weeks. After LASEK/PRK, most patients start to notice a visual improvement in one day with variable vision over the first week.

12. Are the results achieved from LASIK permanent?

Based on the results of a clinical trial we published in 1998, approximately 93% of patients achieve stable improved vision 6 months after LASIK. For most patients, the visual results of LASIK appear to be permanent.

A few patients may have long term changes, but such changes are generally small compared with the original visual problem.

13. After LASIK, how will my vision be at night or in low light?

Depending on your night vision with glasses or contact lenses before LASIK, some patients will note improved night vision, others little change, and others worse night vision. Testing before LASIK can help to identify patients who may have night vision problems.

If so, the treatment plan may be modified to minimize any night vision effects, or we may decide that you are not a good candidate. If you do have night vision problems after LASIK, many resolve over time.

Night driving glasses, contact lenses, or laser retreatment may help the problem in others. Custom Cornea wavefront LASIK may help to improve night vision in some cases.

14. If I’m corrected for distance will I lose my ability to see well close up?

The need for reading glasses is age-dependent. As you get older, the natural lens in the eye becomes less flexible and less able to focus up close. LASIK is used to improve distance vision without glasses or contact lenses.

Since it is like wearing permanent contact lenses, your reading vision after LASIK will be similar to that with your contact lenses.

15. If I wear bifocals now will I still need to wear reading glasses even after LASIK?

If both eyes are corrected the best possible for distance vision, then you will still need reading glasses. In some cases, monovision, or blended vision, is used for older patients to retain some reading vision without reading glasses.

In this approach, one eye is made as good as we can for distance vision, and the other eye is tuned for reading vision.

There is one drawback to this approach. Although reading vision is retained, since the reading vision eye is not as clear for distance, overall distance clarity may not be quite as good. In such cases, glasses for driving may be necessary.

16. Will my eyes be dry after LASIK?

There may be some dryness in the first few weeks after LASIK. This is usually well controlled with artificial teardrops. In rare cases, dryness may persist. During the examination before the laser, we will check to see if you are at particular risk for a dry eye.

17. Will my insurance cover the procedure?

Although most insurance companies consider laser vision correction procedures to be elective surgery (which isn’t covered), all plans and individual policies are a little different.

If your plan does cover the procedure, we will give you the necessary codes for reimbursement.  We also offer convenient and affordable payment plans.

18. How can I find out if I am a candidate and which procedure is best for me?

You can see us for a complimentary evaluation. During this visit, the Institute’s staff will perform testing to determine if you are a good candidate and which procedure is best for you.

They will also discuss the risks and benefits at length. The findings will be reviewed with the doctor. Call (201) 883-0505 to arrange an appointment.

19. What if I live far from the Cornea and Laser Eye Institute?

We are located adjacent to a Marriott hotel and The Hampton Suites.  We can also arrange for transportation. In addition, we work closely with doctors throughout New Jersey, the United States, and overseas who would be able to perform some of your checkups closer to home.

If you have further questions, you can ask us directly at Ask Dr. Hersh

Some useful websites to further answer your questions are:


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Thank you so much Doc! When I first came to you I was 20/50 now I'm 20/10. I'm ready to have a great year!

Randy Foye
Pro Athlete, Utah Jazz #8
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My experience at The Cornea and Laser Eye Institute has been amazing. All of the staff have been helpful and courteous...

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Dr. Hersh and his staff were excellent. I was comfortable from the time I walked in until the time I left after the procedure.

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