LASIk Self-Evaluation Test
LASIk Self-Evaluation Test
Ask Dr. Hersh
Hear From Our Patients LASIK
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Hear From Our Patients LASIK
LASIK Laser Eye Surgery New Jersey
The Most Advanced LASIK Technology
Laser in situ keratomileusis (LASIK) is the most popular and successful method of laser eye surgery. LASIK uses an excimer laser to correct nearsightedness, farsightedness, or astigmatism by removing a thin lenslet of tissue from the surface of the cornea (the clear, front "watch crystal" of the eye). This is analogous to removal of a "tissue contact lens". Dr. Hersh has been performing LASIK for over 20 years.
In LASIK, a pancake-like thin flap of the cornea is first prepared with a high speed femtosecond laser called Intralase. Unlike many other practices, here at the Cornea and Laser Eye Institute - Hersh Vision Group, we use the all-laser technique exclusively. The flap acts to preserve the surface epithelial cells (which are like tiles on a floor) to promote quick healing and recovery of vision (most patients can drive and return to work the day after LASIK). Next, the Wavelight excimer laser is used to remove a small amount of tissue from the corneal surface beneath the flap. The excimer laser used in LASIK produces a beam of invisible ultraviolet light energy, which when applied via an eye tracking mechanism, results in meticulous removal of this "tissue contact lens".
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 excimer laser removed tissue, causing the surface to change shape with the effect of decreasing nearsightedness, farsightedness, or astigmatism.
LASIK procedures are performed under eyedrop anesthesia and are not painful. A lid retainer supports your lids to avoid blinking during the procedure and a video eye tracking mechanism compensates for any eye movements. At the end of LASIK, clear protective eye goggles are placed. Eyedrops to avoid infection and control inflammation are used for one week, in addition to artificial tear drops.
You are generally comfortable after the LASIK procedure. There may be some stinging for a few hours afterwards. 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.
There are two basic types of possible side effects with LASIK. Because patients may respond and heal differently, it is possible that the entire refractive error may not be corrected or that there might be some overcorrection. If undercorrected, your vision will be clearer without glasses, but less powerful glasses may still be necessary to fine tune to your best vision. For some patients who are overcorrected, especially those patients who are somewhat older, reading vision might be difficult without glasses. Furthermore, older patients, 40 years and older, may require reading glasses after the procedure. Patients who do not achieve full correction usually can undergo a retreatment procedure to further improve their vision. These retreatment procedures, if necessary, are usually done after the 3 month visit.
The following animations demonstrate the 2 parts of the all-laser LASIK procedure: Laser flap creation and Wavelight correction of nearsightedness, farsightedness, or astigmatism. (Click on icon to right to choose video).
We will discuss the expectations for your personal outcome in particular, and what you may reasonably expect to achieve with your vision. In general, around 5% of patients will undergo a retreatment enhancement procedure to further improve vision if it is not clear after 3 months. In addition, other optical side effects include haloes 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 LASEK/PRK 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
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 a beautiful facility in Teaneck, New Jersey, an easy commute from Paramus, Morristown, and Princeton, and is the preferred destination for LASIK patients across the bridge in Manhattan, New York City. Our NJ LASIK patients are encouraged to visit our office and have their questions answered personally.
In depth articles and studies:
In the news:
Should bilateral LASIK be performed sequentially or simultaneously? - January 1, 2000
Re-treatment requires forceps to maintain clear interface, avoid flap damage - February 1, 2000
Tracking trends in LASIK enhancement - March 1, 2000
When two refractive surgeries are better than one - May 1, 2000
At Issue: LASIK enhancement preferences - February 15, 2002
At Issue: Refractive procedures in 2010 - December 15, 2002
At Issue: Lens exchange vs. corneal refractive surgery - June 15, 2004
What are practical applications to civilian refractive surgery from extensive military refractive results, and how could civilian surgeons incorporate those applications into practice? - March 25, 2010
|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 flap problems
LASIK: A Step-by-Step Surgical Approach (adapted from Dr Hersh's textbook, Opthalmic Surgical Procedures)
Laser in Situ Keratomileusis (LASIK)
■ 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
1. Discontinue soft contact lens wear at least 1–2 weeks and rigid contact lens wear 2–4 weeks preoperatively. Confirm stability and regularity of corneal topography.
2. Patient should not wear eye makeup on day of 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 ultrasonic pachymeter.
Note: Corneal thickness minus flap thickness minus ablation depth should be > 250 μm to minimize 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
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 LASIK flap.
For mechanical microkeratomes:
i. Choose proper ring size and nominal thickness of microkeratome head, depending on corneal thickness, keratometric steepness, corneal width, and expected ablation depth.
ii. Optional: Premark cornea at anticipated junction of flap and cornea using 3 mm optical zone marker and gentian violet in two or three positions.
iii. Place suction ring, centered on patient’s pupil or geometric center of cornea.
iv. Engage suction.
v. Ensure proper suction pressure with handheld tonometer.
For translational microkeratomes, ensure full engagement of head on ring. For rotational microkeratomes, ensure engagement of head on vertical post.
vii. Ensure there are no impediments to the translational path of the microkeratome head.
viii.Engage foot pedal for complete microkeratome pass.
ix. Reverse microkeratome pass.
x. Discontinue suction.
xi. Remove microkeratome assembly from cornea.
For femtosecond laser flap creation:
i. Choose flap diameter and thickness, hinge width, and side cut angle. Typical settings:
(a) Diameter: 8.5–9 mm.
(b) Flap thickness: 100–120 μm.
(c) Hinge width: 45–55 degrees.
(d) Side cut angle: 70 degrees.
ii. Confirm energy settings.
iii. Choose hinge placement (superior, nasal, temporal).
iv. Optional: Mark cornea over pupil center with 3 mm OZ marker or Sinskey hook impregnated with gentian violet.
v. Place suction ring centered on pupil.
vii. Dock applanation cone into suction ring.
I. Maintain centration.
II. Ensure size of meniscus is larger than flap width.
viii.Perform laser application.
5. Lift LASIK flap with LASIK or cyclodialysis spatula (Fig. 22.1). For laser flap procedures, use cyclodialysis spatula to break flap adhesions.
a. Enter edge of dissection with spatula near hinge.
b. Release flap edge using edge of spatula or Sinsky hook starting from hinge and proceeding around edge for ~180–270 degrees.
c. Advance spatula across cornea at hinge.
d. Sweep approximately one third to one half of cornea from hinge to opposite end of flap.
e. Repeat spatula entry at hinge and sweep gently to break all lamellar and edge adhesions.
6. Retract flap and place on moistened section of cellulose sponge (Fig. 22.2).
a. Perform intraocular pachymetry to ensure postoperative corneal bed will be > 250 μm to minimize risk of corneal ectasia.
b. May perform “bubble” pachymetry before lifting flap in laser-flap procedures.
8. Gently wipe bed with cellulose sponge to remove residual fluids.
9. Engage laser eye tracker and align laser as necessary
a. Alignment technique varies with laser platform.
b. Center over pupil.
10. Encourage patient to maintain gaze at fixation target.
11. Perform laser ablation with laser focused at corneal plane.
12. Replace flap.
a. Use irrigating cannula or spatula.
b. Float flap into proper position usdest irrigation.
c. Align gutter with preplaced gentian violet positioning marks (Fig. 22.3)
d. Ensure there are no flap sriae or interface debris. Irrigate, reposition, or gently
smooth with spatula as necessary.
13. Administer corticosteroid and antibiotic drops.
14. Administer nonpreserved lubricant.
15. Remove lid speculum carefully so as not to disrupt flap position.
1. Place protective shields or goggles until 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 patient.
1. Postoperative day 1: General examination with attention to flap striae. If significant striae are present, reposition flap in 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 status and consider retreatment if necessary)
5. Months 6, 12 as necessary
Intraoperative Flap Problems
1. Short flap
2. Thin flap
3. Buttonhole in flap
4. Free flap
Early Postoperative Complications
1. Slipped flap or flap macrostriae
2. Epithelial defects or sloughing
3. Iris tuck by the intraocular lens
1. Diffuse lamellar keratitis (DLK)
2. Microbial keratitis
4. Epithelial ingrowth
1. Over- and undercorrections
2. Induced astigmatism
3. Induced topography irregularities
4. Corneal ectasia and keratoconus