Lasic Surgery

Understanding How LASIK Works

If you wear lenses or spectacles, then your ophthalmologist has most probably informed you about LASIK. In fact, if you’re reading this article, you’re probably considering the surgery but are just not very sure. You’ve probably heard of LASIK as:
• a fast and painless surgery
• the best alternative to contact lenses and spectacles, or even,
• a one-time corrective surgery for perfect vision
While all of this is true, there is a lot more to LASIK surgery that you need to know before you decide to go through with it. And you’ve come to the right place. This website will provide you with all the information you need on LASIK and will explain to you in easy terms what LASIK does, whether you require it, and what you need to be aware of if you decide to go under the laser.

How do we see?

LASIK is a surgery that corrects refractive errors, much like your spectacles or lenses. In order to understand the surgery, you need to first understand how you see. You see an object, when light rays reflected by the object enter the cornea or the outermost layer of your eye. The cornea then bends (refracts) the light rays in order to focus them on the retina of your eye. The retina is a tissue lining the back of the eye ball. The rays form an image on the retina. A refractive error occurs when there is a flaw in the shape of the cornea and it cannot focus the rays properly on the retina creating a blurred image. Spectacles, contact lenses as well as LASIK surgery, correct this error, in different ways. In LASIK it is done by surgically reshaping the cornea.

How LASIK works

LASIK is the abbreviation of Laser-Assisted In situ Keratomileusis. Imagine viewing a cross-section of your eye, seeing the layers front to back. During LASIK, a blade device called the microkeratome or a laser device called a laser keratome is used to cut a hinged flap in the cornea. This flap is folded back revealing the middle layer of the cornea called the stroma. Parts of the stroma are then vaporized with what is known as an excimer laser in order to reshape it. (The surgeon will know beforehand how much reshaping is required) The flap is then placed back on the cornea and allowed to heal. The entire procedure takes no more than 20 minutes.

Frequently Used Terms Related to Eye Surgery

While talking to your ophthalmologist about LASIK, you are bound to get confused by certain terms he uses. Most terms you will understand while reading the explanations in the later sections. The following guide will get you familiar with others that might not appear in the explanation but you might come across when discussing LASIK with your doctor.

Ablate – in surgery, is to remove.

Acuity – clarity or sharpness of vision.

Astigmatism – a distortion of the image on the retina caused by irregularities in the cornea or lens.

Endothelium – the inner layer of cells on the inside surface of the cornea.

Epithelium – the outermost layer of cells of the cornea and the eye’s first defense against infection.

Excimer laser – an ultraviolet laser used in refractive surgery to remove corneal tissue.

Hyperopia – the inability to see near objects as clearly as distant objects, and the need for accommodation to see distant objects clearly.

In Situ – a Latin term meaning “in place” or not removed.

Keratomileusis – carving of the cornea to reshape it.

Laser – the acronym for light amplification by stimulated emission of radiation. A laser is an instrument that produces a powerful beam of light that can vaporize tissue.

Myopia – the inability to see distant objects as clearly as near objects.

Ophthalmologist – a medical doctor specializing in the diagnosis and medical or surgical treatment of visual disorders and eye disease.

Optician – an expert in the art and science of making and fitting glasses and may also dispense contact lenses.

Optometrist – a primary eye care provider who diagnoses, manages, and treats disorders of the visual system and eye diseases.

Pupil – a hole in the center of the iris that changes size in response to changes in lighting. It gets larger in dim lighting conditions and gets smaller in brighter lighting conditions.

PRK – the acronym for photorefractive keratectomy which is a procedure involving the removal of the surface layer of the cornea (epithelium) by gentle scraping and use of a computer-controlled excimer laser to reshape the stroma.

Radial Keratotomy – commonly referred to as RK; a surgical procedure designed to correct myopia (nearsightedness) by flattening the cornea using radial cuts.

Refractive Power – the ability of an object, such as the eye, to bend light as light passes through it.

LASIK – What are the Risks Involved?

The risks related to LASIK are not so much due to flaws in technology, as due to inefficiency in handling the technology. The risks are results or consequences when surgeons do not administer the treatment well and patients do not choose surgeons well. If the procedure is carried out as it should be, it is close to perfect, and patients will not develop any permanent damage. However, in the rare case that you’re not sure of your surgeon’s credentials, it will help to know what you stand to lose. This section deals with what might go wrong with LASIK surgery for various reasons.

Symptoms like halos, glares or double vision that hamper vision during night-time or in fog are developed with some patients. Not all patients attain perfect 20/20 vision – many still need glasses after surgery or require additional treatment. Some patients develop permanent dry eyes that cause much discomfort and blurring of images. Many complications arise due to flawed cutting of the flap. Some common complications are:

Irregular astigmatism: Develops when laser correction is not centered properly on the eye, causing one to see double images.

Diffuse Lamellar Keratitis: Occurs when foreign matter gets collected beneath the corneal flap causing inflammation that at times can lead to scarring. In rare cases there might be permanent vision loss if treatment is not sought immediately.

At times the corneal flap is cut too deeply or too much tissue is removed from the cornea. This condition is called keratectasia or keratoconus. It results in distorted images that cannot be corrected with further laser treatments. Rigid contact lenses or implants are then used to hold the cornea in place.

Dry Eyes are a very common symptom that occurs for about 6 months to a year after the surgery. Artificial tear drops and prescription dry eye medication can provide some relief in this case. The symptom very rarely becomes permanent, unless the patient has been suffering from this condition prior to the surgery. Such patients are however, eliminated as candidates for surgeries.

At times, due to carelessness on the surgeon’s part, you might be overcorrected or under corrected leading to less than optimal vision. This happens when the diagnosis is incorrect or when the specifications are not accurately programmed into the software guiding the laser.

Patients at times develop eye infections, irritation and inflammation requiring antibiotic eye drops and anti inflammatory medication. Such infections happen particularly when the blade device (microkeratome) is used to cut the flap as opposed to the laser keratome.

Is LASIK Surgery the Right Choice for You?

Although your ophthalmologist will tell you if you’re a candidate for LASIK, there are certain criteria you must consider yourself apart from the doctor’s suggestions. The decision to opt for LASIK surgery must be based on three factors: Your requirements, medical history, and financial condition.

Requirements: If you wear lenses or spectacles on a very irregular basis, and can manage fine even without them, you might want to reconsider spending so much on LASIK. Same if you are over 40 years of age, since vision more or less tends to deteriorate around this age, with or without LASIK. Keep in mind that post-operation you will not be able to play sports that involve direct contact with the face for 6 months to a year. If you’re a professional, taking a year off might not be very easy.

Medical History: This is by far the most important factor in deciding if LASIK is for you. Your doctor must examine your medical history in detail particularly for the following:
• Herpes simplex or Herpes zoster (shingles) involving the eye area.
• Glaucoma, glaucoma suspect, or ocular hypertension.
• Eye diseases, such as uveitis/iritis (inflammations of the eye)
• Eye injuries or previous eye surgeries.
• Inflammation of the eyelids with crusting of the eyelashes, known as Belaphritis that may increase the risk of infection or inflammation of the cornea after LASIK.
• If you have large pupils, then you are susceptible to symptoms such as glare, halos, starbursts, and ghost images (double vision) after surgery. Post surgery, some patients with large pupils develop debilitating symptoms like not being able to drive at night or in fog.
• Thin Cornea: Performing LASIK that involves reshaping on a cornea that is too thin may result in blinding complications.
• Previous refractive surgery (e.g., RK, PRK, LASIK). If you decide to go in for additional refractive surgery, then you must carefully take into consideration your situation after consultation with multiple surgeons, if required

Financial Condition: Take a realistic view of your current financial conditions, the cost you incur on contact lenses and/or spectacles and what you will incur if you opt for LASIK. While calculating the cost of LASIK surgery, include the preoperative and post operative expenses as well as what you might incur to correct any mistakes that might happen during the procedure.

What You Need to Know About Pre-Operative LASIK Care

Although LASIK surgery is painless, fast and takes very little time for recovery, it is still not suitable for everyone. In order to determine your suitability your ophthalmologist will first examine your eyes to determine their health, what kind of vision correction you need and how much ablation is required. He will also check for dry eyes symptom and correct it before the surgery. The doctor will also use a corneal topographer to ‘photograph’ and create a map of your eyes. If you opt for wavefront LASIK, you are also likely to undergo wavefront analysis, which sends light waves through your eyes to create a better, more precise map of aberrations affecting your vision.

There are certain precautions you will need to observe before the surgery. Mainly you will have to stop wearing contact lenses for some weeks before your first evaluation. Contact lenses alter the shape of the cornea considerably for over a few weeks after you have stopped wearing them. This will cause improper measurements of your cornea while evaluation and a flawed surgical plan which will have disastrous impacts on the surgery. Typically if you wear:
• soft contact lenses, you should stop wearing them for 2 weeks before your initial evaluation.
• toric soft lenses or rigid gas permeable (RGP) lenses, you should stop wearing them for at least 3 weeks before your initial evaluation.
• hard lenses, you should stop wearing them for at least 4 weeks before your initial evaluation.

Be sure to inform your doctor of any medications that you might be taking, and medications you might be allergic to. Stop using any perfumes, creams, lotions or eye make-up the day before surgery as their particles collected in the eyelashes can cause infection after the surgery. It is also advisable to arrange for transportation to and from the clinic on the day of surgery, since there is bound to be some discomfort immediately after the surgery.

Ensure that you have a frank discussion and clarify all doubts with your doctor or surgeon. Do not hesitate to ask any questions. Look up additional information on the internet (like this website) or medical journal. Always remember to take the opinion of more than one doctor. While filling up the consent form do read the fine print and ensure you understand what you are agreeing to. It is important that you do not feel pressurized by anyone while making the decision to undergo surgery.

How to Care for Your Eyes Post LASIK Surgery

Along with preoperative, post operative care is also important to ensure success of the surgery. You doctor will obviously provide you with all the instructions required, but it will only help if you know beforehand.

There is bound to be some discomfort and you will face the following symptoms:
• Mild pain, irritation and itching for a few days after operation
• Blurry or hazy vision and sensitivity to light for about a week after the operation
• Halos, glares, starburst are also quite normal for up to 4 weeks after surgery.
• Fluctuations in vision for up to six months after surgery.

In some cases your doctor might prescribe a pain reliever to give you some relief. It is important that you do not scratch or rub your eye as this will damage the flap and not allow it to heal. It is obvious that you might not be able to go to work and your routine will also get disrupted. During this time, it is advisable to have help at home and preferably get someone to drop and pick you up from the clinic.

If your symptoms get worse instead of better you need to visit your doctor immediately without waiting for the scheduled visit. Regardless of your symptoms, you must visit your doctor within 24 to 48 hours of the surgery.

Your eye will be quite sensitive for a few months after the surgery, and is susceptible to much damage by any strenuous activity. Hence it is imperative that you do not:

• Indulge in any kind of sport for 3 weeks after surgery
• Indulge in any strenuous or contact sports (sport that involves direct contact with face) for 4 weeks
• Indulge in swimming or use a whirlpool or hot tub for 8 weeks
• Use make-up, creams or lotions around the eye for about two weeks after surgery

It is important to realize that vision stabilization will take a few months, and during this period halos and glares will persist. Hence you need to wait for at least six months before going in for enhancement surgery. Also note that although enhancement surgery will improve vision, it is unlikely that symptoms of glares and halos will improve. Another point is that the FDA does not conclusively state the safety or guarantee of any enhancement surgery.