Cataract, a clouding of the lens of the eye, is the leading cause of vision loss in people older than 55. More than half have some degree of cataract development, and more than half of people over age 80 either have a cataract or have had cataract surgery.

If you smoke, have diabetes, or have a family history of cataracts, you’re at increased risk for developing them your­self. In 2009 researchers iden­tified sev­er­al gen­e­tic mu­ta­tions that are associated with age-related cataracts. [Read more…] about Cataracts are common, but easily treatable

Laser in Situ Keratomileusis is a procedure that employs the use of a laser under a corneal flap to reshape the cornea i.e. the transparent layer covering the eye. The position under a corneal flap is referred to as ‘in situ’, while the reformation of the cornea is keratomileusis. A specialized excimer laser is used and the procedure is applied to treat refractive errors and enhance vision to do away with the need for eye lenses. Ioannis Pallikaris is widely recognized for the advancement of LASIK in 1991, although the excimer laser had been used in previous years.

The LASIK surgery is an elaborate procedure in which the surgeon first creates a corneal flap with the use of a micrkeratome. This slight flap is opened to reveal the corneal tissues, after which the cornea is restructured into a predetermined pattern that is unique for each individual using an excimer laser. The corneal flap is then replaced on the corneal tissues.

Refractive errors occur in the eye when the power of the cornea and that of the lens are not compatible with the physical length of the eye, and this surgery is used to correct these occurrences.

a)      Short-sightedness/Myopia – In these cases, the refractive error causes distant objects to appear blurry and out of focus while closer objects remain more apparent.

b)     Long-sightedness/Hyperopia – The refractive error in these cases causes objects that are close to the eye to be blurry and out of focus, while those at a distance remain clearer.

c)      Astigmatism – Thos refers t the disfiguration of either the cornea or lens shape. This results in multiple images appearing on the retina, and objects appear blurry whether they are near or far. It is common for people to have a blend of myopia or hyperopia with astigmatism.

The Effects of Spectacles and Contact Lenses

Eye lenses are employed to bend light rays in a bid to recompense for the refractive error involved. They are not corrective measures, and eye surgery is purposed to eliminate the need for such lenses.

Aging and its Effect on Vision:

When we are young, our eyes can alter their shape and power so that we can focus on close objects naturally as our eye lens changes power. With age, the lenses of our eyes stiffen and their aptitude to change shape and power is reduced, resulting in a condition referred to as presbyopia. This gives rise to the need for spectacles designed for reading, and doing other activities that require us to see objects that are nearer to the eye. While LASIK cannot be used to treat presbyopia, some other techniques can work e.g. monovision, which treats one eye to see closer objects better while the other is treated to see distant objects better.

There are many types of lasers in the realm of ophthalmology, but LASIK can only be performed using an excimer laser. There are different companies that manufacture lasers, and each has developed a specific excimer laser. In addition, there are various laser ablations, from conventional treatments to wavefront-guided laser procedures. It should be noted that a different type of laser can be used to create a LASIK flap; this is a femtosecond laser which can stand in for a microkeratome laser.

Traditional LASIK employs the ablation pattern on most lasers. This conducts treatment on the basis of a patient’s eye lens prescription by setting parameters for each individual patient. While this is an effective approach to LASIK, it can cause irregularities like glares and night vision impairment.

The use of the Wavelight laser is the basis for Wavefront-optimized LASIK, which is founded not only on the individual’s eye lens prescription, but also on the cornea’s shape and thickness. It directs laser energy to the cornea’s margins and is known to limit the problems that arise from traditional LASIK. This type of LASIK is also known as custom LASIK, and the only deviation it offers from the conventional method mentioned above is that it treats both the general refractive problem, and also considers individual abnormalities in the eye that can also be dealt with.  Irregularities are identified before the surgery and if the wavefront mapping shown noteworthy irregularities, the treatment will be adjusted to cater for them.

Some people may be better suited to undergo alternative refractive surgery other than LASIK. Some other procedures are:

a)     Advanced surface ablation (ELASA) – While the LASIK procedure demands that a corneal flap is created, some surgeries omit this flap and use the excimer laser to change the cornea’s shape. They include techniques like Epi-LASIK, epipolis laser, LASEK and others.

b)     Phakic intraocular lenses – LASIK is not an advisable procedure for people that have extreme myopia. This alternative method implants a lens in the eye to treat myopia.

Conductive keratoplasty – This technique offers an alternative and temporary solution for presbyipia and hyperioia. Radio frequency waves are directed to the margins of the cornea to cause it to shrink and steepen centrally. While this is a safe procedure, its effects are only temporary.

People with milder cases of myopia in the USA can be treated with Intacs, or Intercorneal ring segments. These are extremely slight plastic layers that are inserted into the margin of the cornea to centrally flatten it. They cannot be felt by the patient, and can be removed from the eye. In addition, the effects of Inacts can be undone. Inacts can only be used in myopic cases that are no more than -3 diopters.

Your eyes must be well examined to determine if you are fit for refractive surgery, and before you make a decision regarding eye surgery, you must consider the following factors:

–         Can I accept the risk of complications that may arise from surgery?

While complications are rare, the risk is real, and complications may have a detrimental effect on your vision.

–         Is my line of work agreeable with eye surgery?

Ensure that your employer or professional society allows you to undergo refractive surgery.

–         Do I have vision that is stable enough for this procedure?

If your eye lens prescription changes progressively and negatively, eye surgery may not be a good idea for you.

–         Am I a fit patient for surgery?

Some health conditions like autoimmune diseases have negative effects on healing process after surgery.

–         How does my lifestyle affect the viability of my candidature for surgery?

Once LASIK has been done, there is a permanent danger of the displacement of the LASIK flap. Engagement in sporting activities that introduce the chance of trauma to the eye may make it more sensible to consider alternative refractive procedures.

–         How does my age affect my candidature for LASIK?

While there are no set parameters for the age during which LASIK can be performed, people younger than 18 are often too unstable for LASIK and older individuals have eye complications e.g. Cataracts that prevent them from being viable candidates as well. An eye examination can determine whether a patient is fit for eye surgery or not.

–         Is my cornea healthy?

Keratoconus results from weakening of the cornea, and it often seen as irregular shape or curvature of the cornea. People that have keratoconus cannot safely undergo LASIK.

In conducting your eye evaluation, your doctor should look out for features that would make you anything less than an ideal contender for surgery. These include factors prior to surgery, and any findings should be discussed with you in detail. Some risk factors for refractive surgery are:

a)      High lens prescriptions – For patients with high myopia or hyperopia, LASIK is not a good idea. This is because the surgery would require the expulsion of too much corneal tissue.

b)     A thin cornea – LASIK and other laser surgery procedures demand the elimination of some corneal tissue. The thickness of your cornea is hence of great importance, and thin corneas present the danger of extreme weakening of the cornea due to this procedure.

c)      Irregular curvature of the cornea – Topographers are used to measure the shape of your cornea. Irregular curvature may be a telltale sign of a weak cornea

d)     Dry eyes – With eyes that are red or teary, LASIK may elevate the irritation and have a detrimental effect.

e)      Pupils that are larger than usual – LASIK may cause vision incongruities like halos and glares, and candidates that have large pupils are more exposed to this risk.

f)       Prior refractive surgery – Earlier refractive surgery, principally radial keratotomy, may cause difficulties in future procedures,.

Dangers Associated with LASIK

While LASIK has positively changed the lives of most patients that undergo this procedure, there are risks associated with it. Before making a decision regarding LASIK, it is important to be informed about the potential problems that may arise from this type of surgery.