Dr. Zoran Aleksic performs Laser Refractive Eye Surgery (Laser Vision Correction) in Cape Town, South Africa.
Everybody has the desire for clear, crisp, sharply focused vision. Many people, however, do not have perfect vision; they are either nearsighted, farsighted, or have astigmatism. These common eye conditions are called refractive errors. An eye surgeon can correct these by using a laser to reshape the cornea so that light is properly focused onto the retina to achieve improved vision without glasses and contact lenses.
We perform two methods of Laser Eye Surgery: 1) LASIK, which stands for laser in-situ keratomileusis, is surgery used to correct the vision of patients who are nearsighted, farsighted or have astigmatism. All laser vision correction surgeries work by reshaping the cornea, the clear front part of the eye, so that light traveling through it is properly focused onto the retina located in the back of the eye. 2) Laser epithelial keratomileusis, or LASEK, combines benefits of the two most commonly performed procedures — LASIK and PRK. LASEK eye surgery is used to treat astigmatism, nearsightedness or farsightedness. We may recommend LASEK surgery if you have thinner corneas.
Learn more about refractive eye conditions & Laser Eye Surgery below.
Short-sightedness (Myopia) is caused by an imbalance between the curvature of the cornea (the front window of the eye) and the focal length of the eye which is too long. With short-sightedness, near vision is better than far vision. Excimer laser works by shaving a microscopic tissue layer off the front of the cornea. This flattens the curvature of the cornea and thus corrects the focus.
NORMAL EYE
EYE WITH MYOPIA
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THE LONG EYE / SHORT-SIGHTEDNESS (MYOPIA)
THE OVAL EYE / ASTIGMATISM
Astigmatism is commonly associated with shortsightedness. With astigmatism the eye is not perfectly round, the curvature from the top to bottom is different to the curvature from side to side – much like the shape of a rugby ball. The shape is corrected with the laser.
HEALTHY EYE
EYE WITH ASTIGMATISM
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Farsightedness is caused by the eye being too short. With farsightedness both distance and near vision are not in perfect focus.
HEALTHY EYE
EYE WITH HYPEROPIA
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THE SHORT EYE / FAR-SIGHTEDNESS (HYPEROPIA)
WAVEFRONT OPTIMIZED LASER SURGERY
The WaveLight EX500 is the fastest growing laser system both in Europe and the USA and is soon expected to overtake the older systems as the laser chosen by most laser specialists. Our eye surgery facility upgraded to the WaveLight EX500, making it the most up-to-date laser in Southern Africa at the time of writing. We are committed to keeping our practice at the leading edge of technology.
Older laser systems correct shortsightedness and astigmatism in the same way as spectacles and contact lenses. Technology now allows the measurement of Higher Order Aberration. These are additional irregularities of the corneal shape that cannot be measured with conventional glasses testing. Higher Order Aberration (HOA) is measured in two ways. Wavefront analysis looks at the way light reflected off the retina passes through the lens and cornea to detect errors in the focus. Scheimpflug imaging uses a rotating camera to create 3-Dimensional maps of the cornea to detect shape irregularities.
When treating the cornea, Scheimpflug imaging has the advantage that it measures only the cornea and is not influenced by irregularities of the lens, unlike wavefront analysis which is influenced by the lens.
The most important HOA is spherical aberration, which is a mismatch between the curvature at the centre of the cornea and the curvature at periphery of the cornea. Older lasers tend to cause spherical aberration by flattening the centre of the cornea more than the peripheral cornea, this can affect the quality of vision and affect night vision. The Allegretto Wavelight system uses Scheimpflug imaging to analyse the corneal shape for irregularities. A small percentage of patients will require a customised ablation to correct these irregularities. Unlike most other lasers, the Allegretto Wavelight does a standard wavefront optimized ablation on all patients. This reduces spherical aberration and is believed to account for the superior results. This is widely considered to be the treatment of choice and is leading the development of this technology.
RESULTS OF LASER SURGERY
LASIK is a quick and painless procedure that takes about 30 minutes for treatment of both eyes. The procedure is done with local anaesthetic; we might use a mild sedative if you feel nervous. The vision will be blurred and your eyes will be scratchy for a few hours after treatment. You will need someone to drive you home after surgery. The majority of patients are able to drive the next day and can go back to work within 48 hours. Some precautions are necessary after surgery. You will wear protective shields for the first 2 nights, you may not swim or wear make-up for the first week and will not be able to do contact sports for one month.
The majority of patients will have 20/20 vision after surgery without glasses. Less than 5% of patients do not achieve full correction with the first treatment and a second treatment is needed – there are no additional costs for the second treatment. Patients over the age of 45 years will need reading glasses after treatment – usually standard off-the-shelf readers. As we get older the natural lens of the eye loses its ability to flex and change focus from distance to near - an ageing change called presbyopia. Laser treatment primarily corrects distance vision. Younger patients can see both far and near after surgery, but for patients over the age of 45, readers are needed.
Minor side effects may include a deterioration of night vision and haloes around lights at night in some patients. These effects are mild and improve after 3-6 months. Patients may have slightly dry and scratchy eyes and lubricant drops are routinely used during the first month. The risks of serious side effects such as infection, scarring or distortion of the shape of the cornea are extremely low. LASIK is one of the safest and most commonly performed surgical procedures of this decade.
HOW IT WORKS
Correcting focus errors with laser surgery:
Before surgery, detailed measurements are done on the focus of the eye and shape of the cornea. This data is transferred to the computer that controls the laser and the optimum treatment profile is generated for the eye. The two most commonly performed laser techniques are LASIK and PRK/LASEK. Both of these treatments are done with the same laser machine and the long term results are the same.
LASIK technique involves lifting a very thin flap of tissue off the cornea (much like an onion skin). The laser treatment is performed on the exposed corneal tissue, after which the flap is put back into position. LASIK has the advantage that there is very little discomfort after surgery and the vision recovers very quickly.
PRK laser treatment is done directly onto the corneal surface without a flap. It takes a few days for the surface to heal and vision takes longer to recover. We may use the PRK technique if your cornea is not thick enough to do the LASIK technique. Your surgeon will advise which is the best technique for you.
