Laser surgery is performed in a doctor’s office or eye clinic. Before the surgery, Dr Aleksic will: Dilate your pupil and apply drops to numb your eye. In some case, the doctor also may numb the area behind the eye to prevent any discomfort. The lights in the office will be dim. As you sit facing the laser machine, your doctor will hold a special lens to your eye. During the procedure, you may see flashes of light. These flashes may eventually create a stinging sensation that may make you feel a little uncomfortable.
The long eye / Short-sightedness (Myopia)
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 then far vision. Excimer laser works by shaving a microscopic tissue layer off the front to the cornea. This flattens the curvature of the cornea and thus corrects the focus.
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.
The short eye / Far-sightedness (Hyperopia)
Farsightedness is caused by the eye being too short. With far sightedness both distance and near vision are not in perfect focus. Near vision is worse then far ( this is the opposite of short-sightedness).
Visit the American Academy of Ophthalmology website | European Cataract and Refractive Surgery Society Website
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 Cape Town Laser Vision 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 CT Laser Vison 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 don’t 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 aging change called presbyopia. Laser treatment primarily corrects distance vision. Younger patients can see both far and near after surgery but 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.
Some facts about LASIK with WaveLight technology:
93% of nearsighted patients see 20/20 or better.
92% of patients described their vision as “good” or “excellent.”
3/4 of nearsighted patients actually see better than 20/20!
For more detailed and technical info please visit www.myoptilasik.com, the official website of Allegretto WaveLight.
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. 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.
For more information please visit the video information page.