WHAT IS LASER EYE SURGERY ?
Laser refractive eye surgery is a form of vision correction and involves reshaping the cornea to correct a refractive error. This occurs when the eye is abnormally shaped and can’t focus light directly on the retina at the back of the eye, resulting in out-of-focus, blurry vision. Examples of refractive error include short-sightedness (myopia), long-sightedness (hyperopia), age-related loss of near vision (presbyopia) and astigmatism. Astigmatism commonly occurs together with short- or long-sightedness.
LASIK
Laser in situ keratomileusis (LASIK) is the most common type of laser eye surgery performed. It is a suitable laser treatment for eyes with adequate corneal thickness.
LASIK is a two-step, two-laser vision correction procedure. The laser eye surgeon will have pre-programmed the two lasers to the individual requirements of the patient being treated.
An infrared eye tracker is locked in position prior to laser eye treatment. It measures eye movements during the procedure and is capable of following and actively adjusting the laser beam as tiny eye movements are detected.
Once a patient has been prepared (including being given a series of eye drops and a mild sedative), he/she will be taken into the laser eye correction suite and will lie flat on the bed.
After preparing the first eye, the surgeon will use the femtosecond laser to create a flap in the top layer of the cornea (the epithelium and stroma), exposing the tissue bed underneath. The excimer laser is then used to gently and precisely reshape this corneal tissue bed to correct the patient’s refractive error. Finally, the surgeon places the corneal flap back in its original position.
LASIK laser eye correction is painless. You may feel some pressure on the eye but no discomfort. Because the flap adheres to the corneal bed, the healing process begins immediately. The eye has a remarkable ability to heal itself and patients are able to return to most of their daily activities the next day.
ASLA/PRK
Advanced surface laser ablation (ASLA) is also known as photorefractive keratectomy or PRK. During this procedure, the laser eye doctor uses a topical solution to soften the top layer of corneal cells, allowing them to be gently removed. The excimer laser is then used to reshape the exposed corneal tissue bed to correct the patient’s refractive error. Once the procedure is complete, a ‘bandage’ contact lens is placed on top of the eye for 4 days to aid the healing process.
ASLA is generally the procedure of choice for patients who have thin or unusual corneas.
Monovision/blended vision
During this procedure, the laser eye doctor will correct one eye (usually the dominant one) for distance vision and the other eye for reading/near vision. When looking into the distance, your brain pays more attention to the eye that is focused for distance and vice versa when looking at close objects (i.e. your brain relies more on the eye that is focused for near distance). Overall, the images from both eyes are processed by your brain as one blended image.
Many people who have monovision find that they adjust within a matter of days and many can minimise their use of glasses. Before proceeding with surgery, your ophthalmologist will usually get you to trial a set of contact lenses to make sure you can adapt to the change.
Monovision can be achieved using laser eye surgery (e.g. LASIK or ASLA) or artificial lenses (e.g. replacement lenses or implantable phakic lenses.
What to expect on the day of surgery
Immediately before your procedure, you will receive anaesthetic (numbing) eye drops and anti-inflammatory eye drops. Patients can also choose to have a sedative to help them relax. After allowing the sedative to take effect (around 30 to 45 mins), you will be taken into the procedure room and asked to lie down on a surgical bed. The procedure itself will vary depending on which type of surgery is being performed (e.g. whether one or two lasers are used).
If you have had a sedative, you will be given time to recover before being discharged. You will also be given protective glasses and eye drops to go home with. A follow-up appointment for later that same day or the next day will be scheduled before you leave.
You can expect to be in the laser suite for between 10 to 20 minutes (depending on the type of procedure), and in the day surgery for approximately 2 hours.
Reference :
Vision Eye Institute
