The problem with spectacles
Whenever the light focusing system in front of the eye (mainly the cornea, also the lens) produces an image either in front of (myopic or shortsighted) or behind (hyperopic or longsighted) the retina, vision is blurred and some additional focusing system such as spectacles or contact lenses are necessary to shift the focus onto the retina.
The further the image is from the retina, the thicker the spectacles (or contact lenses) must be to achieve this focus on the retina and therefore clear vision.
I EXCIMER LASER SURGERY
We cannot shorten or lengthen the eyeball, but we can now alter the shape of the front of the cornea sufficiently in most cases to shift the focus (image) from it’s abnormal position to the retina, and therefore restore good vision without glasses. There is obviously some risk associated with this, so however small this risk might be, surgical approach is not considered if patients are comfortable with their glasses or their contact lenses.
The altered shape of the front of the cornea can be achieved via Laser (Excimer) Refractive Surgery as follows:
I A Laser in-situ keratomileusis
Laser in-situ keratomileusis, or LASIK, is considered safe and effective for patients with low to high myopia (up to +-10 diopter of shortsightedness), with or without astigmatism, and low to moderate hyperopia (up to +- 3 diopter of farsightedness). The ophthalmologist uses an automated microkeratome to cut a thin, hinged layer in the cornea, called a flap. The flap is then laid back and the surgeon uses an excimer laser beam to flatten the underlying cornea by vaporising a thin layer of tissue. The flap is gently put back in place. The cornea heals without any stitches. 
Local anaesthetic drops are used (no injections) to render the eye insensitive. Mild sedation is also usually advisable. Because of this you should not drive your car for at least 12 hours after the operation.
NB. Stop cosmetics at least 5 days before Laser Surgery, soft contact lenses at least 1 week before surgery and hard contact lenses 2 weeks before surgery – confirm these times with your Ophthalmologist as some patients need longer.
Possible Complications:
An imperfect flap at operation. If this happens, no laser is applied, the flap is replaced – and reoperation performed 1 – 3 months later.
Epithelial defects at operation – these heal within 48 hours and will be covered with a bandage contact lens.
Infection – extremely rare, statistics show this to be about 1:50 000 operations.
Corneal “haze” or light scarring – about 3%. This would cause mistiness of vision, halo’s around lights (especially at night), and may need lifting of the “flap” to remove unwanted material.
Regression. Some patients tend to revert partially to their previous refraction. Excimer / Lasik “top up” may be done on these patients.
Haloes around lights, especially when driving at night – this gets better after 6 months but never completely disappears.
With all types of surgery there is a possibility of other complications including those due to anaesthetic agents, drug reactions etc, and factors which may involve other parts of the body. Since it is impossible to state every complication which may occur as a result of any surgery, this list is incomplete.
Frequently asked questions:
Who can have this ?
Not all people with refractive errors are good candidates for refractive surgery. Your ophthalmologist is the best source of information on refractive procedures and the options you have to correct your particular refractive error. Patients with thicker spectacles benefit most from this procedure.
Laser Surgery aims to eliminate (or substantially reduce) this handicap. You may need thin glasses afterwards for very sharp vision, but should have about an 80% chance of going without spectacles 80% of the time – depending on your refractive error.
How can I find out if I am a good candidate for Excimer Laser ?
You need to be screened and assessed by your local Ophthalmologist. Your eye surgeon will be able to give you a good idea whether you are a possible candidate. The procedure, as well as advantages and disadvantages will be discussed with you. You will need to remove soft contact lenses five days before this assessment, and hard contact lenses at least two weeks before the assessment.
What age do I have to be ?
Minimum of 18 years, with a stable refraction for at least one year.
There is no maximum age, but short sighted patients over 45 years old should remember that they are unlikely to be able to read without glasses after this procedure.
Is the treatment permanent ?
World wide experience shows that patients experience longterm benefits. However, laser surgery does not prevent the natural changes that occur with ageing, and this may include gradually increasing shortsightedness or longsightedness.
Can I wear contact lenses after this surgery ?
Yes – most people will be able to wear soft contact lenses if necessary. Sometimes, a hard contact lens might be necessary.
Can they have both eyes operated on at the same time ?
Most possibly, but only after thorough discussion with your eye surgeon.
How long do I need to be off work ?
About two days after surgery.
Is there any post-operative follow up ?
Yes – you will have post-operative checks until your vision is stable.
Do I need to use eye drops after the surgery ?
Yes, most patients need drops for about one week.
When will I be able to drive ?
You will probably be able to drive after a few days. However, driving at night may be affected by glare for a while.
How long does the procedure take ?
About 10 minutes per eye.
Is the procedure painful ?
No – anaesthetic drops numb all pain. You will be aware of the eye surgeon working on your eye though.
Is there pain afterwards ?
Normally there is only a slight scratchy feeling for a day or two.
Will I be able to drive myself home after the surgery ?
No, you will have eye shields covering both eyes, and you will need someone to drive you home.
I B PHOTOREFRACTIVE KERATECTOMY OR (PRK)
With this method the laser beam is applied directly to the surface of the cornea, after the thin superficial layer of cells has been wiped off. After the laser resculpturing of the cornea is done, it takes a day or two to heal and it can be uncomfortable during this period. The healing process sometimes leads to regression (some refractive error returns) or to scarring.
II PHAKIC INTRA-OCULAR LENSES
In cases of severe refractive errors exceeding the safety limits for Excimer laser surgery, you might be advised by your eye surgeon to have a phakic lens implanted. This is a special “contact lens” designed for permanent implanting into the eye, after which “fine tuning” of the refractive error will be done with the Excimer laser. The advantages and disadvantages of this procedure will be discussed with you. This method is only advised in patients under 40 years of age, who do not require reading glasses yet.
Your eyes will be assessed thoroughly and the phakic intra-ocular contact lens will be manufactured to fit your eye specifically. According to the type of lens chosen, it can either be implanted in front of or behind the iris. Excimer laser surgery can be performed about a week after this surgery.
Possible Complications:
1 Cataract formation (about 30%)
2 Endophthalmitis (about 0.01%)
3 Pressure increase (about 10%)