Eye surgery is a delicate process with some drawbacks, says Dr Muiris Houston
Lasik is one of the techniques that eye surgeons use to correct sight problems.
Others include making deep incisions in the peripheral cornea - known as radial keratotomy - and reshaping the central cornea by laser, or photorefraction keratectomy.
The cornea is the clear curved window on the front of the eye; all sight-correction procedures involve reshaping it to focus light rays on the retina and, therefore, improve vision.
Lasik, or laser-assisted in situ keratomileusis, entails cutting a superficial flap in the cornea, using a laser to reshape the stroma, or middle section of the cornea, then replacing the flap.
It has several advantages over other procedures: it is suitable for severe short-sightedness and the patient's vision stabilises more rapidly following the operation.
Other indications for Lasik include the treatment for short-sightedness and the correction of astigmatism, a condition in which the eyeball is not perfectly spherical.
Lasik is not suitable for the large number of people who have a condition called presbyopia and wear glasses only for reading.
As Lasik is not suitable for everyone, a reputable surgeon will always try to match a patient's expectation with what is achievable.
Probably the most important aspect of Lasik surgery - which, as Rosita Boland describes above, is carried out in minutes under local anaesthetic - is the preoperative assessment.
A patient's eyes should be measured for natural dryness; if your eyes have a natural tendency to dryness or grittiness, your surgeon will formally assess the level of dryness. If this reveals excessive corneal dryness, then expect to be told you are not a suitable candidate for Lasik.
A full preoperative assessment should also measure the size of a patient's pupils.
What are the complications of Lasik? A patient may experience dryness lasting up to two months after the procedure is performed - although a correspondent to this newspaper claims she suffered permanent dryness after having the procedure performed abroad.
Older women do have reduced tear production; more women than men will experience post-operative dryness.
Some patients may notice a glare around lights at night-time, lasting up to three months after surgery. Approximately 3 per cent of patients will require a repeat procedure due to undercorrection or overcorrection of the visual defect.
In about one in 200 cases, the flap raised by the surgical instrument is too thin, the procedure will be halted and you will be invited back some weeks later, for a further attempt.
The risk of post-operative infection is one in 1,000.
Research suggests that 95 per cent of people who have undergone Lasik are no longer wearing glasses two years later. It is probably a good idea to ask the surgeon you see for his or her outcome figures before undergoing the operation.