Some of the most common questions from prospective patients are about the risks involved. While LASIK surgery is a safe procedure, all medical procedures have some risks and these will be discussed at your appointment.
Surgical (Operative) Complications
Rare. This includes difficulties creating a good flap such as creating an incomplete flap. In this circumstance, the flap is not satisfactory and laser treatment may need to be postponed and a new flap cut at a later date. The estimated risk is 1 in 2000 cases, but varies according to the technique, surgeon and equipment used.
Extremely rare. The estimated risk is 1 in 10,000 treated eyes, compared with 1% of contact lens wearers who annually get similar bacterial infections.
It may be safer to have laser eye surgery than continue with contact lens wear. Infection may result in scarring and loss of sight.
In most procedures the surface epithelium heals within hours. In 5% of procedures surface epithelial defects can produce blurring and irritation lasting up to several days. This may go on to produce haze (scarring) and refractive change which may be treated with medication or further surgery. The estimated risk is 1 in 100 cases.
Transient Light Sensitivity
A mild non-infective inflammation of the flap can occasionally develop 1 – 3 months after surgery producing marked glare, but usually settles with a course of steroid anti-inflammatory eye drops. The cause is unknown.
Rarely seen or significant. In approximately 1 in 1000 procedures a layer of epithelium from the surface of the cornea grows between the flap and the underlying cornea. Usually this only evident at the edge of the flap and has no visual significance. It will prevent complete healing of the flap in that area and can compromise the visual result if it extends into the pupil zone. Additional treatment may be required for this.
Dry eyes are common in normal individuals, especially older patients, and often produce irritation with contact lens wear. Those with dry eyes pre-operatively, may find their eyes are more sensitive to dryness for up to 3 – 6 months after LASIK. This can produce some variable blurring or clouding of vision that clears with time. Lubricating artificial tears may be necessary during this period. Less than 1% experience dryness lasting more than six months.
Up to 5 – 10% of the initial refractive treatment can regress normally early in the post-operative phase. The laser treatment will usually take this into account and an allowance for this is made when calculating the amount of laser treatment.
Under or over correction may occur as an increased or decreased response to the surgery. In 2% of all cases treated some fine tuning adjustment is necessary in the first 2 years for best vision.
Very rarely, significant regression can occur with corneal ectasia developing. This can occur if the cornea is too thin to support its new shape. This is seen most commonly in those with initial very thin corneas, abnormal corneas, high refractive errors, re-treatments or with a family history of keratoconus.