Understanding the risks involved in refractive surgery is very important. Your consultant will be able to comment in detail about any particular aspects of risk that might affect you.

Moorfields Private treats many patients each year who feel nervous about laser vision correction. We understand that these procedures need to be fully discussed with patients. Prior to your initial consultation, our surgeons provide comprehensive information packs detailing the risks and benefits of each of the surgical procedures we perform.

Although the risks in contemporary refractive surgery are very well contained, no procedure is risk free, and each has a defined set of risks. These should always be measured against the risk of infection due to wearing contact lenses.

LASIK COMPLICATIONS

Three factors have made refractive surgery safer since initial results were published in the mid 1990s:

• the technology has improved;
• suitability for treatment is better defined; and
• better corrective treatments are available for patients that are unlucky enough to experience problems.

Moorfields Eye Hospital is an international referral centre. If problems occur, our consultants are experienced in putting them right. With a patient approach and the right treatment, most complications can be corrected so that the final visual result is not affected.

Dry eyes

Some patients experience dryness in the first few months after LASIK. This is because the nerves to the front of the eye, which stimulate a normal blink rate and normal tear production have to regrow after treatment. This takes up to a year. Artificial tear drops are often helpful in this period, but continued long-term use is unusual in patients who did not have dry eye problems before surgery.

Glare and halo effects

These effects whilst night driving are commonly observed after LASIK. They tend to be most prominent in the early postoperative period, and are more likely to affect people with higher corrections. These symptoms are rarely severe, and as with any dry eye feelings, will typically resolve within a year of surgery

Loss of vision

Significant loss of vision is now rare after LASIK. In a survey of 1000 consecutive cases treated at Moorfields Eye Hospital, no-one with corrected vision better than the driving standard before surgery ended up with corrected vision worse than this level afterwards. Patients with complications still attained a good visual result. The risk of losing vision after LASIK or surface laser treatments is probably similar to the risk of visual loss associated with a 5-10 year period of contact lens wear. There are no reported cases of complete loss of sight after either LASIK or PRK.

Keratectasia

Excessive thinning of the eye wall can cause the shape and focussing power of the eye to become unstable after treatment. This is rare, and careful screening to detect pre-existing corneal abnormalities, conservative limits on treatment, and pre-operative measurement of corneal thickness all combine to limit this risk.

Implant based refractive surgery (RLE and ICL surgery) complications

The risks for clear lens extraction are the same as for cataract surgery. Cataract surgery is now a very safe operation.

Overall, around 1 in 1000 patients has a disastrous result, with near total loss of vision in the operated eye. This is usually the result of infection, or a failed repair of a retinal detachment.

Around 1 in 100 patients requires a second corrective operation after problems in the original procedure.

Around 1 in 10 patients requires a one-off, minor laser procedure to correct a gradual deterioration in vision caused by a healing response in the tissues encasing the lens implant.

Retinal detachment

Patients with high levels of short sight are at particular risk of developing this sight-threatening problem. The risk of developing a retinal detachment within 10 years after cataract surgery or RLE is approximately 10%. Without surgery the risk is approximately 5%. It is not clear whether cataract extraction simply precipitates a detachment that would have occurred eventually anyway, or whether there is a genuine increased lifetime risk. 9 out of 10 retinal detachments are successfully repaired at the first attempt. Whether or not you opt for surgical correction of high levels of short sight, if you experience a sudden change in your vision, particularly a new shower of floating shadows, flashing lights in your eye, or a curtain coming across your visual field, you should always attend an eye department for an emergency examination. Catching retinal detachments at an early stage will improve the chances of successful surgery.

ICL surgery

The risk of serious permanent visual loss associated with ICL surgery is similar to that for RLE (1/1000).

Revision surgery is required in approximately 1 in 50 patients. The main additional risk is cataract.

Contact between the natural lens and the ICL may, in some cases, cause the natural lens to lose clarity. If lens opacification progresses to interfere with vision, the cloudy lens is called a cataract. Recent studies suggest that the chances of developing a cataract within 2 years of ICL surgery are less than 1%. ICL removal can be combined easily with cataract surgery in which a new artificial lens, equivalent in focussing power to the ICL, is implanted to take the place of the natural lens. Good distance vision is normally maintained.

Painful blockage of fluid flow within the eye (glaucoma) has been reported in 4% of cases immediately after ICL surgery, but this problem can be avoided with contemporary implantation techniques.