What you want to know about laser eye surgery

Laser eye surgery is a range of techniques that corrects sight problems, including short-sightedness, long-sightedness and astigmatism. In this article, a consultant ophthalmologist shares all about laser eye surgery, and what patients may not know.

What is laser vision correction?

Laser vision correction (LVC), also commonly referred to as laser eye surgery, is a collection of techniques in which myopia (short-sightedness), hyperopia (long-sightedness), and astigmatism (irregular defocus) are corrected by altering the front surface shape of the cornea – the clear window at the front of the eye wall.

The main types of LVC are:

• LASIK (laser in situ keratomileusis)
• PRK (photorefractive keratectomy)
• SMILE (small incision lenticule extraction)

These are all 15-minute treatments performed with drop anaesthetic. Both eyes are normally treated on the same day. 

Modern techniques are safe, effective, and transformative for patients whose lives are restricted by reliance on contact lenses or spectacles.

What are the benefits?

Most patients are able to see at a normal level after a single treatment, and the effects are lasting. With modern techniques, you should expect to see what you are able to see in soft contact lenses, but without the discomfort and the hassle.

More than 98% of patients undergoing LASIK for myopia and astigmatism, the commonest LVC treatment, are happy with the results and many describe it as life changing.

Although LVC is not currently available as an NHS treatment, and is therefore often bracketed with cosmetic surgical procedures, the benefits are functional. By freeing you from glasses and contact lenses, LVC helps you to engage in a healthy, active lifestyle more easily.

Who is suitable?

You need to have a stable spectacle prescription for 2 years, and very few clinics treat patients under18 years of age. Changes in reading glasses strength with age are normal from the mid-40s on and do not affect eligibility for surgery.

You need a normal eye surface, a healthy cornea, and a clear natural lens. Your surgeon will have access to a bank of pre-treatment tests to help determine your suitability, and will be able to give you pre-treatment advice on optimising your eye surface health.

Many patients are told incorrectly that discomfort in contact lenses means they have dry eyes, and that this means they are unsuitable for LVC. Contact lens related discomfort actually has a range of causes, and most dry eye problems in younger patients can be treated effectively. So LVC is often a good way out of contact lens related discomfort.

What is the best treatment for me?

The main techniques all work well and produce similar end results in the right patients. The difference largely boils down to speed of recovery. It is possible to go back to work the day after LASIK, whereas surface treatments such as PRK require a week off work. SMILE is somewhere between.

It is essential that you meet your surgeon to discuss procedure choice once all your tests have been done. Different patients suit different LVC techniques, and implant based procedures may often be a better option. These include ICL (implantable contact lens) implantation for younger patients with a high spectacle prescription, and refractive lens exchange (RLE) for older patients.

What are the risks?

The best way to understand risk in laser eye surgery is to consider the two ends of the spectrum: what is the worst situation I could find myself in after surgery; and what is the most likely problem that I might run into?

Corneal transplantation is required in approximately 1 in 5000 cases. It normally works well when necessary. So there is no real risk of blindness as a result of LVC.

Revision surgery is commonly required for the best results in LVC. This may be to intercept a problem with healing, or to adjust the final visual focus. Revision treatments all feel similar to the original LVC procedure, and work is normally possible from the following day.

LVC is not risk free, but neither is contact lens wear, which is the main functional alternative for many patients who would otherwise require glasses. Approximately 1 in 3000 contact lens wearers each year will develop a serious corneal infection. So, you probably do not have to wear contact lenses for long to exceed the risk of having LVC performed.

What are the side effects?

Temporary red marks are common after any form of eye surgery. These are caused by minor leaks of blood beneath the mucous membrane covering the white of the eye. They are painless and clear in 3-4 weeks.

Eye surface discomfort is also normal in the first few weeks after any form of eye surgery. But permanent discomfort resulting from LVC is rare. Most patients, and contact lens wearers in particular, report better eye comfort by 6 months after surgery than they had before.

Most patients also notice some light scatter in the first few weeks after treatment, and this may affect night driving. Problems that persist after 3-6 months are unusual with modern laser systems, and can normally be treated effectively.