Myopia - Treating short-sightedness

Glasses or contact lenses are the most common method of correcting short-sightedness (myopia). Laser surgery is also becoming increasingly popular.

Implanting artificial lenses in the eyes is a fairly new technique that can be used if laser surgery is ineffective or not possible.

Corrective lenses

Glasses

Short-sightedness can usually be corrected using glasses made specifically to your prescription.

Concave lenses are used that are thicker at the edge than at the centre. The curvature of the lens, its thickness and weight will depend on how short-sighted you are.

Wearing a lens that is made to your prescription will ensure that light rays fall onto your retina and you can focus accurately.

The lens of the eye becomes less flexible as you get older, which means you may need to use two pairs of glasses, with one pair for close vision activities such as reading and the other pair for distance vision activities such as watching television.

Some people prefer to use bifocal lenses that allow them to see objects clearly that are both close up and far away without changing their glasses.

You can also get multifocal lenses that help you see nearby objects and those at intermediate and long distances. Monovision is another option, where one lens is set for distance and the other is set for close work.

Contact lenses

Contact lenses can also be used to correct vision in the same way as glasses. Many people prefer contact lenses to glasses because they are lightweight and almost invisible.

There are two types of contact lenses – rigid gas-permeable contact lenses and soft contact lenses. However, there are many different lens materials and designs.

Contact lenses can be worn on a daily basis and discarded each day (daily disposables), or they can be disinfected and reused. They can also be worn for a longer period of time. However, eye specialists generally recommend that contact lenses are not worn overnight because of the risk of infection.

Some opticians occasionally use a technique called orthokeratology. It involves wearing a hard contact lens overnight to flatten the curvature of the cornea so that you can see better without a lens or glasses during the day.

It is not a cure for short-sightedness because the cornea usually returns to its normal shape, but it can reduce reliance on lenses for mild or moderately short-sighted people.

Your optician will be able to advise you about the most suitable type of contact lenses for you. If you decide to wear contact lenses, it is very important that you maintain good lens hygiene to prevent eye infections.

Availability on the NHS

You can get vouchers towards the cost of glasses or contact lenses if you're eligible – for example, if you are under 16 years of age or if you are receiving Income Support.

If you are not eligible, you'll have to pay for glasses or contact lenses. The cost of glasses can vary significantly depending on your choice of frame. Entry-level glasses start at around £50, with designer glasses costing several hundred pounds.

The cost of contact lenses will vary depending on your prescription and the type of lens you choose, but they typically cost £30-50 a month.

Laser surgery

Laser surgery involves using a laser to burn away small sections of your cornea to correct the curvature so light is less tightly focused through your lens and on to your retina.

There are three main types of laser surgery, which are briefly outlined below.

Photorefractive keratectomy (PRK)

In photorefractive keratectomy (PRK), a small amount of the cornea's surface is removed and a laser is used to remove tissue and change the shape of the cornea.

The amount of tissue removed is controlled by a computer and will depend on how poor your eyesight is. After the procedure, the surface of the cornea is left to heal.

Laser epithelial keratomileusis (LASEK)

Laser epithelial keratomileusis (LASEK) is a similar procedure to PRK, but involves using alcohol to loosen the surface of the cornea before it is lifted out of the way.

As with PRK, a laser is then used to change the shape of the cornea. Once the treatment is finished, the surface of the cornea is replaced and is held in place by natural suction.

Laser in situ keratectomy (LASIK)

Laser in situ keratectomy (LASIK) is similar to LASEK, but only a small flap of the cornea is involved.

A surgical instrument is used to cut a flap in the surface of the cornea, which is then folded back rather than removed. A laser is used to change the shape of the cornea, after which the flap is folded back down to its original position and held in place by natural suction.

The laser surgery operation

Laser surgery is usually carried out on an outpatient basis, so you will not have to stay in hospital overnight. You will need to have one or more appointments at a clinic. The treatment usually takes 30 minutes to an hour.

LASEK or LASIK are usually the preferred methods as they cause almost no pain and your vision will recover within one to two days. However, you may experience some fluctuations in your vision after this. It can take up to a month for your vision to stabilise completely and for you to feel the full benefits of the operation.

Laser treatment can only be carried out if your cornea is thick enough. If your cornea is thin, the risk of complications and side effects occurring, such as loss of vision, is too great.

LASEK and PRK may be possible if your cornea is not thick enough for LASIK surgery. However, the recovery time tends to be longer using these techniques – it can take up to six months for your vision to stabilise after having PRK surgery.

The Royal College of Ophthalmologists has published a Patient's Guide to Refractive Laser Surgery and also provides answers to specific questions related to laser refractive surgery.

You can also read NICE guidance about laser surgery for the correction of refractive errors (PDF, 75.3kb).

Results

The results of all three techniques are usually good. While it may not always be possible to completely cure your short-sightedness, around 9 out of 10 people experience a significant improvement in their symptoms.

Most people who have laser surgery report that they are happy with the results. However, it is important to realise that laser surgery may not necessarily improve your vision to the same degree as wearing corrective lenses. Also, as with any type of surgery, laser surgery carries the risk of complications.

Complications of laser surgery

Laser surgery does carry risks, with dry eyes after the procedure being the most common complication.

Dry eyes can occur if the lasers damage the nerves that stimulate tear production. The nerves will grow back after about six months. During this time, you can lubricate your eyes with eye drops to help lessen the dryness and any irritation.

Other complications include:

• removal of too much cornea tissue – this could leave you with an eye that is long-sighted and occurs in around 1 in 20 cases
• reduced night vision – this usually passes within six weeks
• a haze effect around bright lights – this will usually pass within 6 to 12 months

More serious complications of laser surgery are much rarer and include:

• epithelial in-growth – where the flap that is cut into your cornea begins to grow into the main part of the cornea when it is replaced; this can cause problems with your vision and further surgery may be required to correct it
• ectasia – where the cornea becomes too thin and your vision is reduced or lost
• microbial keratitis – where the cornea becomes infected

Who cannot have laser surgery?

You should not have any sort of laser surgery if you are under the age of 21. This is because your vision is still developing and it would be dangerous to alter the structure of your eyes at this stage.

Your vision can also change if you are over 21. Your clinic should check your glasses or contact lens prescriptions to confirm that your vision has not changed significantly over the last two years.

You may also not be suited to laser surgery if you:

• have diabetes – this can cause abnormalities in the eyes that can be made worse by laser surgery to the cornea
• are pregnant or breastfeeding – your body will contain hormones that cause slight fluctuations in your eyesight and focusing power, making precise surgery too difficult
• have a condition that affects your immune system, such as HIV or rheumatoid arthritis – these types of conditions may affect your ability to recover after surgery
• have other problems with your eyes, such as glaucoma (where increased pressure in the eye can lead to vision loss), or cataracts (where cloudy patches develop in lens of the eye)

Availability

Laser surgery isn't usually available on the NHS because other treatments, such as glasses or contact lenses, are considered to be equally – if not more – effective. You will therefore usually have to pay for surgery privately.

Prices can vary depending on where you live in the country, the individual clinic and the type of equipment used during the procedure. However, as a rough estimate you usually have to pay somewhere around £800-1,500 for each eye.

Lens implant surgery

Lens implant surgery is a relatively new type of surgery for short-sightedness. It involves implanting an artificial lens into your eye.

The artificial lens is specially designed to compensate for any defects in the cornea so that rays of light are focused more clearly on to the retina.

There are two main ways of performing lens implant surgery. They are:

• inserting a phakic implant, which is a contact lens that's permanently inserted into your eye without removing your natural lens ("phakic" means that the eye contains its natural lens)
• replacing the natural lens with an artificial one, which is sometimes known as refractive lens exchange

These two types of lens implant surgery are described in more detail below.

Phakic lens implant

Phakic lens implants are generally used for people between the ages of 25 and 45 who are not suitable candidates for laser surgery – for example, people with severe myopia or those who have difficulty wearing glasses.

Phakic lens implantation is the preferred technique for younger people (those under 45) because their natural unaided reading vision is preserved.

The procedure is carried out using a local anaesthetic and you will be able to return home the same day. Your pupil is dilated using eye drops and a phakic lens implant is inserted into your eye through a small cut in the cornea.

Depending on its design, the phakic lens will be attached to your iris (the coloured part of the eye), placed in the angle between your cornea and iris, or positioned so that it floats over the surface of your natural lens.

Artificial lens replacement

Artificial lens replacement is essentially the same as cataract surgery. During the procedure, your natural lens will be replaced with an artificial lens that corrects your short-sightedness.

Refractive lens exchange is usually a day case procedure performed under a general or local anaesthetic. The operation is not painful and you will be able to see clearly within two days of having surgery. The second eye will usually be treated about seven days after the first.

Results

Phakic lens implants usually achieve better results than a clear lens extraction in terms of improving vision on a long-term basis. However, the technique carries a higher risk of complications such as cataracts.

A refractive lens exchange may be more suitable for older adults with damage to their eyes or an eye condition other than short-sightedness, such as cataracts or glaucoma.

Also, as both techniques are relatively new, there is little information about whether they are safe or effective in the long term. You should talk to your doctor about each procedure so that you are fully aware of any risks involved.

Complications of lens implant surgery

Posterior capsule opacification (PCO) is the most common complication of lens implant surgery. PCO is where part of the artificial lens becomes thickened and causes cloudy vision.

Around half of all people who have lens implant surgery will develop PCO. It usually occurs between six months and five years after having surgery. Treatment for PCO can involve having laser surgery to remove the thickened part of the lens.

Other possible complications of lens implant surgery include:

• retinal detachment
• cataracts
• seeing a halo of light around objects at night
• reduced night vision
• glaucoma 

Availability

As with laser surgery, lens implant surgery is not usually available on the NHS. Both types of surgery can be quite expensive, with many clinics quoting prices of around £4,000-5,000 for treating both eyes.

Reducing the progression of short-sightedness in children

It can be worrying when your child's short-sightedness gets worse as they grow. There are no 100% proven treatments yet that can stop this happening, but the most effective treatment is probably an eye drop called Atropine 1%.

However, this has significant side effects, such as dilating the pupil and making your child sensitive to light, or blurring reading vision, resulting in the need for bifocal or multifocal (varifocal) glasses.

Research is currently being carried out to look at more dilute Atropine eye drops, specialised contact lens designs (multifocal contact lenses) and orthokeratology (gas-permeable contact lenses that temporarily reshape the cornea to reduce refractive errors).

However, these treatments won't become available until their safety and effectiveness has been thoroughly assessed and confirmed.