Hypermetropia - Treating long-sightedness

Long-sightedness (hyperopia) is often corrected with prescription glasses or contact lenses. In some cases, laser surgery is also an effective treatment option.

Glasses

Long-sightedness can usually be corrected with glasses made to your prescription. Convex lenses (thinner at the edge than at the centre) are used to correct long sight.

The curvature of the lens, its thickness and weight will depend on how severe your long-sightedness is. By wearing a lens made to your prescription, light rays will fall onto your retina, allowing you to focus accurately.

The lens of the eye becomes stiffer with age, so the strength of your prescription may need to be increased as you get older.

It is possible to be both long- and short-sighted. If this is the case, you may need to wear two different pairs of glasses. Alternatively, you could wear varifocal or bifocal lenses, which allow you to clearly see objects that are both near and far.

Contact lenses

Contact lenses can also be used to correct long-sightedness in the same way as glasses. Some people prefer contact lenses to glasses because they are lightweight and virtually invisible.

Contact lenses are available in many different materials and designs. Some lenses can be worn for a day and discarded (daily disposables). Others can be disinfected and re-used, or worn for longer periods and kept in overnight. Your optometrist can advise about the most suitable lens for you.

If you wear contact lenses, it's important that you maintain good lens hygiene to prevent eye infections developing.

Surgical treatments

There are various surgical techniques to treat long-sightedness. The most reliable uses laser surgery.

Surgical treatment for long-sightedness involves increasing the curvature of the cornea to improve its focusing power by removing some tissue from the edge of the cornea.

The benefit of laser surgery compared with traditional surgery is that instruments do not have to enter the eye, which means that the risk of damage or infection is lower.

There are three main types of laser surgery:

Laser in situ keratectomy (LASIK)

Laser in situ keratectomy (LASIK) is the most common procedure used for laser surgery in the UK.

A small instrument is used to cut a flap in the surface of the cornea, which is then folded back.

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.

Photorefractive keratectomy (PRK) 

Photorefractive keratectomy (PRK) is where a small amount of the surface of the cornea is removed, and a laser is used to remove tissue and change the shape of the cornea.

The removal of tissue is controlled by a computer, and the amount removed will depend on how poor your eyesight is. The surface of the cornea is then 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 removed.

As with PRK, a laser is used to change the shape of the cornea. The surface of the cornea is then put back and held in place by natural suction.

The surgical procedure

Laser surgery is usually carried out on an outpatient basis. This means that you will not have to stay in hospital overnight, but will have one or more appointments at a clinic. The treatment usually takes between 30 and 60 minutes.

LASIK is usually the preferred treatment option, because it causes virtually no pain and your vision recovers quickly (within one or two days).

However, LASIK is a more complicated procedure, and if complications do occur, they may be more serious.

Although your vision will recover quickly after having LASIK, you may experience some fluctuations in vision, and it can take up to a month for your vision to stabilise completely.

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

It may be possible for you to have LASEK or PRK if your cornea is not thick enough for LASIK surgery. The recovery time tends to be longer for these techniques – for example, it can take up to six months for your vision to fully stabilise after having PRK surgery.

The Royal College of Ophthalmologists provides more information about laser refractive surgery.

Who cannot have laser surgery?

You should not have any sort of laser surgery if you are under 21, because your vision is still changing and it is dangerous to alter the structures of your eyes at this stage.

If you are over 21, changes to your vision can still occur. Before having laser treatment, your clinic should check your glasses or contact lens prescriptions to confirm that your vision has not changed significantly over the last two years.

Laser surgery may also not be suitable if you:

• have diabetes – which can cause abnormalities in the eyes that can be made worse by laser surgery
• 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; this may affect your ability to recover after surgery
• have other problems with your eyes – such as glaucoma (a condition that causes pressure changes in the eye and may lead to blindness) and cataracts (where the lenses harden and become cloudy)

Risks of laser surgery

As with all types of surgery, laser surgery carries some risks, and you should discuss these with your surgeon before deciding to have the procedure.

Some possible complications of laser surgery are:

• Following surgery, your vision may be worse if the surgeon misjudges the amount of tissue taken from your cornea (this is known as a correction error).
• The flap cut into your cornea may start to grow into the main part of your cornea when it is replaced (this is known as epithelial ingrowth, and it can cause vision problems that may require further surgery to correct).
• Your cornea can become too thin, leading to a reduction in or loss of vision (this is called ectasia).
• Your cornea can become infected (known as microbial keratitis).

It's important to note, however, that the above risks are rare.

Treating age-related long-sightedness (presbyopia)

Laser surgery is not suitable for age-related long-sightedness (presbyopia), as it is caused by changes in the lens rather than the shape of the cornea.

Age-related long-sightedness is usually treated with glasses or contact lenses (see above).

Presbyopic lens exchange (PRELEX)

In some cases, surgery may be used to insert an artificial lens in the cornea. This is known as presbyopic lens exchange (PRELEX). PRELEX is usually offered to people who struggle to use glasses or contact lenses.

The procedure is normally performed using local anaesthetic (where you are awake, but the eye is numb) on the weaker eye. A small flap is made in the cornea, and an artificial lens is placed inside. The flap is then folded down and stays in place naturally, without stitches.

Corticosteroids and antibiotics are usually prescribed for a short period after surgery, and artificial tears may also be needed.

As PRELEX is a newer type of treatment, there is currently a lack of good evidence on its long-term safety, and the risks should be discussed with you before the procedure. The decision about whether this procedure can be performed on the NHS will be made by your local clinical commissioning group (CCG).