Frequently asked Questions


Frequently asked Questions

What is AK?

Acanthamoeba keratitis (AK) is a rare eye disease caused by a free living protozoan, Acanthamoeba present in soil, water and air. Without treatment AK can cause severe vision deterioration and lead to blindness. AK is an infection of the cornea, the clear ‘window’ at the front of the eye,and can be very painful. AK is most common in people who wear contact lenses, but anyone with a corneal injury is susceptible to developing the infection. Acanthamoeba has a life cycle of two stages: an active form (when the organism feeds and replicates), and a dormant form (when the Acanthamoeba protects itself from attack by developing into a cyst).

What are the symptoms of AK?

Eye pain, eye redness, light sensitivity, eye irritation, blurred vision and excessive tearing are some of the early symptoms of AK. Symptoms of AK are similar to a range of eye infections so it is important to seek medical attention early.

Who is at risk of contracting AK?

While risk of contracting AK is very low, (1 in 100,000 in the EU), up to 85% of AK cases are contact lens wearers. Non contact lens wearers with AK have generally suffered some case of cornea trauma.

How is AK diagnosed?

Your ophthalmologist will use a standard slit lamp microscope to look for signs of inflammation in your cornea, including specific clinical signs characteristic of AK. This is sometimes followed by a corneal scrape and culture (a process by which some cells from the surface of your cornea are removed and sent to a laboratory for further analysis), or a swab of the cornea to check for Acanthamoeba DNA using a test called “PCR”. Results for both these tests take a few days to come through. In some cases, AK can be detected using a confocal microscope, a powerful scanner that can see Acanthamoeba cysts within the various layers of the cornea. Your ophthalmologist will use these tests together with other clinical signs and symptoms in order to decide on the appropriate treatment plan.

Why is it difficult to make a diagnosis?

 In the early stages, AK and other microbial corneal infections have similar signs and symptoms, making it difficult to tell immediately which one you may have. This is why a variety of tests and clinical signs are observed. Sometimes diagnosis can change when the doctor receives more information from lab tests. Diagnosis can also change depending on how your eye(s) respond to treatment.

The primary difference between AK and other microbial infections is that it is challenging to treat, due to its resistance to many forms of therapy. Acanthamoeba in the dormant cyst form can survive for long periods of time. AK cannot be treated with antibiotics because it is not a bacterial infection.

Why is my eye so painful and red?

AK can be extremely painful, although not all patients experience intense pain. The cornea is one of the most sensitive organs, with the highest density of pain receptors in the body. This means that any injury to the cornea can be very painful. Pain can also be triggered by the body’s immune response to the infection in your cornea - this is called an inflammatory response and may be one of the reasons your eye is red as well as painful. The medicines used to treat AK can be quite harsh and, in some cases, can also irritate the surface of your cornea. Your doctor will try to strike a balance between effective treatment of the infection and preventing further irritation on the corneal surface.

Why am I so light sensitive and why is my eye watering so much?

Light sensitivity is also a symptom of the inflammation and infection in your cornea because the cornea, which is usually clear, turns cloudy and scatters the light around. You may have light sensitivity because you have been given an eye drop that temporarily widens the pupil, the hole through which light enters the eye.

Sometimes the iris (the coloured part of the eye) can go into spasm when the cornea is infected, which can also cause pain, so these drops may help relieve the pain but may also make you more light sensitive. We sometimes call light sensitivity “photophobia”. The tears are a natural reaction to disruption of the corneal surface and are a reflex response to the infection. They act to remove irritants from the surface of the eye.

Why has my vision deteriorated so suddenly?

In the early stages of the disease, the corneal surface can become irregular due to inflammation, which can affect vision. This can occur quite suddenly and you should inform your ophthalmologist as soon as possible if this happens to you. As the infection responds to treatment, patients can notice their vision improve as the inflammation reduces and the surface heals. In later stages of the disease, scarring on the front of the cornea, resulting from long-term inflammation, is usually the reason for vision loss. In some patients, scarring can be quite extensive and may need further therapy (e.g. a cornea transplant) to rehabilitate vision once the infection is over. A degree of permanent vision loss occurs in around a quarter of cases.

How could I have got AK?

Around 85% of cases of AK have been associated with contact lens wear. There are a number of different factors which are known to increase the risk of contracting AK. The biggest risk factor is exposure to water (generally through swimming or showering in contact lenses, rinsing or storing lenses in water and handling lenses with unwashed or wet hands). Poor contact lens hygiene, including failure to disinfect lenses properly and to clean and dispose of contact lens cases regularly have also been shown to increase the risk of infection. Those who do not wear contact lenses may still contract AK, although it has a much rarer incidence than in contact lens wear.

I have AK in one eye. Can it spread to the other eye or to other parts of my body?

Generally cases of bilateral AK (affecting both eyes) is rare but has occurred where the patient has been infected in both eyes at the same time rather than it spreading from one eye to the other. Acanthamoeba is an opportunistic organism in that it is widespread in the environment, but fortunately only rarely invades human tissue to cause disease. It’s extremely unlikely for Acanthamoeba to spread from person to person. There are some extremely rare strains of Acanthamoeba that can affect the brain; most of these cases occur in immunocompromised patients and are not related to contact lens wear. However, it’s still a good idea to take sensible precautions to ensure that other bacteria or germs do not spread between your eyes or from your nose/mouth to your eyes. Always wash your hands before and after putting in your eye drops.

How am I going to be treated?

Typically treatment is with antiseptic drops, including PHMB, Chlorhexidine, Brolene or Hexamidine, which have an anti-amoebic effect. Usually you’ll need to take these eye drops every hour for the first few days (including overnight), reducing to 2-hourly by day only, and then less frequently as the treatment progresses. It can be quite difficult to take eye drops through the night during the first few days, but it’s very important to try and stick to the regime outlined by the doctor as best you can.

In addition to the anti-amoebic eye drops, you may be given anti-inflammatories or painkillers to help with the pain. You may also be given a dilating drop early in the infection to stop painful spasms of the coloured part of the eye, the iris. Around 10% of Acanthamoeba infections have dual pathology, which means that another infection, usually bacterial, is also present. If this is the case for you, we may also prescribe you with antibiotics as well as your other drops. Sometimes these are also given to guard against bacterial infection while the eye surface is disrupted in the early stages of the disease. Patients with severe inflammation or scleritis (inflammation of the white part of the eye) are sometimes prescribed steroid eye drops, although not every patient requires these and their use needs to be carefully managed.

As all patients react differently to the infection, your doctor will assess the most appropriate treatment regime for you. The treatment may change depending upon how your eye responds. If you have any concerns about your treatment then make sure you ask the doctor at your clinic appointment.

Is AK treated the same in other countries as in the UK?

There are currently no licensed medicines approved for the treatment of AK in any country, although most ophthalmologists use the same group of antiseptic eye drops which have been shown to kill Acanthamoeba in both its live and dormant forms in laboratory tests and have been effective treating patients in large case series. Some case reports have indicated successful treatment with other types of treatment such as collagen cross-linking and antifungal drugs, although these results have only been reported in a few individual cases. More extensive studies are required to ascertain whether any of these therapies are suitable add-ons or alternatives to existing treatments undertaken.

How long can I expect to be treated for?

Although each patient is different, generally speaking those who are diagnosed and receive appropriate treatment quickly can expect their treatment to last three to six months. Some patients recover sooner, and more complicated cases can last for more than a year. Although the early stages of the disease can be very difficult and put limitations on your ability to undertake your day to day activities, as the infection comes under control you should be able to resume many of these whilst continuing to receive treatment.

Can steroid drops cause any complications?

Although steroid drops can both aid healing and make the eye more comfortable by reducing inflammation, using steroids may also delay the clearing of the infection and cause other complications including cataract (clouding of the lens) and glaucoma (raised eye pressure).The use of steroids will therefore need to be carefully managed by your ophthalmologist.

A small percentage of patients experience scleritis (inflammation of the white part of the eye) which is usually treated using steroid drops and, in more severe cases, additional oral medication is also given.

Are there any other complications I may experience from AK treatment?

Some patients experience complications including a fixed dilated pupil or damage to their iris (the appearance of which can be improved with a cosmetic procedure once the infection is over). Vascularisation (growth of blood vessels into the cornea) and secondary bacterial infections sometimes also occur. Various other complications can form part of severe AK, which is why, at each clinic appointment, your doctors will perform thorough checks on your eye(s) to look out for signs of these complications.

Will I definitely need a cornea transplant?

Around 25% of cases of AK result in a corneal transplant. There are different types of transplant – and these carry different risks. Some are carried out to rehabilitate your vision at the end of infection. Other transplants are carried out, on actively inflamed eyes, as part of therapy. This is usually for corneal perforations, although the success rate of these therapeutic transplants is poorer and so the procedure is rarely used unless absolutely necessary. There is also a risk of a recurrence of AK post-surgery and this is one reason why corneal transplants are generally delayed until the eye has been infection free for some time. Your doctor will discuss what’s right for you and separate information will be provided if you are a possible candidate for a corneal transplant. For patients who do not require a transplant, vision can be improved using a rigid contact lens. Your ophthalmologist will discuss all options with you at the appropriate time.

Can I shower as normal and wash my hair?

Yes, although if you have recently had a corneal scrape or if you have been told you have an epithelial defect (a breakdown on the surface of your affected cornea) you may wish to avoid getting water in your eye for a few days as a precautionary measure. Swimming should definitely be avoided during this time. Ask your doctor at your next clinic appointment if you are worried about this.

Can I wear eye makeup?

Eye makeup should be avoided in the early stages of your treatment, as this can sometimes be a source of additional bacteria entering the eye. You should be careful not to rub your affected eye(s) too much, and removing eye makeup should be done as carefully as possible with gentle cleanser so as not to irritate the cornea. Once your infection has started to settle, it may be ok to wear non- waterproof eye makeup. Ask your doctor at your next appointment.

I am very light sensitive. What can I do?

You may want to buy a pair of prescription sunglasses to help you cope with daylight. Drawing curtains and blinds at home can help. It’s also possible to buy a shade or eye patch to wear over glasses – this can help if you want to watch TV or work at a computer. Most people feel self-conscious at first but it can provide a relief of your symptoms. Try not to wear the patch all the time, so that fresh air can circulate around the eye. Many patients find it helpful to wear a hat and sunglasses when they go out. Check with your doctor before wearing any type of patch that adheres to the eye itself.

Can I continue to go to the gym/play sports?

Yes, many patients have found exercise is a good way of helping them to relax and to cope with their illness. It has also been shown to help improve self-esteem, mood, sleep quality and energy, as well as reducing your risk of stress and depression. You should do as much as you feel like doing, although you should take care with contact sports like rugby. Ask your doctor if you have any concerns.

Can I continue to drive?

You must tell the relevant driving regulation authority if you have any problem with your eyesight that affects both of your eyes, or the remaining eye if you only have one eye. Ask your doctor at your clinic appointment about whether you meet the minimum standards of vision for driving.

When can I start wearing contact lenses again?

This will depend on the extent to which your cornea has been affected by the infection. For those who wish to return to contact lenses after AK, daily disposables are usually the most suitable option. Most patients will need to wait several weeks or months to ensure they are clear of infection and their eye(s) are healthy before wearing contact lenses again. Ask your doctor what’s right for you.

Are there any signs should I look out for in-between clinic appointments?

Any sudden increase in pain, redness or loss of vision should be treated as an emergency. You should attend an eye casualty department or contact your Clinic to arrange to be seen urgently.

How long should I leave in between putting in eye drops?

Generally speaking, you should try to leave around five minutes between drops. This can be difficult when you are using a number of different drops every hour or every two hours, so try and leave at least two minutes between each one if using more than two. Setting alarm clock reminders or using smart phone apps can help you keep track.

Most of the eye drop liquid falls out of my eye. Is that ok? How do I stop it from happening?

Do not worry if some of the eye drop falls out – this is perfectly normal. It is a good idea to tilt your head back and keep your eye closed for a minute or so after you’ve put the drop in – to ensure all the medicine has got into your eye – although this can be impractical if you’re on the move or in a public place. Try your best to do this at least when you are able to. If you miss your eye completely, do the drop again. If a small amount goes in, then wait till your next drop and try and ensure it goes in properly the next time. If a friend or family member is able to help put drops in, this can sometimes be useful, particularly if you have reduced vision in the affected eye(s).

Why do some eye drops sting so much?

If your eye is very inflamed, red or irritated, or if you have an epithelial defect, you may find the drops sting a lot. Different formulations of eye drops designed to kill Acanthamoeba can also sting when they go in and when they mix with the previous one used, so try and keep a decent gap between drops. Keeping drops in the fridge can help ease the stinging. Perhaps try a cold compress or ice pack on your forehead or down the side of your face after the drop has been done. Tell your doctor if you have any concerns.

I keep missing drops because I lose track of time. What can I do?

If you have a number of different drops to take at different times of the day, set an alarm clock and keep a notebook handy to help you tick off the ones you’ve done. There are quite a few helpful ‘reminder’ apps for smart phones, which can also help you keep on top of taking your medication.

My eye drops need to be kept refrigerated, but I’m not at home. What can I do?

Many patients carry a cool bag with ice packs in it to keep their drops cold when they are out. Others use a thermos flask filled with ice cubes. Remember during the summer months non-refrigerated eye drops can also be affected by high temperatures.

I am out and cannot wash my hands before getting drops in. What can I do?

Carry a small bottle of alcohol based antibacterial hand gel for times when you are not able to wash your hands.

How long can I expect to be off work?

It varies enormously and also depends on the type of work you do. Some patients have worked throughout their illness; others have found it necessary to take sick leave. You should return to work when you feel able to perform your duties appropriately. Some people return to work with reduced working hours or duties for a period of time.

Can I still use a computer?

Yes, as long as you feel able to. Reducing the brightness on your screen or wearing an eye patch or shield can also help.

Am I allowed to fly?

Yes, although you should discuss any foreign travel plans with your doctor in order to ensure you will continue to receive appropriate treatment whilst away.

If I am finding it difficult to cope with my illness, what help can I get?

The impact of AK on those affected can be extremely difficult. Some patients feel they need additional emotional support, in particular with adjusting to fluctuating vision and changes in appearance as a result of the infection. Some hospitals provide a dedicated patient support and counselling service for patients, as well as their families and carers, and can provide information, advice and counselling at the time of diagnosis, throughout your treatment and during your follow-up.

Is there anywhere I can find accurate information to share with others about AK?

You may find some other information on the Internet, but bear in mind that much of this information may be inaccurate or out of date. There are a number of social media forums where AK patients from all over the world talk and provide support to each other. 


 These questions are based on information from Moorfields Patient information leaflet and in discussion with patients