How is keratoconus diagnosed?
Keratoconus is usually diagnosed in young people at puberty, late teens or early twenties. It is more common in non-Caucasians and affects up to 1 in 450 people (depending on ethnicity).
If you suspect you may have keratoconus, you can visit your ophthalmologist who will conduct an eye exam, as well as assessing your individual and family medical history. They may also conduct various tests, including eye refraction, a slit-lamp examination and computerised corneal mapping to give you a keratoconus diagnosis.
The eye doctor (ophthalmologist) or optometrist (ophthalmic optician) will examine your eyes with a microscope called a slit-lamp. You might also have a corneal topography scan. This is a quick, painless photo which checks the shape and thickness of your cornea in detail.
Urgent referral is not required, as the various stages of keratoconus can take years to develop. As a result, your ophthalmologist may invite you back for multiple assessments in the years following your initial consultation. These visits will include vision and refraction tests, as well as corneal scans to monitor your condition. Your ophthalmologist will be able to advise if they believe you require further treatment.
Treatment for keratoconus
There is no cure for keratoconus and it cannot be treated with eye drops or medication.
In the early stages, spectacles or soft contact lenses may be used to correct vision. As the cornea becomes thinner and steeper, soft or rigid gas permeable (RGP) contact lenses are often required to correct vision more adequately. In very advanced cases, where contact lenses fail to improve vision, a corneal transplant may be needed. This type of intervention is rare however since the introduction of corneal cross-linking (CXL). CXL is a relatively new treatment that can stop the disease getting worse. It is effective in over 94% of patients with a single 30 minute outpatient procedure.
Early keratoconus clinic
Monitoring keratoconus
CXL is only suitable where the corneal shape is continuing to deteriorate. Once you are past your mid/late 30s, the cornea often naturally stiffens and CXL is generally not required. Below this age, the cornea is more flexible and disease progression (and worsening vision) is more likely to occur. During monitoring, if we detect any deterioration in your eyes we may recommend that you have CXL.
Changes caused by keratoconus can take many years to develop. For this reason we will invite you back for repeat assessments for up to 5 years from your initial visit.
This clinic is solely to diagnose keratoconus and to monitor the disease. It is important to stress that no extended eye examinations will be performed. We will not be checking your eyes for other problems (e.g. glaucoma, diabetes). This clinic is not a substitute for regular eye screening with your local optician or other eye healthcare providers.
Preparing for your visit
In order to obtain the most accurate scans, we ask that you remove your contact lenses prior to your appointment (2 weeks for hard lenses and 1 week for soft lenses). This is because contact lenses distort the corneal shape, which affects the accuracy of our scans. If you are unable to remove your lenses, please discuss this with the clinician at your appointment.
Please note that if you are unable to manage without your lenses, it is often not possible to accurately monitor your keratoconus using the above tests. CXL treatment may still be available and so long as the cornea is not too thin, may be offered based on the likelihood that your keratoconus will progress. Age is the most important factor in determining this risk: because of natural cross-linking as you get older, keratoconus usually stops getting worse mid/late 30s, so CXL is not normally required in this group of patients.
When you visit the clinic
Each time you attend this clinic, we will perform the same tests;
- Vision test
- Refraction (spectacle test)
- Corneal scans
We will compare these results with those from your previous visits. If any of the results show deterioration, we will discuss with you whether CXL is required.
Corneal cross-linking (CXL)
Corneal cross-linking (CXL) is a treatment which prevents keratoconus getting worse. Keratoconus is a non-inflammatory eye condition in which the normally round dome-shaped clear window of the eye (cornea) progressively thins, causing a cone-like bulge to develop.
CXL treatment is successful in more than 90% of cases. After treatment, you will still need to wear spectacles or contact lenses. Your eye will be sore for a few days after the procedure. Although vision is often hazy at first, most patients can return to work after one week. As with all operations, there are risks: CXL is safe, but there is a small chance (less than 3%) of a reduction in vision afterwards.
video transcript
Keratoconus is a disorder affecting the cornea, the clear window of the eye, in which its normal round shape progressively thins, causing a cone-like bulge to develop. Because the cornea does most of the focusing this change in shape causes significant problems with vision. As the disease gets worse the cornea gets steeper, and vision continues to decline.
Keratoconus affects young people. It's normally diagnosed in your late teens or early 20s, and it's much more common in black and Asian patients, although we don't understand why that should be. Although we don't understand the causes of Keratoconus fortunately we are, in most cases, able to improve vision. Early on this usually means just spectacles or soft contact lenses, as the disease progresses often hard contact lenses are required to improve vision. And in very advanced cases, where contact lenses no longer work, patients will require a corneal transplant to restore vision.
In the past up to about 20% of all patients needed a transplant at some point during their life. Now all of this has changed with the advent of corneal crosslinking. For the first time it means that we're able to intervene early on in the disease process, to stop vision loss and prevent deterioration in the future.
The treatment begins by gently brushing the surface layer of the cornea clear. Riboflavin drops are then applied to the surface, which soak through the cornea before an ultraviolet light is switched on. The ultraviolet light and riboflavin react together to create cross links within the cornea, which make it stiffer, mimicking the normal age- related cross-linking effect that occurs from your 30s onwards.
Although corneal crosslinking is a great step forward not every patient with keratoconus will need to have the treatment. We've set up the early keratoconus clinic here at Moorfields to run in the evenings to specifically diagnose, and monitor, those patients with keratoconus to see if they are progressing. We use corneal scans, vision tests and spectacle prescription to look for changes in their condition. If we do find that there is a change occurring we can normally list the patient to have the procedure done within a few weeks.
Crosslinking is performed as a day case procedure. When you arrive at Moorfields you'll be treated in one of the examination rooms. First, anaesthetic drops are used to numb the surface of your eye. You will be then lowered on the chair before a small clip is placed to keep your eyelids open. No needles or injections are used. The surface skin layer of your eye, called the epithelium, is gently brushed clear and riboflavin drops are applied every few minutes, for at least 10 minutes. Following this an ultraviolet light is shown for 8 minutes.
Nurse speaking with patient “That's great, just keep looking at the light. That's good, perfect. Just let me know if you're in any pain”
A soft contact lens is placed on your eye at the end of the procedure, which acts as a sort of bandage to keep the eye more comfortable afterwards. This lens will remain in your eye until your follow-up visit. You will then have a final eye check and your nurse, or practitioner, will take you through your painkillers. You are then free to go home.
So, what this means is that for the first time we're able to intervene early and prevent vision loss. We know from clinical trials that a single cross-linking procedure works in about 90% of cases. It's important to remember that cross linking doesn't cure you, rather it aims to lock in the shape that you have at the time of the procedure and therefore prevent vision loss in the future. Some patients do get an improvement both in the shape of the cornea and in their vision after the treatment, but this is really a bonus. The other thing to remember is that any treatment has risks, and there's about a 3% risk of someone's vision being worse directly as a result of the cross-linking treatment.
Patient interview
“It was very interesting. I wasn't quite sure what to expect, but it wasn't actually painful, the procedure itself. It was more… it felt like your eyes were not under your control anymore, but the local anaesthetic drops worked straight away. It was as comfortable as I could imagine it could have gone, for someone messing around with your eyes!
“I'd say the first day, the day of the procedure afterwards, was the most uncomfortable, adjusting to bright lights and your muscles obviously feeling a bit strange out of the anaesthetic Once the anaesthetic wore off that was the most painful time, but the next morning when I woke up I didn't need any additional pain medication, and I only took what was provided anyway. So, it was more of a tiredness, or an ache of the eye, so I did end up wearing sunglass most of the time and kept my eyes closed. I got to sleep a lot, and every time I woke up I was felt better. So, in general I'd say the worst day was the day of the procedure and then maybe the day after that, but every other day I've not had had actual eye pain, just fatigue.
“So, I was called in, almost a week exactly, since the original procedure and I was met by the nurse who actually did the procedure. Straight away I could see that she recognised me, she could see I recognised her. Which is a good thing because my vision was all over the place for the first few days. She was happy that my eyes were white, so showed there was no infection there. She went through quite a quick follow-up. Did my vision again, took the bandage lenses out and was very happy that I could actually see about 80% of what my original vision was. Then the rest of the vision she said should come back within the next few weeks.
“First impressions are yes [I am happy with how it went] because I'm healing every day, and I feel like it's going the way it should have done. But I suppose the only thing, long-term, is I’ll only know in a year whether the first procedure has been a success, or whether I might need it again. But, so far I'm happy I've had it done. I've actually got a twin brother who needs to go get checked up to see if he has the same thing, so I wouldn't hesitate to recommend he gets it done, because if it can protect your eyes from getting worse then definitely go for it.”
What is CXL?
Keratoconus gets worse because the cornea weakens. CXL, also known as C3R, uses ultraviolet light and vitamin B2 (riboflavin) drops to stiffen the cornea. Used together, they cause fibres within the cornea to cross-link – or bond more tightly. This treatment mimics the normal age-related stiffening of the cornea, which is known as natural cross-linking.
Which patients benefit from CXL?
The treatment is usually recommended only for patients whose corneal shape scans show that their keratoconus is getting worse. In order to obtain the most accurate scans, we ask that you remove your contact lenses prior to your scan (two weeks for hard contact lenses, one week for soft contact lenses).
If, however, you are unable to manage without your lenses, cross-linking treatment may still be available to you. In this situation, so long as the cornea is not too thin, treatment may be offered based on an evaluation of your risk of disease progression. Age is the most important factor in determining this risk: because of natural cross-linking as you get older, keratoconus usually stops getting worse by the mid-30s, so CXL is not normally required for older patients.
What evidence is there that it works?
Collagen cross-linking is the only treatment currently available that appears to stop keratoconus from getting worse.
Evidence from three randomised clinical trials one year after CXL showed success in halting keratoconus progression in more than 90% of treated eyes. Longer term results (up to 10 years) from different studies suggest a similarly high success rate in preventing keratoconus progression. Moorfields’ own results since 2013, when we began treating patients with CXL, show a success rate of approximately 94%, with less than 1% requiring a repeat CXL treatment.
Which type of CXL is Moorfields performing?
We perform an accelerated version of 'epithelium-off’ CXL known as
‘epithelium-off’ or ‘rapid’ CXL, which is an up-to-date and potentially safer variation of standard CXL. Standard CXL involves 30 minutes of ultraviolet (UV) light treatment. Rapid CXL speeds this process up by delivering the same total amount of UV light energy in eight minutes.
Rapid CXL is widely used, but as with any recent variation in treatment, long-term results are not yet available. You will be monitored for up to five years to confirm that your corneal shape has stabilised. CXL can be repeated if the shape does not stabilise after your first treatment.
Moorfields does not currently offer transepithelial (‘epi-on’) CXL, where the front surface of the cornea - the epithelium is not removed. To date, the only randomised controlled trial comparing this with standard ‘epi-off’ CXL concluded that it does not work.
Will I have both eyes treated at the same time?
If you need CXL for both eyes, we can offer you treatment for both eyes at the same time. If you would prefer to delay the second eye treatment, please request this at the clinic appointment prior to your treatment.
What happens during CXL?
CXL is performed as a day-case procedure by a senior ophthalmic nurse. Although the procedure takes less than 30 minutes, there is usually some waiting time before treatment and you will also need to stay for a short while afterwards so we can check that you have everything you need to go home, such as all your medications. Please be prepared to spend up to half a day in hospital.
During the procedure, you will be asked to lie flat on the treatment table. Anaesthetic drops are used to numb the surface of your eye before a small clip is placed to keep your eyelids open. The surface skin of your eye (epithelium) is gently brushed clear and riboflavin drops are applied every few minutes for at least ten minutes. Following this, the ultraviolet light is shone at your eye for eight minutes. A soft ‘bandage’ contact lens is placed on your eye at the end of the procedure.
What happens after CXL?
You will be given eye drops to use after the procedure. The soft ‘bandage’ contact lens will remain in your eye until the surface has healed (about seven days). If the bandage lens falls out during this time, please throw it away – do not attempt to reinsert it. There is no need to have the lens replaced before your first follow up appointment at one week.
The anaesthetic drops will wear off later on the day of your procedure, and your eye will be gritty, red and sensitive to light for several days. Everyone’s experience of pain is different, with some patients reporting very little discomfort and others describing the first few days as very painful. Your eyes could be light sensitive and many patients find wearing sunglasses helpful.
Your vision will be quite blurred at first, but will clear gradually over the first few weeks.
It is normal to experience fluctuating pain within the first two days after surgery. However, if you experience increasing pain three or four days after the procedure this could be signs of infection and you should visit A&E. Please note that infection is rare, affecting less than 1% of patients.
Do I need to take time off work or studies?
Yes. You should allow at least one week off while most of the surface healing occurs, or two weeks if your job involves a lot of computer work and the treatment is being done on your better eye. You will be putting eye drops in every hour for the first day, and then every four hours for the following days.
If you have exams or other important timelines over the coming months please let us know, as it may be more appropriate to postpone your treatment until afterwards.
Day to day activities such as watching TV or using a computer will not do any damage to your eye, but you might find it more comfortable to rest with your eyes closed early on.
You will be given an appointment the following week to check your eye is healing properly.
What should I do, or not do, after CXL?
It is important to put the eye drops in regularly as prescribed. You may wash and shower, but avoid getting any water in your eyes. You may exercise, but should not swim before the surface of your eye has healed.
We will check your vision in the clinic the week after your procedure to confirm if your vision is good enough to drive. It is normally safe to resume contact lens wear once the eye surface skin layer has healed. This typically happens around the end of the second week after your procedure. If you use spectacles, you are advised to see your local optician no earlier than one month after the treatment if you feel your prescription needs updating.
Remember that spectacle prescriptions can take up to a full year to stabilize following cross-linking, although in most cases stability is achieved after around six months.
Vision and spectacle tests, along with corneal shape scans will be repeated in the clinic six months after CXL. We expect most patients’ vision to recover to the same level as before treatment. In some cases, vision improves in the longer term. It is important to remember that the main aim of CXL is to stabilise, and not to improve vision.
What are the risks of CXL?
In general, CXL is very safe, but like all operations your eye needs time to heal and problems may rarely occur. Less than 3% of patients may lose some vision in the treated eye. This may improve spontaneously; in rarer cases where there is infection or scarring, this visual loss is potentially reversible with a corneal transplant.
Remember that without CXL treatment; at least 20% of all patients with keratoconus will eventually require a corneal transplant. The risk of transplantation for patients whose keratoconus is progressing is probably higher.
Keratoconus treatment is available at Moorfields Private
You can self-fund or use private medical insurance to fund your treatment.