Bright Sight

Oliver Backhouse, Consultant Eye Surgeon www.cataract.org.uk

HLA B27 and Iritis

1] What is HLA B27?

This is a name given to part of your genetic make up and is found in 7% of the UK population. It is still unknown how this genetic make up can predispose you to inflammation conditions such as Iritis but it probably is involved in the way your immune system deals with infections.

2] Iritis and HLA B27.

This type of irits can be of sudden onset and can be quite aggressive. It is therefore important that if you feel discomfort in the eye associated with redness and a possible worsening of discomfort in bright light that an Ophthalmologist sees you soon. Quite often the Iritis recurs in the same or other eye but there is no obvious way of predicting or preventing an attack although some patients feel it may be provoked by stress and hormone cycles. I am sure this plays a small part in it but the main reasons are still unknown. Possibly a common infection can reactivate the inflammatory cells which cause the Iritis. Approximately 40% of Iritis can be linked with HLA B27.

3] Is HLA B27 associated with any conditions?

Yes. Certain medical conditions such as Psoriasis (a skin condition); Irritable bowel disorder; Ankylosing Spondylitis (an arthritis of the lower spine) and Reactive Arthritis (joint pain following an infection) are more frequent if you are HLA B27 positive. It is therefore important that you let your doctor know if you or anyone in your family has these conditions or symptoms such as a sore lower back even if they are mild. The importance for this is that early diagnosis can help prevent later possible problems such as a longstanding stiff back and neck.

DiseaseHLA B27 frequency % (approximately)
Ankylosing Spondylitis96%
Reactive Arthritis70%
Irritable Bowel Disorder50%
Psoriasis40%
  
Healthy UK Population7%

4] What is the chance of getting Iritis if I am HLA B27 positive?

Healthy Otherwise1%
Ankylosing Spondylitis 40% (25% if HLA B27 negative)
Psoriasis + Spine Arthritis 33% (5% if non-spine arthritis) Note 2% of the population has psoriasis and only 7% of these will have arthritis.
Reactive Arthritis30%

Approximately 40% of Iritis is HLA B27 associated.

5] How is HLA B27 Iritis treated?

Usually patients will need steroid and dilating (making the pupil big) eye drops to control the inflammation and ease the discomfort. The dilating eye drops will further make the vision blurred and the effect of these drops can last for several days after having been stopped. Warm compressions with a flannel soaked in cooled boiled water can also ease discomfort and help to dilate the pupil. Steroid eye drops may be given every hour for the first few days. Sometimes it may be necessary to give a small injection of anti-inflammation medicine beside the eye. This is so a high dose can be given to where it is needed to try and gain control of the inflammation which can be quite aggressive.

The Iritis will usually resolve on its own in 6-8 weeks but the drops can make this quicker and with less discomfort. The drops should not be reduced too quickly or there will be a rebound of the Iritis. This is the same attack rather than it being a separate recurrence. Should the inflammation be in the back of the eye rather than just the front part then medication by the mouth and further investigation such as blood tests may be asked for.

If there is a clear pattern of recurrent Iritis you may be given some drops to keep at home in the fridge to use when you feel an attack of Iritis is coming on with the full understanding that you will see an Ophthalmologist within 3 days. It is not safe to use Steroid eye drops unsupervised and must never be done.

Will my vision get better?

It is rare for this type of Iritis to cause permanent vision loss. Problems can occur if Steroid medication is used without proper close follow-up by an Ophthalmologist. The dilating drops, which blur the vision themselves, can take a few days to wear off. You should always make sure your glasses are kept up to date. Your Ophthalmologist will let you know if it is alright to see an Optometrist.

How can I prevent involvement of the other eye?

Unfortunately there is little you can do to prevent recurrences in either eye. The best thing is to recognise that it can recur and so get the inflammation treated quickly with eye drops. Sometimes other medications are given to try and prevent frequent attacks and this can be discussed with your Ophthalmologist.