Frequently Asked Questions

What is iritis?

There is a whole page devoted to this.  Click here.

Why is the font size in so big?

This is because many patients with iritis have poor vision, or are using dilating drops which reduce near visual acuity.  If it is too big (or too small), you can change the text size in your browser.  For example, in Microsoft Internet Explorer select View from the menu and then Text Size.

What is the difference between iritis and uveitis?  Sometimes I am told I have iritis, sometimes I am told I have uveitis, but the symptoms are the same to me

Iritis is a kind of uveitis, specifically it is the same as "anterior uveitis".  There are three types of uveitis - anterior, intermediate, and posterior. Intermediate and posterior uveitis are rare conditions. Iritis (= anterior uveitis) is a common condition.

Isn't iritis due to an infection?  I thought most diseases ending in -itis were caused by infection

Few cases of iritis are caused by infection, although infection is a rare cause. The -itis suffix actually denotes inflammation, which is not the same as infection. Infection is caused by an external organism invading the body. 

Inflammation is one response of the body to infection. Unfortunately, inflammation may occur when the body's immune system targets itself inappropriately. In most cases of iritis, it is the inappropriate targeting which occurs.

What are the functions of the drops I have been prescribed?

There are many drops used in the treatment of iritis. The two main kinds of drops used in iritis are

  1. Steroid drops
  2. Dilating drops

Steroid drops

Steroid drops (also known as corticosteroid drops) are used to decrease inflammation, which is the cause of pain and redness of the eye. Steroid drops come in different varieties and strengths, and may be taken as often as every half an hour or as infrequently as twice a week.  For most attacks of iritis your ophthalmologist will advise steroid drops every two hours or so for the first few days.

Examples of steroid drops (brand names in [brackets]):

Prednisolone [PredForte; Predsol is a weaker formulation]
Dexamethasone [Maxidex]
Betamethasone [Betnesol]
Fluoromethalone [FML]
Hydrocortisone [Neo-Cortef]
Clobetosone butyrate [Cloburate]
Rimexolone [Vexol]

Dilating drops

Dilating drops are used to relax (ie. make large) the pupil and the ciliary musle. There are two reasons for this: first, relaxing the pupil helps prevent the formation of posterior synechiae, and second, relaxing the pupil and ciliary muscle decreases the pain associated with iritis.

Dilating drops have differing duration of action, noted below:

Atropine (1 week)
Homatropine (1 day)
Cyclopentolate 0.5% [Mydrilate] (8 hours)
Tropicamide 1% [Mydriacyl] (6 hours)

The duration of action given is approximate.  For example, the effect of atropine may wear off in a few days in some people, a few weeks in others.

Are there any side effects from steroid drops?

About 5% of the population are "steroid responders", meaning that the intraocular pressure goes up when steroid drops are used. Your ophthalmologist will measure your intraocular pressure on your first two visits to determine whether you fall into this group.  

If you are a steroid responder, your ophthalmologist may prescribe anti-glaucoma medication to bring the pressure down, or he may prescribe a weaker steroid such as FML.  A new steroid drop, Rimexolone, which has high potency but low potential to increase pressure has come on the market. 

If you are a steroid responder, you should remember this fact and mention it to your ophthalmologist on your next visit so that he can take appropriate action to minimise a rise in pressure.

Other side effects are few. The purpose of steroid drops is to decrease inflammation. Therefore, while you are on steroid drops your resistence to external infection will be reduced. Since the wearing of contact lenses may encourage infection, contact lenses should not be worn.

Are there any side effects from dilating drops?

Blurred vision is the main side effect. Some people may notice dry mouth. In some people (especially those given atropine) some slowing of the heart beat may occur.

The last time I had iritis I was given steroid drops. However, for my most recent attack I was given different steroid drops!  Why?

The different steroid drops have differing strengths: PredForte and Maxidex are at the strong end of the scale, Betnesol and Predsol are in the middle, and FML is a weak steroid. They have slightly different penetration characteristics. Your eye doctor will have a preference.

Probably the commonest drops used in the UK for the treatment of iritis are PredForte and Maxidex. There is little to choose between them in strength. Some doctors and hospitals prefer one drop, some another.  When I used to work in East Anglia, I prescribed Maxidex; when I moved to the Midlands I started prescribing PredForte mainly because it was advocated by the local iritis expert.

Many ophthalmologists (including myself) don't think there is very much difference between PredForte and Maxidex. There is little or no convincing research to demonstrate any superiority of one over the other.

The last time I had iritis I was given dilating drops. However, for my most recent attack I was given different dilating drops!  Why?

Again, the preferences of your ophthalmologist will have a large part to play. The main difference between the various kinds of dilating drops lies in their duration of action. There are also significant differences in the severity of their side effects.

When I used to work in East Anglia, I prescribed cyclopentolate 1% to people with simple uncomplicated iritis. When I moved to the Midlands, atropine was the standard dilating drop at my new hospital so I started prescribing it instead. The main difference was that people on cyclopentolate recovered sharp vision sooner on discontinuing the drop as it only lasts 8 hours on average. People on atropine had to wait a week. However, there is little or no convincing evidence to demonstrate any long-term advantage of one dilating drop over the others.

If you have had particular preferences for one type of dilating drop in the past, you should mention this to your ophthalmologist.

What about non-steroidal anti-inflammatory drops?

These are sometimes used in place of steroid drops in mild cases of iritis.  Examples are Diclofenac (Voltarol ophtha) and ketolorac (Acular).

My vision has not got better despite the treatment

The aim of iritis treatment is not short-term restoration of vision, but rather the long-term preservation of vision. Very often, the vision remains poor because of dilating drops such as atropine, homatropine, cyclopentolate [Mydrilate], and tropicamide. By keeping your pupil dilated, your ophthalmologist aims to minimise the chances of long-term damage to the eye due to posterior synechiae. The drops also have the effect of lessening the pain in the eye.

If rapid restoration of sight is very important to you, let your ophthalmologist know. It is possible to prescribe short-acting dilating drops to be taken before bedtime. However, nobody knows whether this is more or less likely to lead to complications later. Most ophthalmologists would say that after two or three days of steroids and constant dilation, dilation at night only is safe.

If anything, I have become more sensitive to light since treatment commenced

This is probably because you have been given dilating drops, which enlarge the pupil. This allows more light to enter the eye.

Wear dark glasses.

The doctor gave me an injection in the eye!  Why is this necessary?

In severe cases of iritis, or when the iris  is persistently stuck to the lens, injections into the conjunctiva (the white part of the eye outside the cornea) are very effective in delivering a constant dose of steroids and dilating drops to the eye. The effect lasts for a day or two, and virtually all of my patients are glad that they opted to have it done, as the relief from pain and discomfort is dramatic.

The procedure sounds much worse than it is. The eye is thoroughly anaesthetized with drops before the procedure.  There may be some dull pain after the procedure and the eye may be difficult to close for an hour or so. Your ophthalmologist may advise padding the eye.

The last time I had iritis my left eye was affected.  This time my right eye is affected.  My iritis must be getting worse as it has spread from one eye to the other

The majority of cases of iritis are relapsing and remitting, or in other words, it comes and goes. There seems to be little in which eye it affects. Iritis going from one eye to another, with a quiet period in between, is normal.

I have been given steroid tablets.  What are the side effects?

Steroid tablets (eg. Prednisolone) are given in cases of complicated uveitis, often posterior uveitis. They are used to dampen down the immune system.

The major side effects are

Weight gain in the abdominal area
Purple lines on the abdomen and flanks
Round ("moon") face
Increased susceptibility to infection
Water retention
Osteoporosis resulting in brittle bones
Inappropriate hair growth (eg. facial hair in a woman)
Baldness in men
Muscle wasting
Hypertension (high blood pressure)
Diabetes mellitus

Steroids are given because your ophthalmologist judges that the risks to the eye outweigh these side effects.  If your side effects are very severe, you should discuss the pros and cons of steroids with your ophthalmologist.

I seem to get an attack of iritis at least once a year.  Is there any way I can prevent the attacks from happening?

I'm afraid not!  There have been a few studies which suggest that stress is a factor. In earthquake victims living in tents in Japan, the rate of iritis tripled. There are scientific papers noting that flare-ups of rare kinds of iritis (JCA, Behçet, Vogt-Koyanagi-Harada) are less common during pregnancy. This is probably due to the change in hormones during pregnancy.

I get attacks of iritis frequently.  Do I need to see an ophthalmologist at all?  Can't my family physician prescribe the appropriate treatment?

You need to see an ophthalmologist in order to confirm the diagnosis. If you have only had iritis once or twice, you may be confusing the symptoms of some other eye condition with that iritis.

In particular, corneal ulcers may be mistaken for iritis by both patients and by non eye-trained doctors. This is an important distinction because corneal ulcers are made worse by steroid drops.

I keep an unopened bottles of steroid drops and dilating drops in the refrigerator at home in case I have flare-ups.  Am I taking any risks self-medicating?

If you have had iritis many times, you may come to recognise the symptoms accurately. In an ideal world you would see an ophthalmologist to confirm the diagnosis as soon as you get the symptoms.  

In the real world, you may live 100 miles from the nearest ophthalmologist, or it may be 10 pm on a Saturday night and you may face a six-hour wait at the nearest hospital's casualty (emergency) department.

If you do self-medicate in these circumstances, the risk you are taking is small as long as you see an ophthalmologist the next day.

I'm off to Antarctica for six months.  I won't be able to consult an ophthalmologist if I get an attack of iritis.  What can I do?

This is a difficult question, and you alone must weigh up the benefits and risks. I can only tell you what I would do if it was me myself who had to make the decision.

If I had very frequent attacks of iritis (more than one every six months) over the last few years, and there was a high probability of an attack while I was in Antarctica, I would probably not go.

If attacks were rare (less than one a year), and each attack was not very severe (not needing injections into the eye), and I was confident that I could recognise the symptoms of iritis accurately then I might well pack some unopened steroid and dilating drops. However, I would be aware that iritis is a potentially blinding condition and take that risk accordingly.

What other conditions can cause symptoms of a painful red eye?

  1. Corneal ulcer -- in young people, often associated with contact lens wear. Treated with antibiotics/antiviral drops depending on the cause. Made worse by steroid drops.
  2. Corneal abrasions -- due to superficial scratches of the cornea (from direct trauma or from a foreign body in the eye). Very painful. May lead to corneal ulcers if not treated with antibiotics as a precaution.
  3. Recurrent corneal erosions -- Very painful, recurrent red eyes due to unstable corneal epithelium (the surface covering of the cornea). 
  4. Bacterial conjunctivitis -- causes a sticky red eye which is more uncomfortable than painful. Often starts in one eye then spreads to the other. Treated with antibiotics.
  5. Allergic conjunctivitis -- causes itchy red eyes which are not particularly painful. Usually affects both eyes. More common in people with multiple allergies, with asthma, with hayfever, and with eczema (ie. with an atopic disposition). Treated by drops which reduce the allergic response.
  6. Viral conjunctivitis -- causes a watery eye which is not usually very painful. Often starts in one eye then spreads to the other. No effective treatment. May last for a long time (weeks to months).
  7. Chlamydial conjunctivitis -- causes a slightly sticky discomfort in both one or both eyes which grumbles along for weeks before becoming significant enough to see a doctor for. Usually sexually transmitted. Effectively treated with antibiotic tablets.
  8. Episcleritis -- reddening of part of the eye only. May be accompanied by pain, in which case steroid drops may help. Otherwise goes away by itself after about a month.

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