A painful, light sensitive red eye needs seeing quickly

The symptoms

Pain and redness, marked sensitivity to light, watering, blurred vision and floaters. Not every red eye is uveitis, and most red eyes are not. But a red eye that hurts and hates light is different from a red eye that itches, and it should be looked at rather than treated with whatever drops are in the cupboard.

Where the inflammation sits

The location determines both the likely cause and the treatment.

• Anterior uveitis: the iris and ciliary body at the front. The most common, and the most painful
• Intermediate uveitis: the middle of the eye. Floaters and blurring rather than pain
• Posterior uveitis: the choroid and retina at the back. Threatens central vision directly
• Panuveitis: inflammation throughout the eye

Finding the cause

Many cases are idiopathic, meaning no cause is ever found, and those are still treated. But uveitis can be the first sign of an infection or an autoimmune condition elsewhere in the body, so where the pattern suggests it, a workup follows: full blood count, ESR and CRP, HLA typing, ANA, VDRL, a chest X ray, urinalysis, and targeted infection testing. Sometimes the eye is how a systemic condition is caught.

Treatment

Steroid and anti inflammatory drops for anterior disease, with dilating drops to ease the spasm that causes much of the pain. Injections around or inside the eye for deeper inflammation. Oral immunosuppressants for recurrent or severe disease, usually alongside a physician. Vitrectomy or a slow release steroid implant in selected cases.

It tends to come back

Uveitis recurs in many people. Learning your own early warning signs, and coming in when you notice them rather than a fortnight later, is what keeps each episode short and prevents the complications that do the lasting harm.

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