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Some people's eyes burn and hurt every day, but when they are examined by an eye doctor they are told that the eye "looks fine". If this sounds familiar, part of the pain may come from the nerves of the eye and not only from dryness. This page explains what neuropathic eye pain is, how it is checked and what can be done.
What neuropathic eye pain is
The cornea (the clear window at the front of the eye) is one of the tissues in the body richest in sensory nerves. These nerves warn of dryness, dust or injury, and make us blink and tear. Neuropathic pain (pain that comes from damage to, or abnormal function of, the nervous system itself) appears when these nerves become oversensitive and send pain signals even when there is no real danger.
In simple terms, the eye's "alarm system" is set too sensitive. Hence the professional expression "pain without staining": a lot of pain, and few signs on examination.
Why it happens
Several pathways can lead to neuropathic eye pain, and sometimes they combine:
- Damage to the corneal nerves: after eye surgery (such as vision-correction surgery or cataract surgery), after an infection such as shingles around the eye, or after an injury.
- Long-standing dryness: ongoing inflammation of the eye surface can, over time, change the way the nerves behave. Even after the dryness improves, the pain may persist.
- Central sensitisation: sometimes the central nervous system (the brain and spinal cord) also amplifies the pain signals. This is more common in people with other chronic pain conditions, such as migraine or fibromyalgia.
For years neuropathic eye pain was rarely diagnosed, partly because it closely resembles ordinary dry eye, and the usual tests focus on the surface of the eye and not on the nerves. Today awareness of it is higher, and the current professional definitions of dry eye describe it as one of the possible components of the disease. In practical terms, this means that in some people with dry eye, the pain comes from the nerves as well, and not only from the dryness.
Poor sleep, long-term stress and depression are also linked to stronger pain. This does not mean the pain is "in your head"; the nervous system is simply affected by all of these.
How it is recognised
Several clues point to neuropathic pain:
- The pain is stronger than the examination explains.
- Burning, stabbing or a feeling of an "exposed eye" that appears even when the eye is moist.
- Unusual sensitivity to wind, air conditioning, light or gentle touch (allodynia: pain from a stimulus that is not normally painful).
- Lubricating drops help very little, or only for a few minutes.
- The pain started after surgery, an injury or an infection of the eye and has lasted for months.
These clues are not enough for a diagnosis on their own, but they are worth telling the doctor about, because they change the direction of the examination and treatment. An overview of the types of eye pain and of warning signs is on the painful eyes page.
What the eye doctor checks
First of all, it is important to rule out other causes of pain and to treat any dryness, eyelid inflammation or meibomian gland problem that is actually present. So the examination includes the usual dry eye tests: a symptom questionnaire, a slit-lamp examination, fluorescein staining, measurement of tear break-up time, examination of the eyelids and a corneal sensation test. Details are on the dry eye testing page.
When the pain is much stronger than the findings, the doctor may carry out an anaesthetic drop test (a drop that temporarily numbs the surface of the eye). If the pain disappears almost completely after the drop, it probably comes from the nerves in the surface of the eye. If the pain remains, there may be a component of central sensitisation. The test is simple, and it helps choose the direction of treatment. Anaesthetic drops are used only for testing and are not a treatment, because repeated use damages the cornea.
Treatment options
Treatment of neuropathic eye pain is often long and combines several approaches. There is not always a quick solution, but many people can achieve a significant improvement.
Treating the surface of the eye
Even when the dryness is mild, it is treated: preservative-free lubricating drops, treatment of the eyelids and meibomian glands, and reduction of irritating factors. The eye doctor may prescribe anti-inflammatory drops when there is inflammation of the eye surface. It is important to reduce exposure to preservatives, which can irritate sensitive nerves.
Clinic treatments that may be combined
- Autologous serum eye drops: they contain natural growth factors that support healing of the eye surface and perhaps the nerves too. In some patients with a neuropathic component they may help, but research in this area is still limited.
- Meibomian gland expression and IPL, when an examination shows that the meibomian glands are blocked and contribute to the symptoms.
- Bandage contact lens, in selected cases and for a limited period, when the surface of the cornea is damaged and the touch of the eyelid is painful.
Treating the nerves themselves
When there is a clear central component, drops alone are usually not enough. In such cases medicines taken by mouth that affect pain signals are sometimes used, of the kind also used for other neuropathic pain in the body. These medicines are prescribed and monitored by a neurologist or a doctor from a pain clinic. Treatment of sleep, anxiety and stress, including focused psychological therapy, may reduce the intensity of the pain, just as with chronic pain anywhere else in the body.
What to expect, and daily steps
Improvement in neuropathic pain is usually slow, over weeks and months. It is worth keeping a short diary: when the pain is stronger, what makes it worse and what eases it. The diary helps you and your doctors see whether a particular treatment is working, even when the change is gradual and not noticeable from day to day.
- Protect your eyes from wind and direct airflow, for example with glasses with side shields.
- Reduce the number of different drops you use, in coordination with your doctor. More drops do not always help, and sometimes they actually irritate.
- Keep to regular sleep as much as possible, because poor sleep increases sensitivity to pain.
- In front of screens, take short breaks and remember to blink.
- Do not use anaesthetic drops at home, even if they brought relief during the examination. They damage the cornea with repeated use.
Working together with other doctors
Neuropathic eye pain sits on the border between ophthalmology and pain medicine. The eye doctor treats the surface of the eye and monitors the cornea, and a neurologist or pain doctor treats the nerve component. If you have migraine, fibromyalgia or another chronic pain condition, tell both sides. Coordination between the doctors saves duplicate tests and helps build a single plan.
When to see a doctor straight away: new, strong eye pain, especially with reduced vision, a very red eye, marked sensitivity to light, haloes around lights, headache with nausea, or pain after a blow to the eye or something getting into it. These are not signs of neuropathic pain, and they require an examination by an eye doctor or at an eye emergency department the same day.
In summary
If your eyes hurt much more than the examination explains, it does not mean you are imagining it. There may be a neuropathic component that needs a different approach. A thorough examination by a dry eye specialist can separate dryness that needs treatment from nerve sensitivity, and build a plan that combines both.
Want a basic explanation first?For basic information on dry eye symptoms and diagnosis: the guide on the Mitzmutz site
Frequently asked questions
If the examination is normal, does that mean the pain is not real?
No. In neuropathic pain the problem is in the nerves that carry the sensation of pain, and it cannot always be seen with a slit lamp. The pain is completely real, and there are ways to diagnose and treat it.
Why don't lubricating drops help me?
Lubricating drops treat dryness of the eye surface. When the pain comes mainly from oversensitive nerves, they may help only a little. This is one of the clues that it is worth checking whether there is a neuropathic component.
Can neuropathic eye pain appear after vision-correction surgery?
Yes. In a minority of people who have the surgery, the nerves in the cornea regenerate abnormally, and pain and burning appear that persist after the eye has already healed. This is a recognised condition worth telling your eye doctor about.
Do autologous serum eye drops help neuropathic pain?
Some patients feel an improvement, perhaps thanks to growth factors that support the nerves, but research is still limited. The decision is made after an examination and a discussion of the benefits and limitations.
Home care not enough? We can look into it.
At the dry eye clinic in Haifa we find out what is causing the dryness and build a personal treatment plan.
Sources
- Galor A, Moein HR, Lee C, et al. Neuropathic pain and dry eye. Ocul Surf. 2018;16(1):31-44.
- Bron AJ, de Paiva CS, Chauhan SK, et al. TFOS DEWS II pathophysiology report. Ocul Surf. 2017;15(3):438-510.
- Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15(3):276-283.
- Wolffsohn JS, Arita R, Chalmers R, et al. TFOS DEWS II Diagnostic Methodology report. Ocul Surf. 2017;15(3):539-574.
- Pan Q, Angelina A, Marrone M, Stark WJ, Akpek EK. Autologous serum eye drops for dry eye. Cochrane Database Syst Rev. 2017;2:CD009327.
The information on this site is general only. It is not medical advice and does not replace an examination by an eye doctor.