Eye pain is a very common disorder of a non-specific nature, as it can have causes not only of ophthalmological, but also neurological origin. This should not be surprising, as conditions that can cause problems with the nerves that reach the eyes are not uncommon, as the orbits are innervated by the trigeminal nervefrom which the ophthalmic nerve is formed. Thus, a number of intracranial diseases, including vascular diseases and tumours, can also manifest with ocular pain.
Eye pain: what it signals
Pain is the biological alarm signal which can be a sign of damage and is essential for our survival.
Our ocular pain system is uniqueand its main role is to stimulate a reaction aimed at protecting visual function.
Ocular pain may be intermittent or continuous, occur sporadically or have a chronic character.
Pain and inflammation
A recent study conducted between Switzerland and the United States identified the most common causes of eye pain by examining a total of more than 80,000 patients.
In general, it was found that more than 60% of patients with ocular painexamined in ophthalmological facilities had inflammatory conditions, while in neurology departments, pain was more associated with headaches and migraine.
But let us look in more detail at the results of the study and the different types of pain that affect the eyes.
Ophthalmological causes of eye pain
Inflammation
As anticipated, most of the patients (60%) evaluated in the ophthalmology clinics had eye pain due to inflammatory eye diseases, which were easily diagnosed during the eye examination.
L'inflammation o inflammation  is a condition present in many diseases, the most frequent were keratitis, conjunctivitis and blepharitis.
Let us devote a few more words to conjunctivitis and keratitis.
Conjunctivitis
Conjunctivitis is an extremely common eye disease in both adults and children. It can have a great variety of aetiologies, infectious and non-infectious. In most cases of infectious conjunctivitis, the origin is viral, but a bacterial aetiology is also possible, usually recognisable by the presence of purulent discharge.
In these cases, effective treatment requires both the elimination of the inflammation of the ocular surface and the eradication of the responsible bacterial strain. For this reason, although conjunctivitis is often self-limiting in nature, patients are usually prescribed a broad-spectrum topical antibiotic. Moreover, since conjunctivitis in the active phase is best controlled with preparations containing steroids, combinations of steroids and topical antibiotics are often used.
Keratitis
The word keratitis indicates an inflammatory process that affects the cornea and can be infectious or non-infectious in nature. Symptoms vary greatly depending on the cause. Typically present are eye irritation, pain, blurred vision and photophobia (hypersensitivity to light).
Each type of keratitis requires a specific treatment that must be determined by the ophthalmologist and that may involve the use of antibiotic, antiviral, antifungal, and anti-inflammatory drugs.
Glaucoma
1.7% of the patients presented with eye pain due to glaucoma, in which increased intraocular pressure causes the onset of pain not only in the eye, but also headaches, visual changes or nausea and vomiting.
Glaucoma is a progressive, multifactorial neurodegenerative disease that is the most frequent cause of irreversible blindness. It was recently estimated that the number of people suffering from glaucoma worldwide will increase from 76.5 million in 2020 to 111.8 million by 2040, mainly due to an ageing population.
The term glaucoma, however, encompasses several conditions. Primary open-angle glaucoma (POAG) is the most common form in Western countries. The aetiology of POAG is generally mechanical, when intraocular pressure leads to compression of axons, or vascular, when blood flow and ocular perfusion pressure are reduced.
Pain associated with eye movement
Optic neuritis
About 32% of the patients with pain due to eye movement had optic neuritis, i.e. inflammation of the optic nerve. The symptoms of optic neuritis are usually unilateral, with ocular pain and partial or complete loss of vision. The diagnosis is mainly clinical. Treatment is directed at the underlying disease, which could also be multiple sclerosis or systemic lupus erythematosus.
Other pathologies
Pain due to eye movement was also associated with orbital myositis, headache/ migraine, uveitis and ocular surface diseases. In particular, orbital myositis, an inflammation of the orbital muscles, was present in 0.5% of the patients.
Other causes of eye pain
Migraine
With regard to causes of ocular pain that are not strictly related to ophthalmic conditions, the study showed that migraine/headache is the most frequent cause, associated with a characteristic 'stabbing' pain, which may be unilateral or bilateral.
This type of pain may affect only one or both eyes.
Patients with migraine often also have other ocular symptoms, such as photophobia (discomfort and pain in the presence of light).
Vascular causes of eye pain
Although rare, vascular causes of eye pain are often associated with serious conditions, so early diagnosis is crucial.
Vascular disorders
In this context, the study found that 2% of the patients with ocular pain who visited the neurologist had vascular disorders, such as unruptured cerebral aneurysms. In these cases, the pain is due to compression of the optic nerve.
Intracranial tumours
The study identified pituitary and meningeal tumours among the causes of ocular pain. This is because these types of tumours, as well as aneurysms, can compress the trigeminal nerve or optic nerve.
Intracranial hypertension
Intracranial hypertension, i.e. increased pressure inside the skull, can also cause eye pain, which often occurs in both eyes.
This condition is also associated with headaches and pain when moving the eyes.
What to do
In case of eye pain, it is important consult the doctorespecially in the presence of the following conditions:
-eye pain is intense and/or persistent;
-Eye pain is accompanied by headache, fever, nausea or vomiting, unusual sensitivity to light or presence of visual halos;
-the visual function has changed suddenly;
-Eye pain is given by a foreign body or a chemical substance, penetrated into the eyes;
-in the presence of swelling in or around the eyes, difficulty in movement and opening of the eyes;
-in case one has soft contact lens wearers or those with a weakened immune system.
Conclusions
For all the conditions discussed in this article, it is always recommended to consult your family doctor and undergo a comprehensive eye examination as soon as possible.
Consultation with an ophthalmologist is absolutely essential if pain is associated with red eyes or loss of vision.
If the pain is associated with migraines or headaches, on the other hand, it may be necessary to consult a neurologist to rule out the presence of more serious pathologies.
In conclusion, the optimal medical management of many patients with ocular pain often involves the collaboration of a multidisciplinary team, consisting of both ophthalmologists and neurologists.
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