A variety of things like stress, caffeine, food or your vision can cause headaches. Vision-related headaches specifically have many causes, but most often are caused by a person squinting and overworking the eye muscles in an attempt to see better. In other more serious cases, internal problems from pressure or swelling within the eye can translate pain into other areas of the head.

Headaches resulting from difficulties with vision can be corrected with prescription glasses or contact lenses. Other issues, such as glaucoma, need to be medically treated. Once you find the source of your headache, the pain should subside and eventually go away.

Eye strain

The cornea and the lens work together to focus images on the retina at the back of the eye. Sometimes, this delicate mechanism stops doing its job and the small muscles of the eye are forced to work harder causing eye strain. The result is tired, aching eyes, blurred vision and headaches. Most conditions can be corrected with prescription glasses or contact lenses.

The main problems that cause eyestrain and associated headaches include:

Astigmatism – the cornea is not a regular shape, which means that objects look blurry from certain angles. A person with astigmatism tends to squint in order to better focus their vision, which can contribute to headaches.

Hyperopia – or far-sightedness. Instead of focusing the image squarely on the retina at the back of the eye, the image is focused to a point behind the eye.

Presbyopia – the lens becomes hard and inflexible with age. Symptoms include difficulties in focusing closely, sore eyes, sluggish changes in focus when looking from one distance to another, and headaches.

Eye Alignment -- eyes are designed to work in unison, but if eyes aren't aligned properly it can cause headaches. Think of it as a team of horses pulling a cart: if one horse doesn't follow the others it creates problems and inefficiency.  

Glaucoma

The eye disease glaucoma can cause severe headaches in some cases. Intraocular pressure refers to the amount of pressure inside the eye caused by a build-up of fluid, due to insufficient drainage. The result is damage to the optic nerve. It is not possible to prevent glaucoma from developing, but early detection may help to slow its progression.

The two main types of glaucoma include:

Open angle glaucoma – is the slow build-up of intraocular pressure over time. This type usually presents no symptoms.

Angle closure glaucoma – a sharp increase in intraocular pressure results in severe pain, blurred vision, watering of the eyes, nausea and vomiting. This type of glaucoma attack needs prompt medical intervention.

Papilledema

The optic nerve transmits information from the eye to the brain. Brain tumors, hemorrhages or swelling are just some of the disorders that can cause the optic nerve to swell with excess fluid. This disorder is called papilledema.

Symptoms can include headaches, blurring and double vision, although it is possible to have no symptoms at all. In chronic cases, there may be nausea, vomiting and permanent loss of vision. If a headache is present, it may feel worse with coughing or sneezing, but eases a little when lying down.

Seek professional advice

If you think your headaches may be due to eyestrain, it is important to have your vision checked by a qualified eye specialist. Some people who already wear prescription glasses may not be aware that their eyes may have changed a little over time. It is important to have your eyes regularly tested and your glasses or contact lenses updated. We also encourage a team approach to health care. Pain is often referred to other parts of the body, so it won't be uncommon if your eye doctor recommends a trip to your dentist, primary care doctor or specialist.