Eye Strain

Staring at a computer screen can cause eye strain.

• Eye strain complaints are one of the most common reasons people seek eye care.
• Eye strain from reading can significantly impact schoolwork and productivity at work.
• There are several causes of eye strain, most of which are not dangerous to one's health. However, in rare cases, it can be a sign of an underlying medical condition.

Eye strain is generally defined as pain or discomfort in or around the eyes while focusing on a visual task. Most commonly, it occurs when focusing on up-close work or reading material, reading at an intermediate distance such as a computer screen, watching TV, playing a video game, or when engaging in other visual tasks that require focused visual attention with few rest breaks. Less commonly, it can occur when straining to focus at a distance.

There are several causes. Some of the most common include the following:

• Blurry vision due to refractive errors (under or over correction of glasses or contact lenses)
• Dry eyes
• Ciliary spasm, in which the ciliary muscles inside the eyes (which are used to focus up close) become temporarily tight and create a cramping sensation
• Convergence insufficiency, which is difficulty aligning the eyes properly when focusing up close, particularly when tired
• Heterophoria, which a misalignment of the eyes in certain directions of gaze that is typically worse when tired
• Brow and lid ptosis (drooping upper brow and lids), resulting in aching and fatigue as the muscles of the forehead contract in an effort to hold the lids up
• Various eye diseases that produce blurred vision, floaters, glare, or light sensitivity, all of which can lead to eye strain

Eye strain felt around the eyes can originate from sources outside of the eyes, such as from sinus congestion, migraine, or tension headaches.

Uncommonly, more serious eye conditions such as elevated eye pressure or intraocular inflammation may cause eye strain. However, in these cases, the symptoms persist even when the eyes are resting and not focused on a task.

• Refractive error (for example, nearsightedness [myopia], farsightedness [hyperopia], astigmatism, and/or presbyopia) is a risk factor. Presbyopia is an especially common cause of eye strain. It is the inability to accommodate (focus up close) easily as we get older, due to the gradual stiffening of the eye's natural lens. Typically, people notice it in their early to mid-40s, and it gradually worsens with time.
• Dry eye is a common risk factor for eye strain. We tend to blink far less frequently when we concentrate on reading (either print material or electronic device screens). The tear film that coats our eyes' surface evaporates between blinks, leaving the eyes with a dry, sandy feeling and fluctuating vision. Wind from air conditioning and heating vents, fans, and open windows can make the symptoms even worse. A large number of chronic conditions are associated with dry eye. Most common among these is meibomian gland dysfunction (MGD), a form of acne of the eyelid margins. Other conditions that lead to dry eye include overuse of drops that irritate the eyes' surface (for example, redness reliever drops, antihistamines, and eyedrops containing certain preservatives or chemicals that interfere with the eye's tear film), contact lenses that fit too tightly, and autoimmune disorders that result in chronic inflammation of the eye's surface or the lacrimal glands.
• Long periods of continuous close work without breaks is a risk factor for ciliary spasm. The ciliary muscles in the eyes that you use to focus up close (accommodate) normally relax when you focus your sight off to the distance, but with long periods of close work, they can spasm, resulting in a cramping ache.
• Fatigue is a risk factor for eye strain, particularly in people with convergence insufficiency, heterophoria, or eyelid ptosis.

Symptoms and signs range from

• a cramp-like ache in and around the eyes,
• a dry or sandy sensation,
• excess tearing,
• trouble focusing,
• intermittent double vision, and
• headache.

Accompanying neck pain may develop from leaning forward in an attempt to focus on a computer screen. Symptoms of nausea, feeling dizzy, or experiencing vertigo are sometimes brought on by eye strain. However, these symptoms can be due to other underlying health conditions and your physician should investigate.

Signs of eye strain are usually not outwardly visible. The eyes may be red in severe dry eye. Eyelid twitching can accompany eye strain and is thought to be caused most often by stress, fatigue, or too much caffeine.

Because eye strain is a group of symptoms felt by the patient, the eye doctor will be alerted to the presence of eye strain only when the patient provides a history of symptoms. It is helpful if the patient can be specific in describing the type of eye strain symptoms, the time of day when they're worse, and what activities seem to bring them on. The eye doctor can arrive at a diagnosis of the most likely causes by taking this history into account, as well as by carefully examining the eyes for signs of underlying problems.

Eye strain due to dry eye can often improve with treating MGD (ask your doctor about warm compresses and cleaning the eyelid margins with diluted baby shampoo), using artificial tears (preservative-free versions are usually tolerated well), and positioning yourself away from any wind coming from air conditioning/heating vents, fans, or open windows.

Blinking more frequently is certainly a good way to lubricate the eyes, however, it is unrealistic to try to remember to blink more frequently when you are mentally concentrating on reading material. The next best thing is to set a timer to take breaks from up-close work. Many doctors suggest following the 20/20 rule, meaning that every 20 minutes you should take 20 seconds to focus on a distant object (to relieve any ciliary spasm) and blink several times (to lubricate the eyes' surface).

Adjustments in lighting can sometimes provide relief from eye strain. When working with computer screens and electronic devices, it may help to alter monitor brightness, increase font size, and adjust contrast.

Blue-blocking glasses are being promoted as a way to reduce eye strain. Whether blue light coming from an electronic device screen or LED does any harm to the eyes is controversial. However, there is a large body of evidence pointing to the importance of blue light's effects on our sleep cycles. It is the timing of blue light that is important. Natural light patterns include plenty of blue light during the day and reduced blue light in the evenings. However, evening and late-night blue light exposure from electronic device screens can interfere with the body's circadian rhythms, resulting in poor quality of sleep. This could in turn result in fatigue, which can exacerbate eye strain. Therefore, it may be helpful to reduce screen time in the evenings or perhaps try blue blocking filters for evening screen time.

In addition to the home remedies mentioned above, your eye doctor may recommend other treatments. If the source of eye strain is due to an underlying eye health issue, your doctor can guide you in how to reduce the eye strain symptoms further.

For example, eye strain due to dry eye may respond to additional treatments such as prescription anti-inflammatory eyedrops, punctal plugs, or oral medications designed to improve the quality of the tear film. Glasses, contact lenses, or refractive surgery can correct refractive errors (for example, nearsightedness [myopia], farsightedness [hyperopia], astigmatism, and/or presbyopia). Convergence insufficiency symptoms can be relieved with prism in the glasses and certain eye muscle exercises. Heterophoria symptoms can be relieved with prism in the glasses or surgery, depending on the type. Surgery can correct brow and lid ptosis (drooping upper brow and lids).

Thankfully, the prognosis is generally very good since the causes of eye strain are rarely threatening to one's health, and the above-mentioned remedies can relieve most symptoms. It is important to remember that the symptoms themselves do not cause any damage to the eyes and using the eyes do not alter the structures of the eyes.

The best prevention is to identify and address the underlying conditions that lead to eye strain. The above-mentioned home remedies of proper lighting, proper correction of refractive error, and implementing the 20/20 rule to rest and properly lubricate the eyes prevent the most common forms of eye strain.