Enfermedad del Ojo Seco: Qué es, Síntomas y Tratamiento
What is Dry Eye?
Dry eye disease (DED), also known as dry eye, xerophthalmia or keratoconjunctivitis sicca, is a common condition that occurs when the quantity or quality of tears is insufficient to keep the surface of the eye properly lubricated.
As the eye is unable to maintain a high-quality tear film, a disturbance occurs on the ocular surface (eyelids, cornea and conjunctiva), resulting in insufficient ocular hydration and causing discomfort such as a foreign body sensation, irritation, itching, blurred vision and other vision-related problems.
According to the definition revised by TFOS DEWS II – The Tear Film and Ocular Surface Society Dry Eye Workshop II: “Dry eye is a multifactorial disease of the ocular surface characterised by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles.”
Experts estimate that dry eye affects millions of adults worldwide, and the risk of developing this condition increases with age. This condition can affect anyone, but it is more common in women than in men.
Dry eye is one of the most common reasons for consulting a specialist, affecting around 20% of the population.
Types of Dry Eye
Not all cases of dry eye are the same; there are different types of dry eye, and it is important to identify them correctly through a thorough eye examination and specific diagnostic tests, as an expert assessment is essential for providing personalised advice and, consequently, a tailored and effective treatment plan.
Aqueous-deficient dry eye
Reduced tear production, generally of the aqueous component. The most severe cases are associated with Sjögren’s syndrome.
Evaporative dry eye
Rapid evaporation of tears. This is the most common cause, primarily due to dysfunction of the Meibomian glands.
Inflammatory dry eye
Clinical or subclinical inflammation present in the majority of patients with dry eye.
Neurotrophic dry eye
Deficit in corneal innervation, which limits tear secretion and ocular surface regeneration.
Neuropathic dry eye
A disorder of corneal innervation whose cause and mechanism are still unknown, characterised by severe symptoms despite an ocular examination showing normal results or only minimal abnormalities.
Symptoms of dry eye; how do I know if I have dry eye?
The most common symptoms are usually:
- A gritty or foreign body sensation
- Burning, itching or redness in the eye
- Blurred vision
- Watery eyes
- Heavy eyelids
- Sensitivity to light
These symptoms tend to worsen in dry environments, or in rooms with air conditioning or heating, and in windy conditions.
People with dry eye often tend to have watery eyes. This is because, when the eyes are dry, the body responds by increasing tear production. Those suffering from dry eye may feel that they cannot keep their eyes open for very long. They may also feel that their eyes are uncomfortable after reading or watching television.
Why does it happen? Causes of dry eye
There are many causes and risk factors for dry eye; the most common factors contributing to its development are:
Screens
Spending a lot of time in front of a computer, television or mobile phone significantly reduces the frequency and speed of blinking, which makes lubrication less effective. You blink an average of 10 to 15 times per minute, but this can be affected by the screens of various electronic devices.
Contact lenses
Contact lenses can sometimes irritate the eye and may lead to dry eye. Switching to a different type of lens or limiting how often you wear them can help resolve this issue.
Old age
Dry eye and blurred vision are more common in older people. As we get older, the eye produces fewer tears and the eyelids become less effective at spreading the tear film across the entire surface of the eyes.
Menopause
This happens because, after the menopause, women do not produce as many tears as before due to hormonal changes and imbalances.
Environmental pollution
Environmental pollution causes respiratory problems in some people, whilst airborne particles containing soot, smoke, sulphates, nitrates, dust and rubber also cause eye irritation and can lead to dry eye syndrome. In some countries, in fact, people resort to wearing protective face masks and goggles for dry eyes.
Dry air
Dry air, whether outdoors or indoors, can aggravate dry eye syndrome. People living in dry climates are more likely to develop this syndrome, as are those living at high altitudes. Dry indoor environments with air conditioning and heating can also have the same effect.
Frequent flying
Aircraft are prime examples of dry indoor environments, as the air inside is heavily regulated by air conditioning and heating. People who use this mode of transport very frequently may suffer from dry eye.
Smoking
Cigarette smoke contains certain chemicals that greatly irritate the eyes. Therefore, not only smokers may be prone to dry eye, but also people who are involuntarily exposed to second-hand smoke.
Health conditions
There are a number of medical conditions that increase the risk of developing dry eye syndrome. One of these is blepharitis or Meibomian Gland Dysfunction (MGD), in which the edges of the eyelids become inflamed, which can block the glands that produce oils for the tear film. Blepharitis can occur at any age and in healthy people, although it is sometimes caused by a bacterial infection. Other conditions include: allergic conjunctivitis, rheumatoid arthritis, Sjögren’s syndrome, contact dermatitis, lupus, scleroderma, Bell’s palsy and HIV.
Medicinal products
Certain medicinal products cause side effects that contribute to dry eyes. Some of these include: antidepressants, oral contraceptives, beta-blockers, diuretics, amongst others.
Dehydration
The body’s initial response to fluid loss is to preserve the fluid that remains. This leads to various symptoms of dehydration, such as thirst and a dry mouth, reduced urine output, muscle cramps, headaches, and a lack of tear production. Dry eye occurs when there are not enough tears to nourish the eye; tears are necessary to provide clear vision and proper lubrication.
Diet low in omega-3 fatty acids (ω-3)
Recent studies suggest that omega-3 fatty acids may reduce the symptoms of dry eye. As omega-3 cannot be produced by the body, a diet that includes it is necessary. These compounds are found in fish, particularly salmon and sardines, and in walnuts. A deficiency can cause dry eyes, as well as other changes in appearance, including skin irritation and dryness, hair loss and brittle nails.
LASIK and other corneal refractive surgeries
Some people who have undergone certain types of laser eye surgery find that they experience dry eyes in the weeks following the procedure. These symptoms usually disappear after a few months, but in some cases they persist.
Instability in the tear film, due to a decrease in tear production or increased tear evaporation, can damage the epithelium, causing inflammation (due to hyperosmolarity, an increase in the concentration of substances in the tear due to a decrease in tear volume) and ultimately dry eye syndrome.
Diagnosing dry eye
How is dry eye diagnosed?
Mild to moderate dry eye
People with mild to moderate dry eye generally need to use artificial tears or eye drops for dry eyes more than four times a day. This stage is not as severe and the condition is not as advanced, but it is still important to apply preservative-free ointments before going to bed. Controlling the environment also helps people with mild to moderate dry eye; that is, keeping fans away from the face, consciously blinking frequently, using a humidifier in the winter months and drinking plenty of water.
Severe dry eye
Severe dry eye requires a little more care and attention. And, fortunately, there are also treatments for this stage of the condition. One option is punctal occlusion, a surgical procedure that blocks the small drainage channels in the eyelids using tear plugs. Similarly, oral antibiotics may be prescribed to help keep the sebaceous glands in the eyelids functioning properly.
To make a complete diagnosis and provide comprehensive treatment for dry eye, it is also important to conduct the aforementioned tests and supplement them with additional examinations to quantify each individual tear component. It is important to examine the lipid, aqueous and mucin or mucus components.
Treatment of dry eye
Treatment involves a multi-faceted and long-term approach to the condition. It is worth noting the use of eye drops as the main element for stabilising, hydrating and lubricating. Eye drops, known colloquially as artificial tears, should lubricate, protect and facilitate the recovery of the ocular surface; they should not impair vision, be sterile, non-toxic, have a long duration of action and be preservative-free.
The exact treatment will depend on whether the symptoms are caused by reduced tear production, rapid evaporation of tears, or whether there is any other underlying condition.
In other extreme cases, surgery is recommended, which involves permanently closing the tear ducts that drain tears into the nose, thereby ensuring that there is always a sufficient supply of tears in the eyes. This occlusion is usually achieved using tear plugs, which can be temporary, as they dissolve after a short time, or permanent, made of silicone.
How to combat dry eye
- Use artificial tears.
- Blink frequently.
- Take regular breaks from looking at screens.
- Ambient humidity.
- Wear protective eyewear.
- Get enough sleep.
- Take nutritional supplements.
- Practise proper eyelid hygiene.
- Limit the use of contact lenses.
Hyaluronic acid eye drops
How to choose eye drops for dry eyes.
Currently, the most commonly used active ingredient in lubricating eye drops is hyaluronic acid, a natural component found in tears, which offers excellent lubrication and protection for the surface of the eye in patients with dry eye syndrome.
The chain length of hyaluronic acid is very important, as longer chains provide greater lubrication and help tears remain on the eye for longer, significantly reducing the symptoms of dry eye.
The use of preservative-free eye drops is recommended to prevent future complications on the corneal surface, particularly in patients with severe dry eye, as they require more frequent instillations.
In more severe cases, treatment should be accompanied by other therapeutic measures such as eyelid hygiene or topical anti-inflammatory treatments, always under the supervision of a specialist.
Unfortunately, no. Dry eye syndrome is a persistent, chronic condition that cannot be cured by treatment. However, symptoms such as dryness, stinging and burning can be successfully managed.
There can certainly be asymmetry in dry eye syndrome, but although this is possible, it is not very common. Fewer than 10% of patients with this condition experience it in just one eye.
Most people do not experience complications caused by dry eye. However, if left untreated, it can lead to worrying symptoms. Some consequences of dry eye include: more frequent eye infections, scarring on the surface of the eye, thickening of the corneal surface, epithelial defects, corneal ulcers, neovascularisation and corneal scarring, thinning of the cornea and even corneal perforation.
Yes, although it may seem strange and illogical. This happens because dryness on the surface of the eye overstimulates the production of the watery component of tears.
Medicinal products that can cause dry eye include those for high blood pressure, such as centrally acting agents and diuretics; antihistamines and decongestants; hormones; antidepressants; painkillers such as ibuprofen and Lortab; and dermatological agents.
There are many treatments available to relieve the symptoms of dry eye; some are natural, others chemical, but both are effective and help manage the most troublesome aspects of this condition.