Dry Eye Treatments

In most cases dry eye has no definitive treatment and will persist for life. When this is the case, the patient should be informed by the ophthalmologist and helped to accept it: this is not unusual and patients with diabetes or arterial hypertension also face a pathology that they will carry until the end of their lives, it is something frequent, possible and bearable.

Although it is not a definitive treatment in all cases, there are treatments that dry eye patients can and should follow:

Environmental treatment for dry eye

In most cases, etiological treatment is not possible, either because the exact cause of the dry eye is not known, or because the cause is known but there is no effective medical treatment. For the patient with dry eye, it is recommended to avoid the symptoms by taking measures in their daily life, such as avoiding drafts, environmental dryness and pollution:

Air currents favor tear evaporation, so that they worsen the symptoms. It should be noted that strong air currents are picked up by the skin’s sensory system, but light currents go unnoticed, such as air conditioners or hot air from ovens. Some measures that can be taken are:

• Do not direct fans towards the face.
• Use heating radiators instead of air conditioning.
• Do not drive with open windows.
• Use glasses that avoid direct air against the eyes.

Avoid environmental dryness: in order not to produce symptoms of ocular dryness, the ideal is 35-45% humidity. In air-conditioned rooms, airplanes (between 5-15%) and in most kitchens, air humidity is much lower than recommended, which causes dry eyes.

The main measures to avoid environmental dryness are:

• Avoid dry environments or humidify the environment, either with commercial humidifiers or by placing a container with water over hot areas such as radiators.
• Create ocular microclimates by means of normal or airtight glasses. The use of glasses reduces eye evaporation and protects the eye from drafts.

Avoid environmental pollution: patients with dry eye, as they have less tears, have more difficulty in eliminating dust particles that may enter the eyes and that in normal conditions would be dragged and eliminated by tears. These particles will be retained on the ocular surface and irritate it, so the patient should avoid dusty environments, such as the beach and the countryside when it is windy, or house dust when it is stirred up during cleaning.

Other substances, such as tobacco smoke and paint solvents, have components capable of reducing the stability of the tear film.

As for habits, exposure to computers, TV screens and reading at night favor tear evaporation due to the less frequent blinking rhythm. On the contrary, voluntary blinking is recommended to moisten the eye.

Tips to prevent or reduce dry eyes: eye treatment

1. Forced blinking: forced blinking should be repeated several times a day to expel the sebum content to the free palpebral edge of the eye.
2. Massaging the eyelids increases the release of the aqueous, mucin and lipid components of the tear: it is recommended to massage the upper and lower eyelids with the fingers several times a day, when getting up, when going to bed and before doing activities such as entering air-conditioned places, air currents, staying several hours in front of a computer, watching TV or at the cinema, etc.
3. Applying warm compresses on the eyelids is useful and can be done when waking up in the morning, and if the clinical case requires it, repeat it once or twice during the day. It can also be done as a step prior to massages, enhancing their effectiveness.
4. The cleansing of the glands is performed on the palpebral margins, which are the oiliest surface of the whole organism. Special care should be taken with the soaps used, as the inevitable entry of these soaps into the tear duct causes ocular irritation and destruction of the lipid layer.
5. Using therapeutic contact lenses: using contact lenses with dry eye is not advisable, as they are in fact one of the causes of dry eye. But it can be done is the occasional use of highly moisturized therapeutic contact lenses to treat dry eye. Once in place, these lenses need to be continuously rehydrated with artificial tears.
6. Years ago, other techniques now in disuse or completely forgotten, such as soft laser therapy and radiotherapy, were also used.

Substitutive treatment of dry eye with artificial tears

Substitutive treatment with artificial tears and lubricants is currently the most widely used therapy for dry eye. Not only does it relieve dryness and make the patient more comfortable, some studies have shown that the use of tears softens the surface of the cornea and makes it more regular, and may contribute to improved vision.

But this treatment has its limitations: natural tears have a complex composition of water, salts, hydrocarbons, proteins and lipids that are very difficult to match with a substitute treatment.

In addition, natural tear secretion is continuous, while artificial tears are instilled only periodically. To overcome this limitation, there are preparations with substances to increase the contact time of the artificial tear with the ocular surface, many formulated as viscous gels, with the disadvantage that they can cause blurred vision and deposits on the eyelashes.

In fact, artificial tears should not only reproduce the characteristics of natural tears, but also provide new features: they should last longer in the tear basin and their composition should include drugs and principles that repair primary and secondary dry eye lesions that may be present.

A common component of artificial tears are buffers that serve to maintain the natural pH of the tear. This is important because the pH of the tear film must be kept constant to maintain normal epithelial cell function. In addition, the pH decreases after instillation of eye drops and rapidly becomes more alkaline before normalizing in approximately 2 minutes. The addition of buffers to tears is done to produce this change more slowly.

A drawback of many artificial tears is that they include preservatives, stabilizers and other additives. These substances often cause worsening of the disease, so the ideal is to use tears in single-dose format, as they are preservative-free. In fact, patients who need to apply tears more than four times a day, wear contact lenses, have ocular surface disease or blocked tear drainage should use preservative-free preparations.

Pharmacological aqueous lacrimal stimulation for dry eye

This treatment is very useful in patients with Sjögren’s syndrome, an immune disorder that affects the tear and saliva-producing glands. However, when the disease is very advanced it may not be a good therapeutic alternative.

The only substances capable of increasing tear production are parasympathomimetics, especially pilocarpine and cevimeline. Oral pilocarpine increases tear production, thus improving dry eye symptoms, reaching a maximum after 10 minutes and persisting after 30 minutes. As for side effects, it also acts on cardiac M2 receptors, potentially stimulating them, and on intestinal and bronchial smooth muscle, contracting it; it also causes sweating, headache and nausea. However, these adverse effects are usually well tolerated.

• The optimal dose is considered to be 20 mg/day and with lower doses the drug loses lacrimal effectiveness, although salivary effectiveness is maintained. Treatment should be started gradually: 5 mg/day the first week, 10 mg/day the second week, 15 mg/day the third week and 20 mg/day the fourth week, in this way the adverse effects will be less. It is contraindicated in patients with severe COPD, severe renal disease and heart disease.

Treatment of dry eye with mucosecretors and mucolytics

Bromhexine orally at doses of 24-48 mg daily in 3 doses seems to improve mucous secretions, as well as some authors observed that it also improves aqueous lacrimal secretion.

N-acetyl-cysteine is a mucolytic, stimulator and facilitator of mucin production administered orally at a dose of 300 mg daily in 3 doses. The mucous layer of the tear is usually altered in patients with dry eye. This can be very viscous and form plaques and filaments on the ocular surface causing irritation and pain, so the application of mucolytic solutions can be very useful.

Pentosan polysulfate sodium is an anticoagulant with mucorregulatory action, which has been used in mucodeficient cystitis, and has also shown efficacy in dry eye.

Dry Eye Drainage System Occlusion

Occlusion of the lacrimal canaliculi or puncta prevents tear drainage: it is the most widely used non-pharmacological treatment for dry eye.

This technique improves the quantity and quality of the aqueous component, improving dry eye symptoms and reducing the frequency of administration of artificial tears.

There are some possible complications, such as rupture of the lacrimal puncta, pruritus, suppurative canaliculitis, canalicular stenosis, and pyogenic granulomas have been described in the silicone plugs used for occlusion.

This treatment is usually reserved for severe dry eye, when frequent use of preservative-free artificial tears is not sufficient, especially in aqueous deficient types.

The most commonly used lacrimal punctal occlusion procedures are:

• Surgical: They are not widely used because of their difficulty to reverse them, with the exception of the punctal patch technique.
• Thermal: They produce the closure of the canaliculus by destroying and retracting its wall. To perform this procedure cautery, diathermy or argon laser can be used. The first one has the disadvantage that in a high percentage of cases the canaliculus is recanalized and also the burns it produces can distort the eyelid. The argon laser allows partial or total obstructions and openings of the lacrimal punctum.
• Tamponade methods: These are the most commonly used and consist of occluding the drainage pathway by implanting a foreign body, a resorbable or non-resorbable implant. They are the most frequent because they do not require surgery and can be easily reversed.

Non-resorbable implants are divided into:

• Punctal plugs, which can be made of silicone, HEMA or Teflon. The head of the plug protrudes outside the canaliculus, so it can irritate the conjunctiva and cornea. Other possible complications include itching, suppurative canaliculitis, intrusion, plug fragmentation and canalicular stenosis due to local irritation.
  Placement of a punctal, non-absorbable plug.
• Canalicular plugs, which are made of silicone and are inserted past the lacrimal punctum in the horizontal portion of the canaliculus, so as they do not protrude through the lacrimal punctum they do not irritate the eye.

Resorbable implants for dry eye treatment can be made of hydroxypropylcellulose, a material that causes them to dissolve slowly with body temperature, collagen, which only partially decreases canalicular flow by 60-80%, or catgut. This method of tamponade is very popular because it not only allows a clinical improvement in patients, but also allows to treat dry eye temporarily.

Lacrimal punctal occlusion with collagen resorbable plug

Surgery to treat Dry Eye

There are multiple surgical solutions for dry eye, such as blepharorrhaphy, blepharoptosis, lacrimal transplants, cisternoplasty, transposition of Stenon’s duct, salivary gland transplants, etc. In addition, there are also surgeries that treat diseases that originate or worsen dry eye, such as conjunctivochalasia or floppy, among others.

Alternative Treatments for Dry Eye

Topical vitamin A: It is essential for normal epithelial growth and its deficiency can cause dryness of the eye, even keratinization in severe cases. Although topical vitamin A derivatives are capable of reversing squamous metaplasia and keratinization of the ocular surface, this occurs only in severe cases of dry eye as most moderate dry eyes do not have these ocular surface changes.

Topical antiologic serum: Its use diluted to 20% in saline for four weeks has been shown to improve the results of rose bengal and fluorescein staining tests in patients with dry eye. It is indicated primarily in patients with severe disease and persistent epithelial defects.

Topical cyclosporine: due to the inflammatory origin of dry eye, at least in part, its use as an anti-inflammatory and immunomodulator improves dry eye, also cases linked to Sjögren’s syndrome.

Oral polyunsaturated fatty acids: improvement in ocular dryness after supplementation with omega 3 essential fatty acids such as DHA (docosahexaenoic acid) and GLA (gammalinolenic acid) has been attributed to the change in the glandular phospholipidic composition and its excretion product, to the increase in the quantity and thickness of the lipid film and to the stimulation of prostaglandin E1 stimulation that would activate the glandular tear secretion. Also in cases of treatment with polyunsaturated fatty acids prior to LASIK surgery, tear lactoferrin levels, a diagnostic marker of ocular health, have been elevated.