Modern diagnostic methods and therapeutic algorithms
Pathophysiology in dry eye syndrome (DES)
Dry Eye Syndrome is a common condition which affects 10-18% of the population of Poland (up to 30% in certain groups). The probability of DES occurring is connected with age and contemporary living conditions. DES is generally connected with instability of the tear film, which can have two major causes:
- insufficient production of tears by the tear gland
- excessive evaporation of the tear film
Dry eye with insufficient tear discharge occurs when the main or other tear glands operate inefficiently.
The standard diagnosis is based on the Schirmer test, by placing special diagnostic strips on the outer corners of the lower lids of both eyes, and observing and measuring the degree of dampening after 5 minutes. This is invasive diagnosis, and the results for some patients are not reliable due to the irritation. Current diagnostic capabilities allow for a precise assessment of the amount of the water layer of tears by measuring the height of the tear meniscus and assessing the curve at its edge.
The procedure of choice in the case of failure of the glands producing the water layer is to apply plugs to the tear ducts. Therapy begins with the application of temporary plugs to the lower tear points, which are completely absorbed after three months.
The 3-month plugs are available in three basic sizes – 0.3, 0.4 and 0.5 mm in diameter with a standard length of 2 mm and cylindrical in shape.
Due to the great anatomical range, tear point sizes and diameters which exceed 0.5 mm and prevent the application of the largest 3-month plugs, the use of permanent plugs of a Parasol structure, enabling points measuring from 0.63 to over 0.9 mm, should be considered.
In the event that the results from using 3-month plugs are satisfactory, it is possible to apply hydrogel plugs (FormFit), which remain in the tear ducts for up to two years.
In cases of severe Dry Eye Syndrome, as well as using plugs on the lower points (3-month, FormFit or Parasol), temporary plugs are applied to the top points.
Excessive evaporation of tears is responsible for 80% of all cases of DES and is usually connected with a deficit of its most external layer, i.e. the lipid layer produced by the Meibomian glands.
This deficit results in excessive tear evaporation, which subsequently leads to inflammation of the conjunctiva. Inflammation of the conjunctiva causes a chain of further symptoms, such as a foreign body being felt inside the eyeball, tiredness, burning, reddening, etc. As the disease progresses, the discomfort associated with it begins to accompany the patient constantly. Interestingly, excessive tear production could happen at this stage. Overproduction of tears is the body’s defensive mechanism.
A further stage of the untreated condition may be anatomical changes, such as:
- atrophy of the Meibomian glands affected by frequent infections
- cysts on the Meibomian glands
- secondary conjunctival infections
- in the most severe cases – ulceration of the corneal epithelium
The tear film necessary for the proper functioning of the eye is composed of three layers:
- the mucous (mucin) layer, produced by the goblet cells of the conjunctiva, is in direct contact with the surface of the eyeball,
- the aqueous layer, secreted by the lacrimal gland,
- the lipid layer, secreted by the Meibomian glands,
The standard diagnostic method for assessing the fatty layer and the quality of the tear film is the tear breakup test (BUT). This is not a highly sensitive test, the methodology requires several tests to be carried out and the average calculated, with the fluoroscein given affecting the stability of the tears, thus affecting the result.
Non-invasive tests enable an objective measurement of the thickness of the fatty layer and the quality of the tear film, to assess the amount of active Meibomian glands producing the lipid layer, and in graphic form.
Failure of the Meibomian glands may be obstructive in nature, when the lipid discharge cannot leave the canal of the gland, or productive in nature when there is no lipid discharge produced in the gland.
Depending on the nature of the changes, a procedure should be considered aimed at changing the concentration of fat blocking the openings of the Meibomian glands using hot compresses, mechanical cleaning of the ridges of the eyelids to remove the dried discharge blocking the openings of the glands, mechanical expression of the eyelids with the aid of special tweezers.
In the event that the openings of the Meibomian glands are closed or the channel of the gland is blocked, the procedure of choice is to puncture and rechannel the Meibomian glands with a Maskin needle.
This is a modified injection needle bent at an angle allowing it to be freely manipulated in a slit lamp, with a capillary needle at the end measuring 110um i diameter and 1, 2, 4 and 6mm long. The procedure is carried out with local anaesthetic of the ridges of the eyelids. It takes about 20 minutes and involves systematically revising and rechanneling each Meibomian gland opening.
In a situation of production failure, once other possible causes of the failure have been excluded the only effective treatment is intracutaneous stimulation of the Meibomian glands using polychromatic pulsating light (IrPL).
One of the devices which uses this technology is E-Eye.
E-EYE was designed and produced in France by E-Swin, the leading French manufacturer of phototherapy equipment.
E-EYE generates polychromatic pulsating light using a new technology: IRPL®(Intense Regulated Pulsed Light). This technology enables the creation of a sequence of uniform and calibrated light pulses, it emits “cold light”, which stimulates the Meibomian glands in an entirely safe way. The glands respond to this stimulation by renewing their secretion, which results in normalisation of the structure of the tear film and gradual subsidence of the symptoms of the condition. The treatment is non-invasive, painless and completely safe for the eyeball. The device is produced in France and has a CE certificate. New IRPL® technology ISO 9001 ISO 13485 I
During the treatment
- the session only lasts a few minutes
- the patient is laid in a treatment chair
- the eyes are covered with special EYE MASK protection
- special hydrogel is applied to the cheeks and around the temples
- the person conducting the treatment applies a series of 5 flashes, stating from the inner corner of the eye and finishing around the temple
- the same cycle is repeated for the other eye
- the specialist removes the gel and washes the skin with water
After the treatment
- no other treatment should be applied to areas which have been subjected to phototherapy
- if the areas subjected to the treatment are expected to be exposed to UV rays, they should be protected with SPF cream
- make an appointment for the next treatment
- there are no obstacles to normal hygiene on the area subjected to the treatment