The test method in question is named after the ophthalmologist who developed it, Otto Schirmer. This test determines the level of secreted tear fluid, the degree of maintenance of the moisture content of the corneal surface.
Indications and contraindications
Schirmer's test is used if you suspect the presence of:
- inflammation of the cornea of the conjunctiva;
- dry eye syndrome;
- Sjogren's syndrome (a chronic progressive lesion of the connective tissue that affects the glands secreting external secretion - salivary and lacrimal);
- tear formation disorders due to medication.
Dry eye syndrome can develop for a number of reasons:
- Dehydration
- The elderly age of the patient.
- Conjunctivitis or other eye infection.
- Hypovitaminosis A (vitamin A deficiency in the body).
- Belmo eyes.
- Postoperative or permanent complication after laser vision correction.
- The so-called secondary syndrome, which manifests itself in rheumatoid arthritis, leukemia, lymphoma.
Schirmer's test is contraindicated in:
- perforation (change in shape) of the eyeball;
- fistula;
- a developing ulcer of the corneal layer;
- large-scale erosion of the stratum corneum.
Test Methods
Schirmer's test strips are special filtered paper in a standard size: 5 mm wide and 35 mm long. Having retreated 5 mm from the marked edge of the strip, the ophthalmologist folds it at an angle of 45 degrees and lowers the patient’s lower eyelid, focusing on the area between the outer and middle parts. It is important not to touch the cornea during the procedure.
According to some methods, the patient during the procedure should close his eyes, according to others - look in front of him and a little up. The lighting in the office should be comfortable - not dim and not very bright.
Schirmer's test lasts about five minutes. During this time, paper strips absorb the lacrimal precorneal film and moisture from the tear lake.
Types of Test Techniques
Schirmer's test is carried out in two ways:
- Using local anesthesia. An anesthetic eliminates the addition of a tear to the basal fluid to irritate the paper. After instillation of the anesthetic, the lower conjunctival arch is drained so that the extra drops of the drug do not mix with the tear fluid, thereby increasing its volume.
- Without the use of an anesthetic. Such a test is considered more accurate by a number of ophthalmologists, since it completely eliminates the mixture of tears and the administered drug, it shows only a “clean” result. This type of test is typical for diagnosing the symptom of "dry eye".
Also, the Schirmer test is divided into I and II. The first is carried out using test strips according to our methodology. The second type helps to investigate the amount of reflex (reactions to the stimulus) lacrimal secretions. It is carried out similarly, but the ophthalmologist stimulates the secretion of lacrimal secretion by irritating the passages of the nose of the examined with a cotton swab.
Schirmer test: norm and deviations
In severe cases of dry eye syndrome, the indicators on the test strip may be at zero. The norm for young patients is indicators exceeding 15 mm. If the indicators are lower, then the subject suffers from one of the types of dry eye syndrome:
- 14-9 mm - a slight variation of inhibition of secretion of lacrimal secretion;
- 8-4 mm - the average degree of development of the syndrome;
- less than 4 mm - severe corneal dryness syndrome.
Optimum performance: 10-30 mm. If the patient is over 60 years old, then a test strip below 10 mm will be considered normal for him, but he should not tend to zero either.
The norm for sample II, which determines the amount of discharge of the reflex tear, is not lower than 15 mm. Significant differences for both types of samples are considered to be differences of test results for a pair of eyes by more than 27%.
Subsequent diagnosis after a Schirmer test:
- inspection on a slit lamp;
- pink Bengal or fluorescent dog coloring;
- studies on finding the time gap of tear film rupture.
Schirmer's test is a simple and quick, effective method for the initial diagnosis of dry eye syndrome and similar manifestations of it, diseases that affect the secretion of lacrimal secretions. The test helps the ophthalmologist to quickly determine the level of secreted tear fluid (basal, reflex) and their total indicators in the examined patient.