Carrying out the Schirmer test in dogs and cats: study features
The content of the article
- 1 Technique of
- 2 Interpretation of the results
- 3 What are the causes of violations slezoproduktsii
- 4 When should the Schirmer test
- 5 Conclusion
In this article we want to introduce you to a simple, but fairly effective procedure.
This new testing to determine the amount of tears produced. This study is safe and discomfort during a minimum.
Due to the fact that the problems associated with lack of tear production in animals occur often, this test is very popular in veterinary medicine. It is named after its creator, the German ophthalmologist Otto Schirmer in 1903. In dogs, the first time a study has been described in 1962. Despite some criticism, it remains the standard determining the amount of tear production in veterinary ophthalmology.
Schirmer test is conducted at the beginning of the survey, before the implementation of any manipulation of the patient’s eye as a bright light, or the use of drugs can lead to false results.
There are studies Schirmer 1 and 2. For the first procedure usually uses special test strips of 5 mm width and 35 mm in length (Fig.1). They are packed in 2 or 1 piece in a sterile package and is retrieved immediately before the procedure.
Avoid contact with the working part of the test strip to avoid contamination with bacteria and getting fat components with your hands. Indicate the end of the test strip is placed in a lateral (side) part conjunctival arch (under the lower eyelid), trying to avoid unnecessary contact with the cornea.
The lids may be kept open or closed, it prevents the latter from premature loss of the test strip. Intersect one minute, then the patch is extracted. The result should be read at once (Figures 2 and 3). This assay allows to investigate the total tear production, which consists of a basal (core) and reflex.
To evaluate only the first applies Schirmer test 2. Prior to the survey instilled a local anesthetic, which is almost completely blocks the reflex secretion of tears. Then the lower conjunctival layer was dried.
Further actions are similar to those described above. Schirmer test 2 is not widely used in veterinary practice, but it is sometimes referred to in the clinical studies.
In some cases, to place the test strip into the lower fornix of the conjunctiva may be difficult because of the bulk tumors, corneal and other defects. In this case, permissible room test strip under the upper eyelid.
But it must be borne in mind that a normal result will be lower in comparison with the standard.
interpretation of results
Schirmer test values help to diagnose and monitor such diseases as dry eye syndrome (CCV). But it has other names: “dry” eye, keratoconjunctivitis (JCC).
Cats have a large difference in performance due to the presence of stress. For this reason, the Schirmer test in these animals may be questionable and should be considered by taking into account the clinical manifestations.
Table № 2. Interpretation values
|Schirmer test 1
mm / min
|0-5||heavy SSG||Often poor prognosis. Response to treatment may be unsatisfactory.|
|5-10||RESS||Most favorable prognosis. Required therapy.|
|10-15||Suspected SSG||Treatment is indicated. Constant monitoring is important.|
|more than 25||Norma or excessive||You may need additional tests.|
In young individuals slezoproduktsii norms indices less than that of adults.
It was determined that the age, weight, and gender affect the production of tears. Thus, it was revealed that the male tear production is higher than in females. As for weight, the higher it is, the higher the value of the Schirmer test. Age also plays an important role. Every day the amount of tears in the puppy is added at 0.15 mm / min until the age of 9-10 weeks.
That is, by this time the level of secretion of tears puppy reaches normal values of adults. The results are shown in Fig. 4 (taken from the journal «Veterinary ophthalmology» (2010) 13, 5, 321-325).
What are the causes of violations slezoproduktsii
So, we have seen that the values of the Schirmer test can differ dramatically. Now let’s look at the reasons that led to this.
Signs of increasing tear production:
- irritants: conjunctivitis of different etiologies; problems cornea (erosion, ulcer); mechanical trauma (inversion c and, as a consequence, hair touch the cornea), wrong growing eyelashes (distichiasis, ectopic eyelash), tumor; intraocular inflammation (uveitis, glaucoma); the presence of foreign bodies;
- idiopatichekaya epiphora.
Typically, higher values of the Schirmer test have no diagnostic value. The most important evaluation with a lack of tears.
Reasons for decreasing tear production:
- Chronic Blepharoconjunctivitis. It can lead to fibrosis of the lacrimal gland (herpes simplex virus type 1 in cats, leishmaniasis in dogs).
- Congenital: aplasia / hypoplasia of the lacrimal gland (Yorkshire terrier, pug and other small breed).
- topical / systemic (atropine, NSAIDs);
- local / general anesthesia (effect can persist for up to 24 hours).
- Drug toxicity. sulfonamides drugs (sulfasalazine, trimethoprim-sulfa).
- System (Sjogren’s syndrome (dry mouth and eyes), systemic lupus erythematosus, the leaf pemphigus, rheumatoid arthritis, hypothyroidism, diabetes, polymyositis and polyarteritis, atopy, glomerulonephritis and ulcerative colitis).
- Breed predisposition to the development of the CCV:
- Cavalier King Charles Spaniel
- English bulldog
- Lhasa Apso
- Shih Tzu
- West Highland Terrier Wide
- American Cocker Spaniel
- Boston Terrier
- miniature schnauzer
- Samoyed dog
- Radiation exposure (in treatment of certain tumors).
- Neurogenic. Loss of parasympathetic innervation of the lacrimal gland (CN VII), and loss of sensory innervation and other neurological disorders, including particularly the trigeminal nerve lesion (CN V) and dizautonomiya.
- Iatrogenic causes:
- removal of the lacrimal gland third century (often mistaking for an adenoma (tumor) of the lacrimal gland third century);
- prosthetic eye.
- Systemic diseases:
- metabolic diseases: diabetes mellitus, hypothyroidism, hyperadrenocorticism ( Cushing syndrome in dogs ).
- Orbital and supraorbital injury.
- Age. Senile (senile) atrophy of the lacrimal glands. Risk group: dogs over 10 years old.
When should the Schirmer test
It’s time to find out when it is necessary to conduct a study. The most basic indicator – is the presence of a particular clinical picture.
In the presence of a pet such expressions as:
- lacrimation (may be the first symptom of the syndrome of “dry” eyes);
- muco-purulent discharge of yellow, yellow-green;
- redness of the conjunctiva;
- itching of the eye area;
- corneal opacity;
- squinting eyes;
- keratitis pigmentosa.
If you find at least one of the above symptoms, you should visit an ophthalmologist, who will measure the amount of tears produced.
Particular attention should be paid to owners of the rocks, above the list.
Pets with a history of which there are endocrine disorders (diabetes, hypothyroidism, Cushing’s syndrome) should undergo preventive eye exam at least 1 time per year. It should be mentioned that these pathologies can cause serious and other ophthalmic diseases (e.g., cataract).
Dry eye syndrome is common in animals with various autoimmune skin problems.
As well as an indication for this test is the old age of the animal.
And, of course, constant monitoring is needed to animals in which the third eyelid lacrimal gland or third century was removed, and the animal undergoing surgery for prosthetic eyeball.
As seen from the above, the Schirmer test is a simple, but very useful. Despite the fact that the conduct did not cause too much trouble, yet do not recommend testing your own home to avoid causing corneal injury. And we must not forget that the diagnosis – Dry eye syndrome is based on a set of clinical indicators, and Schirmer test.
The results are within normal limits, but the doctor still makes the diagnosis a syndrome of “dry” eyes. This is due to the fact that the disease is divided into qualitative and quantitative SSG. In a qualitative quantity of tears is normal, but the quality – poor.
In this case, all the symptoms will be like at a standard dry eye syndrome. Therefore it is better to leave these subtleties professional. In your power to assess symptoms of ocular discomfort to the pet and to react.
Unfortunately, in practice, the specialists carry out inspections already in advanced stages, which, in turn, worsens the prognosis of treatment.
The second way out – is to hold annual preventive eye examinations, especially animals who are in the risk group (see above).
Article prepared ophthalmologist “Belanta” veterinary clinic
Formenova Svetlana Igorevna .