Schirmer's test
Encyclopedia
Schirmer's test determines whether the eye
produces enough tears to keep it moist. This test is used when a person experiences very dry eyes or excessive watering of the eyes. It poses no risk to the subject. A negative (more than 10 mm of moisture on the filter paper in 5 minutes) test result is normal. Both eyes normally secrete the same amount of tears.
It is named for Otto Schirmer
.
is placed into the eye before the filter paper to prevent tearing due to the irritation from the paper. The use of the anesthetic ensures that only basal tear secretion is being measured.
This technique measures basic tear function.
A young person normally moistens 15 mm of each paper strip. Because hypolacrimation occurs with aging, 33% of normal elderly persons may wet only 10 mm in 5 minutes. Persons with Sjögren's syndrome
moisten less than 5 mm in 5 minutes.
How to read results of the Schirmer's test:
The inability of tears to drain into the nose can occur with:
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
produces enough tears to keep it moist. This test is used when a person experiences very dry eyes or excessive watering of the eyes. It poses no risk to the subject. A negative (more than 10 mm of moisture on the filter paper in 5 minutes) test result is normal. Both eyes normally secrete the same amount of tears.
It is named for Otto Schirmer
Otto Schirmer
Otto Schirmer was a German ophthalmologist from Greifswald. He studied medicine at several universities including the University of Greifswald. In 1896 he attained the chair of ophthalmology at Greifswald, a position earlier held by this father, Rudolf Schirmer...
.
Test procedure
Schirmer's test uses paper strips inserted into the eye for several minutes to measure the production of tears. The exact procedure may vary somewhat. Both eyes are tested at the same time. Most often, this test consists of placing a small strip of filter paper inside the lower eyelid (conjunctival sac). The eyes are closed for 5 minutes. The paper is then removed and the amount of moisture is measured. Sometimes a topical anestheticTopical anesthetic
A topical anesthetic is a local anesthetic that is used to numb the surface of a body part. They can be used to numb any area of the skin as well as the front of the eyeball, the inside of the nose, ear or throat, the anus and the genital area. Topical anesthetics are available in creams,...
is placed into the eye before the filter paper to prevent tearing due to the irritation from the paper. The use of the anesthetic ensures that only basal tear secretion is being measured.
This technique measures basic tear function.
A young person normally moistens 15 mm of each paper strip. Because hypolacrimation occurs with aging, 33% of normal elderly persons may wet only 10 mm in 5 minutes. Persons with Sjögren's syndrome
Sjögren's syndrome
Sjögren's syndrome , also known as "Mikulicz disease" and "Sicca syndrome", is a systemic autoimmune disease in which immune cells attack and destroy the exocrine glands that produce tears and saliva....
moisten less than 5 mm in 5 minutes.
How to read results of the Schirmer's test:
- 1. Normal which is ≥15 mm wetting of the paper after 5 minutes.
- 2. Mild which is 14-9 mm wetting of the paper after 5 minutes.
- 3. Moderate which is 8-4 mm wetting of the paper after 5 minutes.
- 4. Severe which is <4 mm wetting of the paper after 5 minutes.
Alternatives to Schirmer's test
Even though this test has been available for over a century, several clinical studies have shown that it does not properly identify a large group of patients with dry eyes. Newer and better tests of tear production and function are now emerging.- One test measures an iron-binding moleculeMoleculeA molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
called lactoferrinLactoferrinLactoferrin , also known as lactotransferrin , is a multifunctional protein of the transferrin family. Lactoferrin is a globular glycoprotein with a molecular mass of about 80 kDa that is widely represented in various secretory fluids, such as milk, saliva, tears, and nasal secretions...
. The amount of this molecule appears to be closely related to tear production. Patients with low tear production and dry eyes have low levels of this molecule. This test may be especially valuable for patients with dry eyes since it can point to specific treatment strategies for dry eye.
- The tears may also be examined for their content of lysozymeLysozymeLysozyme, also known as muramidase or N-acetylmuramide glycanhydrolase, are glycoside hydrolases, enzymes that damage bacterial cell walls by catalyzing hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in a peptidoglycan and between...
, an enzymeEnzymeEnzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
normally found in tears.
- Another test involves fluoresceinFluoresceinFluorescein is a synthetic organic compound available as a dark orange/red powder soluble in water and alcohol. It is widely used as a fluorescent tracer for many applications....
eye drops, which contain a dye that is placed in the eye. The dye should drain with the tears through the lacrimal duct into the nose within 2 minutes. If patients do not have enough tears to flush the dye into the nose, this time will be longer. A new test is also available to more accurately measure the flow of dye out of the eye.
Eye dryness
Dry eyes can occur from conditions such as:- Aging
- Dehydration
- Corneal ulcerCorneal ulcerA corneal ulcer, or ulcerative keratitis, is an inflammatory condition of the cornea involving loss of its outer layer. It is very common in dogs and is sometimes seen in cats...
s and infectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
s - Eye infections (for example conjunctivitisConjunctivitisConjunctivitis refers to inflammation of the conjunctiva...
) - Vitamin A deficiencyVitamin A deficiencyVitamin A deficiency is a lack of vitamin A in humans. It is common in developing countries but rarely seen in developed countries. Night blindness is one of the first signs of vitamin A deficiency. Xerophthalmia and complete blindness can also occur since Vitamin A has a major role in...
- Sjögren's syndromeSjögren's syndromeSjögren's syndrome , also known as "Mikulicz disease" and "Sicca syndrome", is a systemic autoimmune disease in which immune cells attack and destroy the exocrine glands that produce tears and saliva....
- Secondary tearing deficiency (associated with disorders such as - lymphomaLymphomaLymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...
, leukemiaLeukemiaLeukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...
, GVHD (graft vs. host disease, after a transplant), and rheumatoid arthritisRheumatoid arthritisRheumatoid arthritis is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks synovial joints. The process produces an inflammatory response of the synovium secondary to hyperplasia of synovial cells, excess synovial fluid, and the development...
) - As a temporary or permanent side effect of LASER vision correction surgery such as LASIKLASIKLASIK or Lasik , commonly referred to simply as laser eye surgery, is a type of refractive surgery for correcting myopia, hyperopia, and astigmatism...
or PRKPRKPRK could refer to:*Phase Reversal Keying, see BPSK*Photorefractive keratectomy, a laser eye surgery procedure*ISO 3166-1 alpha-3 code, International Olympic Committee country code, and FIFA country code for North Korea...
The inability of tears to drain into the nose can occur with:
- Some eye infections
- Blockage of the tear duct
