Dry eye

Dry eye introduction Dry eye refers to a type of disease that causes symptoms of ocular discomfort due to tear film instability and damage to the surface of the eye caused by abnormal amounts or quality of tears. It is currently the most common ocular surface disease. Dry eye is a continuous pathological process from mild to heavy continuous development, and there is no obvious boundary between light, medium and heavy. In general, any symptomatic or combined signs should be diagnosed as pathological. For example, in some areas of the United States, the diagnostic criteria for dry eye is keratoconjunctivitis. As long as the patient has symptoms of dry eye (with or without signs), it can be diagnosed. The nouns and corresponding standards that can be used in China are: dry eye syndrome: refers to the condition that the patient has symptoms of dry eye but no signs of dry eye, especially no eye damage, no local and systemic causes of dry eye. . These symptoms may be transient, such as occasional reading or computer-induced eye discomfort, but return to normal as long as the rest or short-term application of artificial tears. Dry eye disease: refers to patients with not only the symptoms and signs of dry eye, but also local or systemic causes of dry eyes. Conjunctival xerostomia: refers to ocular surface changes caused by Sj?gren syndrome (Sj?gren's syndrome, SS), which is one of dry eye diseases. Such diagnosis should be placed in dry eye disease. Dry eye: dry eye A general term for diseases and dry eye disease. A survey in the United States showed that 14.6% of the population aged 65-84, or 4.3 million, had dry eyes, 17.0% in Japan and 10.3% in Australia. Although China has no clear findings on dry eye epidemiology so far, its incidence may be higher than that of the United States based on China's sanitary conditions and environmental conditions. basic knowledge Sickness ratio: 35% Susceptible people: no specific population Mode of infection: non-infectious Complications: corneal ulcer

Dry eye cause

Lacrimal gland lesions (20%):

Primary Lacrimal Deficiency (PLD), congenital absence of tears, no or lacrimal gland, but lack of secretion; non-SS KCS, sometimes called acquired PLD, or KCS for short, B. secondary Secondary Lacrimal Deficiency (SLD), such as vitamin A deficiency, lymphoma, sarcoma-like disease, human immunodeficiency virus (HIV) infection, and most lacrimal gland resection.

Mesenteric lesions (20%):

Obstructive meibomitis is the most common cause, often primary, or secondary to burns, conjunctivitis, or systemic diseases such as sebaceous glandular dermatitis, rosacea, ichthyosis, psoriasis, meibomian gland cysts, Mumps, stones, etc., sometimes congenital absence of meibomian glands, secondary hyposecretion, double ciliary, suppurative inflammation, tumors, etc., sometimes the oil in the meibomian glands is stagnation, the meibomian gland secretion function seems normal, But the oil is not enough. 2 neurological disorders: such as VII cranial neuropathy, long-wear contact lens, nerve paralytic keratitis.

Large area of ocular surface damage (15%):

Large area of ocular surface damage leads to obstruction of lacrimal duct gland such as trachoma, thermal or chemical eye burns, Stevens-Johnson syndrome, scar pemphigus, sputum defect, atopic keratoconjunctivitis, trauma, etc.

Teleclinical abnormalities: reduced blinks or prolonged intervals can cause dryness of the ocular surface as seen in VDT (Visual Dislpay Terminal) computer workers, or office eye syndrome, Parkinson's disease, etc.

Ocular surface lesions: diseases that cause a decrease in goblet cells, such as vitamin A deficiency, cause local bulging of the ocular surface for any reason, such as surgery, sputum, abnormal cleft palate, exophthalmos and sacral deformities can cause local ocular surface dryness.

Pathogenesis:

The classification method of dry eye developed by the National Eye Institute of the United States in 1995 is to divide the dry eye into "tears lacking" and "evaporatively strong" dry eye. The former mainly refers to insufficient tear production, and the latter includes abnormal lipid layer. (such as meibomian gland dysfunction, MGD), including increased tear evaporation caused by blinking, another classification method to divide dry eye into aqueous tear deficiency (ATD) And lipid tear deficiency (LTD), wherein ATD is divided into Sjögren syndrome and non-SS ATD.

According to the elements that maintain the stable tear film, it is recommended to divide the dry eye into five categories, and the different types of pathogenesis are different:

1. Evaporation of excessive dry eye

This type of dry eye is mainly caused by abnormalities of the lipid layer (abnormality of mass or quantity), such as meibomian gland dysfunction, mumps, blepharitis, etc., eyelid defects or abnormalities cause evaporation, etc., screen Patients with video-digital termination syndrome have fewer blinks and more evaporation; they have large cleft palate and more exposure, which can also be classified as dry eye.

2. Water-deficient dry eye

Insufficient production of hydrothermal tears, such as Sjögren syndrome, many systemic factors cause such dry eyes, abnormal water-liquid tears also lead to tear film instability, causing dry eyes.

3. Mucin-deficient dry eye

Mainly caused by damage to ocular surface epithelial cells, including chemical damage to the ocular surface, thermal burns, limbal dysfunction, in some chemical injuries, some patients have normal tear volume, such as Schirmer test is more than 20mm, but these patients still occur The problem of corneal epithelium is mainly due to the lack of mucin.

4. tear dynamics abnormal dry eye

Caused by abnormal kinetics of tears, including blink abnormalities, delayed tear discharge, ocular surface inflammation caused by conjunctival relaxation and kinetic abnormalities.

5. Hybrid dry eye

Dry eyes caused by two or more causes.

Dry eye prevention

To prevent and treat dry eye syndrome, daily emotional stability should be maintained, so as to avoid inflammation of the liver, use eye time should not be too long, eat less hot food and eat more fish; and use "ironing eye" massage, first hot hands Massage the eyes with the palm of your thumb for about 30 times, 3 times a day. You can also use the back eye massage method to have two depressions on the back of the head and close the eyes for about 10-15 minutes.

Dry eye complications Complications corneal ulcer

Corneal infective inflammation causes corneal ulceration, perforation, and even eyeball atrophy.

Dry eye symptoms common symptoms fatigue visual impairment corneal ulcers dark spots conjunctiva congestion tear film disappearing photophobia

1. Symptoms and medical history

Common symptoms of dry eye are: dryness, foreign body sensation, burning sensation, itching, photophobia, redness, blurred vision, visual fluctuations, etc. In addition, 71.3% of dry eye patients have symptoms of visual fatigue, indicating that Fatigue is also one of the common symptoms of dry eye. The positive rate of objective examination is significantly lower than the incidence of dry eye symptoms. For example, in the above survey in the United States, only 2.2% have both symptoms and ST (Schirmer's test) is low (5mm/ 5min), 2.0% has both symptoms and high ocular surface red staining score (5). Therefore, in order to reduce the missed diagnosis of dry eye, attention should be paid to the symptom inquiry. For more serious dry eye, please ask if there is dry mouth or joint pain. It can prompt the possibility of SS, ask about the past systemic and topical medications, the history of surgery and the working environment, which is of great help to the diagnosis of dry eye.

2. Clinical examination

Dry eye inspection methods mainly include:

(1) slit lamp inspection: routine slit lamp examination can find the cause of dry eye, such as upper corneal marginal keratoconjunctivitis, limbal edge, surgical scar at the limbus, etc., for severe and some moderate dry eye Immediate diagnosis, the main contents of the slit lamp inspection include: 1 tear line width: the height of the tear at the junction of the border of the eye and the surface of the eye (normally not less than 0.3mm), this indicator can help diagnose dry eye faster in clinical, but must Have more clinical experience; 2 corneal changes: keratinization, blisters, degeneration, ulcers, leukoplakia, vasospasm, etc., pay special attention to changes in the limbus, such as whether there are new blood vessels at the limbus; 3 corneal surface and lower iliac Department of debris; 4 ball adhesion; 5 conjunctiva: congestion, nipple hyperplasia, the presence or absence of conjunctival capsular film wrinkles, conjunctival fold patients in the blink of an eye, the conjunctiva friction occurs to produce ocular surface inflammation; 6 eyelid examination, very Emphasis on the examination of the palpebral margin, so that the meibomian gland dysfunction (MGD) can be found. Clinical investigation shows that MGD is the most common cause of dry eye and the most common disease in clinical practice. Pay great attention to the examination of the patient's sacral margin, pay attention to whether the patient has: blepharospasm, irregular, thickening, dullness, valgus, glandular mouth is yellow sticky secretion obstruction, blurred, etc., pressure glands can be found no Lipid secretions are excreted, or excess morphologically abnormal lipids are excreted. At the same time, it should be noted that the lipids in the meibomian glands are normal, such as insufficient lipid secretion, which will lead to lipid-deficient dry eyes.

(2) Shirmer I and II tests: The Shirmer I test (SIt) reflects the basal secretion of tears. The inspection method is as follows: take a 5mm × 35mm filter paper (Whatman No. 41 filter paper), one end folded back 5mm, gently placed in the lower 1/3 junction of the conjunctival sac of the subject, the other end naturally droops, the patient is down Look or gently close your eyes. Remove the filter paper after 5 minutes and measure the wet length. It is generally considered that >10mm/5min is normal. The Shirmer II test (SIIt) reflects the reflex secretion of tears. The examination method is as follows: firstly, the SIt test is performed, and then a cotton swab (length 8 mm, top width 3.5 mm) is gently inserted into the nasal cavity along the side wall of the nasal cavity, and the nasal mucosa is stimulated, and then the filter paper is placed (method with the SIt test), after 5 minutes. Remove the filter paper and record the wet length. It is generally considered that >10mm/5min is normal.

(3) tear-break time (BUT): BUT reflects tear film stability. The examination method is as follows: 1 drop (1 ~ 2 l) of 1% sodium fluorescein in the conjunctival sac of the subject, blinking, and the time from the last blink of the eye to the first dark spot of the cornea is BUT. The non-invasive tear break-up time (NIBUT) is the direct observation of the tear film rupture time using a tear film. It is generally considered that BUT > 10s is normal.

(4) ocular surface staining: fluorescein (FL) staining and rose bengal (RB) or lissamine green (LG) staining, tiger red and lissamine green staining positive reaction Dry and necrotic corneal epithelial cells, tiger red can stain epithelial cells not covered by mucin, the two methods are the same. Although there are many recording methods, the simplest and commonly used method is to divide the ocular surface into nasal cleft palate. The conjunctiva, the temporal condyle, the bulbar conjunctiva and the cornea, the degree of staining in each region is 0 to 3, 0 is no staining, 3 is flaky, 0 to 9 points, fluorescein staining Positive reaction corneal epithelial defect (discontinuous), the scoring method divides the cornea into 4 quadrants, stipulates that no staining is 0, and staining is divided into light, medium and heavy grades, so a total of 0 to 12 points.

(5) tear clearance rate (TCR) examination: the purpose is to understand the delay of tear clearance, using fluorescence spectrophotometry, called fluorescein clearance test (FCT), in the test eye Into the conjunctival sac, 5l of 2% sodium fluorescein was instilled. After 15 minutes, the tears of the tear lake were taken and analyzed by a fluorophotometer. The simple method can detect the TCR by ST test, and drop 1 drop of 0.5% C in the conjunctival sac of the subject. Oxytetracaine, 5 l of 0.25% sodium fluorescein was added, and the SIt test was tested once every 10 minutes. Each filter paper was placed for 1 min for 3 times. The normal tear removal function began to fade after staining with the first filter paper. It shows that the results obtained by the two methods are similar.

(6) tear osmotic pressure: is a sensitive method for diagnosing dry eye. Although there are several methods for laboratory diagnosis, the examination method is more complicated, and there is no simple and practical method for clinical use.

(7) Other examinations: including determination of lactoferrin (LF), tear ferning test (TFT), tear scope plus or tear film intervention Tear film interferometry, contrast cytology, corneal topography and serology.

Dry eye examination

Laboratory inspection

The necessary laboratory tests can be performed for other systemic diseases such as rheumatoid arthritis and lupus erythematosus.

1. Tear lactoferrin measurement is often 100 mg%.

2. Determination of tear lysozyme lysate area 21.5mm.

3. Determination of tear osmotic pressure at KCS 312 mOsm / L.

4. Hematology and immunology check for anemia, leukopenia, lymphocytes and eosinophilia, hypergammaglobulinemia, accelerated erythrocyte sedimentation rate, anti-gamma globulin antibody, anti-nuclear antibody, anti-thyroid antibody, anti-smooth muscle and striated muscle Antibodies, anti-thrombotic antibodies, anti-mitochondrial antibodies, etc. increased significantly, rheumatoid factor 75% (+), lupus cells 10% to 50% (+), decreased cellular immune function, higher specificity as follows:

(1) Anti-SS/A and SS/B antibodies: the primary SS increased, the positive rate was 76% and 19%, respectively; in the secondary SS, both were less than 10%.

(2) Membrane FC (macrophage) receptor function damage: The circulatory clearance rate can be determined by sensitizing autologous red blood cells with 51Cr-binding IgG.

(3) The immune complex is about 85% (+).

(4) Serum monoamine oxidase activity is about 35U.

(5) As lymphocyte infiltration increases, 2m increases proportionally.

(6) Rheumatoid arthritis precipitin, primary, secondary SS is 5% to 15% and 70% to 90%, respectively.

(7) Anti-sacral ductal antibody 46% (+), but it can also be seen by ordinary people.

5. Histopathological examination

(1) Conjunctival biopsy: the serous gland shows lymphocytic infiltration (developed in SS with dry eye syndrome, synchronized with changes in lacrimal gland), fibrosis, and finally atrophy, superficial conjunctival epithelium separated and layered, cupped The cells are reduced or disappeared (normally about 10 per millimeter), but in early conjunctival scrapings, goblet cells often increase.

(2) Labial gland biopsy: in SS, lip mucosa and small parotid gland epithelial and myoepithelial cells swell, interstitial lymphocytes and plasma cells infiltrate, first scattered, after the foci, and finally replace all glandular tissue, tear film and The conjunctiva has the same changes, and the degree of disease is the same, so as to understand the lesions of the lacrimal gland (due to SS, mainly due to lacrimal gland lesions, should not be done for lacrimal gland biopsy), non-SS KCS lip gland biopsy (-).

If you have conscious dry eyes, foreign body sensation and other symptoms of fatigue, increased mucous glands in the conjunctival sac, positive keratoconjunctival infection, especially in the elderly, should first suspect dry eye syndrome.

Auxiliary inspection

1. Schirmer test in KCS, reflection and basal secretion are involved, so the Schirmer I, II test, the basic Schirmer test and the mandatory Schirmer test are reduced in wet length, but the various Schirmer tests are repeated, the results are difficult to agree, severe KCS Only significant reduction, the basic Schirmer test is more accurate, but the margin is not anesthetized, the operation should avoid or reduce the stimulation of the gingival margin, the clinical use of Schirmer test, wet length 5.5mm as the dry eye standard, the method is misdiagnosed The rate is only 1/6, and the wet length of the Schirmer test is 15mm. Dry eyes should be suspected.

2. After RB or LG live staining 1% tiger red or 1% lissamine green eye drops, the palpebral conjunctiva is stained in a point (also other shapes but rare), more than 4 points, the conjunctiva is the bottom of the limbus Triangular staining, point or sheet should consider dry eye.

3. Tough film rupture time BUT measurement 10s, tear film rupture or permanent dry spots, repeated measurements repeatedly, the results are difficult to agree, must be measured three times in a row, take the mean.

4. The X-ray tube of the parotid gland showed spotted shadows, lumen expansion or pseudocyst formation, and the glandular duct disappeared.

5. The sputum gland radionuclide scanning nuclides intake and secretion were reduced, the rising curve was absent, and tartaric acid stimulation did not respond.

6. The sputum assay reduced the gum test <10 ml/10 min; <1.5 ml/15 min without irritation.

Dry eye diagnosis

Two of the RB, BUT and SIT3 items are positive (RB 4 to 10 points, BUT 6 to 10 s, SIT 6 to 10 mm) or 1 strong positive (RB 11 to 50 points, BUT 2 to 5 s, SIT 2 to 5 mm) ), can diagnose KCS, if only 1 positive, is suspicious, must determine the lactoferrin. If <100mg%, you can confirm the diagnosis. Two of the RB, BUT and SIT3 items are positive (RB 4 to 10 points, BUT 6 to 10 s, SIT 6 to 10 mm) or 1 strong positive (RB 11 to 50 points, BUT 2 to 5 s, SIT 2 to 5 mm) ), can diagnose KCS. If only 1 positive is suspicious, the lactoferrin should be determined. If <100mg%, it can be diagnosed. After more than 10 years of clinical application, it is found to have high accuracy. The results of the above three tests generally vary with the degree of dry eye disease. The following methods and criteria for scoring points and grading of the three dry eye examinations were developed. If the cornea staining point of RB is 3 points, BUT 11 s, SIT 11 mm, each score is 0. Add 3 0s, divide by 3, and still be 0. The score is zero, which is a zero-level dry eye, that is, it is not dry eye syndrome.

1. If the results of the three tests are 4 to 10, 6 to 10, and 6 to 10, each score is 1 point, and the integral is 1; the score of 2 positive is 0.7 (2÷3), and the score is 0.7 to 1 is I. If the dry eye is only 1 positive, the score is 1 and its integral is 1÷3 equals 0.3, which is a suspicious dry eye.

2. If the results of the three tests are 11 to 50, 2 to 5, and 2 to 5, each score is 2 points and the score is 2. If 1 item, 2 points, 2 items, 1 point, the integral is 4÷3, which is equal to 1.3, so the score is 1.3~2, which is a class II dry eye.

3. If the three results are 50, 1, 1, then each score is 3 points, and the integral is 3. If only 1 item is 3 points, the other 2 items are 2 points each, and the score is 2.3. Therefore, the score is 2.3 to 3, which is a grade III dry eye.

The number of points or dry eye level clearly indicates the degree of dry eye, which is especially convenient for comparing the effects of drugs. If the treatment is III grade 3 points before treatment, it will become grade II after treatment or although it is still grade III, but the score is 2.3, the score is 3-2.3=0.7 points.

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