Corneal inflammatory reaction caused by various reasons is commonly known as keratitis. Keratitis patients are accompanied by obvious vision loss and strong irritation symptoms. Ophthalmic examination showed that corneal luster disappeared, transparency decreased, ulcer formed and ciliary congestion.
According to the anatomical level, it is divided into deep and shallow layers. Deep keratitis: inflammatory lesions are confined to the deep matrix and near the posterior elastic layer, while superficial keratitis: inflammatory lesions are confined to the epithelial layer, anterior elastic layer and superficial matrix. Histologically, inflammatory lesions are mainly in epithelium and sometimes spread to the surface of matrix.
According to anatomical position, it is divided into central part and peripheral part. Central keratitis: Inflammatory lesions are located in the optical zone of the cornea (4mm in the central zone), which are more common in viral keratitis, creeping keratitis and Pseudomonas aeruginosa corneal ulcer. Peripheral keratitis: Inflammatory lesions located at the edge of cornea are more common in acute catarrhal keratitis, spring catarrhal keratitis and bullous keratitis.
According to pathological changes, it can be divided into acute, subacute, chronic, suppurative, non-suppurative and granulomatous. Acute keratitis: keratitis with sudden onset and severe symptoms, which can quickly form corneal ulcer or perforation, such as Pseudomonas aeruginosa corneal ulcer, peristaltic corneal ulcer and gonococcal keratitis. Chronic keratitis: keratitis with hidden onset, mild symptoms, slow development and long course of disease, which rarely causes corneal perforation, such as corneal parenchyma, discoid keratitis and fungal keratitis. Subacute keratitis: keratitis whose pathogenesis is between acute and chronic. Purulent keratitis: refers to keratitis that causes corneal ulcer and purulent secretion. Non-suppurative keratitis: refers to keratitis that does not cause corneal ulcer or has ulcer but no purulent secretion.
According to exogenous, endogenous and mixed pathogens. Exogenous keratitis: inflammation caused by infectious pathogenic factors invading corneal epithelial cells from the outside. Endogenous keratitis: refers to corneal inflammation caused by systemic internal diseases, mostly caused by allergic reactions, such as bullous keratitis.
According to clinical manifestations, it is divided into points, lines, plates, money, trees and pictures. Punctate keratitis: In the corneal epithelial layer, there is needle-sized infiltration, which decomposes rapidly, and fluorescein can be colored, which is more common in viral infection. Linear keratitis: the punctate infiltration and fusion of corneal epithelium or subepithelial skin expands into linear or deep strip opacity located in the posterior wall of cornea. Discoid keratitis: the lesion is located in the matrix layer, round and gray, with a diameter of more than 4mm, but it remains intact and has a clear edge. Money keratitis: It is a kind of small disc keratitis with different sizes, quantities and shades caused by various viruses, which looks like money. In China, most of them are infected by adenovirus type 8. Dendritic keratitis and map keratitis: Both of them are caused by the infiltration, necrosis and shedding of corneal cells caused by herpes simplex virus infection, resulting in ulcers and turbidity of different shapes and depths.
According to the nature of inflammation, it can be divided into ulcerative and non-ulcerative. Ulcerative keratitis: corneal inflammatory infiltration is further expanded and deepened, and epithelial to matrix necrosis falls off to form a wound.
According to the etiology, bacteria, viruses, mold keratitis, etc.
What is the most common pathogen of bacterial corneal ulcer?
Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus hemolyticus, Pseudomonas aeruginosa, Proteus and Moraxella liquefaciens are the most common pathogens of bacterial corneal ulcer. The cause of infection is often closely related to minor corneal trauma or contamination after foreign body removal, and also related to the low immunity of patients.
Pneumococcal corneal ulcer, also known as peristalsis corneal ulcer, is common in rural harvest season, which is mostly the result of corneal injury or corneal infection after foreign bodies are taken out. It is characterized by sudden pain and irritation of the eyes, mixed congestion of the eyes, gray-white micro-convex infiltration focus at the corneal injury, which rapidly develops into an ulcer with gray-yellow pus attached to the surface, which is filthy. One side of the ulcer is dense yellow infiltration with chisel-like edge; The other side is relatively clean, and the progressive margin continues to expand outward, while progressing to a deeper level. Sometimes the ulcer is not obvious, and yellow-gray pus accumulates in the matrix, which is called corneal abscess. Abscess and corneal perforation often heal gradually after perforation, forming corneal adhesive leukoplakia. Bacterial toxins invade the anterior chamber and cause hyphema, so it is also called hyphema bloody corneal ulcer. Infection can also involve intraocular tissues and even destroy the eyeball.
The clinical manifestations of streptococcal corneal ulcer are similar to those of pneumococcal corneal ulcer, but there is less tendency to peristalsis.
Pseudomonas aeruginosa corneal ulcer is mainly caused by trauma and contaminated eye drops, and can also be seen in people wearing contact lenses. Pseudomonas aeruginosa is more active in cornea than in culture medium. Once infected, it often destroys the whole cornea within 24 hours or 48 hours, showing a large number of yellow-green secretions or necrotic tissues.
Moraxella liquefaciens corneal ulcer often exists in human respiratory tract and is generally non-toxic. This kind of ulcer is mostly central, small in shape and slow in progress. It is characterized by rare perforation, but it also has hyphema, but the amount of pus is very small. The patient's symptoms are mild.
What are the causes, clinical features and preventive measures of Pseudomonas aeruginosa corneal ulcer?
Pseudomonas aeruginosa corneal ulcer is an extremely serious acute suppurative corneal ulcer caused by Pseudomonas aeruginosa. The most common causes are corneal trauma and the use of contaminated eye drops, which can also be seen in exposed keratitis or people wearing contact lenses. Pseudomonas aeruginosa exists in soil and water, but also in normal human skin and conjunctival sac. The activity of Pseudomonas aeruginosa in cornea is higher than that in culture medium, so the probability of infection caused by using contaminated eye drops after corneal trauma or corneal foreign body removal is very high.
Clinically, the disease is fierce and urgent, and the onset time is within a few hours. Severe eye pain, photophobia, tears, blepharospasm and other irritating symptoms can be seen at the onset. The clinical manifestations have four characteristics: ① The development is extremely rapid. ② It mainly affects the corneal stroma, and quickly spreads to the whole cornea, which can pierce the cornea within dozens of hours, and sometimes a grayish-yellow infiltration ring appears at the corneal margin in the early stage, and the cornea is completely ulcerated soon. ③ A large amount of hyphema. ④ Pseudomonas aeruginosa can produce yellow-green pigment, so the secretion is green.
People should pay attention to labor protection in their daily life. Once an eye injury occurs, you must go to the hospital immediately and be handled by professionals. At the same time, it is forbidden to use unclean eye drops. Because Pseudomonas aeruginosa can pollute and survive in many kinds of eye drops, such as Dionin, Dicaine, Cortisone, and even sulfanilamide, penicillin and fluorescein solution, it is dangerous to use eye drops stored for several days when the cornea is damaged, especially for fluorescein solution examination.
Once diagnosed, gentamicin, polymyxin B or colistin antagonist should be used locally and systemically, and gentamicin drops should be put into infusion bottles for eye irrigation, with good results.
What are the etiological characteristics and clinical manifestations of fungal corneal ulcer?
Fungal corneal ulcer is a kind of refractory suppurative keratitis with high blindness rate caused by fungal infection. In recent 20 years, due to the wide application of antibiotics and corticosteroids, the incidence of fungal corneal ulcer has increased relatively, and it is no longer a rare disease. At present, the most reported materials in China are Aspergillus, followed by Fusarium, Candida, Yeast and Cephalosporium. Most patients are farmers. Although it can occur all year round, it is mainly concentrated in agricultural summer harvest and autumn harvest season. The most common corneal injuries are cuts, nail gouges and fungal infections secondary to other keratitis. Some people think that long-term use of corticosteroids or antibiotic eye drops can easily lead to fungal infection. In recent years, more and more people have been polluted by wearing contact lenses, and low general or local immunity is also one of the factors.
Clinically, different pathogenic bacteria may have different clinical manifestations, but the symptoms of * * * are the same, with slow onset and mild irritation. The early ulcer is superficial, with gray or milky white "moss scale" on the surface, which is dry and dull, and the "moss scale" is slightly raised and easy to remove. There are hyphae in the basal layer, and the infiltration is dense. The boundary extends around because of hyphae, forming pseudopodia. Sometimes, due to the dissolution of collagen, shallow grooves appear at the edge of infiltration. When the infiltration develops to the deep part, the tissue is necrotic and falls off, forming an obvious ulcer. With the invasion of mycotoxins into the anterior chamber, iriditis and hyphema are caused, and the late hyphema is viscous and often contains fungi. The ulcer can finally break through and cause endophthalmitis. The whole course of the disease develops slowly and can last for 2 ~ 3 months. Because fungal mycelium has the ability of deep growth, it is easy to recur, and sometimes the ulcer heals at the initial stage, but it recurs.
Diagnosis is generally confirmed by fungal smear examination or repeated cultivation of fungi. Because the smear detection rate is low and the culture time is too long, the possibility of fungal ulcer should be considered first, and active treatment measures should be taken, especially for cases with less sudden onset.
How to treat fungal corneal ulcer?
Fungal corneal ulcer is mainly treated with antifungal drugs, such as 0.25% amphotericin B (subconjunctival injection is easy to cause conjunctival necrosis, so special attention should be paid in clinic), chlortetracycline eye ointment, nystatin eye ointment and 10% Dafukang, 1% miconazole, 1% clotrimazole, etc. For 3 ~ 0 days. No matter systemic or local use of corticosteroids, it is forbidden. Because this disease often causes iriditis, we should always pay attention to dilating the pupils.
Penetrating keratoplasty is a surgical treatment method established in recent years, and its indications are mainly ineffective drug treatment, or serious complications such as corneal ulcer perforation, intraocular content prolapse or secondary glaucoma. It's a rescue operation to save the eye. Because fungal hyphae grow vertically, combined with mycotoxins, proteolytic enzymes and soluble fungal antigens, fungal hyphae can grow very deep and even invade the eyes, and it is difficult to clean up the fungi in the eyes during surgery, so postoperative recurrence often occurs. Therefore, for patients without surgical indications, it is emphasized that antifungal drugs should be used first.
Traditional Chinese medicine believes that this disease is mostly caused by damp-heat, so it is necessary to distinguish the focus of damp-heat in treatment and choose drugs to clear away heat and dampness. Commonly used prescriptions are Chushi Decoction and Ganlu Drink. In addition, traditional Chinese medicine fumigation or atomization treatment can also be used.
What are the common types of viral keratitis?
Viral keratitis can be caused by many viruses, and its clinical manifestations are different. The degree of damage to vision varies with the location of the lesion, the severity of inflammation, the duration of the disease, the number of recurrences and whether there is mixed infection. Clinical common viral keratitis includes herpes simplex keratitis, vaccinia keratitis and herpes zoster keratitis.
Herpes simplex keratitis: Keratitis caused by herpes simplex virus. According to antigenicity and biological characteristics, viruses can be divided into type ⅰ and type ⅱ. Corneal lesions caused by herpes simplex virus can invade all layers of cornea and transform with each other. Typical forms are dendritic, map-like, discoid and corneal uveitis.
Vaccinia keratitis: keratitis caused by vaccinia infection, often caused by vaccinia splashing into the eye or being brought into the eye by a finger contaminated with vaccinia pus. It usually occurs after the incubation period of 3 days. Except for the cowpox rash on conjunctiva and eyelid, about 30% have keratitis. Superficial keratitis and superficial corneal ulcer are the main causes, while stromal keratitis and discoid keratitis are less. Since 1980s, smallpox has been eliminated all over the world, so vaccination against vaccinia has been abandoned, and this disease will be extinct in the future.
Herpes zoster keratitis: superficial dendritic or interstitial keratitis caused by varicella-zoster virus invading the ophthalmic branch of trigeminal nerve, accompanied by severe neuralgia, with beaded herpes on the skin in the distribution area. Herpes zoster virus and varicella virus belong to the same virus, so they are also called V-2 virus. Herpes zoster keratitis is a latent viral infection disease. Herpes zoster virus lurks in trigeminal ganglion at rest and recurs under the induction of decreased cellular immunity and external stimuli. This kind of keratitis can be manifested as punctate, money-shaped, dendritic and interstitial keratitis, discoid keratitis and so on. This disease is often complicated with herpes zoster of eyelid, accompanied by severe uveitis, causing hyphema or pus accumulation. Steroid deposition is often seen in the turbid area of the stroma layer, and the iris can atrophy.
What is the cause of herpes simplex keratitis?
Herpes simplex virus, abbreviated as HSV in English, causes corneal infection and is called herpes simplex keratitis (HSK). It is one of the most harmful infectious eye diseases in the world, and its incidence ranks first in corneal diseases. It is characterized by many types and easy recurrence, and its pathogenesis is related to immune status. Due to the wide application of antibiotics and corticosteroids, its incidence rate has an obvious upward trend, which often seriously damages visual function due to repeated attacks. There is no effective drug to control recurrence in clinic, so it is still one of the main blinding eye diseases.
How to treat herpes simplex keratitis?
Once you get herpes simplex keratitis, you should treat it in time. Treatment can be done by drugs, surgery and other methods.
Antiviral drugs, such as iodine glycoside, also known as herpes simplex, are mainly used in drug treatment, which is mainly suitable for the first attack cases, and other drugs should be used for recurrent cases; Cytarabine has a certain curative effect, but it is toxic to normal cells, so its derivative cyclic cytidine is often used; Ribavirin, also known as ribavirin, is a broad-spectrum antiviral drug with good curative effect and low toxicity to normal cells. Acyclovir, also known as acyclovir, is an effective antiviral drug, especially for herpes virus. Other antiviral drugs such as cytarabine, trifluoromethyl thymidine, etc. Adrenal cortical hormone can also be used, because it can inhibit corneal immune response and anti-inflammatory, and it is often used in the treatment of herpes simplex keratitis in the later stage, but the following principles should be mastered: ① Epithelial or superficial corneal inflammation is prohibited. Because it can activate the activity of virus and collagenase, promote virus reproduction and make the disease develop to a deeper level. It can also inhibit epithelial regeneration and even cause ulcer perforation. ② It is only used for patients with deep inflammatory reaction without ulcer. Because the pathogenesis of deep HSK, especially discoid keratitis, is also allergic to virus antigen, it is reasonable to use corticosteroids, but antiviral drugs should be used at the same time. 1 ~ 2 was stained with fluorescein once a day. If there is an ulcer, stop using it immediately and treat it as an ulcer.
Surgical treatment, choose the surgical method according to the condition. Commonly used methods include: mechanical debridement, anterior chamber puncture, conjunctival flap covering, corneal transplantation and so on.
Traditional Chinese medicine treatment is based on etiology and syndrome differentiation. Wind-heat offenders, choose Yinqiao powder to dispel wind and clear heat; If the liver and gallbladder are inflamed, choose the liver-clearing and fire-purging agent of Longdan Xiegan Decoction; Because of damp-heat fumigation, Sanren decoction was selected as a heat-clearing and dampness-removing agent; Those who are deficient in positive energy and still have evil spirits need to strengthen the body resistance and eliminate evil spirits, and the modified Dihuang Pill is used for treatment. In addition to oral administration, traditional Chinese medicine is also combined with local treatment, and eye drops of traditional Chinese medicine preparations for clearing away heat and toxic materials, such as Scutellaria baicalensis eye drops, are often used; Yinhuang injection can be used as subconjunctival injection if the condition is serious. In addition, traditional Chinese medicine decoction can be smoked or atomized before taking.
What are the causes and treatments of superficial punctate keratitis?
Shallow punctate keratopathy is a series of punctate lesions involving corneal epithelium, epithelial basement membrane, anterior elastic membrane and its adjacent shallow corneal stroma, which is collectively referred to as shallow punctate keratitis in clinic. Clinically, it is divided into three types, namely punctate epithelial keratitis, punctate epithelial erosion and punctate subepithelial infiltration. In most specific diseases, these three kinds of diseases coexist at the same time, but the severity and scope are different.
The causes of superficial punctate keratopathy are complex and diverse, generally including:
Bacteria: staphylococcal blepharitis is often accompanied by L/3 epithelial erosion under the cornea, with superficial punctate inflammation and subcutaneous infiltration at the edge; Other types of bacterial conjunctivitis are often accompanied by three types of superficial punctate keratopathy, which can be scattered or diffuse throughout the cornea, and typically involve the peripheral parts of the cornea.
Viral: Any early stage of acute viral conjunctivitis may lead to punctate epithelial erosion.
Toxins: eye drops (antibiotics, antimetabolites) and ultraviolet rays (snow blindness, electric welding, etc.) are often used externally. ) irradiation.
Mechanical and chemical injuries: epithelial abrasion, trichiasis, exposure, various chemical debridement (iodine tincture, trichloroacetic acid, etc. ), epithelial basement membrane degeneration and malnutrition after PR K.
Others: The causes include immune-related keratitis sicca, conjunctivitis of upper sclera margin, conjunctivitis in spring, pollen and drug allergy, and neurotrophic keratitis.
The treatment is mainly to remove the etiology, anti-inflammatory and anti-infection and nutritional preparations such as calf serum and artificial tears. Traditional Chinese medicine often divides this disease into wind-heat syndrome and lung-kidney yin deficiency syndrome. Wind-heat syndrome is treated with wind-dispelling and heat-clearing drugs, and lung-kidney yin deficiency syndrome is treated with Chinese medicine for nourishing lung and kidney. It can also be fumigated or atomized by traditional Chinese medicine. The eye center of Jiangsu Provincial Hospital of Traditional Chinese Medicine has a good effect in treating this disease with Chinese medicine eye patch.
What are the types of stromal keratitis and what are its etiological characteristics?
Stromal keratitis refers to diffuse inflammatory infiltration of corneal stroma, which does not cause ulcerative tissue defect, and is an antigen-antibody reaction of cornea. There are mainly tuberculous stromal keratitis, syphilitic stromal keratitis and leprous stromal keratitis.
Tuberculous corneal stromitis: Tuberculous keratopathy occurs on the basis of tuberculosis in other parts of the eye, which is secondary and can be seen in the following situations: ① Tuberculosis spreads from the surrounding conjunctiva or sclera; (2) Extending from the uvea along the anterior chamber angle or the back of cornea; ③ The tuberculous nodule of ciliary body breaks through the scleral venous sinus, which makes the mycobacterium tuberculosis spread in the posterior part of cornea; ④ It is caused by tuberculous uveitis spreading and directly invading the posterior part of cornea. Monocular disease, which only invades part of cornea, has punctate or nodular infiltration focus in the middle and deep layer of stroma, which is grayish yellow and invaded by new blood vessels, leaving a thick scar. The course of disease is slow and easy to recur.
Syphilitic stromal keratitis: diffuse stromal inflammation caused by allergic reaction of cornea to Treponema pallidum. Its pathogenesis is immune inflammatory reaction, and the spirochete infected in embryo or acquired spreads to cornea, sensitizing corneal tissue with blood. Later, when the spirochete antigen or toxin hidden in other parts of the body reaches the sensitized cornea with blood flow, it is caused by local antigen-antibody reaction or antigen-antibody reaction. Complement reaction and pathogenesis. Syphilitic corneal stromitis mainly occurs in patients with congenital syphilis, and both eyes develop simultaneously or successively. Acquired syphilis occasionally occurs, but most of it is monocular, and the disease has almost disappeared in China. Eye manifestations: there are obvious irritation symptoms, deposits at the back of cornea, foggy corneal parenchyma and brush-like neovascularization, and finally more or less turbid spots and atrophic blood vessels remain in corneal stroma.
Leprosy corneal stromatolitis: Leprosy can infect the eyes and face through blood source, causing injuries to the temporal and zygomatic branches of facial nerve and facial branches of trigeminal nerve, making the eyelid position abnormal, normal blinking action and corneal reflex disappear, leading to exposed keratitis, causing corneal opacity and injury, and leprosy can also directly attack the cornea, causing corneal stromatolitis. The main manifestations are early fine punctate keratitis, which later developed into diffuse superficial punctate keratitis, followed by discoid matrix infiltration or diffuse matrix infiltration and neovascularization.
Auxiliary training method for restoring vision
1, staring into the distance:
/kloc-find a meadow or green tree 0/0 meters away: green is imaged in front of the retina due to the short wave length, which can promote eye adjustment and relaxation, relax the ciliary muscles of the eyes and reduce eye fatigue. Don't squint, don't blink all the time, eliminate distractions, concentrate on staring for 25 seconds, and recognize the outline of grass leaves or leaves. Then put the left palm slightly higher than 30 cm in front of your eyes and read the palm prints one by one from beginning to end for about 5 seconds. Look at the palm print, then stare at the grass or leaves in the distance for 25 seconds, and then look at the palm print. /kloc-repeat 20 times in 0/0 minute, three times a day, and increase the number of trainings if the vision drops badly.
2, crystal operation
● Blinking: Hold your chin with both hands, let your eyes rotate 10 times in the order of up, down, left and right, and then rotate 10 times counterclockwise and clockwise respectively.
● Find a scene 3 meters away (such as calligraphy and painting on the wall). ), at the same time, raise your left hand slightly higher than your eyes and straighten it (about 30 cm). After seeing the handprint clearly, look at Qingyuan again, and move your eyes between them as quickly as possible, going back and forth for 20 times.
3. Massage practice
Lie on your back or supine, close your eyes naturally, and then massage the acupoints around your eyes in turn. Need to choose accurate points, gentle techniques, there is a feeling of local pain.
1. Kneading Tianying Point: Gently press Tianying Point (lower brow and upper angle outside orbit) with both thumbs.
2. Squeeze Jingming point: Gently press Jingming point with the thumb of one hand (the root of the nose is close to the inner canthus of both eyes), first press down and then squeeze up.
3. Knead Sibai Point: Knead Sibai Point with your index finger in the center of your cheek (straight down to the middle of the lower edge of your orbit).
4. Press the temple wheel to scrape the eye socket: press the temple with the thumb (a horizontal finger backward between the brow tip and the outer corner of the eye), and then gently scrape the eye socket with the inner side of the second section of the curved index finger, from the inside up-> External top->; Outside-> Under the inside, massage the acupoints around the eye socket, such as bamboo waist, hollow bamboo pole, pupil dredging, ball back, weeping and so on. Conducive to pseudomyopia or prevent myopia from deepening.
References:
2004 65438+February 02 13:09 Sina parenting
Netizen Persian sugar: TV can be managed, and computers can also be managed, as long as they are controlled within a reasonable time. I think reading is more eye-consuming than watching TV and computer, so the most important thing is to use eye hygiene, pay attention to posture, pay attention to light and so on. If you feel nearsighted, let your child play table tennis for a month. Recently, it has been seen that it has a preventive effect on myopia.
Netizen Peter's mother: insisting that children practice rolling their eyes 20 times a day can improve myopia. His child's vision used to be 0.8, but now it has returned to 1.2 after several months. It is also said that this kind of exercise can prevent myopia and is more effective than eye exercises. You might as well let the children try. Yesterday, I went to the specialist clinic of Capital Institute of Pediatrics to see an ophthalmologist (Peter has chalazion in his eyes). Many children go to check their eyesight and prepare glasses. Alas, seeing my parents' anxious eyes, I am really worried that this is my son's future. Therefore, under the current pressure of study, firstly, children should participate in sports and outdoor activities, increase the chances of overlooking and rolling their eyes, and reduce the use of screens and eyes at close range. Obviously, there are more children wearing glasses nowadays than in our time. Is this also the progress of the times?
Netizen Dan Qing 0604: I recently bought a preventive alarm for my son and hung it on my ear. When the head is close to the desk, it will make a sound. I think it's quite scientific. I bought a shelf for correcting sitting posture before, but it affected the effect of writing, and my son was uncomfortable with it.
For people who often watch computers-prevention and treatment of dry eye.
Our eyes, especially the cornea, often rely on lacrimal glands for water supply. By blinking, tears become a layer of "tears" and spread to the cornea to keep the eyes comfortable. The so-called "dry eye" refers to a symptom of leaving tiny scars on the eyes due to the decrease of tears or the decline of lacrimal gland function. In the past, dry eye, cataract, glaucoma and other diseases were mainly common eye diseases of the elderly, but now it is found that more and more young people and white-collar workers often contact computers, televisions and game machines in some cities. According to the investigation of relevant departments, 90% of people who work in front of the computer for more than 3 hours every day have eye problems. This so-called "computer vision syndrome" is a manifestation of dry eye.
1. Clinical symptoms of dry eye
The common symptoms of dry eye are dry eyes, burning pain and more gums; Acid eyes, itchy eyes, fear of light, decreased vision. Other symptoms include headache, irritability, fatigue and difficulty in concentration. In severe cases, corneal softening and perforation will occur, and conjunctival congestion can be seen during examination.
2. Causes of dry eye syndrome
There is a layer of tears between the upper and lower eyelids, which contains substances to protect the eyes from infection. When people blink, tears are evenly distributed on the eyeball, cleaning the dust on the conjunctiva and keeping the eyes bright. The average person's tear secretion will decrease with age, so the incidence of dry eye in the elderly is higher. There are many factors that cause dry eye, including: the decrease of tear secretion after middle-aged and elderly people, and the symptoms of the eyes themselves, such as corneal degeneration, blepharitis and trachoma. Various immune diseases and connective tissue diseases, such as rheumatoid arthritis, lupus erythematosus, xerostomia, arthritis syndrome (more common in middle-aged and elderly women); It is caused by certain drugs, such as birth control pills, sleeping pills, sedatives, cough medicines, stomach medicines, etc. ; It may also be caused by vitamin A deficiency.
In recent years, the trend of dry eye is obvious, mainly because in modern life, young people have more and more contact with TV and computers for work and entertainment, and they face the fluorescent screen for a long time, lacking in blinking or letting their eyes rest in time, which affects the secretion of tears in their eyes; Or use some eye drops for a long time, such as vasoconstriction.