corneal disease
Introduction
Introduction to corneal disease Keratopathy is an important cause of vision loss. The transparent cornea appears grayish white turbidity, which can blur vision, reduce, and even blindness. It is also one of the most important eye diseases for blindness. In the early stage of corneal disease, if it can be treated promptly and accurately, it can be cured. However, if the lesion is severe or recurrent, it will leave a thick scar on the cornea. At this time, the only treatment is corneal transplantation. The opaque cornea is removed and replaced with a transparent cornea to regain vision. basic knowledge The proportion of illness: 0.03% Susceptible people: no specific population Mode of infection: non-infectious Complications: iritis, iridocyclitis, secondary glaucoma with iridocyclitis, corneal staphyloma
Cause
Cause of corneal disease
Trauma and infection (35%):
It is the most common cause of keratitis. When the corneal epithelial layer is damaged by mechanical, physical and chemical factors, bacteria, viruses and fungi will enter, infection will occur, and the invading pathogenic microorganisms can be sourced. In the case of external injuries, it can also come from various pathogenic bacteria hidden in the eyelids or conjunctival sacs, especially chronic dacryocystitis, which is a risk factor for corneal infection.
Systemic disease (30%):
Is an intrinsic factor, such as allergic keratitis caused by tuberculosis, rheumatism, syphilis, etc., systemic malnutrition, especially corneal softening caused by vitamin A deficiency in infants and young children, and nerve paralysis caused by trigeminal nerve palsy Keratitis, etc., in addition to autoimmune diseases such as mooring corneal ulcers with unclear causes.
Tissue disease (20%):
Acute conjunctivitis can cause superficial punctate keratitis, scleritis can lead to sclerosing keratitis, uveitis can also cause keratitis, and keratitis can occur when the eyelid defect is combined with cleft palate.
Course of disease and pathological changes
After the occurrence of keratitis, the course of disease and pathological changes can be generally divided into three stages: inflammatory infiltration, progression and recovery, the outcome of inflammatory lesions, on the one hand depends on the strength of the pathogenic factors, the body's resistance Size; on the other hand, it depends on whether the medical measures are timely and appropriate. The list is summarized as follows.
(1) Infiltration period
When the pathogenic factor invades the cornea, the first is the vasodilation of the limbus, congestion (ciliary congestion, such as conjunctival vascular congestion, called mixed hyperemia), due to the role of inflammatory factors, the permeability of the blood vessel wall increases Plasma and white blood cells, especially neutrophils, migrate into the lesion, forming a gray-white turbid lesion with unclear borders in the corneal damage area, corneal edema around, corneal infiltration, and infiltration of the cornea due to edema. The size, depth and shape of the corneal infiltration are different depending on the severity of the disease. After treatment, the infiltration can be absorbed, and the self-absorbed, the corneal transparency can be recovered and healed; if the condition is serious or the treatment is not timely, the inflammation will continue to develop.
(2) Progress period
If the inflammation in the infiltration phase is not controlled, the infiltration will spread and the new blood vessels will extend into the infiltrating area, especially in the peripheral part of the inflammation. In the infiltrating area, neutrophils dissolve, releasing the lysozyme containing the hydrolase. Body particles, hydrolase and corneal protein reaction, resulting in infiltration of the corneal epithelial layer, the front elastic layer and stromal layer necrosis, corneal tissue defects, the formation of corneal ulcer (corneal ulcer), also known as ulcerative keratitis (ulcerative keratitis ), the edge of the ulcer is gray or gray-yellow turbid. If the ulcer develops in depth, it forms a deep ulcer, the bottom of the ulcer is uneven, and the iridocyclitis can be complicated by the stimulation of the toxin. In severe cases, a large amount of fibrinous exudate accumulates. In the lower part of the anterior chamber, hypophnea is formed. When the corneal stroma is completely destroyed and the ulcer spreads to the posterior elastic layer, the intraocular pressure can cause the posterior elastic layer and the endothelial layer to bulge forward due to the reduction of local resistance. The posterior elastic layer bulges (descemetocele), and the "black" transparent vesicles are visible at the bottom of the ulcer during clinical examination. This is the cornea. Symptoms of perforation, at this time, if the eyeball is compressed, such as blinking, colliding, sneezing, coughing, constipation, etc., the cornea may be suddenly perforated. During the perforation, the patient may suddenly feel pain in the eye and have tears ( That is, the aqueous humor flows out, which can cause a series of complications and sequelae after perforation.
Infiltration in the corneal stroma, no ulceration, said no ulcerative keratitis, mainly lymphocytic infiltration, this type of keratitis is more related to the body's allergic reaction, such as corneal stroma.
(3) Recovery period
That is, the stage of inflammation, after treatment, the ulcer can gradually turn to clean, the surrounding healthy corneal epithelial cells grow rapidly, the ulcer surface is completely covered, under the cover of corneal epithelial cells, the fibroblast proliferation of the corneal stroma and the synthesis of new collagen Repair the defect of the matrix, the corneal ulcer is cured, the ulcer healing in the central cornea is mostly no neovascular healing; the peripheral ulcer is mostly vascular healing, and the newly formed corneal matrix collagen fibers are disorderly arranged, forming an opaque Scar tissue, dense scar in the central area can cause severe loss of vision in the affected eye, superficial ulcer, only the corneal epithelial layer covers the wound, and no connective tissue hyperplasia, the transparent concave surface is formed at the injury, fluorescein is not stained. It is called the cornea facet.
Prevention
Corneal disease prevention
Patients should pay attention to adequate rest, so that the eyes are more exposed to fresh air, to facilitate rehabilitation, to listen to more relaxed music, but also to relieve eye pain and local irritation.
Diet should eat more vegetables and fruits rich in vitamins and cellulose, eat more high-calorie, high-protein foods such as beans, soy products, lean meat, eggs, etc., to repair the cornea, should quit smoking, do not eat fried , spicy, fatty and sugary foods, the spirit is very important in the disease, the most fear of anger, so as not to aggravate the liver fire, unfavorable rehabilitation, but it is not appropriate to talk too ridiculous, to a comfortable, quiet degree.
In order to prevent keratitis, we should pay attention to establish a healthy lifestyle. Because patients with vesicular keratitis are poisoned for life, any factors affecting immune fluctuations will cause recurrence of old diseases. Patients should live regularly, avoid staying up late, drinking alcohol, overeating, and catching colds. Fever, sun exposure and other incentives can reduce the risk of recurrence of old diseases. Once the old disease recurs, it is necessary to go to the hospital for medical treatment and consultation in time, and do not use drugs indiscriminately, so as not to complicate the disease and increase the difficulty of treatment.
Complication
Corneal disease complications Complications iritis iritis ciliary inflammatory disease secondary to iridocyclitis secondary glaucoma corneal staphyloma
(1) iridocyclitis and shallow corneal scar, deep corneal ulcer or keratitis, in the inflammatory phase, may be complicated by iritis or iridocyclitis, at this time if the formation of anterior chamber empyema, it is sterility Anterior chamber empyema, when corneal ulcer or stroma inflammation, after repair, the opaque part formed on the cornea is called corneal scar, its impact on vision, depending on the thickness, size and position of the scar.
1. Corneal nebual thin cloud-like corneal scars can be found by oblique or slit lamp inspection.
2, corneal macula (corneal macula) thicker, grayish white turbid, translucent, visible to the naked eye.
3, corneal leucoma (cornel leucoma) is the thickest corneal scar, milky white or porcelain white turbid, opaque, it is known.
(B) complications and sequelae caused by perforation of corneal ulcer
1. Corneal fistula: After the small cornea is perforated, if the corneal epithelial cells grow into the wound along the wound edge, preventing the healing of the perforation, the corneal spasm is formed, and the eyeball is connected inside and outside, which easily causes intrabulb infection. At the time of examination, a small black spot can be seen in the center of the corneal opacity. The anterior chamber becomes shallow, the intraocular pressure is lowered, and fluorescein is dripped on the cornea. The aqueous humor flowing out of the pupil will dilute the fluorescein to form a light The green trickle, such as the fistula, is temporarily blocked by the epithelial cells, where a small vesicle is visible, and the intraocular pressure recovers or rises and collapses, thus repeatedly, threatening the eye.
2, anterior polar cataract (anterior polar cataract): after corneal perforation, the anterior chamber suddenly disappeared, corneal rupture directly contact with the crystal and toxin stimulation, can cause local metabolic disorders of the crystal, the occurrence of crystal front limit turbidity, Pre-polar cataract.
3, iris prolapse (iris prolapse): when the corneal ulcer is perforated, due to the outflow of aqueous humor, the iris can be removed from the perforation, the pupil loses its round shape, is a melon-like shape, its tip is facing the iris prolapse, at this time the intraocular pressure is reduced, the eyeball becomes Soft, in the healing process, the following situations can occur.
(1) Adherent corneal leucoma: After the iris is released, fibrinous exudate is quickly produced on the iris surface, condensed on the perforation and the erupted iris, and the ulcer edge and the iris are partially removed. Up, do not make the anterior chamber communicate with the outside world, the anterior chamber gradually recovers, after the ulcer is healed, in the corneal scar tissue, there is a mixture of exfoliated iris tissue, this corneal scar is called adhesive corneal leukoplakia.
(2) corneal staphyloma: If the corneal perforation range is large, the embedded iris and cornea will adhere, forming a loose scar to seal the perforation, and the pre-adhesive iris obstructs the discharge of aqueous humor, causing the intraocular pressure to rise if the scar When the tissue is unable to resist the intraocular pressure and gradually swells out of the normal corneal surface, the bulging corneal scar is called corneal staphyloma, and when the bulging is limited to a part of the cornea, it is called partial corneal staphyloma, and all corneas are forward. When bulging, it is called full corneal staphyloma.
(3) Secondary glaucoma: The anterior chamber angle is narrowed or blocked due to the extensive pre-adhesion of the iris.
Symptom
Symptoms of keratopathy common symptoms corneal lens adhesion cornea corneal foreign body corneal epithelial erosion on the cornea on the cornea dark gray turbidity teardrop keratitis ciliary congestion visual impairment corneal opacity
Corneal disease is the second most common blind eye disease, and corneal disease is an important cause of vision loss.
(a) Conscious symptoms
Because the trigeminal sensory fibers are stimulated by inflammation, the patient complains of fear of light, tearing, pain, and severe eye irritation. When the corneal epithelium is exfoliated, it can cause severe eye pain. Depending on the degree and location of the corneal lesion, it may be accompanied. Different degrees of visual impairment, in addition to purulent corneal infection, generally no secretions or secretions.
(two) signs
1, keratitis with severe conjunctival edema, can cause different degrees of conjunctival edema.
2, ciliary congestion When the cornea is inflamed, the anterior ciliary vascular network around the limbus is dilated and congested, called ciliary congestion, when the conjunctiva and ciliary congestion appear at the same time called mixed congestion.
3, corneal opacity caused by corneal infiltration, edema or ulcers, must be differentiated from corneal scars formed after inflammation.
4, corneal neovascularization in the process of corneal inflammation or ulceration, the constricted capillary network around the limbus protrudes into the cornea when the neovascular branch protrudes into the cornea. It is called the corneal neovascularization, the subepithelial neovascularization, from the superficial vascular network. Dendritic, bright red, connected to the conjunctival vascular, the anterior stromal neovascular originates from the deep vascular network; the neovascularization of the posterior stromal tissue comes from the branch of the iris artery and the radial iris vessels extending to the limbus, and the deep neovascularization is brush-like. Dark red color, accompanied by the appearance of new blood vessels on the cornea is the performance of the body repair function.
In the inflammatory phase, corneal neovascularization is easy to see. After the inflammation subsides, the new blood vessels remaining on the relatively transparent cornea, only the blood in the lumen, called ghost vessels, are hard to find, corneal neovascularization, On the one hand, the cornea loses transparency, on the other hand, the corneal tissue undergoes biochemical changes, from the immune privilege state that does not participate in the whole tissue, to participate in the immune response, which may lead to rejection during corneal transplantation.
Examine
Corneal disease examination
(1) Clinical examination
1, history of corneal irritation and trauma, local and systemic use of corticosteroids; with or without chronic dacryocystitis, varus and other eye diseases and related systemic diseases.
2, eye examination, severe symptoms, especially in children, you can first drop the surface anesthetic and then check, for those who have the risk of perforation, avoid injecting the eyeball, the corneal surface damage, easy to see by fluorescein staining It is easier to detect the location and shape of the corneal lesions by using a magnifying glass or a slit lamp, and if necessary, a corneal sensory examination and a tear secretion function test.
(2) Laboratory inspection
In order to choose the most effective treatment plan, it is very important to determine the pathogenic factors. For bacterial or fungal corneal ulcers, scribing can often lead to clues, microbial culture and drug sensitivity experiments, which are more helpful for diagnosis and treatment. It must be pointed out that before the results of the experiment are obtained, the necessary treatment should be given first according to the clinical diagnosis, and the timing of treatment should not be delayed.
Diagnosis
Diagnosis and diagnosis of corneal disease
diagnosis
Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.
Differential diagnosis
Mainly with corneal opacity, corneal scar identification.
