There are two types of keratitis: ulcerative keratitis (corneal ulcer) and non-ulcerative keratitis (deep keratitis). It is caused by different factors such as internal and external causes. Inflammation caused by corneal trauma, bacterial and viral invasion of the cornea. The affected eye has a foreign body sensation, stinging pain or even burning sensation. Mixed congestion on the surface of the bulbar conjunctiva with photophobia, lacrimation, visual impairment and increased secretion. The corneal surface is infiltrated with ulcer formation. The vast majority of ulcerative keratitis is due to exogenous factors, i.e. infectious agents invading the corneal epithelial cell layer from outside.
I. Etiology
1, external factors
(1) Damage to corneal epithelial cells, shedding.
(2) Concurrent co-infection.
Only when these two conditions are present, infectious corneal ulcers are likely to occur.
2.Endogenous causes
This refers to endogenous disorders from the whole body.
The cornea has no blood vessels, so acute infectious diseases do not easily invade the cornea. However, corneal tissue is involved in the immune response of the whole body, although the degree of immune response is lower than that of other tissues, but because it is not vascular, metabolism is more sluggish, so that this immune response changes for a long time, the cornea is in a sensitive state for a long time, so it is easy to occur metabolic disorders, such as vesicular keratitis.
3, neighboring tissue spread
Because of the embryological homology and anatomical continuity, the disorders that spread to the corneal epithelium mostly come from the conjunctiva, such as severe conjunctivitis more combined with superficial keratitis.
Second, clinical manifestations
In addition to paralytic keratitis, most patients with keratitis have intense inflammatory symptoms such as pain, shyness, lacrimation, and blepharospasm. Patients with keratitis have not only ciliary congestion, but also iris congestion. In severe cases, the bulbar conjunctiva and even the eyelids may become edematous.
Corneal inflammation inevitably affects vision to a greater or lesser extent, especially if the inflammation invades the pupil area. The corneal scar that forms after the ulcer heals not only prevents light from entering the eye, but also changes the curvature and refractive power of the corneal surface, preventing objects from focusing on the retina to form a clear image, thus reducing visual acuity. The extent of visual acuity depends on the location of the scar. If the scar is located in the middle of the cornea, even though the scar is small, it affects the visual acuity greatly.
III. Examination
1.Check the systemic and local pathogenic factors.
2.Smear examination, bacterial and fungal culture and drug sensitivity test should be done for septic inflammation.
3, dendritic and superficial punctate keratitis do immunological examination, etc.
Diagnosis
Based on clinical manifestations and examination, a clear diagnosis can be made.
V. Treatment
The basic principle of treating keratoconus is to take all effective measures to control the infection quickly, strive for early cure, and reduce the sequelae of keratitis to a minimum. Since most ulcerative keratitis is due to external causes, it is extremely important to remove the causative external causes and eliminate the causative microorganisms. To help diagnose the cause, a smear should be taken from the proceeding edge of the corneal ulcer for bacterial culture and drug sensitivity testing (and mycobacterial culture if necessary). However, do not delay treatment by waiting for the test results, but take the necessary measures immediately.
1.Heat compress
Make the eye blood vessels dilate, release congestion, while promoting blood flow, enhance resistance and nutrition, so that the ulcer can be rapidly recovered.
2.Rinsing
If there are more secretions, use saline or 3% boric acid solution to flush the conjunctival sac 3 or more times a day in order to flush out secretions, necrotic tissue, bacteria and toxins produced by bacteria. This will not only reduce the factors of infection expansion, but also ensure that the concentration of the topical medication is not diminished.
3.Pupil dilatation
Atropine is a commonly used drug with a concentration of 0.25-2% solution or ointment, which is applied 1 to 2 times a day by drops and coatings (pay attention to pressing the tear sac after the drops to avoid excessive absorption of the solution by the mucous membrane, causing poisoning). For simple corneal ulcer or irritation symptoms are not significant can not be used, for irritation symptoms are significant and the potential will be perforated ulcer must be used. This drug has a dual role in the treatment of corneal ulcers; consequences. Further, because the intraocular muscle spasm is released, and thus also has the effect of reducing and relieving pain.
4.Bacteria-making agents
(1) sulfonamide chemical agents such as 10-30% sulfacetamide sodium and 4% sulfisoxazole eye drops.
(2) For gram-positive coccus infection, topical drops of 0.1% rifampicin ophthalmic solution or 0.5% erythromycin or 0.5% bacitracin ophthalmic solution can be controlled 4 to 6 times a day. Some broad-spectrum antimicrobials such as 0.5% chlortetracycline, 0.25% chloramphenicol and 0.5% tetracycline are more effective in their antibacterial effects.
(3) For gram-negative bacillus infection, 1-5% streptomycin, 0.3-0.5% gentamicin, polymyxin B (20,000 units/ml), 0.25-0.5% neomycin, 0.5% kanamycin, etc. can be used.
(4) For ulcers in which the results of bacterial culture and drug sensitivity tests are not yet known and the disease is more serious, a variety of broad-spectrum antimicrobials can be tried simultaneously at the beginning, alternating every few minutes or one quarter-hour drops, and then decreasing as appropriate. In addition, subconjunctival injection can also be used as a route of administration, once a day, and for several days until the ulcer symptoms subside. Conjunctival necrosis sometimes occurs after subconjunctival injection of some drugs, which should be noted.
(5) antiviral drugs such as 0.1% herpes net. The anti-mycotic agents are mycobacterium (25,000 units/ml), 0.1% dicloxacillin B, 0.5% trichostatin and 0.5% pimaricin, etc.
5.Wrapping and dressing
(1) In order to stop the rotation of the eye and promote early healing of the ulcer, wrapping must be performed. This treatment is especially adapted to winter. Because it not only makes the eye not to be cold, but also happens to be hot and protective.
(2) If there is a discharge in the conjunctival sac, it should not be wrapped and can be replaced by a Buller’s eye shield or dark glasses. Furthermore, if the ulcer is about to penetrate, or is about to bulge during the scarring period, a compression bandage should be applied daily, or if daytime is not possible, it should be used at night during sleep to save the adverse consequences.
Six, etiological treatment
(1) While treating corneal ulcer, the cause of the ulcer must be noted and treated.
(2) The most important thing to pay attention to is conjunctival disease and malnutrition. For example, if trachoma vascular opacity ulcer is not treated at the same time, the ulcer will not be healed. Another example is corneal softening. If we don’t pay attention to the whole body nutrition and supplement vitamin A, not only the corneal softening will not be healed, but also will be worsened.
Seven, stimulation therapy
When the ulcer has completely healed and scarring has begun, efforts should be made to make the scar form as thin as possible.
For small, dense and centrally located corneal leukoplakia, augmentation iridotomy can be performed to improve visual acuity. For larger white spots, corneal transplantation may be performed.