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Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
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The best effective prevention is hygiene and not rubbing the eyes by infected hands. Vaccination against adenovirus, haemophilus influenzae, pneumococcus, and neisseria meningitidis is also effective.
Povidone-iodine eye solution has been found to prevent conjunctivitis following birth. As it is less expensive it is being more commonly used for this purpose globally.
Conjunctivitis due to chemicals is treated via irrigation with Ringer's lactate or saline solution. Chemical injuries (particularly alkali burns) are medical emergencies, as they can lead to severe scarring and intraocular damage. People with chemically induced conjunctivitis should not touch their eyes, regardless of whether or not their hands are clean, as they run the risk of spreading the condition to another eye.
Keratoconjunctivitis is inflammation ("-itis") of the cornea and conjunctiva.
When only the cornea is inflamed, it is called "keratitis"; when only the conjunctiva is inflamed, it is called "conjunctivitis".
There are several potential causes of the inflammation:
- Keratoconjunctivitis sicca is used when the inflammation is due to dryness. ("Sicca" means "dryness" in medical contexts.) It occurs with 20% of rheumatoid arthritis patients.
- The term "Vernal keratoconjunctivitis" (VKC) is used to refer to keratoconjunctivitis occurring in spring, and is usually considered to be due to allergens.
- "Atopic keratoconjunctivitis" is one manifestation of atopy.
- "Epidemic keratoconjunctivitis" is caused by an adenovirus infection.
- "Infectious bovine keratoconjunctivitis" (IBK) is a disease affecting cattle caused by the bacteria "Moraxella bovis".
- "Pink eye in sheep and goat" is another infectious keratoconjunctivitis of veterinary concern, mostly caused by "Chlamydophila pecorum"
- "Superior limbic keratoconjunctivitis" is thought to be caused by mechanical trauma.
- "Keratoconjunctivitis photoelectrica" (arc eye) means inflammation caused by photoelectric UV light. It is a type of ultraviolet keratitis. Such UV exposure can be caused by arc welding without wearing protective eye glass, or by high altitude exposure from sunlight reflected from snow ("snow blindness"). The inflammation will only appear after about 6 to 12 hours. It can be treated by rest, as the inflammation usually heals after 24–48 hours. Proper eye protection should be worn to prevent keratoconjunctivitis photoelectrica.
The symptoms of phlyctenular keratoconjunctivitis are primarily treated with application of an appropriate corticosteroid eye drop, such as prednisolone acetate (Pred Forte) or loteprednol (Lotemax). Loteprednol is increasingly preferred due to its lower risk of elevating intraocular pressure. The corticosteroid suppresses the immune response, reducing inflammation and improving most symptoms.
The causative agent (i.e. the source of the antigen that triggered the hypersensitive immune response) should also be identified. "Staphylococcus aureus" is usually the primary suspect, along with "Mycobacterium tuberculosis" in areas where TB is endemic, followed by "Chlamydia trachomatis". Active bacterial infections may be treated with a topical antibiotic or a combination antibiotic-steroid eye drop, such as tobramycin/dexamethasone (Tobradex). An oral tetracycline antibiotic (such as doxycycline) may be used in systemic or particularly severe/intractable infections. Erythromycin may be an effective alternative, especially in pediatric cases where the side effects of tetracyclines are unacceptable.
Artificial tears can reduce dryness and discomfort from corneal lesions. Photophobic discomfort can be mitigated with dark sunglasses.
Epithelial keratitis is treated with topical antivirals, which are very effective with low incidence of resistance. Treatment of the disease with topical antivirals generally should be continued for 10–14 days. Aciclovir ophthalmic ointment and Trifluridine eye drops have similar effectiveness but are more effective than Idoxuridine and Vidarabine eye drops. Oral acyclovir is as effective as topical antivirals for treating epithelial keratitis, and it has the advantage of no eye surface toxicity. For this reason, oral therapy is preferred by some ophthalmologists.
Ganciclovir and brivudine treatments were found to be equally as effective as acyclovir in a systematic review.
Valacyclovir, a pro-drug of acyclovir likely to be just as effective for ocular disease, can cause thrombotic thrombocytopenic purpura/Hemolytic-uremic syndrome in severely immunocompromised patients such as those with AIDS; thus, it must be used with caution if the immune status is unknown.
Topical corticosteroids are contraindicated in the presence of active herpetic epithelial keratitis; patients with this disease who are using systemic corticosteroids for other indications should be treated aggressively with systemic antiviral therapy.
The effect of interferon with an antiviral agent or an antiviral agent with debridement needs further assessment.
Herpetic stromal keratitis is treated initially with prednisolone drops every 2 hours
accompanied by a prophylactic antiviral drug: either topical antiviral or an oral agent such as acyclovir or valacyclovir. The prednisolone drops are tapered every 1–2 weeks depending on the degree of clinical improvement. Topical antiviral medications are not absorbed by the cornea through an intact epithelium, but orally administered acyclovir penetrates an intact cornea and anterior chamber. In this context, oral acyclovir might benefit the deep corneal inflammation of disciform keratitis.
Consumption of dark fleshed fish containing dietary omega-3 fatty acids is associated with a decreased incidence of dry eyes syndrome in women. This finding is consistent with postulated biological mechanisms. Early experimental work on omega-3 has shown promising results when used in a topical application or given orally. A randomized, double-masked study published in 2013 to evaluate the effects of a triglyceride of DHA (Omega-3; Brudy Sec 1.5), showed significant results compared to other methods that are being used.
Phlyctenular keratoconjunctivitis, also known as phlyctenulosis, is an inflammatory syndrome caused by a delayed (aka type-IV) hypersensitivity reaction to one or more antigens. The triggering antigen is usually a bacterial protein (particularly from "Staphylococcus aureus"), but may also be a virus, fungus (particularly "Candida albicans"), or nematode.
Inflammation occurring in response to tears film hypertonicity can be suppressed by mild topical steroids or with topical immunosuppressants such as ciclosporin (Restasis). Elevated levels of tear NGF can be decreased with 0.1% prednisolone.
Diquafosol, an agonist of the P2Y2 purinogenic receptor, is approved in Japan for managing dry eye disease by promoting tear secretion.
Lifitegrast is a new drug that was approved by the FDA for the treatment of the condition in 2016.
Conjunctivitis is prevalent among children of the highlands of Ecuador. The finding supports the hypothesis that prolonged exposure to the sun at altitude—in the less dense atmosphere (with the resultant lower UV absorption)—is the main cause of the disease.
Actinic conjunctivitis is an inflammation of the eye contracted from prolonged exposure to actinic (ultraviolet) rays. Symptoms are redness and swelling of the eyes. Most often the condition is caused by prolonged exposure to Klieg lights, therapeutic lamps, or acetylene torches. Other names for the condition include Klieg conjunctivitis, eyeburn, arc-flash, welder's conjunctivitis, flash keratoconjunctivitis, actinic ray ophthalmia, x-ray ophthalmia, and ultraviolet ray ophthalmia.
Proper diagnosis is essential for optimal treatment. Bacterial corneal ulcer require intensive fortified antibiotic therapy to treat the infection. Fungal corneal ulcers require intensive application of topical anti-fungal agents. Viral corneal ulceration caused by herpes virus may respond to antivirals like topical acyclovir ointment instilled at least five times a day. Alongside, supportive therapy like pain medications are given, including topical cycloplegics like atropine or homatropine to dilate the pupil and thereby stop spasms of the ciliary muscle. Superficial ulcers may heal in less than a week. Deep ulcers and descemetoceles may require conjunctival grafts or conjunctival flaps, soft contact lenses, or corneal transplant. Proper nutrition, including protein intake and Vitamin C are usually advised. In cases of Keratomalacia, where the corneal ulceration is due to a deficiency of Vitamin A, supplementation of the Vitamin A by oral or intramuscular route is given. Drugs that are usually contraindicated in corneal ulcer are topical corticosteroids and anesthetics - these should not be used on any type of corneal ulcer because they prevent healing, may lead to superinfection with fungi and other bacteria and will often make the condition much worse.
Topical antibiotics are used at hourly intervals to treat infectious corneal ulcers. Cycloplegic eye drops are applied to give rest to the eye. Pain medications are given as needed. Loose epithelium and ulcer base can be scraped off and sent for culture sensitivity studies to find out the pathogenic organism. This helps in choosing appropriate antibiotics. Complete healing takes anywhere from about a few weeks to several months.
Refractory corneal ulcers can take a long time to heal, sometimes months. In case of progressive or non-healing ulcers, surgical intervention by an ophthalmologist with corneal transplantation may be required to save the eye. In all corneal ulcers it is important to rule out predisposing factors like diabetes mellitus and immunodeficiency.
Vernal keratoconjunctivitis (VKC) or spring catarrh is a recurrent, bilateral, and self-limiting inflammation of conjunctiva, having a periodic seasonal incidence.
VKC is thought to be an allergic disorder in which IgE mediated mechanism play a role. Such patients often give family history of other atopic diseases such as hay fever, asthma or eczema, and their peripheral blood shows eosinophilia and increased serum IgE levels.
The pain may be temporarily alleviated with anaesthetic eye drops for the examination; however, they are not used for continued treatment, as anaesthesia of the eye interferes with corneal healing, and may lead to corneal ulceration and even loss of the eye. Cool, wet compresses over the eyes and artificial tears may help local symptoms when the feeling returns. Nonsteroidal anti-inflammatory drug (NSAID) eyedrops are widely used to lessen inflammation and eye pain, but have not been proven in rigorous trials. Systemic (oral) pain medication is given if discomfort is severe. Healing is usually rapid (24–72 hours) if the injury source is removed. Further injury should be avoided by isolation in a dark room, removing contact lenses, not rubbing the eyes, and wearing sunglasses until the symptoms improve.
Photokeratitis can be prevented by using sunglasses or eye protection that transmits 5–10% of visible light and absorbs almost all UV rays. Additionally, these glasses should have large lenses and side shields to avoid incidental light exposure. Sunglasses should always be worn, even when the sky is overcast, as UV rays can pass through clouds.
The Inuit, Yupik, and other Arctic peoples carved snow goggles from materials such as driftwood or caribou antlers to help prevent snow blindness. Curved to fit the user's face with a large groove cut in the back to allow for the nose, the goggles allowed in a small amount of light through a long thin slit cut along their length. The goggles were held to the head by a cord made of caribou sinew.
In the event of missing sunglass lenses, emergency lenses can be made by cutting slits in dark fabric or tape folded back onto itself. The "SAS Survival Guide" recommends blackening the skin underneath the eyes with charcoal (as the ancient Egyptians did) to avoid any further reflection.
Allergen immunotherapy (AIT) treatment involves administering doses of allergens to accustom the body to substances that are generally harmless (pollen, house dust mites), thereby inducing specific long-term tolerance. Allergy immunotherapy can be administered orally (as sublingual tablets or sublingual drops), or by injections under the skin (subcutaneous). Discovered by Leonard Noon and John Freeman in 1911, allergy immunotherapy represents the only causative treatment for respiratory allergies.
Experimental research has targeted adhesion molecules known as selectins on epithelial cells. These molecules initiate the early capturing and margination of leukocytes from circulation. Selectin antagonists have been examined in preclinical studies, including cutaneous inflammation, allergy and ischemia-reperfusion injury. There are four classes of selectin blocking agents: (i) carbohydrate based inhibitors targeting all P-, E-, and L-selectins, (ii) antihuman selectin antibodies, (iii) a recombinant truncated form of PSGL-1 immunoglobulin fusion protein, and (iv) small-molecule inhibitors of selectins. Most selectin blockers have failed phase II/III clinical trials, or the studies were ceased due to their unfavorable pharmacokinetics or prohibitive cost. Sphingolipids, present in yeast like "Saccharomyces cerevisiae" and plants, have also shown mitigative effects in animal models of gene knockout mice.
This is another form of conjunctivitis that is usually caused by cosmetics and pollen which are made of or contains a little or high quantity of alcohol. This is common in people with asthma and eczema. It can lead to mild which makes the eye itchy, red and sore. It could be seasonal conjunctivitis which may last for a few weeks or it may be consistent if the individual is allergic to alcohol.
However, individuals who have his type of conjunctivitis usually gave a high chance of beating the condition and also eliminating their future exposure to allergens. By avoiding the allergen, the severity of its symptoms can be reduced send also remove the condition depending on how effective such individual is in his/her avoidance procedures.
The most effective way to experience relief from all sorts of allergy-related conditions is to make use of eye allergy drops. This happens to be the best way to treat all eye allergies. However, these drops are considered safe and effective due to the fact that they help to treat and relieve allergies in the eye which are often characterized by constant itches, sneezing, red and painful eyes. Twin effectiveness comes from the fact that they can be used without the fear of any side effects which are often encountered with the use of other less conventional healing procedures.
Treatments for corneal neovascularization are predominately off-lab with a multitude of complications as a result. The desired results from medical therapy may not always occur, ergo an invasive procedure may be needed to prevent further decrease in corneal avascularity.
For contact lenses related hypoxia, ceasing the use of contact lenses is the first step until corneal neovascularization is addressed by a physician. Modern rigid gas permeable and silicon hydrogel contact lenses have a much higher level of oxygen transmissibility, making them effective alternatives to help prevent corneal neovascularization.
Topical administration of steroids and non-steroid anti-inflammatory drugs are first-line treatment for individuals with CNV. The administration of steroids can increase the risk of infection, glaucoma, cataracts, herpes simplex recurrence. The anti-inflammatory drugs, however, increase the risk of corneal ulceration and melting.
Since VEGF plays an important role in vasculogenesis and pathologic neovascularization associated with eye diseases, a potential treatment for CNV is to inhibit VEGF activity by competing the binding of VEGF with specific neutralizing anti-VEGF antibody. VEGF inhibitors include pegatanib sodium, ranibizumab, and off-label bevacizumab are currently used for treatment of various retinal disease. Anti-VEGF antibodies such as the application of ranibizumab or bevacizumab have has been shown to reduce corneal neovascularization. Both ranibizumab and bevacizumab uses the same mechanism and inhibits all iso-forms of VEGF. The significant reduction in invasion of in-growth blood vessels in terms of neovascular area and vessel caliber suggests that treatment with ranibizumab induces thinning of the blood vessels, however, there's no significant change of the blood vessel's length. Using anti-VEGF antibodies to treat CNV has some limitations such as it is not a cure and may require repeated treatments to maintain positive effects over time. Topical and/or subconjunctival administration of bevaicizumab or ranibizumab have demonstrated short-term safety and efficacy, however long term effects have not been documented. Anti-VEGF therapy is currently an experimental treatment.
If the cornea is inflamed via corneal neovascularization, the suppression of enzymes can block CNV by compromising with corneal structural integrity. Corneal neovascularization can be suppressed with a combination of orally administration of doxycycline and with topical corticosteroid.
Surgical Options
Invasive solutions for corneal neovascularization are reserved when the medical therapies do not provide the desired results.
Invading blood tissues and ablating tissues in the cornea can be obstructed by the use of laser treatments such as Argon and s. Irradiation and/or damages to adjacent tissues caused by the procedure can result in corneal hemorrhage and corneal thinning. Obstruction of the blood vessels can be unsuccessful due to the depth, size, and, high blood flow rate of the vessels. In conjunction, thermal damage from the lasers can trigger inflammatory response which can exaggerate the neovascularization.
An effective treatment is photodynamic therapy, however, this treatment has limited clinical acceptance due to high costs and many potential complications involved that are also related to laser ablation. Complications can include irradiation from previously injected photosensitive dye inducing apoptosis and necrosis of the endothelium and basement membrane.
Diathermy and cautery is a treatment where an electrolysis needle is inserted into the feeder vessels in the limbus. The vessels are obstructed by a coagulating current through the use of unipolar diathermy unit or by thermal cautery.
In advanced stages, corneal neovascularization can threaten eyesight, which is why routine (annual) eye exams are recommended for contact lens patients.
The treatment of corneal perforation depends on the location, severity and the cause of damage
- Tissue adhesive can be used to seal small perforation, but this method cannot be used to treat perforations larger than 1 mm.
- Non infected corneal perforation generally heals when a pressure bandage is used.
- For certain types of corneal perforations, lamellar keratoplasty is used as treatment.
Superior limbic keratoconjunctivitis is an ocular disease characterized by episodes of recurrent inflammation of the superior cornea and limbus, as well as of the superior tarsal and bulbar conjunctiva.
Even though the pathophysiology remains unclear, it is thought that mechanical trauma from tight upper lids or loose redundant conjunctiva could lead to the disruption of normal epithelium. This mechanical hypothesis is supported by the increased lid apposition of exophthalmic thyroid patients, who are known to have an increased incidence of superior limbic keratoconjunctivitis.
Patients present with red eye, burning, tearing, foreign body sensation, mild photophobia. Inflammation and thickening of the conjunctiva is observed, especially at the limbus.Lubrication is an effective treatment for this pathology.
Mydriatic/cycloplegic agents, such as topical homatropine, which is similar in action to atropine, are useful in breaking and preventing the formation of posterior synechia by keeping the iris dilated and away from the crystalline lens. Dilation of the pupil in an eye with the synechia can cause the pupil to take an irregular, non-circular shape (Dyscoria) as shown in the photograph. If the pupil can be fully dilated during the treatment of iritis, the prognosis for recovery from synechia is good. This is a treatable status.
To subdue the inflammation, use topical corticosteroids. If the intra-ocular pressure is elevated then use a PGA such as Travatan Z.
There is a vaccine for FHV-1 available (ATCvet code: , plus various combination vaccines), but although it limits or weakens the severity of the disease and may reduce viral shedding, it does not prevent infection with FVR. Studies have shown a duration of immunity of this vaccine to be at least three years. The use of serology to demonstrate circulating antibodies to FHV-1 has been shown to have a positive predictive value for indicating protection from this disease.