Trauma corneal

The most potent inducers of corneal inflammation are infection and trauma (Plate 1). Infective agents include... 

Blunt trauma to eye Macular edema Retinal detachment Sudden congestive proptosis (bulging of eye forward) Corneal ulcer Corneal abrasion... 

In developing countries, trachoma caused by Chlamydia trachomatis is a recalcitrant form of chronic conjunctivitis that can cause scarring. Endophtalmitis is more frequently seen due to neglected corneal ulceration caused by trauma. 

When the primary survey is complete, a thorough head-to-toe evaluation is conducted to assess for other injuries. This may be done at the scene if time and resources permit or at the first receiving hospital. The secondary survey should include getting an accurate history—the circumstances of the injury and medical history—conducting a complete examination to evaluate for other traumas such as fractures, pneumothoraces, contusions, shrapnel, corneal injury and closely reexamining the burn wound size and depth. 

Clinicians should ask about past and current eye disease as well as past ocular trauma. Practitioners should inquire about a history of contact lens wear. Many topically applied medications can cause corneal complications when used in the presence of soft contact lenses. Obtaining a history of current ocular medications is essential. If their continued use is necessary, the old and... 

Topically applied anesthetics may cause corneal endothelial toxicity when used after perforating ocular trauma or when used topically for cataract extraction. When injected inttacametally, benzalkonium chloride, the primary preservative used in topical ocular anesthetics, can cause irreversible corneal edema in rabbits. 

Staphylococcus epidermidis Trauma and surgical infections Blepharitis, hordeolum, conjimctivitis, dacryocystitis, corneal ulcer, endophthalmitis... 

The endothelium functions as both a barrier and pump and is responsible for maintaining corneal transparency by regulating stromal hydration. The endothelium imder-goes an age-related decrease in cell density due to a reduced proliferation rate that does not keep pace with cell loss. As a result, the endothelium becomes fragile and its function can potentially be compromised as a result of trauma or disease. 

Transient secondary guttata may develop in association with degenerative corneal disease, trauma, or inflammation. Transient guttata associated with corneal edema have been termed pseudoguttata. 

Although cataract surgery is a potential precursor to bullous keratopathy, there are many other causes. Fuchs endothelial dystrophy, infection, trauma, retained foreign body, posterior polymorphous dystrophy, chronic uveitis, chronically elevated intraocular pressure (lOP), and vitreous touch are all known causes of bullous keratopathy. Other less common causes of bullous keratopathy include corneal thermal injury secondary to carbon dioxide laser skin resurfacing, air bag trauma, the use of topical dorzolamide hydrochloride in glaucoma patients with endothelial compromise, and use of mitomycin C during trabeculectomy surgery. 

A patient with a corneal abrasion typically reports a history of recent ocular trauma, such as being struck by a flying object or by a finger striking the eye. Patients with intermediate to large corneal abrasions usually seek treatment within 24 hours of the injury because of the significance of their symptoms. 

Figure 26-28 If a patient is referred for consultation due to a suspected corneal penetrating injury, it is appropriate to tape a metal Fox shield over the eye to protect from further trauma during transportation. Tape is placed over the edge of the Fox shield to enhance patient comfort (here shown partially completed).

Ultrastructural changes include abnormalities in the epithelial basement membrane, defective or absent hemidesmosomes, and decreased anchoring fibrils. The condition may occur after superficial corneal trauma, in conjunction with ABMD, or may be idiopathic. 

Modified from Arffa RC. Corneal trauma. In Grayson s diseases of the cornea, ed. 4. St. Louis, MO Mosby, 1S>97 685-708. 

A wide range of substances that are toxic to the cornea may produce epithelial insult known as toxic keratitis. This terminology is generally reserved for mild superficial corneal irritation after contact with a harmful substance. Solutions foreign to the eye that commonly cause toxic keratitis include shampoos, lotions, and chlorinated pool water. Toxic corneal reactions have been reported from tonometer tips contaminated with 70% isopropyl alcohol or hydrogen peroxide that was not fully removed after disinfection of the probe. Irreversible corneal scarring has resulted from inadvertent ocular contamination with chlorhexidine gluconate, a skin cleanser used preop-eratively. The mistaken use of nonophthalmic products for eyedrops may result in various forms of corneal trauma. 

Corneal ulcers are bimodal in occurrence, with the highest incidence in patients in their twenties and those in their sixties to seventies. This pattern can be attributed to the increased incidence of trauma and contact lens wear in the younger group and to ocular surfece disease and eyelid disease in the older group. 

Herpes simplex keratitis (HSK) is caused by HSV type 1 in adults and is one of the most common infectious etiologies of blindness. It is second only to trauma as a cause of corneal blindness in the United States, where an estimated 50,000 new or recurrent cases are seen each year. Recurrent HSK can be reactivated by many factors in addition to those listed above. Reactivation has been reported in patients after penetrating keratoplasty, argon laser trabeculoplasty, Nd YAG laser peripheral iridotomy, or treatment with excimer lasers, including cases in which ocular herpes had not occurred previously. It is important to realize that because most patients have latent HSV it is possible for a reactivation to occur despite a negative history of a primary infection. 

Patients who develop fungal keratitis frequently have a history of previous corneal trauma with vegetation such as sticks, branches, and soil. Agriculture workers and gardeners are specifically predisposed. However, in metropolitan areas where agricultural... 

Corneal edema is a common finding postoperatively after uncomplicated, sutureless, scleral tunnel or clear corneal incision cataract surgery. More severe involvement (Figure 30-5) with persistent stromal edema, epithelial microcysts, and bullae may be found in patients with low endothelial cell counts, excessive inflammation from corneal trauma during the surgery, or an increased lOP secondary to retained lens material or inflammatory response. Bullae are typically secondary to increased corneal aqueous absorption due to high lOP or to a breakdown of the corneal endothelial aqueous pump. 

Summary Stimulating effects of some silatranes and silocanes leadmg to activation of corneal reparative regeneration afler mechanical trauma, protein-synthesizing components, and cicatrizing of experimental bums of rats were studied. Several aspects of the mechanisms of these stimulating effects are discussed. 

In animals of the control and experimental groups after eye treatment with 0.5% dicain solution, a mechanical trauma in the central part of the cornea was produced by a trepan. Wound depth achieved was half of the corneal thickness diameter was 4 mm. 

Obtained data demonstrate that dropping 0.8% aqueous CMS solution (pH 5.5 - 6.0) into eyes afler corneal trauma intensifies inflammatory reaction and activates early processes of elimination of necrotic tissue at the point of trauma. CMS provides limitation of pathological process development in the cornea, and everywhere stimulates processes of wound epithelization. Its use ensures histo-characteristics of the epithelium layer, and arranges orderly fibers of the corneal substance itself. This provokes full comeal recovery and prevents leukoma. 

THera Cat Diagnostic aid (corneal trauma indicator). Sodium Rose Bengal 1 131 as diagnostic aid (hepatic function). 

Topically applied ophthalmic drugs are used for their local effects (see Chapter 63) requiring absorption of the drug through the cornea corneal infection or trauma thus may result in more rapid absorption. Ophthalmic delivery systems that provide prolonged duration of action (e.g., suspensions and ointments) are useful, as are ocular inserts providing continuous delivery of drug. 

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