Clinical featuresĬorneal and conjunctival chemical injury produces a similar constellation of symptoms as keratitis: eye pain, reduced visual acuity, photophobia and watering. For detailed instructions on performing this, see the Geeky Medics guide to eye trauma. Injuries involving ammonia and sodium hydroxide tend to be severe.Īny suspected chemical injury should be immediately irrigated until the pH neutralises, even before conducting any further examination. These may be accidental or secondary to assault.Īlkali burns tend to be more severe as it penetrates more deeply into the ocular tissues, whereas acids coagulate proteins, forming a protective barrier. 3Ĭhemical injury to the eye is an ocular emergency requiring prompt management. Dense infiltrates (white fluffy area of inflamed corneal stroma) that will have an overlying epithelial defect. Topical steroids should never be initiated by non-specialists as there is a risk of worsening the infection and corneal perforation. Topical cycloplegics, oral analgesics and antiemetics should be prescribed to improve patient comfort. Systemic therapy may be used in severe cases. Timely diagnosis of the aetiology of the corneal ulcer is key to initiating the correct treatment regimen, which may involve topical antibiotics, antivirals or antifungals. Left untreated, corneal ulcers can cause rapid, permanent sight loss. The pattern of corneal involvement seen on examination can indicate the likely aetiology and is discussed in more detail in our keratitis article. A hypopyon may be present in severe cases. A corneal epithelial defect is almost always present, visible as an area of green uptake following fluorescein drops under cobalt blue light. These symptoms may then escalate, involving worsening pain and visual acuity.īacterial keratitis is associated with mucopurulent discharge, whereas viral aetiology presents with a clear discharge or watering.Ĭommon examination findings include conjunctival injection with associated focal corneal haziness, representing the area of corneal inflammation. Clinical featuresĬorneal ulcers may initially present with similar symptoms to a corneal abrasion (e.g. Other risk factors include ocular trauma, ocular surface disease (such as dry eye) and immunosuppression. Any red eye in a contact lens wearer is keratitis unless proven otherwise. For more information, see the Geeky Medics guide to keratitis.īacterial and viral keratitis represent the most common forms of microbial keratitis in the western world, but rarely the cause may be fungal or protozoan (acanthamoeba).Ĭontact lens wear is the most significant risk factor for keratitis. Microbial keratitis or corneal ulcer refers to sight-threatening infection and inflammation of the cornea. You might also be interested in our medical flashcard collection which contains over 1000 flashcards that cover key medical topics. Linear vertical abrasions noted on examination suggest a foreign body embedded underneath the upper eyelid. It is important to evert the lower and upper eyelid as foreign bodies may be embedded underneath. Visible foreign body embedded in the conjunctiva or cornea: a metal foreign body embedded for several days will develop a rust ring around itĪfter instilling fluorescein 2%, under a blue light, areas of corneal or conjunctival epithelial injury will glow green. Abrasions may appear as large geographic areas of green staining or fine lines.A clear cornea with no areas of whitening (i.e. Conjunctival hyperaemia: this may be focal and point to the area affected or diffuse.Typical clinical features using high magnification under a white light may include: Visual acuity is unaffected unless the injury involves the visual axis (in front of the pupil). The patient will complain of ocular surface symptoms (pain, discomfort, grittiness, epiphora and photophobia). The history will often confirm the likely source of the injury and may point to the possibility of an intraocular foreign body (for example, the use of power tools without eye protection). It is important always to maintain a high index of suspicion for an intraocular foreign body.įor more information, see the Geeky Medics guide to eye trauma. They may also become embedded superficially. Small particles (metal, sand, organic material etc.) may result in a superficial abrasion to the cornea and/or conjunctiva. You may also be interested in our overview of the causes of a painless red eye and our OSCE guide to ophthalmic history taking.Ĭorneal abrasions and superficial foreign bodies
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