Related articles: Corneal ulcer
Definition
Corneal ulcer is a serious corneal injury.
The cornea is a thin transparent membrane that covers the front of the eye and through it you can see the iris and the pupil. This structure allows the focusing of light on the retina, therefore it is not vascularized, but it has numerous free nerve endings that make it extremely sensitive.
The corneal ulcer is similar to an open wound and is characterized by the interruption of the corneal epithelium (superficial) with underlying inflammation. The lesion, therefore, can extend to involve the entire corneal surface and / or penetrate deeply, resulting in necrosis of the corneal stroma and giving rise to the formation of an excavated ulcer.
Corneal ulcers can depend on many causes. Usually, they result from an inflammatory process or an infection, but can also be caused by mechanical trauma (penetration of foreign bodies or abrasions of the ocular surface) and chemical damage. Among the main causes there is also a wrong use of contact lenses: people who wear them for a long time or during sleep, even if expired or not properly cleaned and disinfected, have an increased risk of developing corneal ulcers. These behaviors, in fact, predispose to the onset of a keratitis from Acanthamoeba or from Pseudomonas aeruginosa . Other common infections that can lead to the onset of a corneal ulcer are Herpes simplex or fungal keratitis (more frequently secondary to trauma with plant material). The corneal ulcer can also be induced by eyelid abnormalities (eg chronic blepharitis, entropion, trichiasis, incomplete closure of the eye due to trauma or Bell's palsy), trachoma, dry eye, severe allergic reactions or nutritional deficiencies (in particular: protein malnutrition and vitamin A deficiency).
Most common symptoms and signs *
- Altered color vision
- Burning eyes
- Ocular pain
- Pus formation
- Fotofobia
- Eyelid swelling
- hypopyon
- Tearing
- leukocoria
- Eyes reddened
- Corneal opacity
- itch
- Reduced vision
- Ocular secretion
- Double vision
- Blurred vision
Further indications
The symptoms consist of blurred or confused vision, progressive conjunctival redness, a foreign body sensation in the eye, eye pain, photophobia (light sensitivity), excessive tearing and purulent discharge. Other manifestations depend on the causes, size and depth of the lesion.
Corneal ulcers caused by Acanthamoeba and fungi are sluggish, but progressive; those caused by Pseudomonas aeruginosa, on the other hand, develop rapidly, causing deep and extensive necrosis.
The corneal ulcer is evaluated with a slit lamp, fluorescein staining and microbiological tests (following curettage of the lesion). The presence of a corneal infiltrate with a defect of the corneal epithelium colored with fluorescein and an underlying greyish opacity confirm the diagnosis. In the absence of treatment and, sometimes, even with the best available therapy, uveitis, corneal perforation (with possible prolapse of the iris), ipopion (collection of pus in the anterior ocular chamber) and panophthalmitis (purulent inflammation of the eyeball with risk of eye loss).
Corneal ulcers tend to heal with scar tissue formation, causing corneal opacification and reduced visual acuity. Furthermore, there is a risk of corneal neovascularization, ie the blood vessels can grow towards the corneal tissue infiltrating from the limbus (border area between cornea and sclera). Treatment must be urgent to prevent permanent damage. Usually, this involves the application of topical eye drops directed to the triggering cause. If the exact etiology is not known, patients can initially be given broad-spectrum antimicrobial therapy. At the same time, supportive therapy such as pain medications and cycloplegic eye drops (eg atropine) can be prescribed to stop spasms of the ciliary muscle and reduce inflammation.
