The location of the ulcer depends somewhat on the cause. Central ulcers are typically caused by trauma, dry eye, or exposure from facial nerve paralysis or exophthalmos. Ulcers in the inferior nasal cornea may be caused by foreign material trapped under the third eyelid. Entropion or distichiae may cause ulceration of the peripheral cornea. Immune-mediated eye disease can cause ulcers at the border of the cornea and sclera. Symptoms
Corneal ulcers are painful due to nerve exposure, and can cause tearing, squinting, and pawing at the eye. There may also be signs of anterior uveitis, such as miosis (small pupil), aqueous flare (protein in the aqueous humour), and redness of the eye. An axon reflex may be responsible for uveitis formation — stimulation of pain receptors in the cornea results in release inflammatory mediators such as prostaglandins, histamine, and acetylcholine. Diagnosis
Diagnosis is through direct observation of the ulcer with the use of fluorescein stain, which is taken up by exposed corneal stroma and appears green (see photos above and below). With descemetoceles, Descemets membrane will bulge forward and after staining will appear as a dark circle with a green boundary, because it does not absorb the stain. Other tests that may be necessary include a Schirmers test for keratoconjunctivitis sicca and an analysis of facial nerve function for facial nerve paralysis. Treatment
Treatment of corneal ulcers includes topical antibiotic therapy to prevent infection, and pain medications, including topical atropine to stop spasms of the ciliary muscle. Atropine may decrease tear production and interfere with corneal healing.
Nevus of Ito (also known as "Nevus fuscoceruleus acromiodeltoideus") is a skin condition with similar features to the Nevus of Ota, but occurring in a different distribution. : 700

See also
Skin lesion

References


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