CALCIFIED SHIELD ULCER IN A KERATOCONIC EYE IN THE ABSENCE OF ALLERGIC OR ATOPIC KERATO-CONJUNCTIVITIS

Corneal shield ulcer is a known complication of Atopic kerato-conjunctivitis (AKC) or vernal kerato-conjunctivitis (VKC). It is believed that active inflammation may trigger adherence of a mucus layer to the corneal epithelial surface, which in turn can cause recurrent epithelial micro-erosion with subsequent deposition of calcium to the plaque. There is, however, no report of a corneal shield ulcer in the absence of AKC or VKC in the literature. 

37-year-old Caribbean male patient, with known keratoconus and history of corneal crosslinking 10 years before, presented with one month history of left eye discomfort, photosensitivity, and reduced vision. His right eye with a maximum keratometry of 79 D has had a long-standing poor vision and his left eye has been his good eye. He was intolerant to rigid gas permeable contact lenses (RGPCL) and lost to follow up for 10 years. His general health was good and denied any history of asthma, eczema, hay fever, itchy eyes or habitual eye rubbing in the past. His best spectacle visual acuity (BSCVA) was counting fingers in the right and 1.06 LogMar in the left eye. Examination showed a distinctive calcified shield ulcer affecting the paracentral region of his left cornea, in the absence of a corneal neovascularization, or any signs of allergic eye disease including limbal Horner-Trantas dots, or palpebral micro/macro-papillae. The calcific deposition was removed at the slit lamp, and he was started on low frequency topical preservative free antibiotics and Dexamethasone. However, he remained symptomatic with persistent epithelial defect, which was surrounded with residue of the plaque. Two weeks from presentation he was taken to the theatre for complete excision of the plaque residue, 360 degrees on the margin of the epithelial defect with a crescent blade, and insertion of a 11mm amniotic membrane disc and a bandage contact lens on the cornea. One week later, his eye was comfortable, and the amniotic membrane had partially disintegrated. Three weeks from surgical procedure, the corneal epithelium was nicely healed and the stroma showed no signs of scarring, and his unaided visual acuity was 0.66 LogMar, improving to 0.4 LogMar with pinhole. His Pentacam scan and anterior segment OCT showed a significant paracentral stromal thinning with subsequent epithelial hypertrophy. Three months from surgical excision of the plaque, his BSCVA is 0.5 LogMar in this eye.