Increased tear flow, redness and foreign body sensation are the initial symptoms associated with foreign body in the eye, followed by pain, photophobia and ciliary injection. Signs of possible deeper ocular penetration include decreased vision and clouding of the cornea .
The majority of patients with conjunctival granuloma (caused by synthetic foreign bodies) were referred to an eye department after the granuloma was visible . This may in children take weeks since children may neglect the symptoms until the granuloma has developed, or because the symptoms communicated to the parents are misunderstood [2, 11]. However, in the present case of conjunctival granuloma signs were seen early and the child was referred after two days.
Even though the patient with the corneal lesion was examined with slit lamp, the examiner was unable to identify the corneal foreign body. A main reason might be that the synthetic fibers were bluish brown similar to the colour of the hypopyon and the iris. However, a slit lamp examination combined with negative bacterial and fungal staining and culturing should lead to a diagnosis of foreign body granuloma.
Cases with tarantula hairs and caterpillar setae penetrating the cornea and giving rise to serious conditions like chronic kerato-conjunctivitis, intracorneal hairs with granuloma formation and chronic iritis are well documented [6–9]. However, so far no similar consequences of synthetic fibers from a teddy bear's hair have been reported. The lesions are considered partly due to infiltration and to the inflammatory/toxic reactions, in the same way as hairs from the tarantula back are supposed to irritate the skin . Whether the same mechanisms are responsible for the severe case of keratitis in our patient is unclear. However, the synthetic fibers in case one were made of polyethylene. When used in joint arthroplasty, polyethylene may cause an osteolytic reaction when small particles are engulfed by macrophages in granulomatous reactions . A similar reaction could be the explanation in our patient. The azo dye applied in the fibers may also have had an influence, however, it has not been documented to have any adverse effect.
In a recent review of the literature, Schmack et al demonstrated the histopathological and ultrastructural features of conjunctival granuloma caused by synthetic fibers . The diagnosis is confirmed by the microscopic features of the conjunctival granuloma showing granulomatous inflammatory tissue with lymphocytes, plasma cells, eosinophils and usually foreign-body giant cells surrounding the synthetic fibers. The simplest method to confirm the diagnosis is excision of the conjunctival granuloma and microscopical examination demonstrating marked birefringence of the synthetic fibers when examined in polarized light [14, 15]. The synthetic fibers are fairly uniform in diameter and generally round to oval in cross sections. The diameter of the synthetic fibers in the cases published by Schmack et al and Weinberg et al ranged from 17-29 μm and 21-27 μm like in our case [1, 2]. The localization of the granuloma in the previously published 15 cases was unilateral and mainly in the inferior fornix, except in one case in the superior fornix .
The ocular surface epithelium not only acts as a physical and mechanical barrier against harmful substances, but also participates actively during allergic inflammatory processes . Patients with asthma might react with a profound ocular hypersensitivity . Thus the formation of a conjunctival granuloma in case two, the patient with known asthma could have been potentiated by local ocular allergic reactions.
Surgical removal of the conjunctival granuloma and postoperative treatment with antibiotics is recommended and has shown to be successful [14, 18]. The crucial element in the treatment of keratitis is the identification of the cause of the keratitis. In young children rare causes such as synthetic fibers should always be kept in mind, especially in children who are attached to their toy teddy bears. Identification and removal of the corneal and conjunctival foreign body granuloma followed by antibiotic administration are the treatment of choice.