·AIM: To assess the biocompatibility of bovine bone as orbital implants in rabbits.·METHODS: Bovine bone graft was used as an ocular implant in rabbits to determine whether it could be successfully used in the anophthalmic socket as an alternative to the expensive synthetic alloplastics. Evisceration of eyes with and without bovine bone orbital implantation was performed in the right eyes of 12 New Zealand white rabbits.Group Y (n =6) was eviscerated without implant, meanwhile Group X (n =6) was eviscerated with insertion of an orbital implant using bovine bone. Observation was carried out on day 1, day 7, day 14, day 28 and day 42. Serial clinical examination was carried out based on a few fixed criteria,which included rate of infection, implant migration, evidence of wound breakdown and any restriction of intraocular movements. The implanted eyes were then enucleated on day 42. The enucleated eyes were sent for histopathological evaluation to record the type of inflammatory reaction and rate of fibrovascular ingrowth.·RESULTS: Serial clinical examination showed presence of minimal infection in all eyes, both in Group X implanted) and Group Y (control) on first postoperative day, which responded well with antibiotics. Infection occurred in the implanted group after first postoperative day, but there was no evidence of orbital migration or extrusion of implant, wound breakdown, restriction of extraocular movement, severe infection or any physical abnormality. Histopathological examination revealed good fibrovascular ingrowth in the implanted group, with minimal rejecting reaction of rabbit eye towards bovine bone implant.·CONCLUSION: This study shows that bovine orbital implant has a good biocompatibility in rabbit eyes and its cost is acceptable.

Isolated optic neuritis as a presenting sign of tuberculosis in children is uncommon. We report a case of an immunocompetent child who displayed features of bilateral optic neuritis secondary to presumed tuberculosis. It is essential to highlight this alarming presentation in a child, as the presence of tuberculosis has re-emerged as a serious public health problem especially in developing countries.