Abstract: Inspection of a fusion splice between the ends of two optical fibres, said splice being reinforced by a support member, is facilitated. In particular, inspection of the joint between the optical fibre cores in a fusion splice is facilitated. The splice is held in a transparent support member by means of a transparent adhesive matched in refractive index to the cladding of the fibre. Apparatus is described which allows the splice to be viewed in two directions at right angles by means of a microscope whose position may be adjusted therefor without rotation relative to the support member. The arrangement is of particular relevance to splices between monomode fibres whose small core diameters call for a high degree of precision in jointing in order to avoid optical loss.