By using a number of aspheric surfaces in a novel afocal arrangement, a new binocular system has been designed which avoids the use of erecting prisms and provides a very wide horizontal field of view. The method uses spherical reflecting surfaces to re-fold the light path so that the field curvature is substantially corrected. This allows larger than normal eyepiece lenses giving a greater eye-relief in spite of the wide field of view. The concept logic impinges heavily on the optimization procedure and necessitates careful choice of parameters and constraints. Designs for magnification from X4 to X10 are discussed. The aspheric surfaces suggest the use of plastic elements for ease of manufacture and these give a potentially lightweight instrument with considerable user appeal.