Abstract: An improved refractor for use in the subjective examination of human eyes. Each half of the refractor includes a plurality of lens supporting disks, a hub assembly for rotatably supporting the disks, and a comb assembly to space the disks along the optical axis. One of the disks supports at least one set of 4 cross cylinder lenses. Each disk is coupled to a stepping motor for selective rotation. Each motor is, in turn, supported by a bracket which permits rotation equivalent to a partial motor step to insure alignment of the optical elements supported on the disks with the optical axis. The cylinder lenses supported on the disks are also rotated by a stepping motor. The Risley prisms of each half of the refractor are always positioned on the optical axis and rotated by stepping motors.

Abstract: An improved refractor for use in the subjective examination of human eyes. Each half of the refractor includes a plurality of lens supporting disks, a hub assembly for rotatably supporting the disks, and a comb assembly to space the disks along the optical axis. One of the disks supports at least one set of 4 cross cylinder lenses. Each disk is coupled to a stepping motor for selective rotation. Each motor is, in turn, supported by a bracket which permits rotation equivalent to a partial motor step to insure alignment of the optical elements supported on the disks with the optical axis. The cylinder lenses supported on the disks are also rotated by a stepping motor. The Risley prisms of each half of the refractor are always positioned on the optical axis and rotated by stepping motors.

Abstract: A compact refraction instrument for use in both the objective and subjective examination of human eyes. The instrument incorporates an alignment mode, a retinoscopy mode, a distance mode and near mode. For carrying out the functions associated with these modes, the instrument includes a Brewster stereoscope and a system for supporting a plurality of binocular/monocular vision testing slides. Positioned along the pair of optical paths between the Brewster stereoscope and the slide supporting system are: a first mask/septum system; a mode change system; a second mask/septum system; and a horizontal/vertical target mask system. The instrument also includes a refractor system and apparatus for suspending the refractor system in the optical paths before the Brewster stereoscope. The slide supporting system includes two rotatable concentric drums. The mode change system includes a first mirror for folding the optical paths when the instrument is used for subjective testing at a distance and near vision testing.