Abstract: An ophthalmic examination chair having an integrated positioning capability for providing wheel chair access to an associated instrument stand accommodating the examining of disabled patients. The chair has a seat member which is configured to receive a seated patient and is movable from a forward position spacing the seated patient at a predetermined distance from an eye examination target. A lower base member is provided as extending along a longitudinal axis between a forward end and a rearward end, and as having an upper and a lower surface. An upper carriage member, having a bottom surface and a top surface supporting the seat member thereon, is supported on the upper surface of the base member for movement between the forward and the rearward end thereof along the longitudinal axis to position the seat member at the forward position and at a rearward position providing access to the instrument stand by a wheel chair patient positioned at the predetermined distance from the eye examination target.

Abstract: A positioning system for moving an ophthalmic examination chair used in conjunction with an associated instrument stand between a forward position spaced a predetermined distance from an eye examination target and a rearward position providing access to the instrument stand by a patient in a wheel chair. A lower base is provided as extending along a longitudinal axis between a forward end and a rearward end, and as having an upper and a lower surface and a widthwise extent configured as being receivable between the wheels of the wheel chair. An upper carriage, having a bottom surface and a top surface configured to receive the examination chair thereon, is supported on the upper surface of the base for movement between the forward and the rearward end thereof along the longitudinal axis to position the examination chair at the forward and the rearward position.

Abstract: An illuminator assembly is provided for ophthalmic refractors which is formed as a singular light guide formed in unitary fashion of a transparent polymeric material. The light guide includes a light input portion located adjacent an incandescent light source mounted within the refractor housing. The light guide has transparent output portions which extend uniformly and continuously about the axis scale and further extend to the cylinder power window and the spherical power window. Through the use of a potentiometer/voltage regulator based circuit, the practitioner may alter the intensity of the light propagated to these readout functions by maneuvering a knob mounted upon the battery housing. To improve the characteristics of the illumination, the transparent outputs of the light guide are formed as Fresnel lenses.

Abstract: A position detector for use with a code carrier which defines a position and has alternating radiation transmissive and non-transmissive regions which define a multi-bit output is disclosed. The position detector includes a photodetector array mounted on one side of the code carrier and a radiation source mounted on the detector on the side opposite the photodetector array. A radiation guide is interposed between the code carrier and the photodetector array and has a plurality of radiation transmissive paths each of which is in exclusive communication with one photodetector.

Abstract: Disclosed is a refractor of the type having a housing which has patient eye position for viewing along a sight axis extendible therethrough, a pair of superimposed cylinder lens assemblies, means for positioning a particular lens in front of the sight axis, axis control means for controlling the axis of each cylinder lens, a cross-cylinder assembly which is synchronously coupled with said cylinder lens assemblies. The improvement of such type of refractor comprises the positioning means including an internally threaded cylinder axis drive gear having a lock shaft, said gear located outside of the housing and having its lock shaft extending through an opening in the housing coincident with the common axis of both carriers, said shafted cylinder axis drive gear riding upon bearing means disposed between it and the housing. The housing opening for the lock shaft has a sleeve within the housing which circumscribes the opening. There is an annular space formed between the lock shaft and the sleeve.

Abstract: An ophthalmic refractor is provided which is configured for carrying out the Jackson cross-cylinder test. To improve accuracy, an optical encoder is provided in conjunction with each cylinder axis control knob and in conjunction with the lens mount of the cross-cylinder test lens. The cross-cylinder test lens is driven by a d.c. motor and worm gear assembly and a control circuit is provided for selectively energizing the drive motor in correspondence with the settings of the optical encoders. For power mode operation, the control circuit effects motor drive to align the axes of the cross-cylinder lens and pertinent cylinder axis. Correspondingly, for axis mode operation, the control circuit further adjusts the positioning by the motor of the cross-cylinder lens by 45.degree.. Illuminated digital displays are provided on the refractor for direct digital readout of cylinder axis diagnostic data as well as test mode identification.