A Scheiner-Principle Vernier Optometer.
Patent Application, Filed 23 Jun 89,
DEPARTMENT OF THE NAVY WASHINGTON DC
Pagination or Media Count:
This patent application discloses a method and optometer apparatus for measuring the dark focus of accommodation. In a preferred embodiment, the optometer apparatus includes a pinhole aperture plate having first and second horizontally positioned apertures disposed on opposite sides of a first optical axis first and second orthogonally-oriented polarizing filters respectively covering the first and second horizontally positioned apertures a positive lens having an optical axis on the first optical axis and being positioned at a distance of approximately one focal length from the pinhole aperture plate a lens system having an optical axis on the first optical axis a slit aperture plate having a vertical slit and being disposed on the first optical axis and between the positive lens and the lens system third and fourth vertically positioned polarizing filters selectively disposed adjacent to the slit aperture plate to divide the slit vertically, a monochromatic light source for propagating light along the first optical axis through the lens system and movable means attached to the slit aperture plate, the lens system and the monochromatic light source for moving the slit aperture plate. jhd
- Medical Facilities, Equipment and Supplies