A lens to transpose cylinders in a refractor unit.
D004864:Equipment and Supplies; D005123:Eye; D006801:Humans; D007908:Lens, Crystalline; D007909:Lenses; D013508:Ophthalmologic Surgical Procedures; D009885:Ophthalmology / Q000600:supply & distribution*; D014787:Vision Tests
LENSES; OPHTHALMOLOGY/equipment and supplies