Ophthalmic Cross Cylinder Lens Sets
Definition : Collections of 2 or more cross cylinder lenses designed to assess refractive error (cylinder power and axis) that requires an examinee's responses by using the cylinder lenses with equal powers and opposite signs in the proper axis positions (two principal meridians). The sets usually contain several cylinder lenses (with optical powers that can be +0.25D, +0.50D, +0.75D, or +1.0D), the lens rotation mechanism, and the lens mount. Ophthalmic cross-cylinder sets are used to determine astigmatism and refine cylinder power and axis for eyeglass fitting.
Entry Terms : "Jackson Cross Cylinder Sets" , "Phorometers" , "Ophthalmic Refraction Measuring Instruments" , "Ophthalmic Measuring Instruments" , "Measuring Instruments, Ophthalmic"
UMDC code : 24545