Toric Contact Lenses: A Consumer Guide. Toric contact lenses correct astigmatism They can be made from HEMA (soft), silicone hydrogel, or gas permeable materials. Unlike spherical lenses, toric lenses have two different powers in the lens. This characteristic means that the toric lens must remain in one position for the best visual acuity.
The Preamble to the US Constitution, the Pledge of Allegiance, and the Declaration of Independence. Unit Objective. This unit is part of Gilder Lehrmanâs series of Common Core State Standardsâbased teaching resources. These units were developed to enable students to understand, summarize, and analyze original texts of historical significance.
The Pledge of Allegiance to the flag of the United States is a pledge that people recite to show devotion and respect for their country. It was first published in the juvenile periodical The Youthâs Companion in 1892. Francis Bellamy, an assistant editor of the magazine, is given credit for writing the pledge.