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 Oath of Allegiance to the United States includes several promises immigrants make when they become U.S. citizens, including promises to: 1  Give up all prior allegiance to any other nation or sovereignty; 2  Swear allegiance to the United States; 3  Support and defend the Constitution and the laws of the United States; and.