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 United States Declaration of Independence is an important document in the history of the United States of America. It was ratified on July 4,1776. It says that the Americans were no longer under British rule. Instead, the thirteen British colonies came together to become a new country.