What is a cataract and how many does the river Nile have?
The word cataract is a Greek word literally “down-rushing”, meaning “rapids”, “floodgate” or “waterfall”. However, none of the Nile's six primary cataracts could be accurately described as waterfalls, and given a broader definition; this is the same with many of the minor cataracts.
How did the cataracts help Egypt?
The cataract system created a natural boundary at Aswan, separating Egypt from its southern neighbor, Nubia.
What is a cataract and why would this hinder navigating the Nile river?
Cataracts occur where outcrops of granite, as well as other resistant rocks, reach the banks of the Nile River. They not only constrict the flow of the river (limiting agriculture since the flood plain is almost nonexistent) but also impede navigation.
What do cataracts mean?
A cataract is a cloudy area in the lens of your eye. Cataracts are very common as you get older. In fact, more than half of all Americans age 80 or older either have cataracts or have had surgery to get rid of cataracts.
What does cataract mean in Egypt?
The word cataract comes from the Greek word Katarakhtes meaning "waterfall". In ancient times, Upper Egypt extended from the Nile Delta to the first cataract. Further upstream, in what is modern Sudan, the land was later controlled by the Kingdom of Kush.
What is a cataract history?
Cataracts may actually be one of the first ailments people attempted to treat surgically. Our earliest records of it date back to 600 BC. In those days, they used something called the “couching” technique, which involved smacking the eye with a blunt object until the lens dislodged entirely.
What does a cataract look like?
Clouded, Spotty, and Double Vision Like we previously stated, a cataract is characterized by cloudy eyes and vision. Because of the cloudiness cataracts cast over the lens of people's eyes, looking through an eye lens that is diseased with cataracts may seem like looking through a fog.
What are cataracts caused by?
Most cataracts develop when aging or injury changes the tissue that makes up the eye's lens. Proteins and fibers in the lens begin to break down, causing vision to become hazy or cloudy. Some inherited genetic disorders that cause other health problems can increase your risk of cataracts.
Where are the cataracts of the Nile?
The Cataracts of the Nile are shallow lengths (or whitewater rapids) of the Nile River, between Khartoum and Aswan, where the surface of the water is broken by many small boulders and stones jutting out of the river bed, as well as many rocky islets.
What is the main cause of cataract?
Most cataracts develop when aging or injury changes the tissue that makes up the eye's lens. Proteins and fibers in the lens begin to break down, causing vision to become hazy or cloudy. Some inherited genetic disorders that cause other health problems can increase your risk of cataracts.
What are the 3 types of cataracts?
There are three primary types of cataracts: nuclear sclerotic, cortical and posterior subcapsular.
- Nuclear Sclerotic Cataracts. …
- Cortical Cataracts. …
- Posterior Subcapsular Cataracts.
What is a cataract in geography?
cataract, a waterfall (q.v.), especially one containing great volumes of water rushing over a precipice.
What is the main cause of cataracts?
Most cataracts develop when aging or injury changes the tissue that makes up the eye's lens. Proteins and fibers in the lens begin to break down, causing vision to become hazy or cloudy. Some inherited genetic disorders that cause other health problems can increase your risk of cataracts.