What is astigmatism, has it anything to do with glaucoma?!

The answer by danish was beautifully written but was so GENERAL it could define most visual defects. Wikipedia has a good page explaining it:

http://en.wikipedia.org/wiki/Astigmatism…

If you google astigmatism there are plenty of user friendly sites that give good explanations. But if I were to try and give a simple description I would say astigmatism refers to having light entering the eye coming to focal points at different distances from the retina. Perfect vision requires ALL light entering the eye to come to a focal point EXACTLY where the retina is.

The most common form of astigmatism is caused by irregularities in the curvature of the cornea. You can't actually see a persons astigmatic cornea if you wanted to because its actually transparent (invisible)
This link below allows you to see what is the physical difference between an astigmatic eye and a normal one. These photos of cornea taken by specialists. It uses colors as a guide to smoothness. Green is normal/regular, blue and red colours however indicate abnormal steepness or flatness in curvature. (i checked the pics myself. They are mainly extreme examples)

http://www.google.com/search?site=images…


Astigmatism is very common and effects a lot of people without them even knowing it. One cause discovered is from the pressure placed on the cornea by the eyelids while a person engages in activity such as reading.
Due to the fixed position of the eye and the infrequent blinking scientists found that depressions can form the surface of the cornea after a long enough period of pressure from the eyelid. They noted though that these depressions usually disappear once the person rests their eyes later.

It's also possible for people to be born with astigmatism. The cause of this is often people being born with oval shaped eyeballs. This is hereditary.

A type of astigmatism with a completely different origin is one caused by irregularities in the crystalline lens (inside the eye) People with diabetes often develop this issue from having changes in blood sugar levels. Treatment of diabetes often brings the effected persons vision back to normal.

Here is a non-technical answer. Astigmatism is a defect in central vision (what we are focusing on at any given moment). It may accompany farsightedness (image is improperly focused behind the retina) or nearsightedness (image is inappropriately focused in front of the retina). Astigmatism usually is caused by an irregularly shaped cornea (the clear, dome-shaped surface that covers the front of the eye). But sometimes it results from an irregularly shaped lens, which is located inside the eye behind the iris (colored part of the eye).

Astigmatism occurs when an irregularly shaped cornea or lens causes light rays to focus on two points in the back of your eye, rather than on just one. It can usually be corrected with eyeglasses, contact lenses, or refractive surgery.

Glaucoma is a chronic disease of the eye that results in ongoing damage to the optic nerve, which if left untreated can lead to blindness. There usually are no symptoms, which is why it is often referred to as "the silent thief of vision". Glaucoma affects peripheral vision first and later progresses to impact central vision. There are many different types of glaucoma, but they all have irreversible damage to the optic nerve in common.

Glaucoma is most common in people with a family history of the disease. Patients with systematic disease such as diabetes, anemia, or hardening of the arteries are at higher risk of developing glaucoma. Nearsighted patients are more likely to develop the disease. African-Americans tend to develop glaucoma more often than other racial groups.

http://www.glaucoma-eye-info.com

astigmatism is when your eye ball is not spherical but has a flat part on it. This defect can not be corrected by any type of lens or contact lens.
This causes eye strain but is not much to worry about.
Glaucoma however is very serious and can cause blindness. Your optician can test for glaucoma by puffing some air at your eye and measuring your eye balls pressure.If you have glaucoma then you will be prescribed eye drops as a preventative measure to protect You from any eye damage.
So don't worry but do visit and listen to your optician , who will be happy to explain your eyes condition to you in a way that you understand.

These are two different things. One you are born with and the other develops usually with age. Take the advice of your optician and optical specialist.