Admittingly astigmatism is not a very exciting topic. Not many people ever had a glass of wine or cracked a couple of frosty cold ones to have a brisk conversation about the ins and outs of astigmatism. However, since it does effect millions of people lets try and make some sense of it.  

Astigmatism is one of three common refractive errors. When the eye has a refractive error light is not focused perfectly onto the retina in the back of your eye. [The retina is the film or the light sensitive tissue of your eye.] Astigmatism typically blurs the vision at near and far. It effects children and adults. Astigmatism is not some terrible disease of the eye, it is a normal aberration of the eyes ability to focus light and is diagnosed during your eye examination. Indeed small amounts of astigmatism may not even need to be corrected. 

How might one know if they had astigmatism? Headaches are common particularly just over the eyebrow, often referred to as browache. Distorted or blurred vision is common. Eye strain can and does occur when the patient has to focus for extended periods of time, say when driving long distances or using the computer for a prolonged time period. Also, sensitivity to light or photophobia may plague the patient with astigmatism.  

Astigmatism may be simple, farsighted, nearsighted, or mixed. Astigmatism is either regular or irregular. Regular astigmatism is most common and is what occurs in nature. Irregular astigmatism is due to injury, corneal disease [scarring], Keratoconus or congenital causes.  

Farsighted astigmatism will result in the image of the object focused by your eye falling behind the retina/eye. Conversely, nearsighted astigmatism will result in the image of the object being formed in front of your retina. [A farsighted eye is too weak and does not bend light enough, the nearsighted eye is too strong and bends light too much!] Either way what results is blurred vision.  

Our astigmatism talk will now turn to geometry. To understand astigmatism we must discuss the cornea. The natural front surface of your cornea resembles an ellipsoid, ie, highly curved in the middle and flat towards the outside. [Visualize an egg.] The cornea is the clear window to your eye just in front of your pupil and this structure comprises sixty percent of the eyes light bending power. It is very powerful. However, it is important to understand that the central part of your cornea, the middle three to four millimeters right infront of your pupil is either spherical like a baseball or elliptical like a football. If the central cornea is elliptical the surface is a toric or astigmatic surface, and you have astigmatism.  

Astigmatism can be corrected while a patient wears either glasses or contact lenses. Astigmatism may be corrected permanently with laser procedures like PRK and LASIK. When using glasses to correct astigmatism it is important to understand even small amounts of cylinder correction [cylindrical lenses are what is used to correct astigmatism] can cause physical discomfort and visual distortions for the patient who is not used to the new prescription. For this reason it is essential to proceed carefully and with caution when writing a new prescription for astigmatism or when increasing the astigmatic prescription. Patients will often complain of eye ache, headache, the perception of curved doorways, slanted floors and feeling like they are walking on uneven surfaces when wearing astigmatic lenses they have not adapted to. Very often astigmatic prescriptions must be increased gradually for the reasons stated above.  

One of the best ways to help the astigmatic patient is with the use of soft toric contact lenses. Since the soft toric contact lens is very small and rides on the cornea the distortions caused by spectacle lenses discussed above are eliminated.  

I hope you have found this information helpful and educational. I would like to think it might even be entertaining but I hesitate to go there. Whether you decide to correct your astigmatism with a soft toric contact lens or with glasses, Champion Eye is ready to help you.