Astigmatism is very common, and occurs in varying amounts in the population but
has a complicated name and little bit hard to explain !
An optician may refer to astigmatism as rugby ball shaped eyes or even egg shaped
Instead of the eye shape being football, spherical shaped - it is rugby ball shaped
- more oval than round.
It is either the cornea or the natural lens inside the eye that may be irregular
Most people can have small amount of astigmatism and it usually co-exists with short
sighted or long sighted.
Symptoms of rugby ball shaped eyes
In Astigmatism , the image formed can have ghosting or shadow effect where the letters
of image could be “split” slightly.
Astigmatism may cause eyestrain as well as blurred vision.
Sometimes even small amounts of rugby shaped eyes can cause symptoms.
Treatment of astigmatism.
Rugby ball shaped eyes can usually be corrected successfully with lenses that have
a cylinder component - which needs to be set at a specific angle which opticians
note down as axis on the prescription.
The axis is needed because a rugby ball can be rotated into any orientation - whereas
a football rotated will look the same.
Power is in Dioptres and noted down as DC ( c is for cylinder)
For short and long sight prescriptions without astigmatism, it is corrected by sphere
shape lenses and is noted down as DS - dioptres and sphere.
Many people need to correct both the astigmatism and spherical error of short or
long sighted - they would have both the sphere and cylinder correction.
Astigmatism may be at 90 degrees and 180 degrees or at any angle.
People with astigmatism at oblique angles such as 45 degrees may find even a small
amount of error may cause symptoms. This is partly due to the real world environment
where most things are at horizontal and vertical degrees like the computer monitor
screen, furniture etc