Astigmatism can cause varying degrees of blurred vision at both distance and near vision. It can also cause eyestrain and headaches during concentrated periods of visual tasks, such as driving at night or using the computer for prolonged periods. In small amounts, it manifests itself in symptoms of asthenopia (eyestrain) rather than visual difficulty, hence it is important to get your eyes checked if you spend many hours in front of a computer as it may be contributing to overall discomfort when carrying out computer work.
Astigmatism is caused by the light being bent incorrectly by a misshapen cornea, which is rugby ball shaped instead of spherical. This causes a distorted and blurred image, often characterised by ‘ghosting’ especially when looking at letters on a screen. The patient perceives a ghost image alongside the original writing, for example when reading subtitles on the TV or looking at digital train timetables / signs at the airport.
It’s important to know that Astigmatism isn’t an eye disease; like short-sightedness and long-sightedness, astigmatism is just a refractive error, which is merely a focussing issue. Approximately 9 out of 10 people have some degree of astigmatism (mostly unnoticed, especially in weak amounts).
There are not a lot of complications of astigmatism. Astigmatism that is vastly different between the two eyes can cause the worse eye to become lazy (amblyopic) in children. The brain can sometimes ignore the weaker eye, causing it to become lazy by using only the dominant eye for focus and visual function. This is probably the most serious complication associated with astigmatism, but is usually detected by having eyetests done at an early age with an optometrist.
By far the most common and affordable way to correct long sightedness is by getting glasses which refocus light onto the retina. Depending on the severity of your astigmatism, you may need to wear glasses full time or only for certain visual tasks such as night driving, watching TV or computer use.
Contact lenses can occasionally be used, but their use is slightly limited as higher levels of astigmatism often cause poor quality correction due to the potential rotation of the contact lens in the eye during blinking, and many people find this unsatisfactory. This is especially apparent if carrying out visual tasks that require critical distance correction, such as shooting, golf, archery, etc.
Refractive surgery is an option after the prescription has stabilised, usually by the early 20s.
Implantable Contact Lenses (EVO Visian ICLs) known as phakic IOLs are another surgical option for correcting astigmatism. This treatment option is ideal for those whose prescription is too high for laser surgery, or whose corneas are too thin. EVO Visian ICLs are surgically placed inside the eye (behind the iris) to help focus light onto the retina. There is no change of rejection by the body.
Clear Lens Replacement
Clear Lens Replacement is a refractive surgery option for people who are presbyopic (need reading glasses, usually after the age of 45 years), where the crystalline lens of the eye is replaced with an artificial (intraocular) lens that refocuses the light to allow it to focus onto the retina. Normally trifocal lenses are implanted which allows the patient to experience clear vision at distance and near.