Astigmatism: Treatment, symptoms, advice and help
Astigmatism is a common eye disorder which occurs as a result of irregular shape of the cornea or in rare instances, the eye lens.
Astigmatism: Incidence, age and sex
Astigmatism is very common occurrence worldwide and is present right from birth. Astigmatism may diminish or progress as an affected individual grows up. Thus it may clinically present itself either in childhood or even in adulthood.
Signs and symptoms of astigmatism: Diagnosis
The signs and symptoms of astigmatism vary from mild to moderate visual impairment. Occasionally individuals may be asymptomatic and may report no vision problems. Vision impairment, when present may include refractory errors like myopia (near sightedness) or hypermetropia (far sightedness). Other complaints are blurred and distorted vision. Occasionally patients may complain of headache and eye strain. Astigmatism in younger children is usually diagnosed on routine eye examination. The eye specialist may conduct a detailed eye examination including refraction and keratometry to establish the diagnosis. Refraction test will help in determining refractive errors like myopia and hypermetropia. Keratometry is a helpful investigation to detect the curvature of cornea.
Causes and prevention of astigmatism
There are two types of astigmatism namely corneal astigmatism which is more common or lenticular astigmatism. Lenticular astigmatism is a rare phenomenon occurring as a result of irregular shape of lens. Corneal astigmatism involves the cornea which is a transparent and spherical shaped covering of outer eye. In individuals with astigmatism, the shape of cornea may be oblong which may lead to vision impairment due to abnormal focussing of images.
The cause of astigmatism is not clearly known. It may be hereditary or may be a result of corneal injury. Another causative factor may be keratoconus, a rare condition in which cornea is very thin and cone shaped.
Health related complications of astigmatism are uncommon and amblyopia is one of them. Amblyopia may be seen if only one eye is affected by astigmatism. Amblyopia, also called ‘lazy eye’ occurs when one eye is healthy and other causes marked visual impairment; the healthy eye suppresses the affected eye, which worsens progressively. Children with amblyopia may show poor performance at school.
Treatment of astigmatism includes the correction of refractive error of eyes by glasses or contact lens or corrective refractive surgery. Hard contact lenses give better results. However soft toric contact lenses may also be used. Moreover another procedure in which cornea is re-shaped by fitting a series of hard contact lens, may provide temporary improvement. Surgical procedures like LASIK or photorefractive keratectomy may also be employed in severe cases of astigmatism.