Here with a recent video showing the effective treatment of astigmatism using laser eye surgery.

We know that astigmatism can be treated with laser eye surgery, but how do we initially diagnose the condition? The ophthalmologist, optometrist, or orthoptist may use the following tools to examine the eyes:

Visual acuity test - this involves reading letters on a chart. The letters become progressively smaller on each line.

Astigmatic dial – this is a chart showing a series of lines which make up a semi-circle. People with perfect vision will see the lines clearly, while those with astigmatism will see some more clearly than others.

Keratometer – also known as an ophthalmometer. This device measures the reflected light from the surface of the cornea. It measures the radius of the curvature of the cornea and can assess the degree of abnormal curvature of the cornea.

Keratoscope – also known as Placido’s disk – this device is marked with lines or circles and observes corneal reflex. It uses light to project rings on the cornea. By measuring the spacing between the rings it calculates the variations of curvature, which in turn calculates the degree of astigmatism. A videokeratoscope is a keratoscope fitted with a video.

The importance of regular eye tests

Astigmatism is very common – experts say most of us are born with a degree of astigmatism. Most children who are born with astigmatism will not realize they have it until they have an eye test. Reading and concentrating at school may be affected if a child has undiagnosed astigmatism. Therefore, regular eye tests are important.

In the UK babies have an eye test soon after they are born. They have a follow-up test about six weeks later. Doctors recommend that children receive a comprehensive eye test when they are four years old; and then every year up to the age of 16. Adults should have an eye test every couple of years.

There are two types of astigmatism, namely – Corneal astigmatism, and Lenticular astigmatism. Let’s look at the root causes of these conditions.

Corneal Astigmatism

The cornea is a clear (transparent) layer of tissue that covers the front of the eye. As well as transmitting and focusing light into the eye, it protects the eye from infection and damage. The cornea needs to have a perfect curve in order to bend (refract) light properly as it goes into the eye.

If the cornea does not curve perfectly – if one half is flatter or steeper than the other – the light that hits it will not refract properly and the retina at the back of the eye will receive an imperfect image. The person will have blurred vision from that eye – astigmatism.

Experts are not sure why some people are born with a cornea that does not curve properly. Some studies indicate a baby has a higher risk of having astigmatism if one or both of the parents have it.

A higher percentage of babies born prematurely, as well as those born with a low bodyweight have astigmatism, compared to other babies.

Certain types of surgery or eye injuries that cause scarring of the cornea may cause astigmatism.

Keratoconus, a degenerative disorder of the eye where the cornea gradually thins and changes to a more conical shape, can also cause astigmatism.

Lenticular astigmatism

The problem is similar to corneal astigmatism, but exists in the lens rather than the cornea. The lens has variations in its curvature, rather than having a perfect curve, causing images to reach the back of the eye (retina) imperfectly. Most patients with lenticular astigmatism have a normally shaped cornea – the defect is only in the curvature of the lens.

People with diabetes commonly develop lenticular astigmatism because high blood sugar levels can cause the lens to change shape. The process usually develops slowly and is generally detected when the patient starts receiving treatment for the diabetes. When diabetes is controlled through treatment and blood sugar returns to more normal levels the lens’ shape will also return to normal – many patients will notice the return as hypermetropia (long-sightedness). It is advisable for patients who start diabetes treatment to wait at least one month for the lens to settle down before being measured for glasses.

In severe cases of astigmatism, vision can be blurred or distorted depending on whether the person is reading close up or looking further into the distance at a far away object.

In milder cases, the patient may complain their vision is blurred at certain distances, that they’ve tired or dry eyes, that it’s a struggle to focus or read, or that they’ve headaches, especially when trying to focus.

A qualified optometrist or ophthalmic surgeon should be able to diagnose the condition timeously. A full eye examination is usually then carried out to assess the degree and extent of the eye problem.

Small children, who may not be able to answer the optometrist’s questions about what they can see, can be assessed using a test called retinoscopy. This test involves reflected light and is an effective method of screening astigmatism.

More info on Astimatism symptoms.

You’ve heard the word “astigmatism” mentioned at dinner parties and in the media, but what exactly is it? Well, astigmatism is a common eye condition which is usually present from birth already. Statistically, two-thirds of UK residents with short-sightedness also suffer from significant astigmatism.

It usually occurs when cornea, the front part of the eye, is not a regular symmetrical spherical shape, but is rather shaped like the back of a spoon(ie: longer in one direction than the other. This then means that the cornea is an irregular shape, and because of it, the eye can’t focus light passing through it correctly on to the retina (the back of the eye). What this all means is that your vision is then blurred from all distances.

Several factors determine the shape of the eye as it develops in the womb, including inherited genetic factors as well as the surrounding environment. Researchers claim that these factors can lead to an irregular curvature of the cornea, although the exact cause isn’t yet known or fully understood.

More info on Astigmatism treatment.