Astigmatism

Astigmatism is where your eye is shaped more like a rugby ball than a football, or more like a dessert spoon than a soup spoon. This means that light is not focused to a single point. Instead, there are two separate focal points – either in front of the retina, behind the retina, or one in front and one behind. Astigmatism is usually just a natural variation in the eye's normal shape, but it does tend to change over time and can occasionally be worsened by other eye conditions or surgery. 

If you have astigmatism, you are not alone. 80% of the population have some degree of clinically relevant astigmatism.

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Here are some facts to be aware of:

  • Astigmatism reduces your uncorrected vision

  • Uncorrected astigmatism reduces your reading speed and contrast sensitivity (Barrett, 2019)

  • You are likely to need glasses if you have more than 0.50 dioptres of astigmatism (Rubenstein & Raciti, 2013)

  • You are 34 times more likely to need glasses, for every dioptre of astigmatism in your better eye (Wilkins et al., 2009)

  • Correcting astigmatism at the time of cataract surgery reduces the cost of future glasses (Laurendeau et al., 2009)

 

Astigmatism can be corrected in several ways:

 

If you are having cataract or lens replacement surgery and your astigmatism is not corrected at the same time, it is likely that you will still need glasses afterwards.

Managing astigmatism with toric lenses is one of my major interests. I spent a year working with Professor Graham Barrett, who is considered to be one of the leading global authorities in toric lenses and lens calculation formulae. I am pleased to be able to use my extensive learning from Prof Barrett in Australia to benefit my patients here in the UK.

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I strongly believe that astigmatism should be corrected when necessary. Managing astigmatism is one of my key areas of expertise, and as such I carefully analyse the measurements of each eye to decide whether or not you require an astigmatism-correcting toric lens. As much time and effort goes into deciding that you don't need a toric lens as goes into deciding that you do, ensuring that I find the best solution for the specific optics of your eye. 

Below are two lectures that I give to eye surgeons and optometrists about correcting astigmatism with toric lenses. As they are aimed at specialists, they contain a lot of technical detail and talk about:

  • The scale of the problem of astigmatism in the UK

  • The evidence supporting the use of toric intraocular lenses

  • How to calculate toric lenses for implantation

  • How to implant toric lenses safely and effectively