Correcting astigmatism with LASIK is the treatment of choice and can make a dramatic improvement to the quality of vision
Astigmatism laser eye surgery
Astigmatism is a refractive error where the cornea (this is the clear window at the front of your eye) is not completely round but instead shaped more like a rugby ball. This creates distortion, double images or shadowing in the vision at all distances.
correcting astigmatism with LASIK is the treatment of choice and can make a dramatic improvement to the quality of vision
Occasionally astigmatism can be found by itself, but much more commonly together with short-sight (myopia) or long-sight (hyperopia). When it is combined with these other refractive errors, it will increase the blur and distortion that the patient sees.
When someone suffers from significant astigmatism (usually anything more than 0.5 of a dioptre) they will require corrective lenses, usually glasses. Contact lenses are available for this condition, known as toric lenses, but are not well tolerated by some patients due to the lens rotating on the cornea, blurring vision.
laser surgery can cure astigmatism once the condition is no longer progressing
The laser part of the procedure takes 5-10 seconds to evaporate a very thin layer of tissue within the cornea, reshaping its curvature to produce a more spherical cornea. This eliminates the double focus that is characteristic of astigmatism, allowing all rays of light to come to a single focus.
The whole procedure is complete in approximately 4 minutes per eye.
The cause of astigmatic blur
In a normal eye, light enters through the clear cornea, passes through the pupil (the central opening in the iris) and continues through the lens located just behind the iris.
If there is no prescription (refractive error), the cornea and lens focus parallel rays of light to converge together to make a clear image on the retina. This light-sensitive layer converts the light into information that passes along the optic nerve at the back of the eye, taking visual data to the occipital lobe within the rear part of the brain. Neural processes then interpret this information so that you get a visual perception and understanding of the world around you.
Astigmatism is most commonly caused by an asymmetric curvature across the cornea. Imagine the shape of a rugby ball instead of a football. Commonly, horizontal rays of light are focused at one point, and vertical rays at a separate point, rather than all rays arriving at a single focal point.
Indeed, the word ‘astigmatism’ is derived from ‘a-stigma’, where ‘a’ means without and ‘stigma’ means point – hence there is no single point of focus of light.
astigmatism is commonly present together with myopia (near-sight, short-sight) or hyperopia (long-sight, far-sight)
Astigmatism is a common refractive error, accounting for as much as 13% of all refractive problems.
Astigmatism: natural progression
It is common in the first months of life when the curvature of the cornea is very steep. As infants grow older, the cornea flattens and the prevalence of high degrees of astigmatism (>1.00 dioptre) decreases, reaching a level of just 4.8% of preschool children.
The steady reduction of the astigmatism to lower values with age is apparently part of normal eye maturation. By the ages of 1-3 years, the vertical and horizontal diameters of the cornea and its elasticity attain adult levels.
Factors that may increase your chance of astigmatism include:
- Heredity—a family history of astigmatism, eye disease, or disorders such as keratoconus
- Eye surgery—certain types of eye surgery, such as cataract extraction and lens replacement
- A history of corneal scarring or thinning
- A history of higher degrees of nearsightedness or farsightedness (myopic astigmatism and hyperopic astigmatism)
Further details on laser eye surgery risks and safety can be found here.
Astigmatism is a common refractive error, accounting for as much as 13% of all refractive problems.
Around 63% of young adults aged 20 to 30 years exhibit 0.25 dioptre or more of astigmatism, although only a few have an astigmatism >1 dioptre.
In a research study, only 4.7% of the total population exhibited astigmatism of more than 1.50 dioptre.
Focus has a 100% 20/20 success rate for short-sight including up to 2.00 dioptres of astigmatism, i.e. almost all astigmatic prescriptions
Some ethnic groups show a higher prevalence of astigmatism. East Asian people show a relatively high prevalence of astigmatism (in addition to myopia), perhaps due to the greater tightness of the Asian eyelids and narrower palpebral apertures.
Most adult astigmatism occurs together with either short-sight or long-sight. Almost all of these prescriptions can be helped by laser vision treatment, excluding extreme cases.
Click here for information on childhood astigmatism
Astigmatism treatment options
Laser surgery for astigmatism
Laser vision surgery (LASIK) for astigmatism is the treatment of choice in most cases. 97% of Focus patients receive dual-laser advanced LASIK, and 3% undergo PRK.
A-LASIK is an advanced form of LASIK utilising a high numerical aperture femtosecond laser to create the LASIK flap, creating a remarkably accurate focus for precision treatment of astigmatism.
Using the WaveLight laser, which removes less corneal tissue per dioptre than other lasers, we are able to treat most patients up to 6.00 dioptres, which represents almost all astigmatic prescriptions.
Focus have targeted the best reported outcomes for treating astigmatism in the UK – 100% of typical shortsighted patients see 20/20 or better after having LASIK eye surgery at our clinic, including up to 2.00 dioptres of astigmatism (more than 95% of all astigmatism prescriptions, and have done so for the past 3 years.
In fact, the great majority of our patients can see even better than 20/20. (What is 20/20 vision?)
We know of no other clinic that has matched our vision results. Click here to learn more about our surgery outcomes.
Laser Surgery Options
The choice of procedure is mainly made on anatomical factors, plus the degree of your refractive error (the size of your prescription).
Glasses and Toric Contact Lenses
Glasses have been used to correct vision since the 13th century, and possibly earlier and are the most common method of correcting astigmatism. Glasses usually incorporate a correction to help short-sight or long-sight which often occur together with astigmatism.
Contact lenses that are specially designed to not rotate on the cornea, known as toric lenses, are also available. Some patients do not tolerate toric lenses well and often present for laser vision correction.
The main risk from contact lenses is bacterial infection, a potentially blinding condition. A recent study from Australia showed the 20 year long-term risk of bacterial abscess from contact lenses is 100 times greater than from LASIK.
Refractive Lens Exchange (RLE)
RLE treatment is possible using intra0cular implant lenses (IOLs) that also correct astigmatism, known as toric lenses, ordered on a case by case basis. You can learn more about refractive lens exchange surgery here.
How does a laser treat astigmatism?
Like other forms of refractive surgery, LASIK and PRK reshape the cornea to enable light entering the eye to be correctly focused on the retina for clear vision. To correct astigmatism, the cornea needs to be reshaped so that the curvature is more equal in all directions. It needs to be changed from a rugby ball shape to more like a football.
This is achieved using an excimer laser, a cool-beam ultraviolet device that can evaporate corneal tissue without heat or burning. Each pulse of the excimer beam will remove a depth of 0.2 microns (thousandths of a millimetre). Pulses are placed across the cornea in a pre-determined pattern to remove enough tissue to correct the specific astigmatic prescription.
Using the extremely fast WaveLight laser, most prescriptions can be fully corrected in only 4-10 seconds. Your two options for astigmatic laser correction are:
The choice of procedure will depend on the severity of prescription and anatomical factors inlacing the shape and thickness of your corneas.
Astigmatism: LASIK procedure
The LASIK Procedure for Astigmatism
LASIK – AN ULTRA-THIN FLAP IS CREATED ON THE SURFACE OF THE CORNEA. AN EXCIMER LASER IS USED TO RESHAPE THE EYE. THE FLAP IS THEN REPLACED AND THE EDGE HEALS IN A FEW HOURS.
LASIK, or “laser-assisted in situ keratomileusis,” is the most commonly performed surgery to correct astigmatism. It can also be used for hyperopia (long- or farsightedness) and short-sight (myopia). At Focus, LASIK is the treatment of choice for 97% of cases.
First, one of our surgeons uses a Ziemer femtosecond laser to create a very thin, precise circular “flap” in the cornea. N.B. An older version of LASIK used a mechanical surgical tool called a microkeratome – this is outdated and should be avoided.
The surgeon then gently folds back the hinged flap to gain access to the underlying cornea tissue (known as the stroma) before using the WaveLight Eye-Q excimer laser to correct your astigmatic prescription.
After the laser has corrected the astigmatism and any other associated prescription, the flap is then laid back in place covering the area where the corneal tissue was removed. The cornea is allowed to heal naturally. The skin surface will heal across the edge of the flap within 4 hours.
the surgery requires only topical anaesthetic drops, and no bandages or stitches are necessary
In most cases LASIK is pain-free and completed within 10 minutes for both eyes. The results are usually obvious instantly – most patients can see fairly well as soon as they sit up and achieve 20/20 vision between 5 and 30 minutes after the end of the procedure.
Astigmatism: PRK & LASEK procedures
PRK (an acronym for photo-refractive keratectomy) is a form of laser surgery to correct astigmatism. It can also be used for mild degrees of hyperopia (farsightedness) and myopia (short-sight).
You will also see this treatment being referred to as LASEK and involves a minor difference in the handling of the surface skin layer. However, both procedures are identical in visual outcomes and pain. Healing time can take longer with LASEK, and so in practice PRK is the most common of these two ‘surface ablation’ techniques. In effect you could use the terms PRK and LASEK interchangeably.
PRK was the initial type of laser eye surgery for vision correction and was first performed in 1988. It is the fore-runner to the most commonly performed procedure: LASIK
PRK recovery takes a longer than recovery from LASIK eye surgery, between 3 and 5 days for most patients. The first 2-3 days are often painful and vision is not very clear.
PRK is still commonly performed and is used mainly when LASIK is not possible, for example a thin cornea or when the patient expresses a preference. Like LASIK excimer surgery, PRK works by reshaping the cornea allowing light entering the eye to be correctly focused on the retina for clear sight.
LASIK preferred over PRK
With the WaveLight system, we do not tell the laser which procedure is being performed – the excimer laser ablation is exactly the same for PRK and for LASIK.
LASIK is much preferred, however, for correcting astigmatism because with higher prescriptions the chance of a second enhancing re-treatment goes up. It is much easier to re-treat when a LASIK flap is already present and the whole second procedure can be completed in 3 minutes. With PRK re-treatment, you get the same pain and delayed healing with another week off work. PRK re-treatments are also less precise than those with LASIK.
For both PRK and LASIK, the excimer laser sculpts the stromal layer of the cornea to correct your astigmatism and other associated correction. The main difference between PRK and LASIK is that with LASIK a thin, hinged flap is created on the cornea to access the inner layers; in PRK no flap is created – just the surface skin layer is removed and the excimer laser energy is applied to the top layer of corneal collagen (the stroma).
Astigmatism: treatment prices
How much does astigmatism refractive surgery cost?
Most patients we treat have some degree of astigmatism. We want to provide the most advanced treatment possible and have invested in the latest technology resulting in incredible outcomes after surgery for our astigmatic patients.
Our prices have no hidden ‘extras’ and simply vary according to the severity of your prescription.
All astigmatism treatments for distance vision include our true Lifetime Care Guarantee – re-treatments to cover any return of myopia are free – for life. At Focus this has only occurred in 0.03% of cases.
All treatments include wavefront optics and blade-free femtosecond LASIK, so you know you are getting the most advanced technology available. Plus the security of one of our world-class specialist surgeons as your doctor.
Prices start from £137.50 per month for both eyes, interest free (0% APR), depending on prescription, for most common astigmatism corrections. Very high cases will come under our specialist treatment fees.
Click here to see procedure prices.
Also click to visit our FAQs to learn more about How much should I pay?
If you are interested in vision correction at Focus Clinics please call us on 0207 307 8250 and book a free consultation.Book your FREE consultation
- Posted on: November 25th 2016
- Posted on: November 23rd 2016
- Posted on: November 18th 2016