If you’ve been told in the past that you’re not a suitable candidate for LASIK eye surgery because you have astigmatism, then you’re not alone. In the early days of LASIK surgery, astigmatism patients may have been ruled out due to the limitations of technology and the ability to make the accurate calculations necessary to correct such a prescription – but fortunately for us, medical technology has advanced to the point where we can now offer LASIK for astigmatism.
What is Astigmatism?
Astigmatism is a type of prescription, often found in conjunction with long-sightedness (hyperopia) or short-sightedness (myopia). It usually arises from an uneven curvature of the front surface of the eye known as the cornea, such that light entering through this surface is refracted and bent to fall on two slightly different points on the retina at the back of the eye. This results in blurry or distorted vision. Patients with uncorrected astigmatism may also experience:
- an increase in glare, perceiving lights as “smeared out” in a starburst pattern
- ghosting, which is the sensation of seeing a faint double image of the one object
- headaches, typically around the brow area after prolonged near work such as reading or computer use
A popular analogy used to explain astigmatism is an AFL football or rugby ball. Unlike a perfectly spherical soccer ball, which would represent an eye without astigmatism, a football has a flatter degree of curvature down end to end when compared to the steeper curvature of the ball going from one side to the other. If light were to be refracted to a degree based on the amount of curvature of the cornea, you would see how light entering along one meridian would be focused at a different plane compared to light entering along the perpendicular meridian. A small percentage of astigmatism cases also arise from uneven curvature of the lens inside the eye, known as lenticular astigmatism. Because correcting astigmatism is a little more complicated than correcting simple hyperopia or myopia, many people may have been told they are excluded from LASIK eye surgery.
How Does LASIK Work?
At a basic level, LASIK works on the concept of reshaping the cornea in a way that the light passing through this tissue is redirected to focus to a clear point on the retina. A flap of superficial corneal tissue is created with a femtosecond laser while the eye is under topical anaesthetic. When this flap is pushed aside it allows access for a second laser, called an excimer laser, to remove select sections of the underlying corneal layers. The flap is then replaced and allowed to self-seal. The improvement in vision once the procedure is complete is almost immediate – many patients can see well enough to even drive within the following day or two.
Does LASIK Work for Astigmatism?
As we’ve established, LASIK eye surgery has come a long way from when it was first invented in the 1990s. Through the use of computer algorithms, we are now able to make the complex wavefront calculations that guide the excimer laser to reshape the cornea and correct astigmatism.
Furthermore, not only can we provide LASIK for regular astigmatism, in the case of the two curvatures of the cornea being perpendicular to each other, mild amounts of the more complicated irregular astigmatism can now be addressed with LASIK eye surgery too.
Am I Suitable for LASIK for Astigmatism?
With the appropriate equipment and expertise, LASIK eye surgery can be performed for degrees of astigmatism up to about -4 dioptres. Other eligibility criteria apply for all patients interested in LASIK surgery, including:
- a stable refraction; this is to ensure that the surgery performed from the calculations at the time of the procedure will be accurate long-term
- absence of other sight-threatening diseases such as macular degeneration or cataract
- a healthy cornea with the ability to undergo reshaping by the excimer laser
Higher degrees of astigmatism, though correctable with LASIK, may experience some regression of the prescription with time as the astigmatism returns. Many laser eye specialists will be happy to re-treat this with a quick touch-up laser procedure.
If you’ve avoided pursuing surgical options to reduce your dependency on glasses and contact lenses simply because you’ve been told you have astigmatism, LASIK surgery for astigmatism may be the answer. For patients who are unsuitable for the LASIK procedure for any reason, there are additional options for surgical correction of astigmatism, including SMILE® surgery and intraocular contact lens procedures.
Call Eye Laser Specialists today for a free preliminary assessment: 1300 297 583