You know that friend of yours? That nerdy friend with the coke-bottle glasses? Well, he went and got LASIK and do you know what he’s getting now? All the attention from the ladies, is what. You, however, have astigmatism, which you manage pretty well with contact lenses but it would also be great to not have to place something in your eye every morning that costs you hundreds of dollars year after year. So, with your prescription being what it is, is there any hope for you?
Astigmatism vs a Stigma
Eyecare providers have lost count of the number of times a new patient will sit in the consulting chair and declare that at their last eye test they were told they have “a stigma.” What they actually have is astigmatism (perhaps they also have a stigma, but it’s beyond the scope of an eyecare practitioner to determine this).
Astigmatism is an eye condition that causes blurry vision and is a form of refractive error. Refractive error means that there is a mismatch between the focusing power of your eye and its physical length, known as the axial length. Light refracting, or bending, through the front components of the eye needs to come to a sharp point on the retina at the back of the eye for sharp vision. In near-sightedness, light focuses in front of the retina; in far-sightedness, it focuses behind the retina. Both these scenarios lead to imperfect vision when looking at objects nearby, far away, or both.
Astigmatism is a bit more complicated compared to near- and far-sightedness because its main cause is an uneven cornea, that transparent surface at the front of the eye. This means that light passing through the cornea is refracted to different degrees, depending on the incoming direction of the light. So, when we get to the retina, there are actually two different focal points of light. One or neither of these points may be clearly focused on the retina. Vision affected by astigmatism is blurry at all distances.
Normal cases of astigmatism (excluding some forms of astigmatism arising from pathology such as corneal scarring or keratoconus), can be corrected with:
- Spectacles
- Soft or rigid contact lenses
- LASIK
LASIK for Astigmatism
LASIK is a popular form of refractive surgery used to modify the shape of the cornea and get those light rays focusing right where you want them. It does this using computer-guided algorithms to selectively and precisely vaporize parts of your cornea with an excimer laser.
LASIK is not the only method of refractive surgery that can address astigmatism. PRK (photorefractive keratectomy) and a newer method, SMILE (small incision lenticule extraction) may also be suitable for patients with astigmatism. These two techniques are also based on reshaping the corneal surface but differ in their approach.
However, there are some eligibility criteria to fulfil before you know if LASIK is right for you. The treatable prescription range for LASIK has its limits. The upper limit for astigmatism fixable with LASIK is often quoted as -6 diopters, but this will also depend on other factors such as your corneal thicknesses, which directly affects how much tissue is available for vaporizing and reshaping. It should also be noted that the higher your prescription is, the more unpredictable the final results of your laser eye surgery will be. The laser device may work perfectly and the computer calculations are flawless, but the human body does what the human body wants, and this can include an unfortunate little phenomenon called regression. Regression occurs when the prescription slowly begins to creep back even after successful laser eye surgery. Higher degrees of astigmatism are more likely to experience regression post-operatively.
The best way to get a clear answer about whether LASIK is the answer for your visual woes, including astigmatism, is to book an appointment with your eye doctor. Here you’ll have a thorough examination, including precise measurements of your refractive error, axial lengths, corneal thicknesses, and have a discussion about your suitability for laser eye surgery.