Laser vision correction surgeries for eyeglasses removal are done mainly for the purpose of correcting farsightedness and nearsightedness, but many do not know that a cylinder (astigmatism) can also be repaired using them. How is the surgery performed, how safe is it and when should intraocular lens implant surgery be considered?
Astigmatism (or 'cylinder' as we know it), is a fairly common and treatable visual disturbance that develops due to the unequal curvature of the cornea or lens.
In an eye with astigmatism, the eye fails to properly focus the light rays that fall on the retina, the light-sensitive surface at the base of the eye, so that blurred vision is created in both, far and near distances.
A cylinder may develop due to irregularity of the cornea, which is the anterior and transparent layer that covers the eye. Another reason for the development of a cylinder is a mismatch between the curves of the lens, so that its shape is like an egg instead of a ball. In both cases the disorder manifests itself in a similar way, interfering with the focus of vision in all ranges.
In many cases, the cylinder is accompanied by other disorders, such as nearsightedness (myopia) or farsightedness (hyperopia). The cylinder can be compensated by using eyeglasses or contact lenses, but these solutions require daily maintenance. Another solution is laser vision correction surgery for eyeglasses removal - also in case of cylinder.
Is it possible to prevent a cylinder and how is this disorder treated?
Astigmatism is most often the result of a congenital deformity in the structure of the eye, so no way is known today to prevent this disorder.
In addition to use of eyeglasses or contact lenses, there are also treatments designed to reshape the cornea using nocturnal lenses. It is important to know that vision improvement is not permanent and lenses should be used regularly in order to see well.
Unlike these solutions, which require daily maintenance and use, laser vision correction surgery allows permanent repair of the cylinder.
How does eyeglasses removal surgery correct vision?
Eyeglasses removal surgeries, performed today with the help of laser, are surgeries that aim to reshape the cornea in order to improve the ability to focus the vision.
These surgeries are very common and are used to correct disorders in the refraction of light from the eye - nearsightedness and farsightedness, or cylinder. Sometimes, it is also possible to perform surgeries of the lens replacement itself and implantation of a toric lens that corrects a cylinder, if the visual disorder is severe.
There are two major methods available today for removing glasses. Both of them have quite similar results and success rates, but also unique advantages and disadvantages:
INTRALASIK is a surgery performed in a combination of two laser technologies, one is used to create a tiny, narrow slot on the surface of the cornea to create a flap that is lifted in the first stage of the surgery. A second laser is used for reshaping the cornea itself in its deeper layers. After that, the top layer (flap) is put back in place, without the need for seams.
PRK or LASEK treatments are also possible. In these treatments, the surgeon removes the most superficial transparent layer that covers the cornea (epithelium) without creating a flap and then the treatment is performed in a more anterior area of the cornea.
"The decision on the method of treatment is made in cooperation with a specialist ophthalmologist according to your eyes and vision conditions, preferences, employment characteristics and lifestyle. To make sure that you are suitable for laser vision correction surgery, we will perform a simple vision test, but we will also use advanced technologies for mapping the eye area, "says Dr. Oren Golan, a senior surgeon at the “Enaim” Medical Center in Tel Aviv and the Tel Aviv Medical Center “Sorasky-Ichilov”, Specialist in corneal diseases, cataracts and laser surgery for vision correction and eyeglasses removal.
Is vision correction surgery different if I have a cylinder?
In general, laser vision correction surgeries are not different for a cylinder, and conventional surgeries are also suitable for cylinder repair, with proper adjustments. "The main difference is the process before the surgery - in the match pre- operation examinations, that allow us to choose the right patients for the right surgery," explains Dr. Golan.
It is also important to remember that not every person with a cylinder can undergo vision correction surgery - sometimes the corneal distortion is too big for the laser to correct it. In this case, intraocular lens implant surgery may be considered.
In this type of surgery, the natural lens is replaced with an artificial one. In the case of a cylinder, a toric lens can be implanted to repair a cylinder.
Is the surgery safe and how reliable can it be?
Laser vision correction surgery for eyeglasses removal is a very common surgery and the medical world has decades of experience in performing it, even in patients with a cylinder. Although there are risks to any surgery, laser vision correction is considered very safe and effective for the right patients "- says Dr. Oren Golan.
A study published by the American Academy of Ophthalmology in the early 2000s, found that laser surgery for the cylinder, as well as myopia of mild to moderate severity, is effective and reliable.
It was also found that the prediction ability of vision correction before surgery is good, so that reliable information can be provided to patients before surgery.
According to the published data, a very high percentage of the patients do not need further correction of the vision and damage to the visual acuity was minimal.
However, not everyone is suitable for laser vision correction surgery and not everyone is suitable for the same surgery. An ophthalmologist who specializes in laser vision correction will be able to provide you with the appropriate tests and advice in order to provide a solution that is specifically tailored for you.