Can I have surgery for astigmatism?

The problem of astigmatism is caused by a person not paying attention to eye health. Due to long-term improper use of the eyes, the cornea will be tortuous, resulting in the inability to focus normally when looking at things, and the phenomenon of double and blurred images will occur. When the degree of astigmatism is relatively mild, it can be corrected by wearing orthokeratology lenses, but once the degree is higher, only laser surgery can completely solve the problem of astigmatism.

1. Optical correction of astigmatism

Optical correction of astigmatism mainly refers to glasses correction, including frame astigmatism correction and contact lens correction.

(1) Frame astigmatism correction should be the first choice. Especially for children and adolescents with astigmatism, their adaptability to wearing contact lenses is not yet mature. Astigmatism lenses contain cylindrical components. When binocular astigmatism is corrected, the cylinders of the two astigmatism lenses will produce a binocular spatial vision effect. When the two column axes are in the oblique position, a spatial deformation effect of the object image will occur. The wearer will feel that the ground is tilted, objects are twisted and deformed, etc., and cannot accept the correction. Therefore, sufficient trial adjustments must be made before prescribing. In principle, the astigmatism should be appropriate and not overcorrected; in the case of small oblique angles, the cylindrical axes of both eyes should be adjusted to 90º or 180º. There is no need to stick to the axis difference of a few degrees in retinoscopy. For example, if the negative astigmatism axis of the right eye is 5º and that of the left eye is 175º, the adjustment axis can be 180º, which may make the patient feel most comfortable. This is because under the condition of accurate cylindrical power, the new astigmatism produced by the oblique crossing of the cylinders at a small angle is already minimal and has little effect on vision; on the contrary, if the cylinder is in the correct axial position, the correction for one eye is perfect, but when using binocular vision, the spatial distortion synthesized by the cylinder can easily cause visual discomfort, so attention must be paid. Otherwise, it is easy to cause visual fatigue and even serious neuropsychiatric symptoms, which can easily affect the learning of children and adolescents.

(2) Contact lens correction of astigmatism refers to hard corneal contact lenses: Reports of correction of astigmatism have become increasingly common in recent years. The principle of correction is to use the contact between the contact lens and the corneal surface, fill the corneal astigmatism on the corneal surface with tears, and there is no astigmatism on the lens surface, thereby achieving the effect of correcting eye astigmatism. This type of lens is very effective in correcting astigmatism, especially oblique astigmatism or high astigmatism. The spatial distortion problem of binocular vision can be significantly eliminated. For irregular astigmatism, wearing an RGP in one eye combined with frame glasses for both eyes can correct the unequal images in both eyes at the same time. It is reported that RGP correction can also inhibit the development of myopia in adolescents.

2. Surgical treatment of astigmatism

Surgical treatment of astigmatism is mainly suitable for correcting high astigmatism, such as congenital corneal astigmatism, or surgical corneal astigmatism (most commonly from penetrating keratoplasty, but also from cataract extraction). For corneal astigmatism caused by surgery, the first thing to do is to make timely adjustments during the operation. The small scleral incision during cataract extraction can greatly reduce postoperative astigmatism. Intraoperative adjustments are particularly important for penetrating keratoplasty, which requires a 360º incision. A corneal astigmatism examination mirror can be used to adjust the incision sutures under a microscope, which has a good effect on reducing corneal astigmatism.

Modern laser keratectomy has reached a more ideal level for the treatment of corneal astigmatism. The shape of the corneal surface is examined using a corneal topographer, and the simulated toric corneal shape that needs to be removed to correct corneal astigmatism is calculated to achieve the goal of complete astigmatism treatment.

(II) Prognosis

Low astigmatism is ideally corrected, but high astigmatism is often poorly corrected.