Undercorrected astigmatism is the key to high myopia

Abstract: high myopia is usually associated with higher degrees of regular astigmatism. In order to improve the success rate of matching glasses, most optometrists often reduce or even abandon the astigmatism prescription to a certain extent. On the other hand, in order to achieve the goal of correcting vision, they often add the degree of myopia spherical lens (i.e. equivalent spherical lens), which eventually leads to the further increase of lens thickness., Astigmatism can not form a focus, but form two front and rear focal lines. The middle of the two focal lines is the smallest dispersion circle of astigmatism. Astigmatism is mainly due to the difference of the refractive power in the meridian direction of the eye. On an optical section, one refractive power is greater than the other refractive power, and can not converge at one point. Therefore, in terms of eye adjustment, it is not the overall force in one direction, but the asymmetric use of eye adjustment power, so the eyes are very prone to fatigue. Therefore, there are no patients who are not timely during optometry, Generally, it is better to give full correction., Astigmatism is generally divided into: 1. Corneal astigmatism (the most common). 2. Crystalline astigmatism. Retinal astigmatism. (4) Axial astigmatism., Astigmatism fitting principle. Astigmatism fitting principle must be based on the patient’s combination of the most clear, comfortable and durable glasses. Generally, there are the following points: 1. Under correction:, that is, reducing the diopter is the most effective and simple method to reduce the lens thickness, which is easy to understand. However, it is not to reduce the degree of patient’s glasses indefinitely or arbitrarily. The “amount” of under correction should be carefully prescribed by the optometrist after weighing the advantages and disadvantages in combination with the specific situation. The control of undercorrection and “degree” shall follow the following principles:

astigmatism is due to the fact that it cannot form a focus, but forms two front and rear focal lines, and the middle of the two focal lines is the minimum dispersion circle of astigmatism. Astigmatism is mainly due to the difference of the refractive power in the meridian direction of the eye. On an optical section, one refractive power is greater than the other refractive power, and can not converge at one point. Therefore, in terms of eye adjustment, it is not the overall force in one direction, but the asymmetric use of eye adjustment power, so the eyes are very prone to fatigue. Therefore, there are no patients who are not timely during optometry, Generally, it is better to give full correction.

astigmatism is generally divided into:

1. Corneal astigmatism (the most common). 2. Crystalline astigmatism. Retinal astigmatism. (4) Optic astigmatism.

astigmatism fitting principle

astigmatism fitting principle must be based on the patient’s combination of the most clear, comfortable and lasting glasses. Generally, there are the following points:

1. Under correction:

is to reduce the diopter, which is the most effective and simple method to reduce the lens thickness, This is easy to understand. However, it is not to reduce the degree of patient’s glasses indefinitely or arbitrarily. The “amount” of under correction should be carefully prescribed by the optometrist after weighing the advantages and disadvantages in combination with the specific situation. The following principles shall be followed for the control of undercorrection and “degree”:

1) meet the subjective needs of patients: that is, patients can be satisfied with the vision with glasses, which is the key to the success of glasses matching. On this basis, it is feasible to greatly reduce the degree of glasses matching. The test frame technology can be used to determine whether the patient is satisfied with the corrected vision.

2) meet the objective needs of patients; In some special cases, if the patient has driving needs or engages in other special industries with certain requirements for vision, the optometrist should grasp the bottom line of correcting vision according to the specific situation. This requires our optometrists to have a certain understanding of the laws, regulations and rules related to vision.

3) age of patients: mainly reflected in whether the patients have the needs of presbyopia and near vision;

4) diopter: consider the “benefits” brought by the reduced diopter, that is, the ratio of the “obtained” lens thinning degree after reducing a certain diopter to the resulting reduction of corrected vision (which can be understood as cost performance). If the change of lens thickness is not obvious after reducing a certain degree, but the corrected visual acuity is greatly reduced, it is necessary to consider whether to cancel the “under correction” scheme and find another method.

2. Choice of astigmatism:

high myopia usually combines high degree regular astigmatism. In order to improve the success rate of matching glasses, most optometrists often reduce or even abandon the astigmatism prescription to a certain extent. On the other hand, in order to achieve the goal of correcting vision, they often add the degree of myopia spherical lens (i.e. equivalent spherical lens), which eventually leads to the further increase of lens thickness.

and

it is very important for high myopia to match with undercorrected astigmatism. Everyone has a clear understanding of undercorrected astigmatism, so we must pay attention to the detection of these two when matching glasses, especially for patients with high myopia. Finally, I wish you to match your own glasses.