Abstract: 45 eyes of 25 cases of ultra-high myopia with myopia spherical equivalent > 10.00d were examined by a-ultrasound and corneal topography. The ocular axis and corneal refractive power were measured respectively. The relationship between myopia spherical equivalent and ocular axis and corneal refractive power was analyzed by SPSS statistical software package., There are many factors affecting the diopter of myopia, including corneal system, lens system, ocular axis and so on. The axis of the eye is one of the important factors affecting the state of ocular flexion. The extension of the axis of the eye directly leads to myopia. High myopia is axial myopia. It is generally believed that the diopter can be increased by 3D for every 1mm increase in the ocular axis. For ultra-high myopia, the relationship between ocular axis and diopter obviously has its particularity. The purpose of this paper is to explore the relationship between ocular axis and diopter in ultra-high myopia., High myopia generally refers to > – 6. 00D myopia, with the deepening of understanding and the progress of refractive surgery and intraocular lens surgery, Ultra high myopia (at least – 10d or above) has attracted the attention of scholars because of the particularity of corrective surgery and cataract intraocular lens surgery for this kind of myopia. The diopter of the eye is mainly determined by the corneal system, lens system and eye axis. The first two of these three elements change little in a person’s life, while the elongation of eye axis varies greatly. In high myopia, especially ultra-high myopia With the increase of age, the axis of the eye continues to lengthen, which directly leads to the deepening of myopia. The axial length of all cases in this group is more than 24mm, and the maximum is 33mm, indicating that the axial length of ultra-high myopia is 100%, that is, ultra-high myopia must be axial myopia., It is generally believed that the normal value of the ocular axis is generally 23 ~ 24mm. For every 1mm increase in the ocular axis, myopia will deepen accordingly. However, this relationship is not true in ultra-high myopia. In this group of cases, the regression equation between myopia degree and ocular axis is se (spherical mirror equivalent) = – 32.69 + 1.64 × Axis (axis of the eye) indicates that the axis of the eye is extended by 1mm, and myopia is deepened by about 1.64d, which is much lower than 3D. Some scholars once pointed out that “1mm = 3D” The relationship is only applicable to a certain refractive range, beyond which it cannot be applied. However, the previous literature lacks a clear record of the relationship between the degree of ultra-high myopia and the amount of ocular axis. Data selection of this paper – 10. Above 25d, 12 on average. 8± 3。 30d ultra-high myopia can reflect the relationship between the degree of axial myopia and the axis of the eye. This study also shows that in the eyes of ultra-high myopia, The degree of myopia has nothing to do with corneal refractive power (P = 0.34), which is consistent with the previous literature. The discussion on the relationship between the degree of ultra-high myopia and the amount of ocular axis is helpful to understand the causes of the calculation error of intraocular lens degree of high myopia. Whether the theoretical formula or the empirical formula, the intraocular lens calculation formula has strong reliability when it is close to the model eye. When it is applied to the degree of high myopia, it is not suitable for the calculation of intraocular lens For each 1mm increase in the axis of the model eye, myopia will deepen by 3D, but in high myopia, the degree of myopia deepening is reduced, such as grade 1 in this group. 64D。 Therefore, the calculation of intraocular lens degree in ultra-high myopia still needs to be explored., High myopia is mainly caused by axial elongation, which has little to do with corneal refractive power. The effect of corneal refractive surgery in high myopia, mainly ultra-high myopia, is far less than that in low and moderate myopia. Therefore, it tends to intraocular surgery, such as lens extraction, intraocular lens implantation, intraocular lens surgery and so on. This kind of surgery also involves the calculation of implanted lens or degree. It is necessary to emphasize the conclusive quantitative relationship between axial elongation and myopia degree., There are many factors that affect the diopter of myopia, including corneal system, lens system, ocular axis and so on. The axis of the eye is one of the important factors affecting the state of ocular flexion. The extension of the axis of the eye directly leads to myopia. High myopia is axial myopia. It is generally believed that the diopter can be increased by 3D for every 1mm increase in the ocular axis. For ultra-high myopia, the relationship between ocular axis and diopter obviously has its particularity. The purpose of this paper is to explore the relationship between ocular axis and diopter in ultra-high myopia.
high myopia generally refers to > – 6. 00D myopia, with the deepening of understanding and the progress of refractive surgery and intraocular lens surgery, Ultra high myopia (at least – 10d above) has attracted the attention of scholars, because the correction of this kind of myopia and cataract intraocular lens surgery have their particularity.
The diopter of eyeball is mainly determined by corneal system, lens system and ocular axis. In a person’s life, the first two of these three elements change little, while the variation of ocular axis elongation is large. In high myopia, especially ultra-high myopia, the axis of the eye lengthens with age, which directly leads to the deepening of myopia. The axial length of all cases in this group is more than 24mm, and the maximum is 33mm, indicating that the axial length of ultra-high myopia is 100% prolonged, that is, ultra-high myopia must be axial myopia.
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generally believe that the normal value of ocular axis is generally 23 ~ 24mm. For every 1mm increase of ocular axis, myopia will deepen 3D accordingly. However, this relationship is not true in ultra-high myopia. In this group of cases, the regression equation between myopia degree and ocular axis is se (spherical mirror equivalent) = – 32.69 + 1.64 × Axis (axis of the eye) indicates that the axis of the eye is extended by 1mm, and myopia is deepened by about 1.64d, which is much lower than 3D. Some scholars once pointed out that “1mm = 3D” The relationship is only applicable to a certain refractive range, beyond which it cannot be applied. However, the previous literature lacks a clear record of the relationship between the degree of ultra-high myopia and the amount of ocular axis. Data selection of this paper – 10. Above 25d, 12 on average. 8± 3。 30d ultra-high myopia can reflect the relationship between the degree of axial myopia and the axis of the eye. This study also shows that in the eyes of ultra-high myopia, The degree of myopia was not related to corneal refractive power (P = 0.34), which was consistent with the previous literature.
The discussion of the relationship between the degree of ultra-high myopia and the amount of ocular axis is helpful to understand the causes of the calculation error of intraocular lens degree in high myopia. The intraocular lens calculation formula, whether theoretical formula or empirical formula, has strong reliability when it is close to the model eye. When it is applied to the degree of high myopia, the effect changes. For each 1mm increase in the axis of the model eye, the myopia deepens by 3D, but in high myopia, the degree of myopia deepens is reduced, such as 1 in this group. 64D。 Therefore, the calculation of intraocular lens degree in ultra-high myopia still needs to be exploredCable.
high myopia is mainly caused by the extension of ocular axis, which has little to do with corneal refractive power. The effect of corneal refractive surgery in high myopia, mainly ultra-high myopia, is far less than that in low and moderate myopia. Therefore, it tends to intraocular surgery, such as lens extraction, intraocular lens implantation, intraocular lens surgery and so on. This kind of surgery also involves the calculation of implanted lens or degree. It is necessary to emphasize the conclusive quantitative relationship between axial elongation and myopia degree.