RU2207831C2 - Surgical method for treating the cases of combined astigmatism in children - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves producing superficial corneal flap. The flap is bent and the stroma tissues are treated with excimer laser radiation. First the weak meridian is adjusted until spherical myopic refraction is achieved, corresponding to spherical myopia with physiological astigmatism of 0.75 D. Then, the built spherical myopia is adjusted to achieve hypermetropia of mild degree. Ablation zone diameter ratio to cornea diameter belongs to an interval from 0.66 to 0.6 and ablation depth belongs to an interval from 50 to 70 mcm. EFFECT: enhanced effectiveness of surgical treatment; reduced risk of traumatic complications. 4 dwg

Description

 The invention relates to the field of ophthalmic surgery.

 A known method of surgical correction of refraction by radiation of an excimer laser (see VV Kurenkov "Excimer laser surgery of the cornea, M., 1998, pp. 34-38).

 However, this method is not applicable to the correction of mixed astigmatism in children.

 This method has a significant drawback: it is not effective enough in the correction of mixed astigmatism in children.

 The technical task is to increase the correction efficiency of mixed astigmatism in children.

 This technical problem is solved by the fact that in the method of surgical correction of mixed astigmatism in children, which consists in the formation of a superficial flap of the cornea, its bending and exposure to stromal tissue by radiation of an excimer laser, the weak meridian is initially corrected to form a spherical myopic refraction corresponding to spherical myopia with physiological astigmatism to 0.75 D, then the resulting spherical myopia is corrected to a mild hyperopia, with the ratio of the ablation zone to the dia meter of the cornea lies in the range of 0.66-0.6, and the depth of oblation is in the range from 50 to 70 microns.

 The set of distinctive features proposed by the authors is necessary and sufficient for an unambiguous positive solution to the claimed technical problem.

 The authors experimentally selected and substantiated the intervals in the parameters given in the formula, which not only increase the efficiency of the proposed operation, but also reduce the trauma of the ocular organ during correction of mixed astigmatism in children.

 The proposed method is illustrated in figure 1-4.

 A method of surgical correction of mixed astigmatism in children consists in the formation of a superficial flap of the cornea, its bending and exposure to stromal tissue by radiation of an excimer laser (not shown).

 Initially, the weak meridian is corrected until spherical myopic refraction forms.

 In this case, the calculation of the ablation value is laid in such a way as to obtain refraction corresponding to spherical myopia with physiological astigmatism up to 0.75 D with a strong axis in the vertical meridian.

 In FIG. 1 shows the position of the axes before the operation (1 - myopic axis, 2 - hyperopic axis). Figure 2 shows the position of the axes after the first stage of the operation.

 Next, the resulting spherical myopia is corrected with the formation of weak hyperopia, with the ratio of the ablation zone to the diameter of the cornea lying in the range of 0.66-0.67.5, and the depth of ablation in the range of 50-70 microns.

 Figure 3, 4 shows the position of the axes after the second stage of the operation.

 The proposed method is characterized by the following clinical examples.

 Example 1

 Patient K., 12 years old.

Clinical diagnosis before surgery:
OD - healthy
OS - mixed direct correct astigmatism
Vis OD = 1.0
OS = 0.3 s sph + 2.0 cyl (-) 3.0 ax 180 ^o = 0.7 n / k.

Refractometry: - OD sph + 0.5 ^D cyl (-) 0.25 ^D ax 180 ^o
At the height of cycloplegia: - OS sph + 2.75 ^D cyl (-) 3.75 ^D ax 180 ^o
Ophthalmometry: - OD 43.5 ^D ax 180 ^o ; 43.75 ax 90 ^o
OS 41.25 ^D ax 180 ^o ; 44.75 ^D ax 90 ^o
Echobiometry - OD = 22.95 mm
Front-rear axle - OS = 23.20 mm
Ophthalmopachymetry: - OD = 532 microns
OS = 521 μm
Appendages, anterior segment, optical media, the fundus is normal.

After treatment according to the method described above:
Vis OD = 1.0
OS = 0.8 n / a
Refractometry: - OS sph + 0.5 cyl +0.25 ^D ax 90 ^o
At the height of cycloplegia:
Ophthalmometry: - OS 43.0 ^D ax 180 ^o ; 43.25 ^D ax 90 ^o
Achieved positive refractive and visometric results.

 Example 2

 Patient D., 13 years old.

Clinical diagnosis before surgery:
OD - mixed direct correct astigmatism.

OS - healthy
Vis OD = 0.2
OS = 1.0
Refractometry: - OD sph + 1,5 ^D cyl (-) 3,5 ^D ax 17 ^o
At the height of cycloplegia: - OS sph + 0.25 ^D cyl + 0.5 ^D ax 92 ^o
Ophthalmometry: - OD 42.25 ah 15 ^o ; 45.75 ^D ax 105 ^o
OS 42.75 ah 180 ^o ; 443.25 ah 90 ^o
Echobiometry - OD = 23.28 mm
Front-rear axle - OS = 23.25 mm
Ophthalmopachymetry: - OD = 512 microns
OS = 521 μm
Appendages, anterior segment, optical media, the fundus is normal.

After treatment according to the method described above:
Vis OD = 0.7 n / k
OS = 1.0
Refractometry: - OS sph + 0.5 ^D cyl +0.5 ^D ax 12 ^o
At the height of cycloplegia:
Ophthalmometry: - OD 43.0 ^D ax 10 ^o ; 43.5 ^D ax 100 ^o
Achieved positive refractive and visometric results.

 The use of the invention allows to increase the efficiency and effect with an unambiguous positive solution to the claimed technical problem - correction of mixed astigmatism in children.

Claims (1)

 A method of surgical correction of mixed astigmatism in children, which consists in the formation of a superficial flap of the cornea, its bending and exposure to stromal tissue by radiation of an excimer laser, characterized in that the weak meridian is initially corrected to form a spherical myopic refraction corresponding to spherical myopia with physiological astigmatism of up to 0.75 D, then the resulting spherical myopia is corrected to a mild hyperopia, with the ratio of the ablation zone to the diameter of the cornea 0,66-0,6 shaft and the ablation depth in the range 50-70 microns.

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