RU2255716C1 - Method for cataractous extraction and implantation of intraocular lens (iol) at correcting initial oblique astigmatism - Google Patents

Abstract

FIELD: medicine, ophthalmology.

SUBSTANCE: the present innovation deals with forming a corneal fragment without its lifting, performing cataractous extraction along with IOL implantation, lifting the cover of corneal fragment in a month, not earlier, affecting with ultraviolet radiation onto stromal bottom and putting corneal fragment to its former place. Moreover, fragment's stem should be oriented by weak meridian, and cataractous extraction through corneal tunnel incision and IOL implantation should be carried out 1-7 d later. Moreover, incision should be placed in projection of weak astigmatism axis being 1 mm against the limbus parallel to it. To obtain complicated myopic astigmatism at detecting IOL optic power one should detect corneal refraction by special mathematical formula depending upon physical refraction of weak meridian, the value of hypermetropic shift of refraction's spherical component for 1.0 D of negative cylindrical ablation, and astigmatism degree. The obtained complicated myopic astigmatism should be corrected due to negative cylindrical ablation of stromal bottom. The present innovation enables to obtain maximally high acuity in patients without any additional spectacle correction.

EFFECT: higher efficiency.

3 dwg, 2 ex

Description

The invention relates to medicine, and more particularly to ophthalmology, and can be used for cataract extraction and implantation of an intra-circular lens (IOL) with correction of the initial oblique astigmatism.

Cataracts are encountered quite often in combination with the initial oblique astigmatism, which is the reason for the inability to get maximum visual acuity without additional (spectacle) correction after cataract extraction and IOL implantation.

A known method of cataract extraction and implantation of IOL with correction of baseline astigmatism, including cataract extraction by phacoemulsification, implantation of IOL and LASIK operation (Maxin Lipner, “Bioptic Vision: New Advances in Cataract Surgery.” Eye World Russia, 2002, No. 3, 24-26 )

However, this method has a significant drawback, because it does not allow to sufficiently effectively correct the initial astigmatism on artifact eyes, since it does not take into account the biomechanics of the corneal flap formed for LASIK operation in combination with the axis of the initial astigmatism.

The closest to the technical solution of the problem is the method of cataract extraction and IOL implantation with astigmatism correction (described by RU 2200520), including the formation of a corneal flap without raising it, conducting a cataract extraction and IOL implantation, lifting with a delay (not earlier than a month later), raising covers of the corneal flap not earlier than in a month, by exposure to ultraviolet (UV) radiation on the stromal bed and the return of the corneal flap in place.

However, when using this method, cataract extraction and IOL implantation is carried out no earlier than a month after the formation of the corneal flap, which lengthens the treatment period, the formation of the corneal flap is performed without orienting its leg relative to the weak axis of astigmatism, which does not take into account the biomechanics of the corneal flap, and the optical power of the IOL is not calculated in such a way as to obtain complex myopic astigmatism after cataract extraction, and then correct it by only negative cylindrical such ablation in order to reduce the depth and area of ablation.

An object of the invention is to provide a method for cataract extraction and IOL implantation with correction of the initial oblique astigmatism in order to obtain the highest possible visual acuity without additional spectacle correction and reduction of treatment time.

The technical result according to the invention is achieved by the fact that in the method of cataract extraction and IOL implantation with correction of the initial oblique astigmatism, including the formation of a corneal flap without raising it, holding a cataract extraction with IOL implantation with a delay in time, raising the corneal flap lid no earlier than a month later , the effect of UV radiation on the stromal bed and the return of the corneal flap in place, while the flap leg is oriented along the weak meridian, cataract extraction and implantation On July IOL is carried out after 1-7 days through the tunnel corneal incision, placing it in the projection of the weak axis of astigmatism 1 mm from the limb and parallel to it, while to obtain complex myopic astigmatism in calculating the optical power of the IOL, the corneal refraction (R) is determined by the formula

R = R _f + KAst,

where R is the refraction of the cornea (D);

R _f - physical refraction of the weak meridian (D);

K is the magnitude of the hypermetropic shift of the spherical component of refraction by 1.0 D of negative cylindrical ablation;

Ast is the degree of astigmatism (D),

and the resulting complex myopic astigmatism is corrected by negative cylindrical ablation of the stromal bed.

Cataract extraction and IOL implantation is carried out 1-7 days after the formation of the corneal flap, because after a day there is sufficient adhesion of the corneal flap, which thus reduces the duration of treatment.

Negative cylindrical ablation of the stromal bed is carried out no earlier than one month after cataract extraction and IOL implantation, because during this time, refraction and keratotopogram stabilize.

Orientation of the flap leg with a relatively weak axis allows the formation of a corneal flap taking into account the biomechanical properties of the cornea, which provides better adaptation of the corneal flap after ablation of the stromal bed, and thus shortens the treatment time.

Orientation of the tunnel corneal incision for phacoemulsification on the weak axis of astigmatism from the temporal side provides the surgeon with convenient access to the surgical field and makes the smallest changes in the shape of the cornea in terms of its biomechanics and location of the corneal flap leg.

Calculation of the optical power of the IOL taking into account the proposed formula makes it possible to obtain complex myopic astigmatism after cataract extraction and implantation of the IOL, which, after only negative cylindrical ablation with the smallest depth and ablation zone, allows to obtain high visual functions.

The invention is illustrated in four rows, where in figure 1 (top view) a corneal flap (1), a leg (2) of a corneal flap (1), a corneal tunnel incision (3), a weak meridian of corneal refraction (4) are depicted; figure 2 (side view) shows a corneal flap (1), leg (2) of a corneal flap (1), a tunnel corneal incision (3); figure 3 (top view) - corneal flap (1) raised, leg (2) of the corneal flap (1), tunnel corneal incision (3), weak meridian of refraction of the cornea (4), stromal bed (5), negative cylindrical ablation ( 6).

The method is as follows:

A patient is placed under local anesthesia with a microkeratum and an incomplete section of the cornea is made with a diameter of 8.0 -9.0 mm, i.e. a corneal flap (1) is formed on the leg (2), while the leg (2) is oriented along the weak meridian (4) . The flap is not reclined; the cornea is dried until the flap is fully adhered. Then, after 1-7 days, with the help of a diamond knife, a tunnel corneal incision (3) is made 3.0 mm long, 3.5 mm wide, while it is projected along the weak axis of astigmatism (4) 1.0 mm from the limb in parallel him, then perform cataract phacoemulsification and IOL implantation. To obtain complex myopic astigmatism in calculating the optical power of the IOL, corneal refraction (R) is taken into account, determined by the formula

R = R _f + KAst,

where R is the refraction of the cornea (D);

R _f - physical refraction of the weak meridian (D);

K is the magnitude of the hypermetropic shift of the spherical component of refraction by 1.0 D of negative cylindrical ablation, which has a constant known value for excimer laser installations of various manufacturers;

Ast is the degree of astigmatism (D),

and then no earlier than a month later, the corneal flap is raised and bent (1), and the resulting complex myopic astigmatism is corrected by negative cylindrical ablation (6) of the stromal bed (5) using UV radiation with a wavelength of 193 nm. Then the flap is laid on the bed.

The method is characterized by the following clinical examples:

Example 1

Patient I., 66 years old. No.amb. cards-2854/03

Diagnosis: OS - Immature cataract. Initial oblique myopic astigmatism.

Handling data:

VisOS = 0.1-0.2 n / a

Refractometry: S - 0.75 C - 3.0 A 38 °

Ophthalmometry:

44.00 - 130 °

41.25 - 40 °

сyl - 2.75 ax 40 °

Eye Length: 23.8mm

Next, the operation according to the invention. A corneal flap with a diameter of 8.5 mm was formed without raising it. A day later, through a tunnel section located in the meridian of 1-2 hours, phacoemulsification with implantation of Acrisof IOL (+22 D) was performed. IOL optical power calculated according to formula SRK II, wherein the corneal refraction of laying - 41.95 D, which is determined according to the invention according to the formula R = R + KAst _f where R _f = 41,25 D, K = _^1/4 to excimer laser installation firm Shwind (Germany), Ast = 2.75 D. The operation and the postoperative period went smoothly, without complications. The eye was clinically absolutely calm the very next day after surgery. The cornea is transparent. The corneal flap is adapted. The IOL in the capsular bag is centered. Stabilization of eye refraction occurred at the end of the first month after surgery. The following objective research data was obtained.

VisOS = 0.6 sph-0.75 ^D cyl - 2.75 ^D ax 40 ° = 0.9-1.0

Refractometry: S - 1.0 C - 2.75 A 43 °

Ophthalmometry:

44.25 - 135 °

41.50 - 45 °

Then, a month later, a horn-shaped flap was raised and negative cylindrical ablation was performed. The operation and the postoperative period went smoothly, without complications. Stabilization of eye refraction and corneal refraction occurred 3 weeks after surgery. The following objective research data was obtained.

Vis OS = 0.9-1.0

Refractometry: S - 0.25 C - 0.25 A 38 °

Ophthalmometry:

41.50 - 140 °

41.25-50 °

Example 2

Patient S., 62 years old. No.amb. cards-3984/03

Diagnosis: OD - Immature cataract. Myopia is moderate.

Initial oblique myopic astigmatism.

Handling data:

Vis OD = 0.1 n / a

Refractometry: S - 5.5 C - 2.5 A 145 °

Ophthalmometry:

44.50 - 52 °

42.00 - 143 °

cyl - 2,5 ax 143 °

Eye Length: 25.7mm

Next, the operation according to the invention. A corneal flap with a diameter of 8.5 mm was formed without raising it. After 4 days, phacoemulsification with implantation of Acrisof IOL (+16 D) was performed through a tunnel section located in the meridian of 10-11 hours. IOL optical power calculated according to formula SRK II, corneal refraction laid - 42.60 D, which is determined according to the invention according to the formula R = R + KAst _f where R _f = 42,00 D, K = _^1/4 to excimer laser installation firm Shwind (Germany ), Ast = 2.5 D. The operation and the postoperative period went smoothly, without complications. The eye was clinically absolutely calm the very next day after surgery. The cornea is transparent. The corneal flap is adapted. The IOL in the capsular bag is centered. Stabilization of eye refraction occurred at the end of the first month after surgery. The following objective research data was obtained.

VisOD = 0.5 sph - 0.5 ^D cyl - 2.5 ^D ax 145 ° = 0.8

Refractometry: S - 0.75 C - 2.75 A 147 °

Ophthalmometry:

44.50-53 °

41.75-143 °

Then, a month later, a corneal flap was raised and negative cylindrical ablation was performed. The operation and the postoperative period went smoothly, without complications. Stabilization of eye refraction and corneal refraction occurred 3 weeks after surgery. The following objective research data was obtained.

Vis OS = 0.8-0.9 n / a

Refractometry: S + 0.25 C - 0.5 A 130 °

Ophthalmometry:

41.25 - 48 °

40.75 - 138 °

Claims (1)

A method for cataract extraction and implantation of an intraocular lens with correction of the initial oblique astigmatism, including the formation of a corneal flap without lifting it, delaying the time of cataract extraction and implantation of an intraocular lens, lifting the lid of the corneal flap no later than a month later, exposing the stromal bed to ultraviolet radiation and the return of the corneal flap in place, characterized in that the flap leg is oriented along the weak meridian, cataract extraction through the corneal nnelny incision and the IOL implantation is performed after 1-7 days, with a section in the projection of the weak axis of astigmatism of 1 mm from the limbus and parallel to it, thus to obtain the compound myopic astigmatism when calculating the optical power of the intraocular lens refraction of the cornea is determined from the formula R = R _f + K A _st , where R is the refraction of the cornea, D; R _f - physical refraction of the weak meridian, D; K is the magnitude of the hypermetropic shift of the spherical component of refraction by 1.0 D of negative cylindrical ablation; A _st - the degree of astigmatism, D, and the resulting complex myopic astigmatism is corrected by negative cylindrical ablation of the stromal bed.

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