RU2727043C1 - Method for correction of myopia and complex myopic astigmatism in patients with high risk of side optical effects - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention relates to medicine, specifically to ophthalmology. Myopia and complex myopic astigmatism are corrected. Correction data are introduced to the patient's refraction in the Wave Light EX 500 excimer laser planning station. Then, excimer laser ablation is performed according to preset parameters. Patients with a high risk of secondary optical phenomena are ensured by using a profile of ablation of Custom Q. A diameter-ablation ablation zone is calculated by increasing a patient's pupil diameter in mesopic conditions by 0.1 mm. Further, the spherical component of refraction is increased in accordance with the selected optical zone, for example, with the diameter of the optical ablation zone of 6.8–6.9 mm – by minus 0.25 dioptre. With the diameter of the optical ablation zone of 7.0–7.3 mm – by minus 0.5 dioptre. With the diameter of the optical ablation zone of 7.4–7.8 mm – by minus 0.75 dioptre. With the diameter of the optical ablation zone of 7.9–8.0 mm – by minus 1.0 dioptre.EFFECT: method enables increasing the refractional result when using the extended optical zone, reducing the risk of secondary optical phenomena following correction of myopia and myopic astigmatism, and providing the possibility of performing a high refractive surgery.1 cl, 3 ex, 1 tbl

Description

The invention relates to medicine, namely to ophthalmology, and is intended for excimer laser correction of myopia and complex myopic astigmatism in patients with a high risk of developing unwanted optical phenomena after surgery.

Keratorefractive interventions, as a rule, are performed for social reasons, less often for medical reasons and are aimed at improving the patient's quality of life, eliminating the need for daily use of optical correction means (glasses, contact lenses). Therefore, when assessing the results of the operation, not only refractive, but also functional indicators are important. There are various methods of surgical correction of refractive errors by programmed changes in the geometry of the cornea: various types of keratotomy, thermocoagulation of the cornea, and others.

The common disadvantages of these methods are high labor intensity and the possible risk of side complications, therefore, at the present stage, they are practically not used. The most safe, predictable and stable results over a long period of time today are the methods of excimer laser correction, which are widely used.

Despite the significant advances in modern excimer laser technologies and the constantly improving software for excimer lasers, the main reason for incomplete patient satisfaction with refractive surgery remains optical side phenomena: "halo" and "glare", which occur in low light conditions and can significantly reduce the quality of patient vision. According to different authors, the reasons for such phenomena can be:

- increased corneal aberrations after ablation (especially coma and spherical aberration);

- the discrepancy between the diameter of the formed optical zone and the diameter of the pupil (when, when the pupil expands, the edge of the ablation falls into the optical zone of the cornea);

- a small transient zone, which creates a sharp transition from the formed optical zone to the intact cornea, which can also fall into the optical zone of the cornea when the diameter of the pupil changes in low light conditions.

Therefore, the risk group for the development of postoperative optical phenomena includes patients with a physiologically wide pupil in mesopic conditions (more than 6 mm) and with high myopia, as well as people who have a visual load in low light conditions (in particular, who spend a lot of time driving in the evening) working in darkened rooms, etc.).

In order to reduce the effect of these optical phenomena after laser correction, it is usually proposed to take into account the patient's pupil diameter in mesopic conditions: the recommended ratio of the diameters of the optical and transient zones is not less than 5.5 mm - 7.5 mm. In order to calculate the effective optical zone, the Volgograd branch of the Federal State Budgetary Institution IRTC "Eye Microsurgery" suggested using the formula:

OZR = DzrhPZR / (PZR-PK),

where OZR is the diameter of the optical zone of the cornea; Dzr - pupil diameter in scotopic conditions; PZR - anterior-posterior size of the eyeball; PC - the depth of the anterior chamber (Blinkova E.S., Fokin V.P., Solodkova E.G. Modern technologies of cataract and refractive surgery - 2012 - p. 184). To prevent the occurrence of postoperative optical phenomena, the diameter of the total ablation zone should be no less than the diameter of the optical zone of the cornea.

Kornilovsky I.M., Shishkin M.M., Karpov V.E. also showed that objective pupillometry under photopic and mesopic conditions allows an individual approach to determining the size of the optical and transitional zones of photorefractive ablation and sharply reduce the frequency of "Glare" and "Halo" effects ("Optical side effects in photorefractive and cataract surgery" - Modern technologies of cataract and refractive surgery - 2009. - S. 222-333).

Modern excimer lasers allow these factors to be taken into account in order to reduce possible negative optical effects after correction, in particular, the WaweLightEx 500 excimer laser unit allows for customized ablation using the CustomQ profile, which maximally preserves the original (natural) spherical aberration (builds an ablation profile taking into account the initial value of Q- factor of the cornea), as well as expand the optical zone to 8 mm in increments of 0.1 mm (while maintaining the total ablation zone of 9 mm). In addition, the "flying spot" technology allows you to maximally save corneal tissue during ablation and to obtain the most smoothed profile of the transient zone.

All these technical advantages make it possible to personalize the excimer laser correction procedure as much as possible, taking into account the individual needs of the patient. However, during the operation of the installation, the surgeons encountered some difficulties in predicting the refractive result: in particular, the diameter of 6.5 mm was taken as the standard of the optical zone, for which a nomogram is attached. However, as the optical zone expands at the same refraction, the ablation depth should also increase. However, at the moment, there are no official recommendations and nomograms for working with an expanded optical zone, and surgeons, when trying to use it, face the effect of incomplete correction of myopia (from minus 0.5 diopters or more), which creates the need for repeated interventions. There was a need to develop special nomograms to work with non-standard ablation parameters.

The closest analogue is the IBRA online nomogram (from the Swiss company Zubisoft (Found on the open Internet: https://www.ibra.com/) for performing calculations in excimer laser and cataract surgery, which are used in foreign countries with the financial support of manufacturing firms excimer laser installations.

The main disadvantages of this method are: the predictability of the refractive result when using these nomograms is about 0.5 diopters of emmetropia, which is not always able to satisfy the surgeon and the patient, as well as the high cost (at least an expensive annual subscription is required on the site), the lack of a Russified interface, as well as the official approval of the representatives of the manufacturing companies of excimer laser units. In this connection, these nomograms have not become widespread in Russia.

The objective of the invention is to provide a method for excimer laser correction of myopia and complex myopic astigmatism in patients with a high risk of developing unwanted optical phenomena after surgery.

The technical result is to increase the predictability of the refractive result when using the extended optical zone through the use of unified and understandable algorithms for calculating the parameters of excimer laser ablation, as well as to reduce the risk of side optical phenomena after the correction of myopia and myopic astigmatism and to ensure the possibility of performing an operation with a high refractive result.

The technical result is achieved by the fact that in the method for the correction of myopia and myopic astigmatism, including the introduction of correction data for the refraction of the patient into the planning station of the Wave Light EX 500 excimer laser, as well as carrying out excimer laser ablation according to the specified parameters, according to the invention, in patients with a high risk of side optical phenomena use the Custom Q ablation profile, the diameter of the optical ablation zone is calculated by increasing the patient's pupil diameter in mesopic conditions by 0.1 mm, and the spherical refractive component is increased in accordance with the selected optical zone: for the optical ablation zone 6.8 mm-6.9 mm - by minus 0.25 diopters, with a diameter of the optical ablation zone from 7.0 mm to 7.3 mm - by minus 0.5 diopters, with a diameter from 7.4 mm to 7.8 mm - by minus 0.75 diopters, with a diameter of 7.9 mm-8.0 mm - by minus 1.0 diopters.

The method is carried out as follows.

1. Measurement of the diameter of the pupil in mesopic conditions, as well as a thorough collection of anamnesis, taking into account professional and daily household activities. The diameter of the optical ablation zone is calculated, which must exceed the diameter of the patient's pupil in mesopic conditions. When the patient's pupil diameter is more than 6.7 mm in mesopic conditions, it is proposed to calculate the diameter of the optical ablation zone by adding 0.1 mm to the patient's pupil diameter.

2. In the planning station of the WaveLightEX 500 excimer laser, the Custom Q ablation profile is selected, which is preferable for the correction of myopia and myopic astigmatism, as it is the most physiological. allows you to maximize the preservation of natural spherical aberration of the cornea in order to reduce unwanted optical phenomena after surgery.

3. In the planning station enter the calculated diameter of the optical ablation zone, and then the refractive index of the patient. The spherical component of refraction is increased by the correction value corresponding to the selected optical zone.

4. Corrections for the spherical component of refraction when using the extended optical zone are presented in the form of Table 1. When using the diameter of the optical zone of 6.8-6.9 mm, it is proposed to enhance the spherical component by minus 0.25 diopters, with a diameter in mm from 7.0 up to 7.3 - by minus 0.5 diopters, with a diameter from 7.4 to 7.8 - by minus 0.75 diopters, with a diameter of 7.9-8.0 - by minus 1.0 diopters.

5. Next, a superficial flap is formed with a microkeratome or a femtosecond laser (for LASIK), or de-epithelialization of the cornea (when correction is performed using the photorefractive keratectomy (PRK) technique, after which ablation is performed according to the specified parameters. Then the interface is washed with a weak solution of antibacterial drugs, the operation is completed installation of antibiotics and application of a soft contact lens (if necessary).

The defining significant difference between the proposed method and the closest analogue is the changes made to the programmable ablation parameters, namely: the diameter of the optical ablation zone is increased by 0.1 mm from the diameter of the pupil in mesopic conditions, while a customized Custom Q ablation profile is used. When using a standard nomogram the risk of undercorrection of myopia is very high, therefore, in accordance with the experimentally established parameters, the spherical refraction component is introduced into the planning station of the excimer laser taking into account its amplifying corrections: minus 0.25, minus 0.5, minus 0.75 or minus 1.0 diopters depending on the calculated diameter of the optical ablation zone (Table 1).

These changes in the calculations of the operation in patients with myopia and myopic astigmatism in combination with a physiologically wide pupil can reduce the risk of unwanted optical phenomena after correction, as well as postoperative residual myopia by performing excimer laser ablation with maximum accuracy of a given diameter, depth, and maximum preservation of the original (natural) spherical aberration (ablation taking into account the initial value of the corneal Q-factor).

The proposed method meets the criterion of "novelty", since it is unknown from the existing level of science and technology. It also meets the “inventive step” criterion, since it does not follow explicitly from the level of science and technology.

The invention is illustrated by the following examples of specific implementation:

Example 1.

Patient M., 31 years old, applied for a consultation at the Eye Clinic of Dr. Belikova LLC with complaints of blurred vision in both eyes. From the anamnesis it is known that the patient has been observed with mild myopia for about 7 years. Due to her professional activity (work on television), she cannot use spectacle correction, and is also forced to often work in the evening and at night in poor lighting conditions. Spends a lot of time at the wheel of a car, incl. in the dark.

After an ophthalmological examination, the diagnosis was made:

Mild myopia in both eyes.

Diagnostic examination data:

Visual acuity of the right eye without correction 0.2. Corrected sph -1.5 = 1.0.

Visual acuity of the left eye without correction 0.2. With sph correction -1.25 = 1.0.

Refractometry data of the right eye (with a narrow pupil): sph -2.0 cyl -0.5 ax 175

Refractometric data of the left eye (with a narrow pupil): sph -2.0 cyl -0.25 ax 5

Pupillometry data in mesopic conditions: right eye - 6.7 mm, left eye - 6.9 mm

Refractometry data of the right eye under cycloplegia: sph -1.25 cyl -0.25 ah 180

Refractometry data of the left eye under cycloplegia: sph -1.0

Taking into account the diameter of the pupil in mesopic conditions and the type of daily activity, the patient underwent myopia correction using the claimed method.

The calculation of excimer laser ablation was carried out according to the claimed method: in the planning station of the WaveLightex 500 excimer laser, the Custom Q ablation profile was selected, the diameter of the optical ablation zone was set to 6.8 mm for the right eye (pupil diameter 6.7 + 0.1 mm), 7.0 mm for left (pupil diameter 6.9 + 0.1 mm). The refraction data entered into the planning station of the excimer laser was calculated by adding to the manifest refraction the corresponding corrections for the optical zone 6.8 and 7.0 mm): for the right eye sph -1.75 (-1.5-0.25 diopters), for left - sph -1.75 (-1.25-0.5).

The formation of a superficial flap was performed under local anesthesia with a Zyoptix microkeratome, which made it possible to obtain a high-precision uniform stromal cut and a uniform flap thickness. During the preparation of the patient and in the process of flap formation, keratoprotection measures were taken (installation of hyaluronic acid preparations, moisturizing of the cornea during flap formation).

After the ablation was completed, the interface was washed with a weak solution of antibacterial drugs; the operation was completed with the installation of antibiotics.

At discharge after 1 month, we received the following survey data:

Visual acuity of each eye without correction 1.2, binocular 1.4.

Refractometry of the right eye with a narrow pupil: sph +0.25 cyl -0.5 ax 175

Refractometry of the left eye with a narrow pupil: sph +0.0 cyl -0.25 ax 5

Refractometry of the right eye under cycloplegia: sph +0.5 cyl -0.25 ax 180

Refractometry of the left eye under cycloplegia: sph +0.25

Refractometry data under cycloplegic conditions correlate with the difference in the patient's manifest and cycloplegic refraction before correction and are explained by the physiological tone of the ciliary muscle at a young age.

It is important to note the patient's high satisfaction with the correction results. With active questioning, she not only notes excellent visual acuity, but also a good quality of vision when working in low light conditions and driving a car at night. There are no complaints about "halo", "glare" and other optical phenomena.

Example 2.

Patient K., 19 years old, turned to LLC "Eye Clinic of Doctor Belikova" with complaints of blurred vision in the distance. From the anamnesis it is known that the patient has been observed with mild myopia since 10 years, the last 3 years myopia has not progressed. For passing honey. the commission requires high uncorrected visual acuity. Often drives a car, incl. in evening time. I applied for an excimer laser correction.

During an ophthalmological examination, the diagnosis was made:

Mild myopia in both eyes. Complex myopic astigmatism (corneal) of the direct type.

Diagnostic examination data:

Visual acuity of the right eye without correction 0.03. Corrected sph -2.5cyl -2.0 ax 10 = 1.0.

Visual acuity of the left eye without correction 0.03. Corrected sph -2.5cyl -2.25 ax 165 = 1.0.

Refractometry data of the right eye (with a narrow pupil): sph -2.25cyl -2.0 ah 10

Refractometry data of the left eye (with a narrow pupil): sph -2.5cyl -2.25ax165

Pupillometry data in mesopic conditions: right eye - 8.0 mm, left eye - 7.9 mm

Refractometry data of the right eye under cycloplegia: sph -2.25 cyl -2.25 aх7

Refractometry data of the left eye under cycloplegia: sph -2.0 cyl -2.0ax 165

Taking into account the diameter of the pupil in mesopic conditions and the peculiarities of daily activities, the patient underwent myopia correction using the claimed method.

The calculation of excimer laser ablation was carried out according to the claimed method: in the planning station of the WaveLightex 500 excimer laser, the Custom Q ablation profile was selected, the diameter of the optical ablation zone was set at 8.0 mm for each eye (pupil diameter 7.9 + 0.1 mm for the left eye; expansion of the optical diameter zones greater than 8.0 mm for the right eye are not possible due to the limitation of the excimer laser software). Refractive data entered into the excimer laser leveling station:

for the right eye sph -3.5 cyl -1.75 ax 7,

for the left one - sph -3.5cyl -2.0 ah 170.

The force of the spherical component introduced into the planning station was calculated taking into account the correction for the extended optical zone:

- 2.5 (manifest refraction data) + (-1.0) (correction for the spherical component when using an optical ablation zone of 8 mm).

Optical power and cylinder axis were calculated taking into account subjective refraction and corneal topography data.

The formation of a superficial flap was performed under local anesthesia with a Zyoptix microkeratome. At the stage of preoperative preparation and in the process of flap formation, keratoprotection measures were taken.

After the ablation was completed, the interface was washed with a weak solution of antibacterial drugs; the operation was completed with the installation of antibiotics.

At discharge after 1 month, we received the following survey data:

Visual acuity of each eye without correction 1.0, binocular 1.2.

Refractometry of the right eye with a narrow pupil: sph +0.0 cy1 -0.25 ah93

Refractometry of the left eye with a narrow pupil: sph +0.0 cy1 -0.5 ah78

Refractometry of the right eye under cycloplegia: sph +0.25 cyl -0.5 ah99

Refractometry of the left eye under cycloplegia: sph +0.0 cyl -0.25 aх 67

The patient was completely satisfied with the obtained visual acuity and quality, with active questioning there were no complaints about negative optical phenomena, even when driving in the evening.

Example 3.

Patient A., 23 years old, turned to LLC "Eye Clinic of Doctor Belikova" with complaints of blurred vision in the distance. The patient has been observed with moderate myopia since the age of 14, the last 3 years myopia has not progressed. He is professionally engaged in water sports, and therefore cannot use glasses and contact corrections. I applied for an excimer laser correction.

During an ophthalmological examination, the diagnosis was made:

Moderate myopia in both eyes. Complex myopic astigmatism (corneal) of the direct type.

Diagnostic examination data:

Visual acuity of the right eye without correction 0.02. Corrected sph -5.5 cyl -1.0 ax 5 = 1.0.

Visual acuity of the left eye without correction 0.03. Corrected sph -4.5 cyl -1.25 ax 175 = 1.0.

Refractometric data of the right eye (with a narrow pupil): sph -5.75 cyl -1.0 ax 7

Left eye refractometry data (with a narrow pupil): sph -5.0 cyl -1.25 ax 175

Pupillometry data in mesopic conditions: right eye - 7.3 mm, left eye - 7.4 mm

Refractometry data of the right eye under cycloplegia: sph -5.25 cyl -1.25 aх7

Refractometry data of the left eye under cycloplegia: sph -4.5 cyl -1.25 ax 178

Considering the diameter of the pupil in mesopic conditions, the patient underwent myopia correction using the claimed method.

The calculation of the parameters of excimer laser ablation was carried out according to the claimed method: in the planning station of the WaveLight ex 500 excimer laser, the Custom Q ablation profile was selected, the diameter of the optical ablation zone was set to 7.4 mm for the right eye (pupil diameter 7.3 + 0.1 mm) and 7.5 mm for the left eye (7.4 + 0.1 mm). Refractive data entered into the excimer laser leveling station:

for the right eye sph -6.25 cyl -1.0 ah 7,

for the left one - sph -5.25cyl -1.25 ax 178.

The calculation of the spherical component introduced into the planning station was carried out taking into account the correction for the extended optical zone:

Right eye: -5.5 (manifest refraction data) + (-0.75) (correction for the spherical component when using the optical ablation zone of 7.4 mm).

Left eye: -4.5 (manifest refraction data) + (-0.75) (correction for the spherical component when using the optical ablation zone of 7.5 mm).

Optical power and cylinder axis were calculated taking into account subjective refraction and corneal topography data.

The formation of a superficial flap was carried out under local anesthesia with a Zyoptix microkeratome, using keratoprotection measures (installation of hyaluronic acid preparations, moisturizing the cornea during flap formation).

After the ablation was completed, the interface was washed with a weak solution of antibacterial drugs; the operation was completed with the installation of antibiotics.

At discharge after 1 month, we received the following survey data:

Visual acuity of each eye without correction 1.0, binocular 1.2.

Refractometry of the right eye with a narrow pupil: sph +0.0 cyl -0.25 ax 5

Refractometry of the left eye with a narrow pupil: sph -0.25 cyl -0.25 ah 178

Refractometry of the right eye under cycloplegia: sph +0.25 cyl -0.25 ah8

Refractometry of the left eye under cycloplegia: sph +0.0 cyl -0.25 aх 177

The patient was completely satisfied with the obtained visual acuity and quality, with active questioning there were no complaints about negative optical phenomena.

The use of the proposed method will reduce the risk of postoperative optical phenomena that reduce the quality of life of patients, reduce the likelihood of undercorrection of myopia requiring repeated interventions, and also increase the clinical accuracy and effectiveness of this method in comparison with standard techniques that do not take into account individual characteristics (pupil diameter, Q- constant) and the visual needs of patients.

Claims (1)

A method for the correction of myopia and complex myopic astigmatism, including the introduction of correction data for the patient's refraction into the planning station of the Wave Light EX 500 excimer laser, as well as performing excimer laser ablation according to the specified parameters, characterized in that the Custom ablation profile is used in patients with a high risk of optical side phenomena Q, the diatropic ablation zone is calculated by increasing the patient's pupil diameter in mesopic conditions by 0.1 mm, and the spherical refractive component is increased in accordance with the selected optical zone: with a diameter of the optical ablation zone of 6.8-6.9 mm - by minus 0, 25 diopters, with the diameter of the optical ablation zone from 7.0 to 7.3 mm - by minus 0.5 diopters, with the diameter of the optical ablation zone from 7.4 to 7.8 mm - by minus 0.75 diopters, with the diameter of the optical ablation zones 7.9-8.0 mm - by minus 1.0 diopters.