All preoperative examinations for myopia surgery are listed in detail

Abstract: Patients with myopia, especially those with high myopia, are more likely to have fundus lesions. The purpose of fundus examination is to exclude fundus diseases, such as fundus hemorrhage, retinal hole and detachment., Perfect preoperative examination of myopia is the premise to ensure the safety and effect of surgery. Limited to space, there is no discussion. But in clinical work, patients often ask: what is the use of this examination? What is that? Today, I would like to explain the significance of the following preoperative examinations on this issue., I. medical history, which contains many items. For example, age and occupation are important factors in surgical design; Generally, surgery is considered only when the diopter is stable for more than 1 year; Soft contact lenses need to be stopped for 1 week and hard contact lenses need to be stopped for more than 1 month, so the inspection results will be more accurate; The history of drug allergy, previous eye diseases, surgery and genetic history are important indicators to determine whether the operation can be performed and which operation method to choose., II. Visual acuity, generally including naked visual acuity, spectacled visual acuity and near visual acuity. A preliminary understanding of the patient’s visual acuity provides a reference for the next examination. For older patients, near vision will be more meaningful and is a reference index for surgical design., III. the dominant eye, as the name suggests, is the eye that is mainly used at ordinary times, just as some people are used to using their right hand and some people are used to using their left hand. Generally speaking, the vision of the dominant eye is slightly better than that of the non dominant eye., IV. external eye / slit lamp examination,

perfect preoperative examination of myopia is the premise to ensure the safety and effect of operation. Limited to space, there is no discussion. But in clinical work, patients often ask: what is the use of this examination? What is that? Today, I would like to explain the significance of the following preoperative examinations on this issue.

I. medical history

medical history contains many items. For example, age and occupation are important factors in surgical design; Generally, surgery is considered only when the diopter is stable for more than 1 year; Soft contact lenses need to be stopped for 1 week and hard contact lenses need to be stopped for more than 1 month, so the inspection results will be more accurate; Drug allergy history, previous eye diseases, surgical history and genetic history are important indicators to determine whether surgery can be performed and which surgical method to choose.

II. Vision

generally includes naked vision, spectacled vision and near vision. A preliminary understanding of the patient’s visual acuity provides a reference for the next examination. For older patients, near vision will be more meaningful and is a reference index for surgical design.

III. dominant eye

as the name suggests, the dominant eye is the eye that is mainly used at ordinary times, just as some people are used to using their right hand and others are used to using their left hand. Generally speaking, the vision of the dominant eye is slightly better than that of the non dominant eye.

IV. external eye / slit lamp examination

is mainly to exclude other eye diseases, such as blepharitis, conjunctivitis and other active inflammation, which can only be operated after being well controlled. Strabismus can only be operated after surgical treatment. At the same time, it is also necessary to check stones, vegetations, pterygium, KP, anterior chamber reaction and iris adhesion, Cataract and other anterior segment problems.

v. optometry

optometry is to determine the diopter and directly affect the final surgical effect. Including small pupil optometry, mydriatic optometry, and comprehensive optometry. Generally, the first two are also divided into optometry and computer optometry. Small pupil optometry is to obtain the preliminary diopter. Mydriatic optometry removes the influence of adjustment, and will obtain a more accurate spherical lens diopter. Comprehensive optometry will determine the final treatment diopter.

VI Corneal topography

corneal topography is the best means to screen potential keratoconus (preclinical keratoconus). No matter which manufacturer or brand of corneal topography, it is best to obtain both the data of anterior corneal surface and posterior corneal surface (it’s better to detect it directly rather than through conversion), because there is a case of posterior keratoconus, that is, the front surface is “very normal”, but the rear surface has obviously expanded. If you operate rashly, there will be very adverse consequences. Corneal topography can also check corneal curvature (of course, it can also be checked by computer optometry), which is also an indicator of surgical design. Another indicator is pupil diameter (which can also be checked by Optometry), which is a reference factor for the treatment light area of surgical design.

VII. Wavefront aberration

In short, the difference between the image formed by the object and the object itself after it passes through the optical system is called aberration. The refractive system of the eye not only has low-order aberrations (we often say myopia, hyperopia and astigmatism), but also has high-order aberrations, such as spherical aberration, Hui aberration, clover, clover, clover and so on (frame glasses or corneal contact lenses) and conventional excimer laser surgery can only correct low-order aberrations such as myopia, hyperopia and astigmatism, but can not correct high-order aberrations. Only personalized laser surgery guided by wavefront aberrations can remove high-order aberrations and make postoperative vision clearer and visual quality better. Of course, we should not blindly pursue the guidance of wavefront aberrations Surgery should be rationally selected according to your actual situation.

VIII Dry eye related tests

and

generally include tear secretion test (Schirmer test) and tear film rupture (but test). Simply understand, tear secretion test is to check whether the amount of tears is enough, and tear film rupture is to check whether the function of tears is normal. Severe dry eye is a contraindication to myopia surgery.

IX. intraocular pressure

and

Generally, it includes non-contact intraocular pressure (NCT) and contact intraocular pressure. If glaucoma is suspected, further investigation is needed to diagnose glaucoma. Myopia surgery can also be considered when intraocular pressure is well controlled. Another purpose of preoperative intraocular pressure examination is to provide reference and comparison for postoperative medication.

X. A-ultrasonic thickness measurement / axial length

Although corneal topography can also measure corneal thickness, the recognized gold standard is A-ultrasonic thickness measurement. The importance of corneal thickness is self-evident. Laser surgery achieves the purpose of treatment by cutting a certain corneal thickness. The higher the degree, the greater the degreeThe more tissue is cut, and the remaining corneal thickness must be in a safe range. Therefore, if the corneal thickness is thinner than the degree of myopia, it is not suitable for laser myopia treatment. The axial length is particularly important for high myopia. Generally, the axial length of high myopia will increase, not by 1mm, more than 300 degrees. If the visual acuity decreases after high myopia surgery and becomes myopic again, The length of ocular axis can be measured (compared with that before operation) to confirm whether it is postoperative refractive regression or re myopia caused by ocular axis growth.

Xi. Fundus examination

Patients with myopia, especially those with high myopia, are more likely to have fundus lesions. The purpose of fundus examination is to exclude fundus diseases, such as fundus hemorrhage, retinal hole and detachment. However, myopia surgery can not improve or aggravate the complications caused by myopia itself (such as vitreous opacity, retinal hemorrhage, degeneration, hole and detachment, complicated cataract, etc.), so it is recommended that patients still need to have fundus examination regularly after operation.