Analysis on the causes of visual acuity decline after myopia surgery

Abstract: if you do not pay attention to scientific eye use after myopia surgery, new myopia may occur. Although myopia surgery is to correct ametropia (myopia, hyperopia, astigmatism) is an effective method, but it can not cure ametropia from the etiology. The purpose of the operation is to remove the existing glasses or reduce the degree of the existing glasses. Although with the development of technology and equipment, the concern about the safety and predictability of myopia surgery has gradually faded out of people’s vision, the possibility of vision loss after operation exists , some may appear in the early stage after surgery, some may appear several years later, some may be related to surgery, some may be caused by other eye diseases… Today I want to make a small summary, hoping to help you more clearly understand laser myopia surgery., I. under correction and over correction, which is the most direct cause of vision loss, is related to the surgical design. Generally, vision loss can occur early after operation. Under correction after operation means that there is still a certain degree of myopia. Poor vision may occur after operation, which may become more obvious over time. Over correction after operation will lead to hyperopia. At the initial stage of operation, better vision can be achieved through adjustment. However, if more eyes are used, especially for patients working close, over adjustment may lead to adjustment spasm, and some even show “myopia”, resulting in decreased vision. Preoperative personalized design of surgical plan according to the patient’s age and occupation can well solve this problem., II. Refractive regression. There are generally two cases of refractive regression: excessive proliferation and posterior swelling of corneal tissue. In popular terms, Laser surgery is precisely grinding a contact lens on the cornea (myopia surgery is to grind a concave lens), that is, a little more in the middle and a little less in the periphery. The cutting part is the corneal stroma, which has no regeneration ability, but a very few people may have excessive tissue proliferation due to individual differences, thus weakening the treatment effect. On the other hand, the residual corneal thickness after laser cutting must be within a safe range Therefore, accurate preoperative examination and simulation calculation are particularly important. Otherwise, the cornea may swell forward due to intraocular pressure after operation, which is similar to the growth of ocular axis, showing certain myopia, resulting in decreased vision., III. corneal reaction. Corneal reaction is mainly DLK after LASIK and haze after surface surgery. DLK is a sterile inflammatory reaction between corneal layers (diffuse interlaminar keratitis) usually occurs in the early postoperative period. With the application of laser equipment and disposable corneal scalpel, the incidence of DLK has been very small. Haze is the corneal subepithelial haze after surface surgery. If haze is serious, it will lead to the decline of visual acuity, and haze is also a cause of refractive regression. Whether it is DLK or H Once aze occurs, hormonal ophthalmic drugs should be applied immediately, and the therapeutic effect is good.,

although with the development of technology and equipment, the concern about the safety and predictability of myopia surgery has gradually faded out of people’s vision, there is a possibility of vision loss after surgery, some may appear in the early postoperative period, some may appear several years later, and some may be related to surgery, Some may be caused by other eye diseases… Today I want to make a small summary, hoping to help you have a clearer understanding of laser myopia surgery.

I. under correction and over correction

this is the most direct cause of vision loss, which is related to the surgical design. Generally, vision loss can occur early after operation. Under correction after operation means that there is still a certain degree of myopia. Poor vision may occur after operation, which may become more obvious over time. Over correction after operation will lead to hyperopia. At the initial stage of operation, better vision can be achieved through adjustment. However, if more eyes are used, especially for patients working close, over adjustment may lead to adjustment spasm, and some even show “myopia”, resulting in decreased vision. Preoperative personalized design of surgical scheme according to the patient’s age and occupation can well solve this problem.

2. Refractive regression

refractive regression generally has two situations: excessive proliferation and posterior swelling of corneal tissue. In popular terms, Laser surgery is precisely grinding a contact lens on the cornea (myopia surgery is to grind a concave lens), that is, a little more in the middle and a little less in the periphery. The cutting part is the corneal stroma, which has no regeneration ability, but a very few people may have excessive tissue proliferation due to individual differences, thus weakening the treatment effect. On the other hand, the residual corneal thickness after laser cutting must be within a safe range Therefore, accurate preoperative examination and simulation calculation are particularly important. Otherwise, the cornea may swell forward due to intraocular pressure after operation, which is similar to the growth of ocular axis, showing a certain myopia, resulting in decreased vision.

III. corneal reaction

corneal reaction is mainly DLK after LASIK and haze after surface surgery. DLK is a sterile inflammatory reaction between corneal layers (diffuse interlaminar keratitis) usually occurs in the early postoperative period. With the application of laser equipment and disposable corneal scalpel, the incidence of DLK has been very small. Haze is the corneal subepithelial haze after surface surgery. If haze is serious, it will lead to the decline of visual acuity, and haze is also a cause of refractive regression. Whether it is DLK or H Once aze occurs, hormone ophthalmic drugs should be applied immediately, and the therapeutic effect is good.

IV. dry eye

dry eye may be ignored by many people, because most of the vision loss caused by dry eye is transient. No matter what type of dry eye, it will eventually lead to tear film instability and irregular corneal surface, resulting in vision loss. After myopia surgery, because the corneal nerve is cut off, the tear film will appear transient instability before the nerve is completely repaired. Therefore, during this period, artificial tears should be used to alleviate eye discomfort and promote corneal nerve repair. It must be emphasized that if there is serious dry eye before operation, it is a contraindication for myopia operation.

v. myopia

such asIf you don’t pay attention to scientific eye use after myopia surgery, you may have new myopia. Although myopia surgery is to correct ametropia (myopia, hyperopia, astigmatism) is an effective method, but it can not cure ametropia from the cause. The purpose of the operation is to remove the existing glasses or reduce the degree of the existing glasses. After the operation, it is equivalent to returning to the refractive state of normal people. If the eyes are excessively tired and do not pay attention to protection, new myopia will appear on the basis of the normal refractive state (from another perspective, it will be easier to understand that if the patient does not undergo surgery and uses his eyes excessively, the degree of myopia may deepen). Another situation should also be paid attention to: high myopia, especially ultra-high myopia, is inevitable to produce some new degrees of myopia due to the continuous growth of ocular axis after surgery.

VI. other eye diseases

Myopia surgery itself does not improve It will not aggravate the complications caused by myopia (especially high myopia) (such as vitreous opacity, retinal hemorrhage, degeneration, hole and detachment, complicated cataract, etc.). In other words, even without surgery, these eye diseases related to myopia may occur, and there is no significant difference in the incidence. Therefore, myopia patients, especially patients with high myopia, should have regular eye health examination whether they are operated or not, so as to reduce the incidence of related eye diseases Adverse effects of disease.