Glaucoma due to penetrating keratoplasty

Introduction to glaucoma caused by penetrating keratoplasty Penetrating keratoplasty caused by glaucoma (Penetratingkeratoplastyglaucomadueto) is a secondary adverse event after penetrating keratoplasty. It is a serious adverse complication after surgery. Patients may have obvious vision loss or even blindness. Clinically, patients with corneal transplantation have eye pain, headache, and decreased vision, especially with nausea and vomiting. It is necessary to pay attention to the possibility of glaucoma after penetrating keratoplasty. basic knowledge Sickness ratio: 0.001%-0.005% Susceptible people: no specific people Mode of infection: non-infectious Complications: malignant glaucoma

Causes of glaucoma caused by penetrating keratoplasty

(1) Causes of the disease

1. The angle of the anterior chamber is closed by extensive pre-iris adhesion and peripheral anterior adhesion caused by postoperative anterior chamber inflammation, causing the angle of the anterior chamber to close.

2. Pupil block the pupillary block caused by the pupillary glass body obstruction of the pupil and inflammation caused by the pupillary membrane closure.

3. Surgical factors The suture is not tight or the suture ligation is not tight, the anterior chamber is poorly formed or the corneal curvature is flattened after surgery, and the surrounding anterior chamber becomes shallow.

4. Long-term use of hormones.

5. The original glaucoma exists.

In addition to the above reasons, secondary glaucoma after penetrating keratoplasty, especially aphakic eyes, is also related to the following two mechanisms:

1 The trabecular meshwork collapsed, because the posterior elastic membrane was cut to lose support in front of the trabecular meshwork, and the removal of the lens and the disappearance of the tensile ligament tension caused the back of the trabecular meshwork to lose support, thus causing the trabecular meshwork to collapse. Water discharge is affected;

2 Conventional suturing methods may cause the iris cornea to be compressed, resulting in increased intraocular pressure after surgery.

(two) pathogenesis

The pathogenesis of glaucoma after penetrating keratoplasty is very complicated, and often a variety of mechanisms lead to increased intraocular pressure. Common mechanisms are:

1. The trabecular meshwork of the trabecular mesh collapsed normal eye has the anterior support of the posterior corneal elastic layer and the posterior support structure of the complete system of the lens-suspension ligament, thus maintaining the corresponding shape and functioning as a normal aqueous drainage function, Olson And Kaufman proposed the concept of "trabecular mesh collapse". It is believed that the occurrence of glaucoma after corneal transplantation is related to the collapse of trabecular meshwork. Penetrating keratoplasty cut off the posterior elastic layer and caused the trabecular meshwork to lose its front support. It was found that the decrease of aqueous humor outflow after corneal transplantation was more obvious, which may be related to the fact that the posterior corneal elastic layer is more likely to reduce the anterior support of the trabecular meshwork. If it is aphakic, the removal of the lens causes the trabecular meshwork to lose its suspension. The tension of the ligament weakens the back support, so the trabecular meshwork that loses both front and rear supports is more likely to collapse, resulting in a decrease in the fluency coefficient of the aqueous humor and an increase in intraocular pressure. Clinical studies have also shown that the surgical method of cataract significantly affects the wear. The incidence of glaucoma after keratoplasty combined with cataract extraction, combined with intracapsular enucleation, the incidence rate of 74%, combined with extracapsular removal Compared with 45%.

2. Pre-iris mucosal anterior adhesion of the iris caused obvious obstruction of the iris corneal water. There are two forms, one is the more common iris and corneal graft/plant bed adhesion, which is characterized by shallow anterior chamber but still Exist, the main reason is due to thickening of corneal implants or implant edema, or thickening of inflammatory edema of the iris, or poor matching of corneal grafts/plant beds, so that the two are easier to contact and adhere; or when suturing the graft Sewing the iris tissue together, once the iris and the corneal graft/plant bed are stuck together, it is likely to further extend to the whole week to form a ring adhesion, resulting in an acute increase in intraocular pressure, and another form is peripheral pre-irisal adhesion. There are often different degrees of pre-irisal adhesion before the operation of the eye. Although the peripheral iris adhesion is separated during operation and the anterior chamber is reconstructed in time, it is easier to form the pre-irisal adhesion, even the pre-adhesion, and the peripheral pre-iris adhesion. Can occur after combined cataract extraction or intraocular lens implantation, multiple intraocular surgical trauma, the possibility of pre-irisal adhesion during anterior chamber hemorrhage and severe inflammation exudation, Penetrating keratoplasty uses a slightly larger graft than the implant to aid in the recovery of the anterior chamber depth, avoiding postoperative pre-irisal adhesions in the surrounding anterior chamber.

3. Diffuse leakage of other corneal grafts and implant bed sutures can cause the iris to move forward, leading to shallow anterior chamber, closed angle of the anterior chamber, shallow anterior chamber present before surgery, narrow angle of the anterior chamber, low angle during keratoplasty Pressure-induced choroidal detachment can also advance the position of the lens, aggravating pupillary block. The inflammatory reaction after corneal transplantation makes the pupillary margin adhere to the lens, intraocular lens or vitreous anterior membrane, or the formation of vitreous ridge in the pupil area. Pathological pupillary block, in addition, the inflammatory response can also involve the ciliary body, resulting in ciliary body edema, sputum and the scleral process as the center of the shift, rotate, press the surrounding iris, so that the iris corneal angle is closed, wear Corticosteroids are used after keratoplasty to prevent immune rejection and to treat postoperative inflammatory responses, and may also cause corticosteroid glaucoma in sensitive individuals.

Glaucoma prevention caused by penetrating keratoplasty

Glaucoma after penetrating keratoplasty is one of the refractory glaucoma. In view of its possible mechanism, effective measures can be taken during corneal transplantation or postoperative surgery to minimize the incidence of glaucoma. These measures include: Perform necessary pre-iris adhesion separation and iris formation, good corneal graft suture and anterior chamber reconstruction to avoid the increase of pre-iris adhesion; maintain normal anterior chamber depth when suture is sutured, and avoid over-tightening of suture The iris corneal angle is crowded and deformed; the viscoelastic agent in the anterior chamber should be as clean as possible at the end of the operation; in the aphakic cornea transplantation, a 0.5 mm larger graft than the implanted bed is beneficial to the opening of the angle. If the incision is poorly combined, the graft is displaced, the aqueous humor leaks, and the anterior chamber is delayed, the wound should be repaired in time to avoid the adhesion of the iris before and after the iris; if the pupil block should be performed early, the iris resection (open) should be performed; Proper anti-inflammatory treatment, rational use of preventive hypotensive drugs.

Glaucoma complications caused by penetrating keratoplasty Complications, malignant glaucoma

Implanted bulge, anterior chamber shallow or poor formation, corneal spasm and pre-iris adhesion.

Glaucoma symptoms caused by penetrating keratoplasty Common symptoms Corneal hypertensive intraocular pressure increased intraocular pressure without lensy nausea keratitis corneal ulcer eye opacity corneal opacity

1. Risk factors Common risk factors for glaucoma after penetrating keratoplasty include: aphakic eyes, preoperative glaucoma, combined surgery, pre-irisal adhesion, anterior segment of infectious inflammation, large graft corneal transplantation and surgery itself Etc., the incidence of glaucoma after aphakic corneal transplantation varies from 25% to 70%, and is reported to be as high as 60% to 90% in the early postoperative period. Patients with a history of glaucoma before surgery have elevated intraocular pressure after corneal transplantation. The incidence rate ranges from 20% to 80%, which is 3 to 10 times that of patients without glaucoma. It is believed that the greater the dose required to control intraocular pressure before surgery, the higher the risk of postoperative IOP loss. There is a dose-effect relationship in these glaucoma patients. Even if the preoperative glaucoma has been operated to control intraocular pressure, the incidence of postoperative intraocular pressure rise is still significantly increased. Corneal transplantation combined with other internal eye surgery is due to intraocular operations. The injury is large, the postoperative inflammatory response is heavy, and the damage to the trabecular tissue is also large, so the incidence of glaucoma is high. Some authors have observed 155 consecutive cases of keratoplasty, and 12% have early glaucoma. 5% of penetrating keratoplasty alone, combined with cataract extraction and intraocular lens implantation, 19% with iris separation, 25% with combined vitreous surgery, glaucoma, preoperative iris Pre-adhesion is also a risk factor for glaucoma after corneal transplantation. The greater the extent of pre-iris adhesion, the greater the possibility of postoperative intraocular pressure elevation. Recent studies have shown that in monosporous keratitis, stromal keratitis Penetrating keratoplasty during active period is more likely to occur in glaucoma, high-risk diseases such as corneal ulcer perforation, anterior chamber disappearance for emergency keratoplasty, the risk of glaucoma is greater. If the corneal lesions are extensive, it is necessary to make large plants with a diameter of 8mm or more. Corneal transplantation or full cornea, with corneal limbal grafting, the incidence of postoperative glaucoma is significantly increased, surgical design, operational problems such as corneal graft / implant bed ratio is small, or the graft is too tight when sewing is easy Iris corneal angle crowding changes, especially in glaucoma after aphakic surgery, in addition, residual muscles in the anterior chamber after corneal transplantation It is a common cause of early postoperative intraocular pressure.

2. Clinical manifestations due to corneal edema after keratoplasty, astigmatism and corneal opacity affect the common corneal features of high intraocular pressure, iris corneal angle and fundus observation and accurate measurement of intraocular pressure, visual field evaluation, plus postoperative The onset of glaucoma is insidious, and the clinical manifestations are often atypical. Clinically, patients with corneal transplantation have eye pain, headache, and decreased vision, especially with nausea. When vomiting, attention should be paid to glaucoma after penetrating keratoplasty. Probably, the examination found corneal epithelial edema, graft bulging, suture collapse, wound rupture, anterior chamber shallow or poor formation, pupillary block, or long-term postoperative corneal fistula and annular pre-irisal adhesion, especially Be alert to the occurrence of glaucoma.

The main diagnostic indicator for glaucoma after penetrating keratoplasty is intraocular pressure. The diagnostic criteria are currently inconsistent. At present, most scholars claim that one of the following conditions can be diagnosed:

1 3 days after surgery for 2 consecutive days, the intraocular pressure is higher than 26mmHg, requiring anti-glaucoma treatment (drugs and surgery);

2 The clinical manifestations of acute high intraocular pressure on the first day after surgery, the intraocular pressure greater than 30mmHg need to be treated with surgery;

3 There is a history of glaucoma before surgery. The postoperative condition is aggravated. The intraocular pressure is greater than 26mmHg. Other drugs or surgery are needed to control the eye pressure. However, the accurate use of tonometer to measure intraocular pressure is the key to the diagnosis of glaucoma after penetrating keratoplasty. Clinically, the Goldmann applanation tonometer is the gold standard for measuring intraocular pressure. It requires a central cornea (with a diameter of at least 3 mm) with smooth surface, regular curvature, no astigmatism and normal tear film, but penetrating keratoplasty. Severe astigmatism often exists in the early postoperative period. Postoperative corneal epithelial damage and tear film structure damage affect the observation of fluorescein ring, which limits the application of applanation tonometer. Non-contact tonometer is less suitable for ocular surface. In the case of irregularly structured penetrating keratoplasty, the commonly used indented Schiötz tonometer can be used for intraocular pressure measurement in such cases, but the intraocular pressure measured after corneal transplantation with significant changes in corneal curvature is Inaccurate, the pen-type Tono-pen tonometer is a portable electric tonometer with a small contact area with the cornea (head diameter 1.5mm), easy to operate, does not require fluorescein, and A sterile disposable latex sleeve can be used to avoid post-operative cross-infection. A comparison study between a normal cornea and a Goldmann tonometer shows a good agreement between the two. Tono-pen tonometer is used for the cornea. Intraocular pressure measurement after transplantation, the results also have good accuracy and repeatability.

Examination of glaucoma caused by penetrating keratoplasty

1. Intraocular pressure measurement is the main diagnostic indicator for glaucoma after penetrating keratoplasty.

2. The iris corneal angle can be observed under the condition of the graft, and the fundus condition can be understood, and the visual field examination can be performed at the same time.

3. UBM examination due to corneal scar and edema and other reasons limit the observation of the angle structure, can be more satisfactory to detect the anterior segment of the eye including the cornea, iris, anterior chamber, iris corneal angle, posterior chamber, ciliary body and lens Morphological structure and their relationship provide a good means for the diagnosis and classification of glaucoma after corneal transplantation.

Diagnosis and diagnosis of glaucoma caused by penetrating keratoplasty

The disease is easily confused with acute iridocyclitis or acute conjunctivitis and needs to be identified. Need to identify different types of glaucoma. Iridocyclitis, the inflammation of the iris often affects the ciliary body, so clinically separate iritis or ciliary body is rare. Often at the same time. Acute conjunctivitis is caused by wind and heat. It refers to the red eye pain of both eyes, the shame and tears, and the fever and headache syndrome. It often occurs in the hot summer and autumn seasons. According to its clinical characteristics, as well as the onset of the disease can be identified clearly.

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