Treatment of closed-angle glaucoma

Iris bombardment and anterior chamber angle closure due to pupillary block lead to a sharp increase in intraocular pressure and the development of secondary glaucoma in patients suffering from uveitis. In case of impaired outflow of intraocular fluid due to pupillary block, communication between the anterior and posterior chambers can be restored using argon or neodymium YAG laser iridotomy or surgical iridectomy. Laser iridotomy may increase or aggravate inflammation in the anterior chamber. To reduce the likelihood of this complication, active treatment with glucocorticoids should be performed before and after the procedure. Unlike argon laser, neodymium YAG laser uses less energy, and therefore postoperative inflammation is expressed to a lesser degree. Since occlusion of iridotomy openings is possible with an active inflammatory process, several iridotomies should be performed to permanently restore the flow of intraocular fluid. Repeat procedures are necessary in approximately 40% of cases. To reduce the risk of damage to the corneal endothelium, laser iridectomy should not be performed in cases of severe uveitis in the active phase and corneal edema and in areas of peripheral anterior synechiae.

If laser iridotomy is unsuccessful or there are contraindications to laser treatment, surgical iridectomy is indicated. It has been shown that surgical iridectomy is effective in uveitis if the peripheral anterior synechiae cover less than 75% of the anterior chamber angle. Despite the higher efficiency of the procedure compared to laser iridotomy, severe postoperative inflammation may develop after surgical iridectomy, which is suppressed by prescribing intensive pre- and postoperative anti-inflammatory therapy. Slower cataract progression is observed with major surgical iridectomy than with laser iridotomy.

When the anterior chamber angle is closed due to anterior rotation of the ciliary body in the absence of pupillary block, laser iridotomy or surgical iridectomy is pointless. When the anterior chamber angle is closed and intraocular pressure increases for this rare reason, immunosuppressive therapy and treatment with drugs that reduce the production of intraocular fluid are performed. If drug control of intraocular pressure is impossible and the angle remains closed due to the formation of peripheral anterior synechiae, surgery may be required to improve the outflow.

It has been shown that when acute angle closure is associated with the formation of extensive peripheral anterior synechiae, goniosynechiolysis reduces intraocular pressure and restores the normal structure of the anterior chamber angle. In children and young patients with uncontrolled secondary glaucoma, trabeculodialysis is used - separation of trabeculae from the scleral spur using a goniotomy knife, which allows intraocular fluid to flow directly into Schlemm's canal.

Due to the thermal effects and the development of laser-induced inflammation, which can cause additional damage to the trabecular meshwork, argon laser trabeculoplasty is not recommended for patients with secondary glaucoma or ocular hypertension due to uveitis.

The main pathological mechanism in secondary inflammatory glaucoma is ocular hypertension. Patients with uveitis are relatively young and usually lack primary optic nerve head pathology, so they have a longer resistance to ocular hypertension, as well as resistance to higher levels of intraocular pressure without surgical intervention. However, if it is impossible to control intraocular pressure at the maximum level with medication, or if the optic nerve is damaged or visual field defects appear, surgical intervention is necessary to normalize intraocular pressure.

Surgical interventions performed in patients with inflammatory glaucoma include trabeculectomy with or without antimetabolites and implantation of Ahmed, Baerveldt and Molteno tube drainage devices. The best surgical treatment for patients with secondary glaucoma has not yet been found.

When performing any surgical procedures in patients suffering from uveitis, there is a risk of developing postoperative inflammation one week after surgery. It is estimated that in 5.2-31.1% of cases of surgical treatment of glaucoma associated with uveitis, postoperative inflammation or exacerbation of uveitis develops. The risk of developing postoperative inflammation is reduced if the eye is calm before surgery. In some cases, it is necessary to have no exacerbation of uveitis for at least 3 months before surgery. In order to reduce the risk of developing postoperative inflammation, local and/or systemic immunosuppressive therapy is increased one week before the planned surgery, which is then gradually reduced in the postoperative period in accordance with the inflammatory response. Periocular glucocorticoids are administered intraoperatively. When performing urgent antiglaucoma interventions with an active inflammatory process, an exacerbation of the disease should be expected, therefore, in the postoperative period, intensive local use of high doses of glucocorticoids (0.5-1.5 mg/kg) orally or even intravenously may be necessary.

A good effect is achieved when using trabeculectomy in patients with inflammatory glaucoma (73-81%). However, the reliability of these data is unknown. When trabeculectomy is performed in patients with uveitis, postoperative inflammation accelerates the healing of the surgical opening, leading to the absence of the effect of the filtering operation. The effectiveness of trabeculectomy in patients with uveitis can be increased by intensive preoperative anti-inflammatory therapy and therapy with antimetabolites, such as mitomycin, which is more effective than 5-fluorouracil. In addition to increasing the effectiveness of filtering operations, the use of these drugs increases the risk of postoperative hypotension, external filtration and endophthalmitis, the incidence of which after trabeculectomy reaches 9.4%. Progression of cataracts is also often observed after operations aimed at improving filtration in inflammatory glaucoma.

When filtration-improving surgeries are ineffective in treating patients with secondary glaucoma, drainage implantation is performed. It has been shown that these surgeries are more effective than repeated trabeculectomy in patients with uveitis. Postoperative complications, such as choroidal detachment, choroidal hemorrhage, and slit-like anterior chamber, are more common in inflammatory glaucoma than in primary open-angle glaucoma.

In case of unsuccessful drug and surgical treatment, as a last resort to normalize intraocular pressure, destruction of the ciliary body is performed. Cyclocryotherapy. Contact and non-contact laser cycloablation equally effectively reduce intraocular pressure. The main disadvantage of these treatment methods is the induction of a pronounced inflammatory response and the development of subatrophy of the eye in approximately 10% of cases.