Complications after surgery for glaucoma

Statistics show that when performing surgery for glauclia early in life, good close and long-term results are obtained, in most cases stabilization of visual functions is noted. However, complications after surgery are possible.

[1], [2], [3],

Shredding the depth of the front chamber

One of the frequent complications after trabeculectomy may be associated with: a pupillary block, hyperfiltration, malignant glaucoma. The pronounced continuous shredding of the depth of the anterior chamber is infrequent and usually restored independently. In other cases, more serious complications may arise: the formation of anterior peripheral synechia, endothelial dystrophy of the cornea, cataracts, hypotension and associated maculopathy.

[4], [5], [6], [7], [8]

Evaluation

There are 3 degrees of chopping the depth of the anterior chamber.

• Degree 1: Iris shift to the posterior surface of the cornea.
• Degree 2: contact between the edge of the pupil and the cornea.
• Degree 3: cornealenticular contact, which can lead to endothelial dystrophy and cataract formation.

Causes

• Obvious peripheral iridectomy and iris configuration, which excludes the appearance of the pupillary block.
• Monitoring the condition of the filter cushion.
• A sample of Seidel with the instillation of a 2% solution of fluorescein into the conjunctival cavity or the filtration pad. In the presence of external filtration in the empty light of a slit lamp, fluorescein dissolved in aqueous humor is detected, which has a bright green color, unlike a 2% solution of fluorescein with a less intense color.
• Control of intraocular pressure.
• Inspection of the fundus to exclude detachment of the choroid.

[9], [10], [11], [12]

Iridectomy Hole

Reason: non-functioning peripheral iridectomy.

Symptoms: high intraocular pressure, flat filter cushion, negative Seidel test, iris bombardment, presence of nonperforating iridectomy.

Treatment: Argon laser excision of the pigmentary leaf in the area of the existing iridectomic aperture with incomplete perforation or a new laser iridectomy.

Pupil block

Causes

• The excessive filtration through the scleral flap zone occurs due to its insufficient adaptation. It can be prevented by tight suturing of the scleral bed. In the early postoperative period, it is possible to increase the outflow by dissecting scleral sutures with an argon laser or weakening them at sliding nodes. These actions are effective up to 10 days after the operation;
• excessive filtration through the pillow (external filtration) in the presence of an opening in the conjunctival seam zone or with insufficient sealing of the conjunctiva and tenon capsule.

Symptoms

• Hypotension.
• The filtration cushion is expressed because of excessive filtration in the scleral flap zone.
• The Seidel sample is negative for hyperfiltration in the scleral flap zone and positive for external filtration.
• Folds of descemet membrane in hypotension.
• In some cases - detachment of the choroid.

Treatment depends on the cause and degree of grinding of the anterior chamber.

• initial conservative therapy is performed in the absence of iridocorneal contact;
  • Instillation of atropine 1% to maintain mydriasis and prevent pupillary block.
  • The instillation of beta-blockers or the intake of acetazolamide inwards to reduce the production of aqueous humor and accelerate healing with a temporary decrease in outflow through the fistula.
  • Point external filtration zones are extinguished with cyanoacrylate or glue fibrin, but large conjunctival defects or diastasis of the wound are surgically eliminated.
  • Often these measures lead to the recovery of the anterior chamber within a few days.
• the subsequent therapy is carried out in the absence of efficiency from the conservative one. A conjunctival tamponade is possible to speed up the healing by pressure on the surgical intervention zone. Apply as a bandage soft contact lenses with a large diameter, collagen frame or a special shield Simmons. If the measures taken do not lead to the deepening of the anterior chamber within a few hours, further actions are ineffective;
• the final therapy is carried out with a progressive grinding of the anterior chamber and the risk of cornealenticular contact (or already present):
  • The anterior chamber of the eye is filled with air, sodium hyaluronate or gas (SF ₆ ).
  • The choroidal detachment is drained only at a very high level or the danger of contact of the blisters ("kissing" choroid).
  • The scleral flap and conjunctiva are sutured repeatedly, which can be difficult to perform because of the loose structure of the operated tissues.

Ciliary block

Syndrome of atypical outflow of watery moisture is a rare, but very serious complication.

Causes: blockade of outflow of watery moisture through the pars plicata of the ciliary body with the reverse (retrograde) outflow into the vitreous.

Symptoms: shallow anterior chamber in combination with high intraocular pressure, absence of a filtration cushion and negative breakdown of Seidel.

[13], [14], [15], [16], [17], [18], [19]

Treatment

Initial conservative therapy.

• The instillation of mydriatic (atropine 1% and phenylephrine 10%) to maximize cycloplegia. This increases the distance between the ciliary processes and the equator of the lens, compressing the zonular zone and returning the lens to its normal position.
• With the inefficiency of mydriatic injected intravenously, mannitol to reduce the vitreous volume and the displacement of the lens back.
• Reducing the production of aqueous humor to control intraocular pressure.

Follow-up therapy with ineffectiveness of drug treatment.

• Nd: YAG-Aa3epOM through the iridectomic aperture destroy the hyaloid membrane and eliminate the ciliary block. At artifacii, the posterior capsulotomy is first performed, then the anterior hyaloid membrane is destroyed.
• The vitrectomy of the pars plana is performed when the laser therapy is ineffective. A sufficient volume of the removed vitreous body allows watery moisture to move freely to the anterior chamber. If vitrectomy is not possible due to fluid accumulation, aspirate with a needle, proceeding 3.5 mm just beyond the limb area towards the center of the eyeball.

"Dysfunction" of the filtration cushion

[20], [21], [22]

Clinical course

Satisfactory filtration: low intraocular pressure and a pronounced filter cushion of types 1 or 2.

• type 1 - thin-walled and polycystic pillow, often with transconjunctival filtration;
• type 2 - low, thin-walled, diffuse filtration zone, avascular with respect to the surrounding conjunctiva. Conjunctival epithelial microcysts are clearly visible at high magnification.

"Dysfunction" of the filtration cushion: increased intraocular pressure and filter cushion types 3 or 4.

• type 3 - because of episcleral fibrosis, the scleral flap is not associated with microcasts and has a characteristic expansion of the superficial blood vessels;
• type 4 - encapsulated filtration cushion (tenon cyst), which occurs 2-8 weeks after the operation as a limited, fluid-filled formation, with indentations in the hypertrophic tenon capsule and surface blood vessels.

In the depressions watery moisture retards and blocks the filtration, sometimes the level of the ophthalmotonus does not change due to the sufficient functioning of the neighboring zones. Risk factors: previous operations with dissection of the conjunctiva, laser trabeculoplasty, the use of local sympathomimetics and an encapsulated filtration pillow on the paired eye.

[23], [24], [25], [26], [27], [28], [29]

Causes of failure

Extraocular

• Subconjunctival and episcleral fibrosis is the most common cause of failure, but a properly formed pillow is never delimited. Intra- or postoperative subconjunctival hemorrhages increase the risk of subsequent fibrosis.
• Encapsulation of the filter cushion.

Scleral

• Excessive tension of the scleral flap.
• Gradual scarring in the area of the scleral bed, which leads to blockade of the fistula.

Intraocular

• Blockade of the sclerostomy hole with a vitreous body, blood or uveal tissue.
• Blockage of the inner opening by various thin membranes from surrounding tissues (cornea or sclera). This may be the result of poor surgical technique.

[30], [31], [32], [33], [34], [35], [36], [37]

Tactics with adverse outcomes

Depends on etiology and is eliminated by the following.

Compression of the eyeball to enhance the outflow of watery moisture through the created fistula.

• finger massage - compression through the lower eyelid with closed eyes when looking forward. The pressure is exerted for 5-10 seconds, after that the filtration zone is monitored. If the fistula is completely closed, the level of intraocular pressure and the state of the filtration cushion will not change. With effective compression, intraocular pressure will decrease, and the filtration shaft will increase. The patient needs to repeat the massage several times a day;
• local compression with biomicroscopic control under local anesthesia using an application with a moistened cotton swab that is placed in the area of the scleral flap projection to improve the outflow.

Manipulations with scleral sutures are possible on the 7-14th day after surgery if there is high intraocular pressure, a flat cushion and a deep anterior chamber.

• Adjustable seams can be loosened or removed depending on the technique of their application;
• Argon-laser sutulolysis of scleral sutures is possible if adjustable seams are not used. Dissection of such sutures is carried out through a special goniolinzu Hoskins or four-mirror goniolinzu. The laser exposure duration is 0.2 sec, the spot size is 50 μm and the power is 500-700 mW.

Nidling cystic pad is performed under local anesthesia and biomicroscopic control. Subconjunctival 1 ml of a balanced solution is administered. The needle is also used to create micro-cuts of 2 mm in the fibrous wall of the cystic pad without disrupting the integrity of the conjunctiva.

Subconjunctival injections of 5-fluorouracil 7 to 14 days after the operation to suppress episcleral fibrosis are used at a dose of 5 mg (0.1 ml per 50 mg / ml) by injecting the needle 10 mm from the filtration pad.

NdrYAG-laser is used in two cases:

• an internal action to open a fistula blocked by any tissue found during gonioscopy, although a filter cushion is formed;
• external transconjunctival effect with late episcleral fibrosis of the filtration cushion.

Audit of the surgical intervention zone to control the existing fistula or the formation of a new one with a different localization. In such cases, additional antimetabolite therapy may increase the success of the surgical intervention.

Medicamentous therapy is prescribed with insufficient effectiveness of the operation performed.

Late outer filter cushion fistula

Reason: conjunctival diastasis over the sclerostomy zone after administration of antimetabolites, especially mitomycin C, and necrosis of superficial epithelium of the conjunctiva.

Complications of undiagnosed fistulas: corneal dystrophy, formation of anterior peripheral synechia, hemorrhagic suprachoroidal detachment, chorioretinal folds, hypotension, maculopathy, intraocular infection.

Symptoms

• Hypotension and avascular cystic pad.
• The sample of Seidel is initially negative, note only numerous zones of blurred spots (sweating). Later, when forming the hole, a positive sample with a pronounced external fistula is fixed.
• In some cases, a small anterior chamber and a choroid detachment are noted.

Treatment is difficult (none of the methods presented below is universal).

• initial measures with pronounced hyperfiltration in the early postoperative period are rarely successful;
• The subsequent actions depend on whether the filtration is just a sweat or it is due to a formed hole.
  • "Flowing" filtration cushions can be blocked by injection of autoblood, using tissue glue or tightening seams.
  • In the presence of a full hole, a revision of the operating zone with the plastic of the filtration cushion with a conjunctival flap, excision of the existing cushion and suturing of the sclera is required to limit the outflow through the scleral opening.

Hypotension and avascular cystic pad

A thin-walled filter cushion with a positive Seidel probe after using antimetabolites is a potential entrance gate of the infection. The patient needs to be warned that he needs to see a doctor if redness, separation or blurring of vision occurs. It is necessary to avoid traumatic manipulations (for example, wearing contact lenses or gonioscopy).

Other risk factors: complete drainage (eg, scheie sclerosis), low or atypical location of the filtration zone and prolonged instillation of antibiotics after surgery.

Blebites

The vitreous humor is not involved in the process.

They show moderate discomfort and redness, which usually last for several days.

Symptoms

• Fouling of the filter cushion (the so-called "milk" pillow).
• Symptoms of anterior uveitis may be absent (stage 1) or manifest (stage 2).
• Reflex from the fundus is not changed.

Treatment: fluoroquinolone or other drugs used in the treatment of bacterial keratitis. Usually this is enough, but the patient needs to watch for some time to exclude the possibility of involvement in the inflammatory process of the vitreous.

[38]

Blebitis associated with endophthalmitis

Are acute, sharp deterioration of vision, pain and redness.

Symptoms

• Light yellow "milk" filtration cushion.
• Clinic of expressed uveitis with hypopion.
• Bitrate and the appearance of a pathological reflex.

Treatment: vitreous biopsy and intravitreal administration of antibiotics.

In this regard, for a greater reduction in ophthalmotonus, trabeculectomy is performed. A non-penetrating kind of intervention involves cutting out two scleral flaps and excising the deep layers of the sclera while maintaining a thin membrane consisting of the trabeculae and descemet membrane through which watery moisture seeps from the anterior chamber into the subcoejunctival space.

[39], [40], [41]

Deep sclerectomy

1. Perform a conjunctival incision with a base to the vault.
2. A thin superficial scleral flap is cut off to the transparent part of the cornea.
3. From the deep layers of the sclera, a second scleral flap 4 mm wide is cut out to the zone of the helmet canal.
4. Collagen drainage is placed in the scleral bed.
5. A free reposition of the scleral flap is made with the closure of the conjunctival incision.

[42], [43], [44], [45], [46], [47], [48], [49], [50], [51]

Viscochannelostomy

1. The conjunctival flap is formed by the base to the vault.
2. Cut out the surface flap of the sclera by 1/3 of its thickness.
3. The second flap is cut from the deeper layers so. So that it provides access to the helmet canal.
4. A special hollow needle injects a high-molecular viscoelastic into the lumen of the helmet channel.
5. Create a "window" in the Descemet's membrane by neatly dissecting the sclera under a deep scleral flap in the area above the helmet canal and then this scleral site is excised.
6. The superficial scleral flap is tightly closed to minimize the subconjunctival outflow of aqueous humor and the formation of a filtration pad.
7. Introduce the area of sclerotomy viscoelastic.
8. Conjunctiva suturing is performed.

Despite the successful treatment, the risk of recurrence of infection remains.