Glaucoma: operations

Modern operations used for glaucoma include:

1. improving intraocular fluid outflow;
2. reduction of intraocular fluid production.

If the production of intraocular fluid decreases, innervation is disturbed, corneal dystrophy develops, etc. On the seeing eye, operations on the ciliary body are undesirable.

To increase the intraocular fluid, surgical interventions are done at the place of intraocular fluid retention.

Another concept is to create new outflow paths:

1. anastomoses around the anterior chamber angle and veins of the portico;
2. myocleisis - a part of the internal rectus muscle with a vascular bundle is transplanted into the anterior chamber angle;
3. part of the episclera along with the vessels immersed in the anterior chamber angle
4. insert various tubes (drainage), create valves.

[1], [2], [3], [4], [5], [6], [7]

Preparing the patient for surgery

1. As much as possible lower intraocular pressure and reduce high blood pressure. 2-3 weeks cancel anticholinergic drugs, as they increase bleeding.
2. 30 minutes before the operation prescribed diphenhydra with promedol and glycerol.
3. General anesthesia (and combined) is desirable.
4. Rational anesthesia - retrobulbar, aminesia (motor muscles are included).
5. Slow opening of the front camera:
   • steroidal anti-inflammatory therapy; surgery;
   • infection prevention (broad-spectrum antibiotics for conjunctiva).

[8]

Types of operations for glaucoma

1. Angular retention - relative and absolute; differential diagnosis - Forbes test. In case of functional block, iridectomy, in organ synechia, iridocycloretraction.
2. Scleral transplants are cut out by 2/3, then they are inserted into the anterior chamber angle, thereby creating additional drainage.
3. Pretrabecular blockade - goniotomy,
4. Trabecular retention - trabeculotomy, destruction of the inner wall of Schlemm's canal.
5. Intra scleral retention - sinusotomy; sinusstrabectomy - excised scleral flap, Schlemm's droplet, trabecula. The effectiveness of this operation - 95%, long-term results - 85-87%, if it is performed in the initial and advanced stages of glaucoma.

Operations aimed at reducing the production of ciliary muscle:

1. cycloanemization (diathermocauterization of the ciliary arteries is performed, which leads to atrophy of a part of the ciliary body and a decrease in the production of intraocular fluid);
2. it is possible to influence the ciliary body through the sclera with cold (cryopexy) or temperature increase, laser (coagulation of the ciliary body).

Laser microsurgery (operation) of glaucoma

Laser microsurgery of glaucoma is primarily aimed at eliminating intraocular blocks in the path of movement of the internal moisture from the back chamber of the eye to the episcleral veins. For this purpose, lasers of various types are used, but argon lasers with a wavelength of 488 and 514 nm, pulsed neodymium YAG lasers with a wavelength of 1060 nm, and semiconductor (diode) lasers with a wavelength of 810 nm are most common.

Laser gonioplasty - the basal part of the cornea coagulates, which leads to an extension of the anterior chamber angle, the pupil, the trabecula is pulled in and the Schlemm's channel opens. 20-30 coagulants are applied. This operation is effective in angle-closure glaucoma with a functional block.

Laser iridectomy is the formation of a small hole in the peripheral part of the iris. The operation is shown with a functional or organic pupil block. It leads to equalization of pressure in the anterior and anterior chambers of the eye and the opening of the anterior chamber. With the preventive purpose of the operation.

Laser trabeculoplasty consists of applying several cauterizations to the inner surface of the trabecular diaphragm, as a result of which its permeability to intraocular moisture improves and the risk of blockade of Schlemm's canal is reduced. It is used for primary open-angle glaucoma that cannot be compensated with medications.

With the help of lasers, other operations can be performed (fistulizing and cyclodestructive), as well as operations aimed at correcting microsurgical "knife" operations.

[9]

Argonlaser trabeculoplasty

It consists in applying point laser coagulates to the trabecular zone, which increases the outflow of aqueous humor and reduces intraocular pressure,

• Equipment

The laser beam is directed to the transition zone of the pigmented and non-pigmented areas of the trabeculae, observing strict focusing. The presence of a blurred contour of the light spot indicates an insufficiently perpendicular pickup of the sensor,

Laser coagulates of 50 microns in size are applied with an exposure time of 0.1 s and a power of 700 mW. The reaction is considered ideal if a dot blanching occurs or an air bubble is released at the time of exposure. When a large bubble appears, the effect is excessive.

In case of insufficient response, the power is increased by 200 mW. With hyperpigmentation, 400 mW is sufficient, with non-pigmented CPC, power can be increased to 1200 mW (900 mW on average).

25 coagulates are applied at regular intervals in the imaging zone from one edge of the mirror to the other.

Goniolinsu rotate clockwise by 90 and continue the laser effect. The number of coagulates: from 25 to 50 around the circumference of 180. Constant visual control of adjacent sectors is important. A good skill allows you to perform laser trabeculoplasty with continuous rotation of the goniolinza, controlling the light beam through the central mirror.

Some ophthalmologists initially prefer coagulation over 180 ° and later, in the absence of sufficient effect, the remaining 180 °. Others offer circular coagulation with up to 100 coagulates applied first.

After the procedure, iopidine 1% or brimonidine 0.2% is instilled.

Fluorometolone is used 4 times a day for a week. The previously developed hypotensive regimen is not canceled.

• Observation

The result is evaluated after 4-6 months. If intraocular pressure is significantly reduced, the hypotensive regimen is reduced, although complete drug withdrawal is rare. The main goal of argonlaser trabeculoplasty is to obtain controlled intraocular pressure and, if possible, reduce the mode of instillation. If intraocular pressure remains high and laser intervention is performed on only 180 of the CPC, it is necessary to continue treatment for the remaining 180. Usually, repeated laser trabeculoplasty around the entire circumference of the CPC in the absence of an effect is rarely successful, then the question of filtration surgery is discussed.

• Complications

1. Goniosinechia may occur if the area of coagulum deposition is posteriorly displaced or the power level is too high. In most cases, this does not reduce the effectiveness of laser trabeculoplasty.
2. Microhemorrhages are possible if the vessels of the iris root or the ciliary body are damaged. When a gonioliosis is applied to the eyeball, such bleeding stops easily.
3. Sharp ophthalmic hypertension is possible in the absence of prior preventive installation of aproclidine or brimonilin.
4. A moderately pronounced anterior uveitis is arrested independently and does not affect the outcome of the intervention.
5. The lack of effect suggests a filtration intervention, but the risk of the development of encapsulated filtration bags after a previously performed laser trabeculoplasty is 3 times higher.

• results

In the initial stage of POAG, the effect is achieved in 7 ^ -85% of cases. The average reduction in intraocular pressure is about 30%, and with initially high intraocular pressure, the effect is more pronounced. In 50% of cases, the result is maintained up to 5 years and approximately 53% - up to 10 years. The absence of the effect of laser trabeculoplasty becomes clear already during the first year. If intraocular pressure is normalized during this period, the probability of normalization of intraocular pressure after 5 years is 65%, and after 10 years - about 40%. If laser trabeculoplasty is performed as the primary stage in the treatment of POAG, in 50% of cases additional antihypertensive treatment is required within 2 years. Subsequent laser trabeculoplasty is effective in 30% of cases after 1 year and only in 15% - 2 years after the first intervention. The effect of laser trabeculoplasty is worse in persons younger than 50 years, does not differ in Europeans and people of the Negroid race, but in the latter it is less resistant.

With normotensive glaucoma, a good result is possible in 50-70% of cases, but the absolute decrease in intraocular pressure is much less than with POAG.

In pigment glaucoma, laser trabeculoplasty is also effective, but its result is worse in older patients.

In pseudo-excoliation glaucoma, high efficacy was noted immediately after the intervention, but later a rapid decrease, as compared with POAG, was noted, with a subsequent increase in intraocular pressure.

[10], [11], [12], [13], [14]

Diodlazernnaja trabekuloplastika

Its results are similar to laser trabeculoplasty with less damaging effects on the hematophthalmic barrier. The main differences between these methods are:

• Higher laser power (800-1200 mW).
• Postcoagulative burn is less pronounced, blanching is observed in this zone, the cavitation bubble is not formed.
• The size of the light spot is 100 microns, using a special contact lens it can be reduced to 70 microns.
• The pulse duration is 0.1-0.2 seconds.

[15], [16], [17], [18]

NdrYAG laser iridotomy

Indications:

• Primary angle-closure glaucoma: acute attack, intermittent and chronic course.
• Acute glaucoma on the double eye.
• Narrow "partially closed" angle.
• Secondary angle-closure glaucoma with pupillary block.
• POAG with a narrow angle and a combined mechanism for the development of glaucoma.

Equipment:

1. Brimondip is instilled with 0.2% to reduce intraocular pressure.
2. Pilocarpine is installed to achieve maximum miosis, although after suffering an acute attack of glaucoma, this is usually not feasible.
3. Conduct local installation anesthesia.
4. Apply a special contact lens type Abraham lenses.
5. The area of the iris is chosen, preferably in the upper segment, so that this zone is covered by the eyelid to prevent monocular diplopia. Iridotomy should be performed as peripherally as possible to prevent damage to the lens, although this is not always possible due to the presence of arcus senilis. The crypt zone for iridotomy is convenient, but this recommendation is not mandatory.

[19]

Abraham laser lens for iridectomy

1. The light beam is rotated so that it is not perpendicular, but directed toward the periphery of the retina to prevent accidental burns of the macula.
2. Laser coagulates vary by laser. Most lasers have a power of 4-8 mJ. For a thin blue iris, a power of 1–4 mJ is required with one coagulation, after 2-3 coagulations, an “explosion” effect is achieved. For thick, velvet, brown iris, a higher level of energy or more coagulates is required, but there is a greater risk of intraocular damage.

Usually effective conventional application of 3 coagulates with a capacity of 3-6 mJ.

1. Laser exposure is carried out after precise focusing of the beam. A successful procedure is characterized by a release of pigment. On average, to achieve the desired effect, up to 7 coagulates are performed (Fig. 9.145), although in practice it can be reduced to 1-2.
2. After the intervention, aproclonidine 1% or brimonidine 0.2% is instilled.

Topical use of steroids according to the scheme: every 10 minutes for 30 minutes, then every hour per day of treatment and 4 times a day for 1 week.

Possible technical problems:

With an ineffective first exposure, the application of pulses is continued, departing from this area, shifting more laterally and increasing power. The possibility of continued coagulation in the previous zone depends on the degree of pigment release and hemorrhage caused by the previous pulse. With a thick brown iris, incomplete iridotomy is characterized by the appearance of a cloud of diffused pigment, which makes it difficult to visualize and focus in this area. Further manipulations through the pigment cloud often increase the amount of pigment and hemorrhage, not allowing to achieve the desired result. In this situation, after the pigment has settled, the pulses are applied to the same area, increasing the impact energy, or affecting the adjacent zone. With insufficient effect, a combination with an argon laser is possible.

Too small iridium hole. In this case, it is sometimes easier and more expedient to do additional iridotomy in another area, rather than trying to enlarge the first opening. The ideal diameter is 150-200 microns.

Complications:

• Microhemorrhages occur in approximately 50% of cases. They are usually minor, and the bleeding stops after a few seconds. Sometimes, to accelerate hemostasis, a slight compression of the contact lens on the cornea is sufficient.
• Irit arising from laser exposure, usually expressed moderately. With more severe inflammation associated with hyper-action of laser energy and inadequate steroid therapy, posterior synechia can form.
• A corneal burn if you do not use a contact lens or the depth of the anterior chamber is shallow.
• Photophobia and diplopia if the iridotomy hole is not located under the upper eyelid.

[20], [21], [22], [23]

Diodlaser cyclocoagulation

As a result of coagulation of the secreting ciliary epithelium, the intraocular pressure decreases, which leads to a decrease in the production of aqueous humor. This conservative intervention is used in terminal glaucoma, which is accompanied by pain syndrome and is usually associated with an organic synechial angle blockade.

Equipment:

• peribulbar or subtenone anesthesia is performed;
• use laser pulses with an exposure time of 1.5 s and a power of 1500-2000 mW;
• the power is adjusted until a clapping sound appears and then reduced below this level;
• approximately 30 coagulates are applied in the area of 1.4 mm posterior to the limbus for more than 270;
• prescribe active steroid therapy in the postoperative period: every hour on the day of surgery, then 4 times a day for 2 weeks.

Complications. The most frequent: moderate soreness and signs of inflammation of the anterior segment. More serious (rare): prolonged hypotension, thinning of the sclera, corneal degeneration, retinal detachment and ciliary body. Since the purpose of the procedure is to relieve pain, the possible complications are not comparable with complications after conventional filtering interventions.

Results depend on the type of glaucoma. Sometimes it is necessary to repeat this procedure. Even when the relief of pain can be achieved, it is most often not associated with compensation of intraocular pressure.

[24], [25], [26], [27], [28], [29], [30]

Trabeculectomy

This surgery is used to reduce intraocular pressure by forming a fistula for the outflow of aqueous humor from the anterior chamber to the subtenon space. Fistula covers the superficial scleral flap.

1. The pupil should be narrowed.
2. The conjunctival flap and the underlying tenon capsule are separated by base to the limbus or the upper arch.
3. Release episcleral space. The area of the proposed superficial scleral flap is delimited by coagulation.
4. Cut the sclera by coagulation marks on 2/3 of its thickness, creating a bed, which is covered with a scleral flap of a triangular or rectangular shape with a size of 3x4 mm.
5. The superficial flap is peeled off to the zone of the transparent cornea.
6. Paracentesis is performed in the upper temporal segment.
7. Anterior chamber open across the entire width of the scleral flap.
8. A block of deep sclera layers (1.5x2 mm) is excised with a blade, Vannas scissors or a special punch tool. Perform peripheral iridectomy for the prevention of the internal scleral orifice block by the iris root.
9. The scleral flap is loosely fixed with sutures in the corners of the scleral bed distal to the cornea.
10. The seams can be adjustable to reduce over-filtration if necessary and prevent the formation of a shallow anterior chamber.
11. The anterior chamber is restored through the paracentesis with a balanced solution, checking the function of the created fistula and detecting leakage areas under the scleral flap.
12. Conjunctival incision sutured. Irrigation through the paracentesis is repeated to check the functioning of the filtration shelf and exclude external filtration.
13. Conduct instillation of a 1% solution of atropine.
14. Subconjunctival injection of steroid and antibiotic is performed in the lower conjunctiva.

Combination of trabecular and facial expressions

Trabeculectomy and phacoemulsification can be performed through the same conjunctival and scleral approaches.

Vannas scissor deep block excision

1. Form the conjunctival flap.
2. Scleral flap cut out 3,5x4 mm base to the limb.
3. Enter the tip "fako" in the anterior chamber with a width of 2.8-3.2 mm.
4. Phacoemulsification performed by the traditional method.
5. A soft intraocular lens is implanted. With a rigid IOL, the size of the conjunctival and scleral flap is determined at the beginning of the operation.
6. Excised block deep layers of the sclera.
7. Perform peripheral iridectomy.
8. Fix the scleral flap.
9. Suture tenon capsule and conjunctiva.

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

Patient Behavior after Glaucoma Surgery

Modern methods of antiglaucoma operations significantly reduce the risk of postoperative complications, so the patient can return to a normal lifestyle a few days after the operation. Depending on the visual acuity, the patient may be unable to drive for some time.

Taking a shower and washing the head (without tilting it) is permitted on the third day after the operation.

The question of returning to work is decided individually, depending on the effectiveness of the operation and on the patient’s profession. Heavy physical labor is prohibited.

In many types of work, for example, in office work, it is possible to resume this resumption soon enough if the unoperated eye has sufficient visual functions. Care must be taken when situations require stereoscopic vision.

[37], [38], [39], [40], [41], [42]

Complications after glaucoma surgery

• ciliochoroidal detachment, as transudates accumulate in the suprachoroidal space;
• shallow front camera;
• low intraocular pressure;
• low vision;
• with low intraocular pressure - “shock of the ciliary body”.

Treatment of complications

1. hospitalization, injections of caffeine, steroids, mydriatics, pressure bandages on the filtration area;
2. surgical treatment - posterior trepanation of the sclera in the projection of the flat part of the ciliary body;
3. according to Fedorov - it is necessary to create new ways for the outflow of fluid;
4. CAAP - scleroangal reconstruction is done for 6 hours, two flaps are separated at the limbus - episcleres (where there are many vessels) and a deep flap, then they are interchanged (superficial vascular plexuses are brought to the anterior chamber moisture);
5. internal sclerectomy (SHE according to Fedorov) - resection of the internal sclera lesions and their excision.

[43], [44], [45]

The postoperative period after surgery for glaucoma

1. sick leave for at least 2 months;
2. "Pupil gymnastics";
3. treatment of postoperative iridocyclitis;
4. with posterior synechia and hyphema - absorbable therapy;
5. in case of hyperfiltration - a pressure bandage with a roller for 2-3 hours a day;
6. in case of insufficient filtration - massage;
7. after surgery - local antibiotic installations, during the first weeks - anti-inflammatory drugs in doses corresponding to the degree of the inflammatory reaction. Non-steroidal anti-inflammatory drugs are more commonly used;
8. if intraocular pressure remains high for several weeks after the operation or is maintained at a normal level due to concomitant antihypertensive therapy, the need to remove stitches on a corneoscleral tunnel;
9. with a long-term decrease in intraocular pressure, vision can be seriously impaired, but with normalization of pressure in almost all cases, it is fully restored.