How to clean silicone from the anterior chamber of the eye. A method for preventing the release of silicone into the anterior chamber of the eye when replacing a liquid perfluoroorganic compound with light silicone in aphakia

To replace pathologically altered vitreous(ST) (blood, exudate, moorings) extracted from the vitreous cavity are often limited to the introduction of an isotonic sodium chloride solution heated to body temperature. However, in cases of subtotal and especially total vitrectomy, there is every reason to give preference to those substitutes that are closer in viscosity to natural ST. Currently, gealon is more often used abroad, and in our country - luronite, honsurid, visiton.

Expanding gases and air

Sterile air has been used as a temporary substitute for many years. Such pneumoretinopexy can be the basis of outpatient surgical treatment fresh retinal detachment, especially if the tears are localized in the upper half of the fundus. More promising, however, is the use of expanding gases, in particular from the group of sulfohexafluorides (SF6) or perfluoropropanes (C3F8), etc. (see table). Their widespread use in our country has long been hampered by the lack of permission from the State Pharmaceutical Committee.

Here it is useful to provide excerpts from the instructions of the ARCEOLE company on the use of ophthalmic gases SF6 (sulfur hexafluoride), C2F5 (hexafluorohexane), C3F8 (octafluoropropane).

The kit includes:

• a cylinder with one of the specified gases with a volume of 30 ml;
• sterile graduated syringes with a volume of 50 ml with a sterilizing filter of 0.22 micron caliber and a device for connecting the syringe to the balloon (adapter);
• a special tape for attaching to the patient’s wrist, designed to identify him with gas endotamponade.

Each cylinder contains pure, non-sterile gas. The gas is non-toxic, inert, non-flammable, colorless and odorless. When introduced into the eye, the gas is not metabolized, but is gradually eliminated through the bloodstream through the lungs. The instructions note that the gas is non-sterile and is sterilized when passing through the sterilizing filter included in the kit. Each syringe included in the kit should be used for sterilization and preparation of only one portion of air gas mixture.

Preparation of the mixture. A sterile 30-gauge needle in a protective cap is placed on the instrument table. A sterile syringe (volume 50 ml) with an adapter and a sterilizing filter attached to it is placed on the instrument table. Check the patency of the syringe by pulling the piston (after releasing, the piston will return to its original position, removing residual air). Place the non-sterile bottle on a flat surface next to the operating table (non-sterile personnel support this bottle during procedures). The gas bottle can be pre-disinfected by immersing it in a chlorhexidine solution, then all manipulations with it are carried out by sterile personnel. A syringe equipped with an adapter and a filter is connected to the cylinder by vigorously inserting the tip of the adapter into a special hole in the cylinder with a protective plug. The gas contained in the pressurized cylinder will passively flow into the sterile chamber of the syringe. The adapter tip is supported inside the stopper until at least 10 ml of sterile gas enters the syringe through the sterilizing filter. Disconnect the syringe with the adapter from the bottle by slightly pulling and rocking the syringe. The bottle must be handled by non-sterile personnel. The adapter and filter remain connected to the syringe. It should be remembered that the adapter tip is not sterile after these manipulations. To prevent infection, you should not manipulate the operating table. By pressing on the piston, excess gas is removed from the syringe, leaving the desired volume. Without placing the syringe on the operating table, add the required volume of air to it, achieving the desired composition of the air-gas mixture. The air will be sterilized as it passes through the filter. Remove the adapter with the filter from the syringe. Immediately apply a sterile 30-gauge injection needle with a protective cap. Place the syringe and needle on the operating table. The air-gas mixture is ready for administration. The air-gas mixture is introduced as quickly as possible. The cylinder should not be reused 15 or more days after the first gas intake.

Composition of the air-gas mixture

• SF6, 20% - in a 50 ml syringe - 10 ml of pure gas per 40 ml of air, preferable for retinal detachments without PVR and diabetic retinopathy, also an option for giant ruptures and eye injuries
• C2F6, 16% - in a 50 ml syringe - 8 ml of pure gas per 42 ml of air, preferable for retinal detachments and macular holes, also an option for giant holes and eye injuries
• C3F8, 12% - in a 50 ml syringe - 6 ml of pure gas per 44 ml of air, preferable for PVR

Warning:

• anesthesia with inhaled nitrogen protoxide should be discontinued at least 15 minutes before using ophthalmic gas;
• gas endotamponade should be performed exclusively by vitreoretinal surgeons trained in this technique;
• before gas administration and during the period of gas tamponade, monitoring of the patency of the central retinal artery is necessary;
• after gas administration, daily monitoring of IOP and the use of ophthalmohypotensive therapy, if necessary, are necessary;
• in most cases, the patient is recommended the preferred position of the head during gas tamponade;
• in patients with a gas bubble in the vitreal cavity, as well as within 3 months after gas administration, anesthesia using nitrogen protoxide is contraindicated due to a significant increase in the risk of intraocular hypertension

For relatively fresh detachments with upper breaks, sulfurhexafluoride is preferable. In more severe clinical cases gases are used long period effective tamponade. The more effective time tamponade, the higher the risk of complications, including irreversible ones.

The effect of gradual expansion of the volume of these poorly soluble gases after their introduction into the eye cavity is based on Fick's rule. According to this rule, a bubble of gas that slowly dissolves in tissues gradually increases in volume if on the other side of the membranes (vascular walls) limiting it, i.e. in the bloodstream, there is another more quickly dissolving gas, in this case nitrogen, entering the blood through the lungs. To mitigate the effect under consideration (to avoid ocular hypertension), polytetrafluoroethylene gases, as noted above, are used not in pure form, but in a mixture with air.

Stages of the surgical intervention itself:

• using a three-way tip inserted through the sclerotoma in the pars plana ciliary body into the vitreous cavity, they begin to fill the eye with air (through a filter) under a pressure of 30-40 mm Hg. Art.;
• to drain the SSF (through the second channel), the cannula is brought closer to the optic disc (in the absence of high detachment bubbles);
• when the eye is filled with air, one of the scleral openings is closed;
• a large 50 ml syringe is filled with a mixture of expanding gas and air;
• 35 ml of the specified gas mixture is injected into the eye cavity from a syringe (15 ml is left in case of necessary elimination of hypotension that may arise due to depressurization of the system at the end of the operation);
• close the second sclerotomy opening.

The gas bubble, which plugs the retina from the inside, usually for 5-7 days, firstly, prevents the penetration of newly formed chamber moisture through the gap from the vitreous cavity under the retina and, secondly, simply presses the latter to the underlying choroid. The presence of gas in the eye cavity creates restrictions for the patient for air travel, climbing mountains, and for anesthesia.

A method for polymerizing magnetic polymers in the form of liquids and scleral fillings directly during anti-detachment surgeries on the eye has been patented in the USA. Protection of the retina against siderosis has not been reported. In general, it is obvious: without adequate vitrectomy this problem not solved.

Silicone oils

Technically, the proposal of R. Cibis et al., published back in 1962, turned out to be much simpler and less dangerous than the methods listed above. It was recommended to straighten and press (“tampon”) the retina torn off over a large area using a practically non-absorbable substance injected into the vitreous cavity. liquid silicone with simultaneous drainage of subretinal fluid.

To enter silicone oil into the eye cavity, the usual system for supplying liquid to the vitreophage is not suitable. Taking into account the high viscosity of silicone oil, it is necessary to take a needle with a wider lumen than usual and create additional “gates” for it in the sclera (in the projection of the flat part of the ciliary body). Through another wound channel there is an outflow of pathologically altered fluid displaced from the vitreous cavity or subretinal space. There are various techniques of the so-called bimanual operating technique. S.N. Fedorov, V.D. Zakharov et al. (1988) believed that the introduction of liquid silicone into the eye to eliminate retinal detachment is indicated:

• for recurrent retinal detachment, if gas administration is ineffective;
• with retinal dialysis with edge inversion;
• with retinal detachments with prolonged hypotension;
• with funnel-shaped retinal detachments, where the break could not be detected.

The authors warn against introducing silicone in the presence of severe vitreoretinal traction in the eye cavity, with subatrophy eyeball and the presence of unabating inflammatory process. In recent years, the most important indication for the use of silicone oil in the surgical treatment of retinal detachment has been the presence of macular holes. However, it is really possible to use this method only on the condition that after the operation the patient will be able to lie face down for several (up to 10 or more) days. During the operation, either the eye is initially filled with air, and through another sclerotoma they begin to fill the posterior part of the eye with silicone oil, maintaining IOP at 10 mm Hg. Art. and allowing air to escape through the first sclerotoma, or immediately inject silicone oil, draining the SSF exiting through anterior gap in the retina.

Silicone tamponade, which lasts longer than air tamponade, allows one to count on success even if light traction is maintained, i.e., when PVR has begun, in particular after injury. During macular surgery, in anticipation of a higher functional effect, biological additives are used, introducing material in the form of a drop (0.5 ml) of autologous serum, bovine blood, etc., which contain a transforming factor, directly into the spot area during the operation for up to 10 minutes. growth (TGF-2), autologous platelet concentrate, thrombin and fibrin mixture.

Initially, so-called light silicones were available to ophthalmic surgeons. Being inferior in density to the vitreous body (0.8-0.9 versus 1.1), silicones with a viscosity of about 400 cSt float upward in the vitreous cavity and are therefore more suitable for blocking ruptures (tears) located in the upper half of the eyeball. Silicone liquid is transparent, colorless, bactericidal. It has a very high viscosity and therefore cannot move freely through narrow gaps. To introduce it into the eye cavity, you need to take cannulas and needles with an internal diameter of more than 1 mm.

There are many proposals for the technique of gradually filling the preretinal space with silicone fluid with synchronous expulsion of subretinal fluid from the eye. During the forced slow (due to high viscosity) injection of silicone, pauses should be avoided, since crushing the drug into small bubbles will adversely affect visual functions in the future and will facilitate the penetration of silicone bubbles into the subretinal space and into the anterior chamber. In general, one of the main problems in the use of silicone oils in ophthalmic surgery is their instability, in particular the tendency to so-called emulsification (crushing into small bubbles). It has been established that among the factors contributing to this is blood (bloodless performance of all manipulations is required). As more and more viscous light silicones (1000-4000 cSt) and then heavy silicones, for example Oxane, purified from low molecular weight components but containing a fluorinated olefin, came into practice, the problem of emulsification was overcome, but the technology for their introduction into the eye cavity became more complicated . Moreover, the problem of removing them from the eye also arose with all its severity. The fact is that in the long term, at the sites of prolonged contact of intraocular structures with silicone liquid, degenerative processes occur: the lens becomes cloudy, the corneal endothelium suffers, and preretinal fibrosis develops; As a result, ophthalmotonus increases. It is for these reasons that in any case, both with and without success, it is advisable to remove silicone from the eye cavity, replacing it with isotonic sodium chloride solution, luronite, honsuride, visitil or healon.

When using high-viscosity silicones (5000 cSt), a problem arises with choosing the caliber of the tip for the vitreophage. R. Gentile (2008) recommends making an incision in the superotemporal quadrant of the sclera for a 20-gauge tip, but you need to have a trocar with an adapter for it, which allows, if necessary, to perform delicate intravitreal operations, switch to a 25-gauge tip. According to V. Gabel (1987), heavy silicones do not cause such pronounced proliferative vitreoretinopathy as the lungs. In search of heavy silicone, ophthalmologists turned, in particular, to fluorosilicone oil, which turned out to be slightly heavier than water (commonly used polydimethylsiloxanes are lighter than water and therefore occupy upper section vitreous cavity of the eyes). It is also essential that heavier silicones turned out to be less viscous. At a viscosity of 300 cSt, a conventional vitreophage system could be used for administration. Silicone, after the necessary purification from low-molecular compounds, loses toxicity and, according to numerous observations, can be left inside the eye for a long time.

Heavy liquids

Back in 1987, St. Chang et al. found that heavy liquids, in particular perfluorotributylamine and other low-viscosity but heavy fluorine compounds, first used by S. Haidt et al., have a more reliable plugging property than heavy silicones. (1982). These drugs, in particular the Soviet perftoran (“ blue blood") and other high-purity liquid perfluoroorganic compounds (PFOS), for example perfluorodecalin from Opsea or Vitreon (perfluorophenanthrene) from Richter, or perfluoropolyether DK-164 (vitreopres), and finally high-purity perfluoropolyether 6MF-130 and perfluoroctalbromine have a high relative density ( 1.94-2.03) with a viscosity of only 8.03 cSt, and therefore can be extremely useful in removing dislocated lenses from the CT, not only natural, but also artificial.

When CT is replaced with perftoran, the lens floats from the fundus to the pupil area. But upon completion of the operation, perftoran must be removed from the eye. Vitreopres H.P. Takhchidi and V.N. Kazaikin (1999) was left in the eye for up to 3 weeks after surgery.

Combined use of silicone oils and heavy liquids.

In the treatment of retinal detachments with breaks localized in the lower part of the eyeball, F. Genovesi-Ebert et al. (2000) found it useful to use a combination of heavy silicone (at 1200 cSt viscosity) and low viscosity perfluorocarbon (FeHg). Both drugs were removed from the eye 1 month after administration. Complete retinal reattachment was achieved in 83% of cases. True, in 33% of cases emulsification was observed and in 8% glaucoma uncontrolled by medications.

For giant retinal breaks exceeding 75° along the perimeter, V.N. Kazaikin (2000) recommends the following intraocular intervention technique. During the so-called three-port vitrectomy, Vitreopres is injected into the vitreous cavity in small portions. As it settles to the bottom of the eye, it squeezes out subretinal fluid in the area of ​​contact with the retina. The epiretinal membranes that are stretched during this process can now be cut atraumatically by the surgeon. Required condition Success involves removing not only these membranes, but also the underlying vitreous. After filling (stage by stage) the entire vitreous cavity with vitreopres, endolaser coagulation of the retina is performed in 4-6 rows. Immediately after this, silicone tamponade is started.

Direct replacement of “heavy” PFOS with “lighter” silicone oil creates conditions under which the “dead space” above the PFOS level is immediately eliminated, since it is occupied by lighter silicone. As PFOS is suctioned from the back of the eye and new portions of silicone oil are introduced, the interface between them drops lower and lower. Thus, while the last portions of PFOS still retain the complete adhesion of the retina created at the beginning of the operation, the last portions of silicone oil come into contact with the concave posterior surface of the fundus. PFOS must be removed from the eye after surgery.

Thus, heavy liquids (PFOS, etc.) are shown primarily as a tool that stabilizes (presses) the retina during surgery, as a way to release (prevent) pinching of the retina in the scleral or cannula holes, as a technique for changing the contour of the retina in search of a break ( with simultaneous compression of the sclera). The rule is that it is necessary to remove heavy fluids from the eye cavity immediately after completion of the operation. Small bubbles of heavy fluid trapped in the anterior chamber are removed with a thin needle using paracentesis. Residues of heavy liquid in the vitreous cavity behind the air are not easy to detect. However, temporary stopping and a new cycle of its removal are not recommended.

In the safe performance of intravitreal operations, operating microscopes with coaxial illumination, surgical contact lenses (concav -20, -40 diopters) or non-contact aspheric lenses (+60, +90 diopters) play a significant role. If there are opacities in the cornea, a domestic ophthalmoendoscope or a temporary keratoprosthesis can be used. The successes in surgical treatment of retinal detachment, achieved over the past 30-40 years, would be simply unthinkable without the use of polymers in the form of fillings, tapes, threads, tourniquets, balloons, and liquid vitreous substitutes.

Owners of patent RU 2448668:

The invention relates to medicine, namely to ophthalmology, and is intended for removing bubbles of silicone oil from the anterior chamber in eyes with previous tamponade of the vitreal cavity. A cannula is inserted into the anterior chamber on a syringe with saline solution, under the pressure of which the silicone oil bubbles are removed through an empty cannula connected directly to them. The method provides visualization of the fundus and helps eliminate danger dystrophic changes cornea in contact with silicone oil and the danger of increasing IOP due to blocking of Schlemm's canal with silicone oil, and also eliminates the emptying of the anterior chamber due to replenishment with saline and the release of new portions of silicone. 1 ill.

In vitreoretinal surgery, one of the tamponing substances is silicone oil (hereinafter referred to as silicone). During subsequent surgical interventions, the silicone must be removed, for which it is proposed various ways(N.A. Pozdeeva, A.A. Voskresenskaya. “Technique for removing silicone oil from the vitreal cavity using the 23-gauge system.” Proceedings of the scientific and practical conference “ Modern technologies vitreoretinal pathology - 2008", pp. 139-141; M.M.Shishkin, N.I.Safaryan, E.V.Kasamkova, E.V.Antonyuk. "A gentle method for removing silicone oil simultaneously with phacoemulsification of complicated cataracts after vitreoretinal surgery." Sat. articles “Modern technologies of cataract and refractive surgery- 2009", M., 2009, pp. 236-239). However, it is not possible to completely remove silicone from the vitreal cavity even in postoperative period its bubbles enter the anterior chamber through defects in the zonules of zonules, as well as with the flow of intraocular fluid, which interferes with visualization of the fundus and can cause dystrophic changes in the cornea (V.D. Zakharov. “Viteral surgery”, M., 2003, p. 158 -159).

A device for removing silicone from the eye cavity is known (RF patent No. 2112482, MKI 6 A61F 9/007, z. 04.07.96, op. 10.06.98, BI No. 162, prototype). The disadvantages of the prototype include the need to use a vitreotome, as well as suturing a dropper to replace silicone in the eye cavity with saline, which complicates the procedure and makes it cumbersome. When using a known device for removing silicone from the anterior chamber, a decrease in it is possible intraocular pressure(hereinafter referred to as IOP) and the release of the next portion of silicone into the anterior chamber.

The object of this invention is to develop a simple, safe and effective way removing silicone bubbles from the anterior chamber of the eye.

The essence of the proposed invention is that under the pressure of a saline solution injected into the anterior chamber using a cannula on a syringe, silicone bubbles are removed through an empty cannula connected directly to them. When using the proposed method for removing silicone bubbles from the anterior chamber, the following technical result is ensured:

Provides visualization of the fundus;

The risk of dystrophic changes in the cornea upon contact with silicone and the risk of increased IOP due to blocking of Schlemm's canal by silicone are eliminated;

Emptying of the anterior chamber is eliminated due to replenishment with saline and the release of new portions of silicone.

The proposed method is carried out as follows. Through a paracentesis in the cornea (see Fig.), a cannula on a syringe with saline is inserted, into the oppositely formed paracentesis - a cannula without a syringe, which is brought to the silicone vials. Using a syringe and cannula, saline pressure is created in the anterior chamber, under the influence of which the silicone bubbles are removed through the empty cannula.

The proposed method is illustrated by the following clinical example.

Patient S., born in 1956, a/k No. 243119. The patient underwent endovitreal intervention for retinal detachment: tamponade of the vitreal cavity with a perfluoroorganic compound was performed, followed by its replacement with silicone oil. When examining the eye after 2 months, a recurrence of retinal detachment was discovered and prescribed repeat surgery. At the beginning of the operation, in the “lying” position on the operating table, silicone bubbles floated to the center of the cornea, and therefore the retina was not visualized, and the operation became impossible.

In accordance with the proposed method, silicone bubbles are removed from the anterior chamber, after which all necessary surgical procedures are performed. Visual acuity: before surgery - 0.01 n/k, after - 0.08 n/k.

Traumatic retinal detachment (TRD) is one of the frequent and severe complications of the traumatic process, the pathogenesis of which has many components (retinal tears, subretinal hemorrhages and exudates, traction component). Based on this, approaches to the treatment of TOS are being developed - extrascleral filling, laser coagulation, retinotomy with retinopexy, as well as tamponade of a detached retina by introducing various implants with a high specific gravity into the vitreous cavity.

Among tamponing agents, researchers have identified silicone oil (SO). Shown good effect action of silicone tamponade (96% fit) with severe forms retinal detachment accompanied by PVR, giant retinal tear, retinal detachment after injury, with macular holes. High-tech methods for synthesizing SM have been developed. Studies have appeared on SMs of varying gravity, the so-called heavy silicones, which is associated with the problem of treating retinal detachment in the lower part of the fundus. These studies showed good tissue tolerance but a greater inflammatory response compared to conventional SM. However, the need to remove silicone became a big problem, which is caused by a number of complications. The most characteristic clinical complications: pupillary block with the development of secondary glaucoma, cataracts, band keratopathy. However, most severe complications were caused by changes in the retina, as revealed by histological examination, both when studying enucleated eyes of patients and the eyes of experimental animals. With prolonged stay of SM in the eye, atrophy of the outer and inner segments in the photoreceptor layer, as well as the layer of ganglion cells, was shown. The appearance of spherical formations in the form of vacuoles surrounded by macrophages was noted. Similar silicone “vacuoles” were found not only in the retina, but also in optic nerve, choroid, retinal pigment epithelium, ciliary body, iris, corneal endothelium. By 18 months, silicone had penetrated the internal limiting membrane, infiltrating the entire retinal tissue. All these data justified the mandatory removal of the SM after 1 month. At the same time, removal of the SM was accompanied by a risk of recurrent retinal detachment with a more severe course, which allowed surgeons not to rush to remove the SM or remove it at a later date. The lack of consensus on the tolerability of the tamponant drug makes further study aimed at identifying the positive and negative properties of SM relevant.

Target- studying morphological changes in the tissues of the eye during prolonged stay of SM in it, as a plugging material used in TOS surgery.

Material and methods. The study of morphological changes was carried out on 14 enucleated eyes of patients who had traumatic retinal detachment after injury, and therefore several surgical interventions. In all patients, SM was used as a tamponade. In one patient, the SM was removed two years after surgery; in the remaining patients, the SM was not removed.

Loss visual functions, the phenomena of sluggish uveitis and signs of subatrophy of the eyeball were the cause of enucleation.

Results and discussion. In all 14 patients, SM was introduced into the vitreous cavity as a tamponing material, the stay of which was long: 6 months. - 3; 1.5 years - 3; 2 years - 3; 3 years - 2; 10 years - 2; 30 years - 1. Retinal detachment in 11 patients occurred after an accidental injury (8 - contusional and 3 - penetrating injury); in 3, retinal detachment was observed after surgical trauma - cataract extraction with IOL insertion. All patients were clinically observed to have a picture of sluggish uveitis in the absence of visual functions. In 11 patients, total retinal detachment was found, in three the retina was adjacent.

During a morphological study, changes caused by trauma, both accidental and surgical, were determined in 14 eyes of patients. However, the most pronounced changes were localized in the retina. It was natural to detect SM droplets on the inner surface of the retina, surrounded by inflammatory infiltration with a predominance of macrophages. Inflammatory infiltration was also localized in the choroid, which was diffusely infiltrated with lymphocytes and edematous.

It should be noted that inflammatory reaction prevailed in the first two years after the introduction of SM, and subsequently fibroblastic processes increased. In the long term (10-30 years), 2 patients noted the formation of bone, which was located on the inner surface of the choroid and was characteristic of a flat bone microscopic structure. Pronounced changes in retinal tissue were noted during prolonged exposure to SM. The retina was infiltrated by SM droplets, varying in size from large cystic cavities to small, oddly shaped vacuoles. Some vacuoles contained contents resembling remnants of emulsified SM. The retinal tissue became atrophic, neuronal elements disappeared, and glial tissue grew. In some cases, as a result of atrophic changes, the retina turned into glial tissue. However, there was no retinal detachment in these patients. A similar situation may have explained the loss of function in the “adjacent” retina during prolonged tamponade with silicone.

Conclusions. A morphological study showed that long stay SM in the eye cavity caused specific complications: development of the inflammatory process around “fat” droplets (FA), formation of epiretinal and subretinal membranes, as a result of fibroblastic processes with possible bone formation, development atrophic processes in the retina with the death of neuronal structures. The results obtained allow us to believe about the destructive effect of SM on eye tissue when it remains in the eye cavity for a long time, and about the advisability of removing SM, and to a greater extent. early dates in order to prevent specific complications.

Retinal detachment - remains formidable eye disease, which can lead to almost complete loss of vision without surgical treatment.
The human eye can be simply compared to the device of a camera. The lens of which is the cornea with a lens, and the photographic film is the retina, and even connected nerve fibers directly to the brain. You could even say that the retina is part of the brain. Modern ophthalmology has achieved a lot, and today it is already routine to change the lens, perhaps change the iris, cornea (transplant from another human eye), but with the retina everything is very, very complicated. The artificial retina is still very far away, so it is necessary to repair and restore the original one that exists.
The cause of retinal detachment, scientifically called rhegmatogenous (regma-tear), or also called primary detachment, is a retinal break. The rupture, as a rule, occurs somewhere on the periphery, in the area of ​​thinning and dystrophy. Comparing it again with photographic film, a scratch in the emulsion layer appeared somewhere on the edge of the frame. Well, what can you say from this, because almost the entire frame and, most importantly, the center of the “composition” is still clearly visible. It turns out that this is not entirely true; liquid begins to penetrate through the gap, flowing under the retina and thereby peeling it off. Drawing again a parallel with photographic film, at this moment the emulsion layer around the scratch begins to swell with bubbles and peel off from the substrate. At this moment, a person sees a rather characteristic picture of a “gray curtain” at the edge of the field of vision. Depending on the location of the rupture, the “curtain” can either spread quickly (in a few tens of hours), covering the entire field of view, or creep more gradually (weeks, and in some cases months) over the field of view. Quite characteristic of fresh retinal detachment is the symptom of “morning improvement”, when a person in the morning (after a long sedentary lying position) discovers a significant improvement (reduction of the curtain, its paleness and the ability to see through it). By lunchtime it gets worse again, and in the evening even worse.
Treatment in this case is necessary, the only treatment is surgical, there is no other option. No drops, ointments, tablets, injections, absorbents help, but only take time, which allows the detachment to develop further and further.
The earlier competent surgical treatment is carried out at this moment, the better results it gives and the more significantly it is possible to restore vision. The goal of surgical treatment was formulated more than 100 years ago and is to close (block) a hole in the retina. At this stage of the disease, there is usually no need to go inside the eye and surgery consists of local external depression in the projection of the retinal tear. For this, special soft silicone fillings are used, which press the area of ​​the tear, thus blocking it. As soon as the hole in the retina closes, everything miraculously improves, the “curtain” disappears, and vision begins to be restored. Peripheral vision is restored first, the person discovers that the “vision” is almost normal, later it actually becomes normal. The periphery of the retina is quite stable, and as soon as it returns to its anatomical place, it immediately begins to “work” and recovers well even with long-term retinal detachment. With central vision, things are not so simple. The most favorable cases are when the detachment has not had time to “crawl” to the center. For example, if vision in the center remained 1.0, and half of the field of vision was already covered by a “curtain,” after a successful operation, vision remains 1.0, and the curtain disappears.
If the detachment has managed to close the central zone, after a successful operation central vision is not completely restored. What visual acuity will be after surgery in this case depends on a number of factors. The most important of them are: the time during which the central zone of the retina was detached and the state of the blood supply to the retina, which directly depends on age and the degree of myopia, if any. As an example, we can give average numbers of 0.2-0.5, that is, from 2 to 5 lines on the vision test table. However, there are often more impressive cases of restoration of up to 8 or even 9 lines. Recovery central vision occurs slowly and almost ends by 3 months. Further improvement also occurs, but at an even slower pace, and we observe that both after a year and after 3 years, visual acuity improves slightly.
If a person with retinal detachment is not operated on in time or is operated unsuccessfully, then the retinal detachment remains and the proliferative process in the vitreous body continues to develop. The eye, as we know, is approaching the shape of a ball, and we already know that it has both a lens and a photographic film (retina), and inside the eye is filled with liquids. These liquids are almost 98-99% water, but with very significant additives. The anterior compartment of the eye is limited by the cornea on one side and the iris-lens unit on the other. This part of the eye is more responsible for optics and is filled with anterior chamber ocular fluid, which in its properties and appearance is almost no different from plain water, with a complex set of minerals and salts. Another thing is the fluid in the posterior compartment, delimited by the lens, ciliary body and retina. This fluid is called vitreous humor, and has the consistency and appearance of a gel or set jelly. In addition, at the base of the vitreous there is a frame consisting of a three-dimensional lattice of Collegan fibers. With retinal detachment, the vitreous body never remains indifferent; in the initial period, only slight structural disturbances are observed, manifested in the form of various inclusions floating in the field of view. With a long-term detachment, strands develop from the vitreous body, which, like ropes, are attached to the surface of the retina and, by contracting, tighten the retina. This kind of detachment is figuratively called “funnel-shaped”. This process is called vitreoretinal proliferation. In such a situation, reconstructive surgery becomes much more difficult. At this point it is almost impossible to close the gap with fillings. The main task is to cleanse the surface of the retina from the vitreous cords, straighten it and then block the tear. For this purpose it is used special methods vitreoretinal surgery. Through pinpoint punctures and long, thin instruments, the surgeon enters the inside of the eye and removes the strands, freeing the retina and straightening it.
This is very reminiscent of the painstaking work of a craftsman who assembles and glues a model of some 18th century sailing ship inside the bottle through the neck of a bottle with long tweezers and scissors. The operation is quite complicated, given that the retina is fragile nerve tissue and almost every part of it is responsible for the visual area. During surgery, the doctor looks at the fundus of the eye through anterior segment eyes “looks through the pupil.” This requires transparent media, that is, the “lens”, cornea and lens must be transparent. If the lens is cloudy and a person has cataracts, then as a rule initial stage The lens is replaced with an artificial one, and then the “repair” of the retina begins. In addition, the natural lens, due to its anatomical location, often interferes with treatment peripheral parts retina. In these cases, it is also necessary to change the lens to an artificial one, otherwise the uncleaned areas of the peripheral retina may not allow it to achieve its anatomical fit.
After cleansing the surface of the retina as completely as possible, it needs to be straightened and pressed to its anatomical location. For this purpose, so-called “heavy water”, a liquid perfluoroorganic compound, is most often used. This substance in its properties is almost no different from ordinary water, but due to its high molecular weight it acts like a press on the surface of the retina, smoothing and pressing it. “Heavy water” copes with detachment very well, in addition, it is absolutely transparent, and the eye filled with this liquid begins to see almost immediately. Its main disadvantage is that the eye cannot tolerate it for a long time. A maximum of a month, but in practice it is not advisable to leave this liquid in the eye for more than 7-10 days. This means that immediately after straightening the retina, it is necessary to close, “seal” all the breaks in the retina, so as not to get a detachment again after removing the “heavy water”. Unfortunately, glue for the retina has not yet been invented, but the laser turned out to be very effective. Microburns are applied with a laser around the breaks, along the edges of all defects in the retina. Laser beam passes through the retina almost freely, since it is a very transparent nervous tissue, all burns appear on the dark choroid, to which the retina should be tightly pressed normally. Everything in the body is more or less interconnected, and if you get a skin burn, then instantly there will be no scar. There will be redness, inflammation, and pain. And only then, after 2-3 weeks, when everything has healed, there will be a scar. The same thing happens in the eye, with the exception of pain; there are no nerve endings on the choroid. That is, after applying laser coagulates, local inflammation occurs, and then a microscar will gradually form on the choroid. All this time, the retina needs to be pressed against the choroid so that inflammation also affects it. Since the eye has a very strong blood supply, scarring after laser exposure begins by the end of 1 week. Therefore, it makes sense to keep “heavy water” in the eye for a week, which presses on the retina all this time, and then it can be removed, since there are already weak scars in place of the laser coagulates and they already last a little. In some cases, this is enough to keep the retina in place; in others, it is necessary to continue holding the retina to form stronger adhesions. In such cases, silicone oil is used to fill the eye cavity. Silicone is a transparent viscous liquid, tissues almost do not react to it, so you can keep it in the eye much longer than “heavy water”. Silicone does not straighten and press the retina so well, but it is ideal for maintaining what has been achieved. An eye filled with silicone begins to see almost immediately, the retina retains its anatomical position, its functions are restored, and adhesions in the places of laser coagulates become very strong over time. One of the features of silicone is a change in refraction in the positive direction, by 4-5 diopters. Typically, silicone stays in the eye for about 2-3 months, after which the retina no longer needs any “supports” and can be removed. Removing silicone is also an operation, but not as complex and voluminous as the previous ones. Sometimes, changes in the internal ocular structures are so large that the only option today to have vision, or to preserve the eye as an organ, is to constantly keep silicone in the eye cavity. In this case, silicone can remain in the eye for years, even decades.
Various gases or air are also used to press and hold the retina during the formation of adhesions. There is only one principle: press the retina from the inside with an air bubble for some time until the scars become stronger. Any gas, and especially air, dissolves in the eye fluid over time and disappears. The air dissolves within 1-2 weeks, the gas can remain in the eye for up to a month. Unlike silicone, a person with injected gas sees practically nothing except light and bright objects. Gradually, a boundary appears between the gas bubble and the eye fluid. A person notices the vibrations of the bubble when moving the head. As the gas dissolves, the image begins to open from above and eventually the entire field of vision becomes clear.
All methods and substances are used today in vitreal surgery; these are just tools for one big task, restoring vision after retinal detachment. Each case of detachment is individual and only a surgeon can decide what and how is best for a particular eye, for a particular patient. We can say with confidence that using and combining modern methods, we are able to cope with almost any retinal detachment. Another question is how damaged and for how long the retinal nerve cells have not worked, and to what extent they will be able to recover after receiving an anatomical fit of the retina.
Approximately, we can say the following: all detachments, unsuccessfully operated on or not operated on for some reason, if no more than 1 year has passed since the detachment and the eye can confidently see the light, you can and should try to treat, operate and achieve vision. If the eye does not see light, as a rule, it is impossible to help, if the detachment lasts for more than a year, it must be considered individually, and sometimes it is possible to help in such cases.