What is the optic nerve fossa? Method of surgical treatment of the optic disc fossa

Pathology of the optic nerve in most cases is a consequence of general diseases, especially diseases of the brain. There are congenital anomalies in the development of the optic nerve, inflammation (neuritis), congestive nipple, atrophy, and damage. Vascular disorders in children are extremely rare. Pathology of the optic nerve, as a rule, leads to impaired visual function, which is the main symptom that patients notice. In childhood, diagnosing diseases of the optic nerve is difficult and they are often discovered late, since children, especially preschoolers, usually do not notice visual impairment, especially with a unilateral process.

Optic nerve abnormalities

Aplasia and hypoplasia of the optic disc. Optic disc aplasia, a congenital absence of optic disc, is a rare unilateral or bilateral anomaly. It is often combined with other malformations of the eye and central nervous system. In cases of true aplasia, the optic disc and fibers, retinal ganglion cells and retinal vessels are absent. Visual functions are absent (Francois J., 1961].

One variant of the anomaly is aplasia of nerve structures with normal development of mesodermal elements in the optic nerve trunk and central vessels. This abnormality is called aplasia of the disc or third neuron, retina.

Optic disc hypoplasia is more common than optic disc aplasia, but is also quite rare. With hypoplasia, the optic disc in one or both eyes is reduced in size to 1/3-1/2 of its normal size. It is often surrounded by a zone of pigmentation. The vascular system of the disc is normally developed; tortuosity of the vessels is less common. X-ray examination sometimes reveals a decrease in the size of the optic foramen, which indicates the spread of hypoplasia in the proximal direction. Hypoplasia of the optic disc is often combined with microphthalmos, aniridia, and underdevelopment of the orbit. At the same time, delayed psychophysical development and hemiatrophy of the face on the affected side may be observed. Visual functions are severely impaired and depend on the degree of hypoplasia. When optic disc hypoplasia is combined with nystagmus and strabismus, as well as its mild severity, it is necessary to carry out a differential diagnosis with amblyopia.

The anatomical essence of aplasia and hypoplasia of the optic nerve head is the absence of all or part of the optic nerve fibers. The anomaly occurs as a result of a delay in the growth of fibers into the optic nerve canal, as a result of which they do not reach the disc.

Pits(grooves) in the optic nerve head- a common congenital anomaly, the pathogenesis of which is not entirely clear. V. N. Arkhangelsky (1960) considers it as a variant of disc hypoplasia with a partial delay in the ingrowth of nerve fibers; other authors associate the formation of pits with the introduction of folds of the rudimentary retina into the intervaginal spaces of the optic nerve.

The pits are easily identified during ophthalmoscopic examination in the form of darkish spots (since their bottom is not illuminated by the ophthalmoscope) with clear edges, oval, round and slit-like. More often, the pits are located in the temporal part of the disc, closer to its edge. Their size ranges from 1/2 to 1/8 of the disc diameter, the depth varies from barely noticeable to 25 diopters, sometimes the bottom is not visible at all. Often it is covered with a grayish veil-like fabric; Vessels may be visible at the bottom. The anomaly is often unilateral. The pits can be single (usually) or multiple (up to 2-4). The central vessels, as a rule, are not changed and bypass the fossa. In more than half of the cases with this anomaly, the cilioretinal artery is detected in the eye.

The functions of the eye are often unchanged. However, visual field defects may be detected: an increase in the blind spot, sectoral loss, and less often central and paracentral scotomas. Decreased vision is usually associated with a variety of macular changes - from a picture of central serous retinopathy, edema of varying severity, macular cysts, hemorrhages, various pigmentary disorders to gross degenerative foci. The pathogenesis of changes in the macular zone is not entirely clear. Due to the location of the pits in the temporal part of the disc, the nutrition of the macula may be disrupted. The results of fluorescein angiography indicate the presence of subretinal fluid flow from the fossa to the macula, which is obviously associated with impaired vascular permeability in the fovea area.

Optic disc enlargement(megalopapilla) is a rare anomaly, unilateral or bilateral. Discs can be enlarged to varying degrees, sometimes almost doubling their area. The abnormality is most likely due to an increase in the amount of mesodermal or supporting tissue due to invasion of the optic stalk. Visual acuity may be reduced to varying degrees.

Optic disc inversion- its reverse, inverted location. It differs from the normal state only in the ophthalmoscopic picture: there is a rotation of the disc by 180° or, less commonly, 90° or less. Disc inversion can be combined with a congenital cone and is often accompanied by refractive errors, resulting in reduced visual acuity.

- a congenital anomaly, which is a limited depression in the optic nerve discs. The disease occurs in the population with frequency 1: 10 LLC-11 LLC; first described by T. Wiethe (1882).

Pathogenesis. The pathogenesis of the optic disc pit is unclear. Some authors suggest that the optic disc fossa; is a mild form of optic nerve coloboma, i.e. is also caused by incomplete closure of the palpebral fissure. Its supporters cite rather rare cases of a combination of coloboma and optic disc fossa as arguments confirming this point of view.

There are facts that do not agree with this hypothesis: firstly, the disc fossae are often located in places related to the embryonic cleft; secondly, disc pits are usually unilateral, sporadic and not combined with other developmental anomalies; thirdly, disc pits are not combined with colobomas of the iris or retina. Although optic coloboma may sometimes present as a crater-shaped deformation resembling a pit of the optic disc, and it may be difficult to distinguish a lower-segment pit from a small coloboma, the facts presented above seem sufficient to demonstrate the obvious difference in the pathogenesis of coloboma and optic pits. nerve. The presence of one or more cilioretinal vessels emerging from most of the optic nerve fossae suggests that this fact is also somehow related to the pathogenesis of the anomaly.

Histological studies. In the area of ​​the fossa there is a defect in the cribriform plate. The retinal fibers descend into the fossa, then return and exit in front of the incoming optic nerve. Some fossae communicate with the subarachnoid space.

Clinical manifestations. With ophthalmoscopy, the optic disc fossa looks like a round or oval depression that is white, gray or yellow (Fig. 13.27).

The diameter of the optic disc pits varies from 1/3 before 1/8 RD. Usually the fossa is localized in the temporal half of the disc, but it can also be located in other sectors. The disease is often unilateral. The bilateral optic disc fossae meet in 15 % cases. When the lesion is unilateral, the abnormal disc appears slightly enlarged compared to the normal one.

If the disc fossa is of significant size, its sagittal section can be obtained using B-echography; for small sizes - optical coherence tomography.

Approximately in 45-75 % eyes with a congenital optic disc pit develop serous macular detachment. Lineoff et al. (1988) studied the course of development of macular complications:

The route of intraretinal fluid has not yet been precisely established. Possible moaners are indicated in the literature:

1. vitreal cavity through the fossa;
2. blood vessels at the base of the fossa;
3. subarachnodal space;
4. al vessels.

Macular retinoschisis and retinal detachment caused by the disc fossa develop with age 10- 40 years. The risk of developing macular complications is higher in cases where the optic disc fossa is large and localized in the temporal half of the disc. In cases where macular detachment exists for a long time (for 6 years or more), pigment is deposited along the edge of the disc and/or along the border of the detachment. Pigment deposits are caused by disturbances in the retinal pigment epithelium layer, in which extensive defects form over time. G. Theodossiadis et al. (1992) found that when macular detachment exists for 10 years or more, the size of the disc fossa increases, and its color becomes gray, which is probably due to the loss or restructuring of glial tissue within the fossa.

Fluorescein angiography. In the arterial and arteriovenous phases, a gradually increasing leakage of fluorescein is determined in the zone of neuroepithelial detachment towards the macula. In the early phases of FA or indocyanine angiography, the disc fossa usually does not allow contrast material to pass through. In the late phase of FA or indocyanine angiography, hyperfluorescence of the disc fossa and the area of ​​macular detachment occurs.

Psychophysical research. Visual acuity in patients with optic disc fossa remains normal until the onset of macular complications. TO 16 -adult age due to the development of macular detachment of the neuroepithelium, visual acuity 0,1 and below note at 80 % patients. Visual field defects are varied and often do not correlate with the location of the fovea. With persistent macular changes, defects in the visual field progress. Scotomas detected in the visual field correspond to defects in the retinal pigment epithelium detected by ophthalmoscopy or FA.

Electrophysiological studies. The ERG remains normal in most patients even in cases of macular complications. VVP are not changed until the development of macular detachment. With the appearance of macular complications, a decrease in the amplitude of the P100 component is noted in all cases. less often - prolongation of its latency.

Treatment. Conservative treatment, including dehydration therapy and topical corticosteroids, is ineffective. Previously, laser coagulation of the retina was used to block the flow of fluid from the disc fossa to the macula, but the effectiveness of this technique was quite low and difficult to predict due to the impossibility of adequately covering the retinoschisis cavity using laser coagulation alone. Currently, a combined technique is used, including vitrectomy followed by intravitreal tamponade with expanding perfluorocarbon gas and barrier laser coagulation. Combined treatment makes it possible to achieve improved visual acuity in all patients and anatomical success in 87 % .

The optic disc fossa is a congenital pathology of the optic nerve, characterized by a deepening in the optic disc and serous detachment in the macular area, as a result of which a decrease in visual functions occurs. The frequency of this pathology is 1 case per 10-11 thousand population. Macular disorders usually occur between the ages of 20 and 40, but this pathology was first described by Wyeth in 1882 in a 62-year-old woman.

There are several theories of fluid migration into the macular zone: from the vitreous body, cerebrospinal fluid, choroidal vessels or optic disc vessels. Fluid from the optic disc fossa spreads into the macular zone, usually into the inner or outer nuclear layers, forming macular schisis. Many authors pay special attention to the influence of the vitreous body in the pathogenesis of macular edema.

Conservative treatment of the ONH pit is ineffective; the use of steroid and non-steroidal anti-inflammatory drugs does not reduce macular edema, since the hole in the ONH does not close.

Various methods of surgical treatment of the optic disc fossa have been proposed: restrictive laser coagulation of the retina along the border of the subretinal cavity with YAG laser retinopuncture along the lower border of the edema, a combination of laser treatment with intravitreal gas injection, vitrectomy with restrictive laser coagulation of the retina along the border of the subretinal cavity with mechanical retinopuncture along the lower border edema, vitrectomy with removal of the ILM and gas-air tamponade. Recently, new methods of surgical treatment have been proposed, such as the use of an inverted ILM flap. The modern technique of cutting out a flap of the internal limiting membrane allows not only to close large holes in the macular area, but also to cover the optic disc fossa.

From our point of view, methods of using platelet mass are very promising in this direction. Currently, this mass is very effectively used to treat patients with idiopathic macular holes.

Purpose Our study was to evaluate the effectiveness of various methods of surgical treatment of the optic disc fossa.

Material and methods

We analyzed 3 cases of patients treated in the Cheboksary branch of the Federal State Institution “MNTK “Eye Microsurgery” named after Academician S.N. Fedorov" in 2016-2017.

Case No. 1

Patient S., 58 years old. Complaints of decreased visual acuity in the left eye over the past 3 months. Upon admission Vis OS=0.2 cyl -0.5D ax 101°=0.3; on OST of the macular zone OS, cystic edema of the retina, height at the fovea level = 538 µm, neuroepithelial detachment; on OST ONH OS there is a pronounced decrease in the layer of nerve fibers.

Surgical treatment was performed: OS - intravitreal injection of C3F8 gas with a forced head position “face down” in the postoperative period.

Case No. 2

Patient K., 68 years old. History of concomitant ocular pathology - o/v glaucoma Ia; in 2011, surgical treatment of OD was performed - FEC + IOL + trabeculotomy.

When appearing for control in 2015, Vis OD=0.7n/k; IOP=20 mm Hg. Perimetry reveals an arcuate scotoma; on OST Mac. zones without features, OST ONH - a pronounced decrease in the layer of nerve fibers. There are no antihypertensive drops.

The patient came for follow-up 1 year later (in 2016) with complaints of decreased vision in the right eye Vis OD=0.3 n/k; IOP=21 mm Hg; on OST Mac. zones of extensive high detachment of the neuroepithelium in the fovea and parafoveolar, spreading to the optic disc, splitting of the retinal layers.

Surgical treatment was performed: OD - vitrectomy with removal of the PGM, ILM, ELKS and tamponade of the vitreal cavity with air.

The patient came for follow-up after 1 month. Vis OD=0.3 n/k; IOP=20 mm Hg; OST mac. zones - weak positive dynamics with persistence of edema in the macular zone.

Then the patient came for follow-up after 3 months. after operation. Vis=0.2-0.3n/k; IOP=20 mm Hg; on OST Mac. zones - edema, detachment of the neuroepithelium in the fovea and parafoveolar. The next visit was 6 months later. after operation. Vis=0.2 n/k; IOP=21 mm. Hg; on OST Mac. zones - neuroepithelial detachment, maximum height of edema - 762 µm, at the level of the fovea - 618 µm (Fig. 1).

Considering the recurrence of macular edema, as well as negative dynamics in visual acuity, repeated surgical treatment was performed: OD - revision of the vitreal cavity with temporary PFOS tamponade, retinopuncture with a 30 G needle with drainage of subretinal fluid, subretinal injection of platelet mass, tamponade of the vitreal cavity with a gas-air mixture (C3F8) .

Case No. 3

Patient R., 35 years old. Complaints of decreased vision in the left eye over the past year, the appearance of a “dark spot” in front of the eye. Upon admission Vis OS=0.3 sph+0.75D=0.4; on OST of the macular zone - retinal edema, height at the level of the fovea = 644 µm, neuroepithelial detachment; on the OST of the optic disc - a pronounced decrease in the layer of nerve fibers.

Surgical treatment was performed: OS - vitrectomy with removal of the optic disc and formation of an inverted flap from the intraocular disc towards the optic disc fossa. To press the flap into the disc fossa, temporary PFOS tamponade was used, followed by the application of platelet mass to fix the flap.

After an exposure of 3 minutes, PFOS was removed and air tamponade of the vitreal cavity was performed. In the postoperative period, the position was “face down” for 7 days.

results

Case No. 1

The patient came for follow-up after 3 months. after operation. She did not notice any changes from the treatment.

Vis OS=0.3 n/k; on OST of the macular zone OS - positive dynamics of reduction of cystic edema of the retina, height at the level of the fovea = 482 µm; on OST ONH OS - a pronounced decrease in the layer of nerve fibers.

As a result of the treatment, macular edema was reduced by 56 µm (Fig. 2).

Considering the positive dynamics, the patient was recommended for dynamic observation with monitoring of the OST. zones in another 3 months. If the situation worsens, the issue of vitrectomy will be decided.

Case No. 2

The patient came for follow-up after 6 months. after reoperation. I felt positive dynamics from the surgical treatment and noted an improvement in my vision.

Vis OD=0.3 cyl-0.75D ax130°=0.5; IOP=19 mm Hg. On OST of the macular zone OS - positive dynamics, absence of edema in the macular zone, height at the level of the fovea = 210 µm. The treatment allowed to eliminate the swelling of the poppy. zones of 408 µm (Fig. 3).

Case No. 3

The patient came for follow-up after 5 months. after operation. She noted a clearing of the “spot” in front of her left eye. Vis OS=0.4 n/k; on OST of the macular zone OS - positive dynamics, almost complete absence of retinal edema, height at the level of the fovea = 278 µm; on the OCT of the optic disc - a reverse flap of the ILM covering the optic disc (Fig. 4).

As a result of the treatment, it was possible to reduce macular edema in this case by 366 µm (Fig. 5).

Conclusion

Thus, vitrectomy with removal of the optic disc and ILM is an effective method for treating the optic disc fossa, allowing to reduce macular edema and improve visual acuity.

Covering the fossa with an inverted ILM flap has also been shown to be an effective and safe treatment option. And even safer, given the absence of the need for retinotomy and additional manipulations with subretinal contents. The use of platelet mass for additional fixation of the flap may reduce the likelihood of recurrence of macular edema. However, more observations are required.

If macular edema recurs, subretinal administration of platelet mass is possible.

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The optic pit is a fairly rare congenital malformation, occurring in 1 in 11 thousand ophthalmic patients. In approximately 85% of cases, the disease is unilateral; men and women are affected equally often. It manifests itself between the ages of 20 and 40 as decreased vision caused by macular disorders.

Although the pathogenesis of the disease is not fully known, as a rule, it is associated with incomplete closure of the embryonic palpebral fissure. No connection between the optic fovea and systemic diseases has been identified. Histologically, expansion and displacement of the scleral canal, penetration of the retina into the optic nerve trunk, rudimentary retinal tissue in the disc area, and retinal nerve fibers on the walls of the coloboma are detected. Inherited in an autosomal recessive manner.

Ophthalmoscopically, the optic nerve fovea is a round or oval depression in the optic disc, grayish in color, with clear boundaries, measuring from 1/8 to 1/2 the diameter of the disc (Fig. 1). Usually the fossa is localized in the temporal half of the optic disc. Very rarely there are two pits; the second in these cases is localized in the nasal half of the disc. The pits have varying depths, sometimes vessels are visible at the bottom. In most cases, the affected disc is enlarged in size.

The most common complication of the optic fovea is retinal separation (schisis) in the macula. One of the probable causes of the formation of retinoschisis in the macular area is the flow of cerebrospinal fluid from the subarachnoid into the subretinal space. It is possible that intravitreal fluid penetrates through the optic nerve fossa, which, if persisted for a long time, leads to the development of cystic macular edema and even a through macular hole. Treatment of the optic nerve fossa is carried out when visual acuity is reduced due to retinoschisis and currently consists of transciliary vitrectomy, gas-air tamponade, possibly in combination with laser photocoagulation along the edge of the fossa.

Optical coherence tomography clearly illustrates optic disc defects and retinal dissection, changes occurring in the fovea (Fig. 2, 3).

Rice. 1. Biomicroscopy of the fundus of a patient with an optic fossa and retinoschisis, which involves the macula. Visual acuity 0.1.

Rice. 2. Tomogram through the macula and optic nerve of a patient with an optic fossa. On a horizontal scan, the retina is separated into several layers. The connection between the intraretinal and vitreal spaces was not identified, while at the same time a channel into the subarachnoid space was visible.

Relevance.

The optic disc pit (ONH) is a fairly rare congenital developmental anomaly, occurring in 1 in 11 thousand ophthalmic patients. In approximately 85% of cases, the disease is unilateral; men and women are affected equally often. It manifests itself between the ages of 20 and 40 as decreased vision caused by macular disorders.

The most common complication of optic disc fossa is retinal separation (schisis) in the macula. One of the probable causes of the formation of retinoschisis in the macular area is the flow of cerebrospinal fluid from the subarachnoid into the subretinal space. It is possible that intravitreal fluid penetrates through the optic disc fossa, which, if it persists for a long time, leads to the development of cystic macular edema and even a through-and-through macular hole.

Surgical treatment of the optic disc fossa consists of vitrectomy, endolaser photocoagulation and gas-air tamponade of the vitreal cavity. The effectiveness of this method is low, which requires repeated interventions.

One of the approaches to treating the optic disc fossa is to create a barrier to fluid flow into the macular area by filling the fossa with autologous sclera. This technique is quite effective, but does not exclude recurrence of macular detachment and is quite traumatic.

Recently, the technology of using autologous internal limiting membrane (ILM) to close central retinal defects has become widespread.

Target.

Development of a new technique for surgical treatment of the optic disc fossa using the ILM.

Material and methods.

Two patients with optic disc fossa were treated, aged 25 and 37 years. Visual acuity before surgery was 0.01 and 0.25, respectively.

Operation technique: a transconjunctival 3-port 25G vitrectomy is first performed using a standard technique, frequency - from 2500 to 5000 cuts per minute, vacuum - from 5 to 400 mm Hg. To detail the structure of the posterior cortical layers of the vitreous body and ILM, standard dyes are used. The separation of the posterior hyaloid membrane is carried out using aspiration technique, starting from the optic disc, gradually lifting it to the periphery.

Then the ILM in the macular zone is removed, performing a circular maculorrhexis. Next, they begin to form the ILM flap, which is carried out in several sequential steps. At the border of the maculorrhexis at 6 o'clock, using microtweezers, the tip of the ILM is separated from the retina with a pinch (action 1). Then, grasping the tip of the ILM with tweezers, the membrane is separated with a movement directed towards the inferior temporal arcade, not reaching it 0.5 mm (action 2). Next, the edge of the ILM is intercepted and it is separated along the inferior temporal arcade towards the optic disc for 2-3 hour meridians (action 3). After this, the edge of the ILM is intercepted and a movement similar to step 2 is performed, but in the opposite direction and up to the border of the circular maculorrhexis, thus separating the ILM section from the retina (action 4).

After the formation and removal of the first ILM section, the formation of the second ILM section begins. To do this, they return to the point from which they began performing step 4, separate the tip of the ILM from the retina with a pinch, then, grasping the tip of the ILM with tweezers, separate the membrane with a movement directed along the inferior temporal arcade towards the optic disc for 2-3 hour meridians (action 5) , after which the edge of the ILM is intercepted and from this point step 4 (action 6) is repeated, as a result of which the second section of the ILM is separated from the retina.

After the formation and removal of the second section of the ILM from the point from which action 6 began, a circular movement is carried out towards the inferior temporal arcade as far as the membrane allows to separate (action 7).

As a result of the above actions, an ILM flap is preserved between the ILM peeling areas. This flap is turned over and placed on the optic disc.

The next step is to replace the liquid with air, then 1.5-2.0 ml of PFOS is injected and in a PFOS environment, using tweezers, a light compression effect is applied to the flap above the optic disc fossa. After this, PFOS is replaced with air under a vacuum of 30-40 mm Hg, avoiding a sharp rise in pressure during PFOS aspiration, trying to remove the liquid as much as possible and prevent displacement of the flap.

The operation is completed by introducing 1 mm³ of 20% SF6 gas into the eye cavity until mild hypertonicity is achieved.

Results.

In both cases, the intervention was performed in full; no intraoperative complications, including iatrogenic damage to the retina, were noted.

Observation period - up to 12 months. In both patients, according to optical coherence tomography, reduction of macular detachment and sealing of the optic disc fossa were observed. Visual acuity at the end of the observation period was 0.1 and 0.5, respectively.

The key stage of the proposed technique, which contributes to the achievement of favorable anatomical results, is the formation of an ILM flap and using it to close the optic disc fossa, which allows it to be sealed and to create a barrier to the flow of fluid into the macular area.

Conclusion.

The developed method of surgical treatment of the optic disc fossa is promising and requires further research on more clinical material to reliably assess its effectiveness.