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Retinal detachment
The role and position of the retina are easy to understand if we compare it to a film in a camera. If the film is ‘damaged’, the quality of picture will not be good, regardless of how perfect the optics of the camera is (concerning the cornea, anterior chamber, pupil – aperture, lens and vitreous body).
A ray of light (a signal) travels through these elements on its way to the receptors on the retina. The retina is a part of the eye’s ‘nervous system’ and is made of a fantastic net of nervous cells – photoreceptors, which collect visual information and send it to the ‘processing centre’ in the occipital part of the brain. All of these segments are important for having a good quality of a picture and its recognition.
Retinal detachment happens when the neural part of the retina, consisting of photoreceptors, separates (ablates) from its foundation-retinal pigment epithelium, and the fluid from the vitreous body accumulates under the retina. The retinal pigment epithelium has an important metabolic and protective role. Therefore, in case of detachment, photoreceptors die, which leads to loss of vision. This is an ACUTE condition and requires an URGENT surgical intervention.
Complains of the patients prior to retinal detachment usually include a feeling of sudden, spontaneous ‘flashes’ or ‘lightening’. This is because of strong tracking of the vitreous body, or forming one or more retinal defects – breaks, so-called ruptures that precede the detachment. If the patient immediately after first signs visits the ophthalmologist, the ruptures as a potential cause of possible detachment could be discovered and laser barrage as prevention could be done.
But, if the retina has already been detached, laser barrage is of no use any more. Surgery is the only way to reattach the retina and preserve visual acuity. As a sign of retinal detachment, the patient could notice a small or a big ‘curtain’ or a ‘shadow’ in the visual field, most frequently in its lower area, since the retinal rupture usually develops in the upper retinal area, which is projected as a reverse picture. A certain number of patients do not pay attention to the first symptoms and think they will not last for a long time, especially when the vision of the other eye is intact.
However, if retinal detachment strikes the better eye, the patient soon takes it seriously and seeks help. Detachment usually progresses fast, and if the macula is off, without surgery loss of vision might comprise only light recognition. The macula (yellow spot) is the most sensitive area. Its functional damage occurs extremely fast and, despite being very small, of only 5 mm2, it is very important for vision function with the largest concentration of the photoreceptors. So, when the macula is detached, its nourishment ceases and the cells are dying.
Full visual acuity can only be preserved if the macula is not detached. For this reason, as soon as the first signs of the disease (‘the curtains’) appear, an URGENT SURGICAL INTERVENTION has to be performed, within 24 hours if possible. Before the operation, the patient has to lie on his back to postpone or prevent macular detachment. If the macula is already detached, the intervention can be done within 3-7 days. If, however, the intervention is delayed for a while, irreversible changes in the retina and especially in the macula appear. The recovery of visual function will not be complete in the case of much delayed surgery, regardless of the technical success of the operation.
According to the mechanisms of retinal detachment occurrence, it is mostly due to a retinal break - rupture, so-called rhegmatogenous retinal detachment. The rupture can occur during the vitreous detaching process, in case of very strong adhesive power between the retina and the vitreous body, causing a retinal tear at the site of significant vitreoretinal adhesion. In this condition, the fluid from the vitreous cavity can easily pass through the break in the retina into the subretinal space and cause the separation of the neural retina from the underlying retinal pigment epithelium-RPE.
A higher risk for that could be expected in some cases: in myopic people, in the normal aging process in the vitreous and increased mobility of the vitreous body, as a result of a sudden trauma of the eye, blunt or perforative, etc. On the other hand, a large number of eyes with a retinal rupture never develop detachment, because in the absence of strong adherence between the vitreous body and the retina, the physiological forces in the choroids and pigment epithelium manage to keep the retina in its place. Retinal breaks (holes, tears, dialyses) in these eyes are discovered by chance during an ophthalmic examination because these patients do not have the typical complains.
Another large group of retinal detachment includes tractional retinal detachments, caused by the traction of the retina due to the presence of retinal membranes, most frequently in cases of long-lasting not operated retinal detachment or the presence of membranes with blood vessels in the vitreous body attached to the retina, e.g. in advanced diabetes. The third group of detachment includes those with the fluid effusion below the retina as in, for example, eye tumor, choroid inflammation and inherited anomalies.
THE TREATMENT
The treatment of retinal detachment is only surgical. The aim of the treatment is to close the rupture, by provoking the cicatrix round the break between the retina and the underlying choroid. This is treated with either cryopexy (local freezing of ruptured places) or laser photocoagulation. In order to achieve this, the rupture has to be drawn near the choroid either from the outside with scleral buckling, silicon sponge, and puncturing the fluid below the retina or from the inside using gas tamponade. Prior to injecting the gas, the vitreous body is removed. This intervention is called VITRECTOMY and is used more frequently than the classic scleral buckling and puncture operation. Thus, by removing the vitreous body the possibilities of the formation of other ruptures and redetacments are less, and the eye length is not changed as in the scleral buckling procedure. Vitrectomy is used as the main surgical approach in retinal detachments with the presence of retinal membranes, in diabetic patients and long-lasting retinal detachments.
During the operation, these structures are totally removed, enabling a sustained retinal attachment. In these complicated cases, silicone oil can be used instead of gas tamponade. Its advantage over the gas is visual recovery almost immediately after the surgery. Therefore, it is always used in case of the last eye, but requires an additional intervention, i.e. extraction of the silicone oil, approximately two-three months after the first operation. It is used in more damaged eyes. In very complicated retinal detachments, like trauma or long lasting retinal detachment, even after uneven, brilliant previous surgery, the formation of new membranes is expected as a normal healing process. In such cases, one or more additional operations are required.
THE SUMMARY
It is important to recognize the signs of a retinal break development and to use laser photocoagulation to PREVENT the detachment. If the detachment is already present, the permanent loss of visual acuity has to be prevented by an URGENT surgical intervention within 24 hours, in the centers where this surgery is performed, before the macula becomes detached. If this does not happen, it is necessary to prevent further progressive loss of vision and the development of other, more serious forms of detachments by an EARLY intervention within not more than 7 days.
The longer the period from the onset of symptoms and the operation, the less satisfactory is the functional result, regardless of the complete anatomical reattachment of the retina. Untreated case leads to definite blindness within a year.
Special Hospital SVETI VID cherishes high-quality contemporary vitreoretinal surgery with a very experienced team of experts in this field. In this place, a new, up to date vitreoretinal surgery has started, a completely new approach, 25 and 23 gauge small incision surgery, sutureless, very much alike the small incision in anterior segment cataract surgery. With the perfect visualisation during the surgery it is possible to reach the very periphery of the fundus and thus make perfect conditions for a very precise and gentle surgical approach which ends in a complete retinal re-attachment and visual recovery.
Macular surgery here is on a very high level with great attention stressed on it. Only a few centres in the world have developed such subtle techniques in treating macular problems, especially macular holes, and membranes in that region (pucker), that track the macula and change its structure with distorted vision, as a consequence. Of great help in diagnostics today is of course optical cocherence tomography (OCT) with an opportunity to see inside the very details, almost histologically, in the structure of the macula, and the optic nerve fiber layer. The frontiers of operability are stretched towards the highest potential, with the precision of surgical techniques and an exceptionally top-equipped hospital with devices of the latest, advanced technology.
