Retina
The Retina is the inner layer of the eye, with a highly complex stratified structure which assures its function as a receptor and transmitter of images
There are several anatomical zones of the retina, but the most relevant distinction can be made between the posterior part situated just opposite the pupil (the only part really used for vision) and the rest of the retina.
There are many retinal conditions which can threaten the sight, but for their high frequency we mention just 4:
Macular Degeneration; Retinal tears; Retinal Detachment and Diabetic Retinopathy.
Macular Degeneration
There are many types of macular degeneration, but the most frequent form in the western world is the one related to ageing. Find out more here.
Retinal tear
A Retinal tear appears hen the content of the vitreous cavity, a gel or liquid-like transparent substance called vitreous, detaches itself from the walls of the eye (this detachment happens to all humans at some moment in life) As the wall of the eye has the retina as its innermost layer, there are cases in which the vitreous instead of completely loosing itself free, detaches itself from all but a little area where its attachment to the retina is too strong, and consequently tears the retina in that area.
Once a retinal tear forms, there is a free way for the liquids contained within the vitreous cavity to pass underneath the retina and completely detach it from the more external layers of the eye’s wall (in that case a retinal detachment forms).
Which are the symptoms of a retinal tear?
Although a retinal tear can be symptom-less, the most common are sudden shower of floating black spots appearing within the field of vision of the diseased eye.
What the patient should do?
Anyone experiencing this kind of symptoms should seek the care of an eye doctor. A swift detection will ensure a successful treatment and avoids the tear transforming itself into a Retinal Detachment.
How is a retinal tear treated?
After diagnosing a retinal tear, the eye surgeon will recommend a treatment called “prophylactic laser retinal photocoagulation, or simply laser treatment.
The rationale behind retinal tear treatment is that if one is able to “seal off” the margins of the tear then no liquids from the vitreous gel find their way through the tear underneath the retina, consequently detaching it.
The “sealing off” is done by creating laser scars around the tear because the scars act as high adhesion “welding” spots between the retina and the layers underneath it.
Retinal Detachment
When the retinal tear goes undiagnosed then a retinal detachment may appear, by the passing of liquid from the vitreous cavity trough the tear underneath the retina.
The most common symptoms of a retinal detachment consist in a “dark curtain surging” – this is because most frequently the detached portion of the retina is the one above the equator of the eye and because of the normal inverted projection of the images within the eye, this is precisely the portion “viewing” the inferior half of the vision field.
This is a serious condition, because if left untreated for a sufficient length of time it generally leads to complete loss of sight.
Retinal tear leading to detachment
How is a Retinal detachment treated?
The treatment of this condition is almost always surgical, and it consists in several techniques depending of the type and degree of retinal detachment. Generally it is followed by a rather prolonged period of rehabilitation, and although the retinal surgery has seen important advances in the last years, the seriousness of the condition and the complexity of the surgery make the final visual outcome a less certain one.
What should a patient suspecting to have a retinal do?
In order to improve the outcome in the management of a detached retina, time is essential.
Any patient experiencing a sudden loss of vision, particularly suggesting a “surging curtain” must seek immediate ophthalmologic assistance. If treated in time, many retinal detachments solve with minimal or no vision loss.
Diabetic retinopathy
Diabetes Mellitus (High blood sugar) is a general metabolic condition affecting all the body, and the eyes are the organs where the disease makes itself more obvious.
The main site of diabetes induced damage is the retinal vasculature. Silently and progressively the tiny retinal vessels suffer alterations which in the latter stages produce loss of vision. If not treated, diabetes retinopathy can lead to blindness.
Diabetic Retinopathy (active bleeding
from
the diseased retinal vessels is clearly visible)
What should a diabetic patient do?
Any recently diagnosed diabetic patient should have the retina explored by the eye doctor, in order to determine the presence of signs suggesting diabetic retinopathy.
Once the base-line situation is known, the ophthalmologist will recommend the retinal checkups with a certain periodicity.
How is Diabetic Retinopathy treated?
When the disease reach a certain stage known to immediately precede serious sight threatening complications, the eye surgeon will opt for initiating laser treatment, which consist in applying laser burns on the parts of the retina not used for vision. This stops the deterioration process and avoids the apparition of serious complications which otherwise would lead to blindness.
Laser treated diabetic retinopathy
Many efforts are presently done by the medical investigators to come up with new medical less aggressive treatments for diabetic retinopathy, but at the time this text is written the base of the management remains to be the laser photocoagulation of the retina. |
