The retina of the eye is the innermost coating of the eyeball and it is essentially a thin membrane formed by pigmented, nerve and photoreceptor cells.
The function of the retina is to transform the light stimuli into nerve impulses, and photoreceptors enable the transmission of the information to the brain.
Among the cells of the retina, there are first the cone cells (responsible for colour vision and sensitive to very bright light), and rod cells, sensitive to dim lights but not to colours, which activate when light is scarce.
The retina can be affected by different kinds of degenerative diseases following general pathologies, such as vascular sclerosis, arterial hypertension, diabetes or vascular pathologies that have different, serious implications on the sight, according to the retinal area affected. Cases of retinopathy or degeneration of retina affect around 20,000 people every year in Italy.
What are the main diseases of the retina
Retinopathy is classified into different kinds that differ on the basis of the causes that
generated them. The main forms are:
- Diabetic retinopathy, which can be divided into proliferating, with neovessels, haemorrhages and membranes, and non-proliferating, characterized by microaneurysm, exudates and microhaemorrhages;
- Arteriosclerotic retinopathy, typical of the elderly people, which causes the shrinkage of arterial blood vessels, vessel wall disorders with the occurrence of exudates, haemorrhages and thrombosis which damage the retina;
- Macular degeneration, that can be congenital, juvenile and senile, which affects the macula, an important area of the retina that provides the central vision;
- Retinitis and inflammation of the infectious retina, caused by bacteria, virus, mycetes and to a lesser extent by protozoan and non-infectious retinitis;
- Retinitis pigmentosa, a hereditary degenerative disorder of the photoreceptors of the retina (cone cells and rod cells) caused by a malformation of these or of the retina;
- Detached retina, the main causes of which are genetic predisposition, myopia, peripheral degeneration, traumas, uveitis, but also eye ageing, diabetes and some genetic diseases like Ehler Danlos and Marfan syndromes.
How to recognize the symptoms of the diseases of the retina
Retinopathy symptoms differ according to the type of disorder that affects the retina.
Diabetic retinopathy is one of the main causes of visual impairment and blindness. In Italy, the patients who suffer from diabetes consist of 4.5% of the population, that is around 2,500,000 inhabitants. It is the most frequent vascular disease of the retina. It comes from the damage inflicted on retinal vessels following a metabolic decompensation which occurs in diabetes. Initially it can be asymptomatic and it can appear only when the patient has reached an advanced stage with partial or total visual impairment.
In arteriosclerotic retinopathy, the thickening of blood vessels or ocular arteries can cause partial or total blindness if the whole retina is affected.
The macular degeneration makes images distorted, gives difficulty of central vision, macular vision, altered colours and blurry lights.
Infective retinitis appears with sensitivity to light (photophobia), ocular reddening (hyperaemia) and eye pain.
In retinitis pigmentosa, the first symptoms appear usually in youths, between 10 and 30 years old, with difficulty in night vision, a slowed adaptation from dark to light and vice versa, a tunnel shrinking of the visual field and photophobia.
Retinal detachment is the separation of the retina from the underlying tissue, the choroid. It is manifested by the occurrence of a curtain or a dark shadow on the visual field, due to the portion of the detached retina that no longer works. Often it is preceded by the sudden occurrence of light flashes (photopsia) or moving bodies (myodesopsia) on the visual field. The detached retina occurs more frequently in middle-aged subjects with a medium-high level of myopia. It affects about one person out of 10,000 every year. The most frequent cause of the detached retina is a retinal tear, but other factors of risk are high myopia, surgical intervention to extract the cataract, and traumas.
How to treat retinopathy
Therapies for the various kinds of retinopathy differ according to the nature of the disorder.
The ophthalmologist assisted by proper diagnostic examinations can prescribe pharmacological treatments suitable for the identified pathology. Promptness is essential to intervene, resolve or limit serious damages that such diseases can cause to the visual apparatus.
For diabetic retinopathy it is important first of all to treat the diabetes and associate laser therapy operations (photocoagulation laser) to stop new capillaries from arising, avoiding the retina from detaching. If the retina is already detached, it is possible to intervene surgically.
If the arteriosclerotic retinopathy concerns the central blood vessel, it is possible to give drugs in order to stop the disease. For the oedematous vein thrombosis, an intravitreal-intraocular therapy is recommended. It uses anti-VEGF drugs injected directly inside the eyeball. These injections are really brief and they are performed using a topical anaesthetic (anaesthetic eye drops), which are unperceivable by the patient. The result is visible in a very short time. In the ischemic form the laser therapy is preferred;
For macular degeneration there are no resolution treatments, but it is possible to limit the damages. The exudative form is treatable with drugs for angiogenesis to inject directly into the eyeball, while for the atrophic form it is possible to delay the evolving process with supplements.
Infectious retinitis must be treated with antibiotics both in topical form (eye drops) and systemic form.
Retinitis pigmentosa is a hereditary disease and nowadays there is still no treatment that can cure the degenerative feature of the disease. The ophthalmologist can, however, slow down the progression, by prescribing supplements that give some results.
In order to prevent the retina from detaching, it is fundamental to undergo regularly ocular examinations whether or not eye problems that can foster the detachment occur. It is possible to intervene with laser therapy to reinforce the retinal tissue, while if the detachment of the retina has already occurred, it is possible to intervene with a traditional extracapsular operation or with the vitreoretinal surgery.
Vista Vision clinics are cutting-edge with technological innovations. They are provided withthe best diagnostic instruments, photocoagulation laser, micropulse laser for diabetic retinopathy with macular oedema and Central Serous Chorioretinopathy (CSCR) and surgery like the mini-invasive vitrectomy (MIVS 27 gauge) to intervene on retinal pathologies.