Age-related macular degeneration
Retina the inner layer of the eye, which functions as the film into the camera, is covered by two other layers: the choroid, and the sclera. These three layers form about 80% of the eye fundus. In the back of the eye beside the optic nerve is a very small part of the retina, the macula. This sensitive area of the eye is able to distinguish details, such as the characteristics of a person, or words of a text. This detailed vision is called central vision. The damage to central vision is very important and most often due to macular disease. Over the years, increasing the age limit and the progress of medical science, several less known diseases appears. One of them is age-related macular degeneration. The incidence of the disease is 6% to 10% of people between 65 and 75 years and 19% to 30% in people aged over 75.
The degeneration in the macula result is loss of central vision, but not the peripheral. Loss of central vision is not considered practical blindness. However, considered legal blindness and is the most common cause of irreversible blindness in the western world.


Age-related macular degeneration occurs more frequently in patients with:
• vascular diseases (hypertension, diabetes) that affect blood flow in the central area of the eye.
• obesity (which avoid the accumulation of sufficient quantities of the very useful fat-soluble carotenoids such as lutein and zeaxanthin).
• first-degree relatives with age-related macular.
• poor eating habits.
• old age.
Additional risk factors:
• family history of hypertension, hypercholesterolemia, and cardiovascular disease.
• solar radiation.
• smoking (causing spasm of blood vessels).
• gender (more often women than men).
Most patients find vision problems after 50. The initial symptom is geometric distortion of the objects, in conjunction with a reduction of resolution and progressively the central part of the visual field of the patient is inactive.

Types of macular degeneration

a) Dry type macular degeneration
It is the most common form and occurs in 85-90% of people with advanced macular degeneration. Usually, it causes a large reduction of vision. It is caused by destruction or thinning of macular tissues. Yellowish deposits in the form of small hunchback (Drusens) under the retina, is usually the first sign. As the deposits grow-up, cause the death of visual cells, creating atrophic areas resulting in the gradual reduction of central vision.
b) Wet macular degeneration
This form of degeneration causes rapid and large decrease in visual acuity and occurs only in 10-15% of people with advanced macular degeneration. In this form, for yet unknown reasons, abnormal blood vessels grow under the retina. These new blood vessels (choroidal neovascularization), are susceptible to produce liquid (edema) or bleeding, destroyed easily and cause scar tissue in the central part of the retina (macula). The patient feel the deformation of the objects observed. The earlier discovered the neovascularization, the more likely it is to save a higher quality of central vision.

Macular examination

The ophthalmologist check the retina for the presence of Drusens or other signs of degeneration, using simple ophthalmic instruments. The slit lamp examination using a special lens is a simple process control. Self-control of central vision, even the smallest possible change is to use the table Amsler. Click here for self-control.
The suspicion of macular degeneration requires special exams by other more specialized imaging systems such as fluoroangiografy and optical coherence tomography (OCT), to identify the location and type of defects.
To make fluoroangiografy mast be injected a dye in your vein. The pigment is transferred through the circulation to the eyes. Using a special camera takes a series of photographs of the retina as the dye fluoresces and recorded a number of anomalies.
Examination with optical coherence tomography (OCT), follow simpler procedures. In my practice as equipment I use the SOCT Copernicus as spectral coherence tomography (Spectral Domain OCT) last generation with an axial resolution of 5,6 μm.
With this method the three-dimensional display is much more analytical than the famous MRI.

Treatment
Recently, there was much progress in the treatment of the wet but not the dry form.
Modern treatments of macular degeneration in addition to prophylaxis and LASER application, the intraocular injection of drugs, LASER application in conjunction with administration of specific substances and surgical treatment.

Prophylaxis


  • The diet should be rich in fish, fruits, vegetables and nuts.

  • Physical activity can reduce the risk of macular degeneration, by 25%.

  • Absolute abstinence from smoking is essential.
  • Avoid taking aspirin if possible. The aspirin is only allowed if the physician has recommended a specific treatment due to a particular health problem. The aspirin with a mild anticoagulant activity could cause bleeding in the retina in patients who already have macular degeneration.
  • A frequent eye check after age of 50.


  • Avoid unnecessary sun exposure and use of sunglasses with UV filter.


  • Taking vasodilator multivitamins and minerals and antioxidants agents - antioxidant enzymes which restrain the accumulation of free radicals which are extremely harmful to the macular cells.
  • Ongoing studies show that high doses of antioxidants (vitamins and zinc) may improve or slow the progression of macular degeneration.

LASER
In some cases, photocoagulation of the neovascular membrane in wet macular degeneration, can enhance or reduce the loss of central vision. The LASER beam (a light with high energy) is converted into heat when falls in part of the retina that needs treatment. The photocoagulation heat is destroys the abnormal vessels, dry the liquid, and prevent the spread of blood vessels. A scar formed as a result of this treatment. The scar cause permanent blind spots in vision that usually does not see the patient.
One of the problems is that only 20% of patients with wet form meet the criteria for this treatment. Since macular degeneration is an aging process, LASER prevents or reduces the loss of vision. However, vision may continue to decline. The decision to use photocoagulation depends on the appearance and location of neovascularization and the amount of fluid or blood. In some cases, LASER can not be usefully. LASER is not useful in cases with dry type of macular degeneration.

Photodynamic therapy (PDT)
When abnormal blood vessels found in the center of the macula, the usual LASER is not recommended because it will result destruction of retinal cells located above the abnormal blood vessels and loss of central vision. In these cases, is used a special treatment called photodynamic. For this treatment, is injected into a vein in the hand a photosensitive drug (dye). The dye is taken up by new vascular vessels of the macula. Special type low-energy LASER is applied to those new vascular vessels. The light activates the drug, resulting in the obstruction of abnormal blood vessels without destroying adjacent healthy tissue.
The goal of this type of therapy is not to improve vision, but to stabilizing or slowing further loss.
Photodynamic usually not permanently destroy the abnormal blood vessels and may need to be repeated every 3 months for at least 1-2 years. About 20% of patients respond to treatment.
Photodynamic therapy works best when applied at early stages of the disease.

Intraocular injections
The most common treatment since 2005 is the intraocular drug administration by injections.
Drugs such as LUCENTIS, MACUGEN AVASTIN, inhibit the production of pathological blood vessels, leading to absorption of retinal edema and reducing inflammation. After one month is retesting with OCT and if there is still pathological findings we perform another injection.
The results are very satisfactory but the patient should be examined frequently for possible relapse.
Peribulbar or retrobulbar injection is similar in action to intraocular administration. The method has not equivalent effect as the intraocular administration, but sometimes are preferred option because this method avoids some complications and side effects.
These treatments take place only in conditions of surgery room.

Surgery
Another therapeutic method for neovascular membranes in the center of the macula is surgical removal, or macular translocation to another area where there is healthy tissue. Unfortunately the possibility of improving vision is about 5-10%. The results of macular translocation are better, but the potential postoperative complications are quite serious.

Low vision aids


In the case of advanced damage or when all methods of treatment have been exhausted or have failed can be used low vision aids. These are special glasses, magnifying lenses, computers witch enlarge the objects or the growing field of patient.


The future...



Many alternatives considered, including the prolonged infusion of substances with special devices implanted intraocular nanotechnology, medicine taken by mouth to reduce the development of abnormal vessels and new surgical techniques, which may in the future to help patients with age-related macular degeneration.
 
hondos-new-banner