Macula lutea is a circular area oriented in the central retina. Retina is the inner, neural tissue of the eye, where the light is transformed in electrical signal and is transmitted through the optic nerve to the brain. Macula is responsible for central vision and recognition of faces and color vision. Any disorder on this area causes central vision damage.
Wet Age Related Macular Degeneration
Wet AMD causes loss of central vision within a few days. The characteristic of this type is the formation of new pathological vessels on the macula. These vessels are very fragile and often there is blood or fluid leakage. As a result, the macula is lifted from its normal position in the back of the eye. In wet AMD, macular damage occurs very quickly.
Age Related Macular Degeneration: Wet type
An early symptom of wet AMD is the straight lines, which appear wavy. If anyone notice such changes in his vision, he should contact to an ophthalmologist for a fundus examination under dilated pupils.
Dry Age Related Macular Degeneration
Dry AMD occurs when macular light-sensitive cells are slowly destroyed, so that the vision is gradually decreased. As the condition becomes worse, patients may notice a blurred spot in their central field of view. Over time, macula loses its function, so the central vision is lost in the affected eyes.
The most common symptom of dry AMD is the blurred central vision. There may be also difficulty in recognizing faces, or maybe there is more need of good light conditions when reading or in other activities. Dry AMD usually affects both eyes, but vision loss precedes in one eye. Characteristic finding on fundoscopy is the appearance of drusen.
Drusen characteristics
Drusens are yellow-type deposits, which are located under the retina. There are seen often in people over 60 years old. The ophthalmologist may notice the drusens through fundoscopy (examination through dilated pupils).
Drusens do not cause vision loss by themselves. In fact, scientists are not sure about the exact connection of drusens with AMD, but it is certain that an increase in the number and size of drusens, increases the patient's risk of developing AMD.
Fundus photo showing drusen in dry AMD
Age Related Macular Degeneration Diagnosis
The ophthalmologist may suspect AMD if the patient is over 60 yo, and mentions recent changes-irritations in his central vision. In order to examine these signs it is necessary to dilate the pupils of the eye, using eye drops. This examination is called fundoscopy and allow us examine the macula in detail.
The AMD is diagnosed during comprehensive eye exam which includes:
Visual Acuity test: How well can a patient see the numbers which are displayed on a screen table.
Fundoscopy: The pupils are dilated using drops and the ophthalmologist uses a special magnifying lens to examine the whole macula, the optic nerve and the retina in general. After the examination and for the next few hours the near vision may remain blurry due to the dilation.
In addition, your ophthalmologist may request further tests for better condition's assessment of your eyes. During the examination, Amsler grid test can be used. The Amsler grid test is a small card which includes small squares like chessboard. Each eye is tested separately and is asked from the patient to focus on a central spot, while observing the straight lines. If the lines become wavy or if some boxes are missing from the network, we may assume the presence of AMD.
You may print your own Amsler grid test and use it at home!
Another useful special examination which is used for AMD diagnosis is fluorescein angiography. Through intravenous injection we use a specific dye and then we can photograph the blood circulation of the fundus. Thus, the ophthalmologist may see any blood vessels leakage. A similar examination which uses another type of dye is called Indocyanine Green Angiography or (ICG Angiography). In addition a non-invasive popular technique which gives us useful results in some seconds about AMD’s diagnosis is called Optical Coherence Tomography (OCT).