The Macula
The macula is located in the central position of the retina. The retina is the neuronal layer in the back of the eye that transmits information to the brain. The choroid is the layer behind the retina that supplies much of the blood supply and nutrition to the retina. The macula receives the sharpest images that have passed through the cornea and the crystalline lens, and through the vitreous cavity, to be focused on the retina in the macular area. This is our central vision and color vision. Although it is small and only about 10% of the total retina, the macula is absolutely necessary to have normal sharpness of vision and color vision. The rest of the retina cannot compensate for damage done to the macula and provides only peripheral vision. The most sensitive part is the fovea. The foveola is located in the center of the macula and is surrounded by a complex and delicate pattern of blood vessels. Abnormalities in these blood vessels, in the retina, and the blood vessels from the choroid immediately under the retina, are responsible for some types of macular degeneration. All nerve fibers run from the retina into the optic disk or optic nerve and back to the brain. However, damage to the macula is one of the leading causes of permanent blindness in the United States. The most common type is known as senile macular degeneration.
There are other types of macular disease. Diabetes can cause damage to the blood vessels in the retina and cause them to leak clear fluid and blood, which can cause significant damage or edema in the back of the eye. It can also be a result of a mechanical trauma to the eye, such as being hit in the eye with resultant edema in the center of the eye. A hole in the macula can develop from such trauma. Damage may be associated with staring at the sun and different types of drugs can affect the pigmentation in this area. Inflammatory reactions in the eye can cause permanent damage to the back of the eye, as can hereditary diseases of the eye.
Macular degeneration can occur at any age, although it is most common in older adults. The most common symptom of macular degeneration is blurring of vision for distance such as a street sign. Close-up reading can be materially affected. Shapes and contours of objects can appear distorted and colors can appear to be dull. Blind spots in the field of vision may be experienced. One must understand that macular degeneration can cause "legal" blindness, but it would not cause absolute blindness. The peripheral retina will remain intact in these conditions, thus you will still have your peripheral vision.
As with all other eye conditions, complete comprehensive examination of the eyes by an ophthalmologist is the most important step in identifying and treating macular disease. Examination requires use of special instruments such as a slit lamp, biomicroscopy, ophthalmoscope, indirect ophthalmoscope, and three mirror examination through a dilated pupil and possibly, after dilation, pictures of these abnormal blood vessels with fundus photography and fluorescein angiography. This is a test in which dye is injected into the arm and then, with rapid sequence photography, one is able to study carefully the dynamic circulation in the back of the eye. If one does determine that there are significant problems with the blood vessels in the back of the eye, some treatment can be instituted with a laser. The expertise in diagnosis and treatment is to be able to follow the disease and treat those cases where progression of the disease is likely and to follow those cases where progression is not likely.
Experimental evidence has shown the possibility that the use of the mineral zinc can be of use in retarding the progression of macular degeneration. There is also some belief that ultraviolet light can cause some damage to the retina. Therefore it is advisable to use an ultraviolet filter in your glasses.
The physician will examine you and be able to determine when and if treatment would be needed. If treatment is not needed, there are other things that can be done to improve your vision, especially at near, namely low vision aids. There are many types of optical devices that are available to improve vision for reading when damage to the macula has occurred. Visual impairment is not correctable by the usual prescription of eyeglasses. These devices magnify the images focused on the retina. They cannot restore vision, but they can maximize the vision that your eyes are capable of seeing.
These visual aids range from hand-held magnifying glasses to magnifying loupe glasses to television screens, telescopic lenses, etc. If vision is more difficult to satisfy and a total determination of your visual needs is done, then the best visual aids can be recommended. In addition, you can enlist the aid of other organizations that provide services for patients with sub-normal vision.
As with all medical conditions, it is important that you understand what medical problems you are facing and, when you do that you will better understand what options for treatment you have.
With one eye covered, focus on the small dot located in the center of the grid. Once you are focused on the small dot, please answer the following questions:
If the lines do not appear straight or areas of the grid are distorted, contact us to schedule an appointment for further evaluation.
Causes & Symptoms
The exact reasons for senile macular degeneration are not well understood. It starts with abnormal pigmentation in the back of the eye and frequently abnormal blood vessels coming from the choroid into the macular area. Damage to the vision may occur in both eyes, and may be progressive.There are other types of macular disease. Diabetes can cause damage to the blood vessels in the retina and cause them to leak clear fluid and blood, which can cause significant damage or edema in the back of the eye. It can also be a result of a mechanical trauma to the eye, such as being hit in the eye with resultant edema in the center of the eye. A hole in the macula can develop from such trauma. Damage may be associated with staring at the sun and different types of drugs can affect the pigmentation in this area. Inflammatory reactions in the eye can cause permanent damage to the back of the eye, as can hereditary diseases of the eye.
Macular degeneration can occur at any age, although it is most common in older adults. The most common symptom of macular degeneration is blurring of vision for distance such as a street sign. Close-up reading can be materially affected. Shapes and contours of objects can appear distorted and colors can appear to be dull. Blind spots in the field of vision may be experienced. One must understand that macular degeneration can cause "legal" blindness, but it would not cause absolute blindness. The peripheral retina will remain intact in these conditions, thus you will still have your peripheral vision.
As with all other eye conditions, complete comprehensive examination of the eyes by an ophthalmologist is the most important step in identifying and treating macular disease. Examination requires use of special instruments such as a slit lamp, biomicroscopy, ophthalmoscope, indirect ophthalmoscope, and three mirror examination through a dilated pupil and possibly, after dilation, pictures of these abnormal blood vessels with fundus photography and fluorescein angiography. This is a test in which dye is injected into the arm and then, with rapid sequence photography, one is able to study carefully the dynamic circulation in the back of the eye. If one does determine that there are significant problems with the blood vessels in the back of the eye, some treatment can be instituted with a laser. The expertise in diagnosis and treatment is to be able to follow the disease and treat those cases where progression of the disease is likely and to follow those cases where progression is not likely.
Treatment
Use of the laser, a high intensity, focused light beam that can seal leaking or poor blood vessels, is used in these cases. When other causes of macular degeneration are found, such as inflammation or injection of the eye, treatment, such as antibiotics or steroid eye drops can be used. The laser does remain one of the mainstays of treatment for macular degeneration or diabetic macular degeneration. The laser is easy to perform on an outpatient basis and need not require hospitalization and there is a minimum of discomfort during and after treatment.Experimental evidence has shown the possibility that the use of the mineral zinc can be of use in retarding the progression of macular degeneration. There is also some belief that ultraviolet light can cause some damage to the retina. Therefore it is advisable to use an ultraviolet filter in your glasses.
The physician will examine you and be able to determine when and if treatment would be needed. If treatment is not needed, there are other things that can be done to improve your vision, especially at near, namely low vision aids. There are many types of optical devices that are available to improve vision for reading when damage to the macula has occurred. Visual impairment is not correctable by the usual prescription of eyeglasses. These devices magnify the images focused on the retina. They cannot restore vision, but they can maximize the vision that your eyes are capable of seeing.
These visual aids range from hand-held magnifying glasses to magnifying loupe glasses to television screens, telescopic lenses, etc. If vision is more difficult to satisfy and a total determination of your visual needs is done, then the best visual aids can be recommended. In addition, you can enlist the aid of other organizations that provide services for patients with sub-normal vision.
As with all medical conditions, it is important that you understand what medical problems you are facing and, when you do that you will better understand what options for treatment you have.
Test for Macular Degeneration
Amsler Grid
The Amsler Grid is a simple test used to assess the center of the retina, or the macula. Consisting of a grid with evenly spaced vertical and horizontal lines and a small dot in the center, the Amsler Grid can aid in detected macular degeneration. To complete the self-test, following the instructions below.With one eye covered, focus on the small dot located in the center of the grid. Once you are focused on the small dot, please answer the following questions:
- Can you see the corners and sides of the square grid?
- Are the lines wavy or straight?
- Do you see any missing areas or holes in the grid?
If the lines do not appear straight or areas of the grid are distorted, contact us to schedule an appointment for further evaluation.
