Retina | Macula | Vitreous | Retinal Detachment | Diabetic Retinopathy
Macular Degeneration | Macular Hole & Pucker | Giant Retinal Tear
Eye Anatomy
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What is the Retina?
The retina is a thin membrane of neural tissue that lines the inside of the eye. Light passes through the front parts of the eye (the cornea, pupil, and lens) and focuses on the retina. The retina is much like the film in a camera. The retina is the seeing tissue of the eye. Messages pass from the retina along the optic nerve to the brain where the messages are decoded as images that we see.
What is the Macula?
The macula is the center of the retina. It is a specialized part of the retina that gives us the sharp 20/20 vision. The macula is the most important part of the retina even though it is only a few millimeters in diameter. The center of the macula is called the fovea.
What is the Vitreous?
| The vitreous is an egg white like substance that fills the middle of the eye. At birth, the vitreous is very solid much like solid Jell-O. As we age, the vitreous becomes more like water and much liquid or melted jello. It is common for the vitreous to separate from its attachment to the retina and shift forward causing flashes and floaters. This process is called posterior vitreous detachment or PVD for short. A PVD can cause retina tears or retinal detachment. Anyone with a new onset of flashes or floaters should see an eye care specialist for a complete dilated eye examination. |
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Vitreous Detachment
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What is a Retinal Detachment?
If a hole develops in the retina from a posterior vitreous detachment, the liquid vitreous can leak under the retina and cause a detachment of the retina from the back of the eye. A retinal detachment is a medical emergency. Symptoms include flashes, floaters, blurred vision or loss of side vision often described like a curtain coming down over the field of vision. Risk factors for retina detachment include nearsightedness (myopia), trauma, previous cataract surgery, and a family history of retinal detachment.
When vitreous scarring causes retinal detachment, it is called proliferative vitreoretinopathy. |
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Retinal Detachment & Tear
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What is Diabetic Retinopathy?
 In diabetic retinopathy the blood vessels of the retina become abnormal and cause the problems that diabetic patients have with their eyesight. Normally, the blood vessels in the retina do not leak. But with diabetes, the retinal blood vessels can develop tiny leaks. This is called background diabetic retinopathy (BDR). Another problem with the retinal blood vessels in diabetes is that they can close. Abnormal blood vessels may then grow in their place, potentially causing bleeding and scar tissue that can result in a total loss of vision. This is called proliferative diabetic retinopathy (PDR).
»» Learn more about diabetic retinopathy
What is Macular Degeneration?
 There are two main forms of macular degeneration: a dry form and a wet form. Macular degeneration usually starts with the appearance of spots called drusen on the retina. Drusen are considered to be a dry form of macular degeneration. When drusen are present for a long time, the macula may thin and stop working. This is referred to as atrophy or atrophic macular degeneration and it often causes a slow and progressive loss of vision.
In the wet form of macular degeneration, abnormal blood vessels grow under the retina and lift the retina up, very much like the roots of a tree growing under a sidewalk, these abnormal blood vessels are called sub retinal neovascularization, or SRNV. The abnormal blood vessels located under the retina may leak fluid, bleed, and lift up the retina. When this happens, vision is reduced. The longer the abnormal blood vessels continue to leak, bleed, and grow, the more detail vision will be lost.
There is a third form of macular degeneration called pigment epithelial detachment (PED) that occurs in less than 5% of people with macular degeneration.
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What is Macular Hole & Macular Pucker?
 A macular hole is a defect in the center of the macula. With aging, the vitreous shrinks and releases from the retina. If it is attached too strongly to the macula, the vitreous may not release properly. This leads to traction on the macula thereby pulling a hole in the center of the macula. Many macular holes are associated with a thin layer of tissue that covers the macula. This is call an epiretinal membrane. It is also known as a macular pucker or a wrinkle on the retina.
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What is Giant Retinal Tear?
 Vitreous traction may cause very large retinal tears. If the retinal tear is very large (more than 1/4 of the eye), it is called a giant retinal tear. Sometimes, the retinal tear is so big that the retina folds over on itself. A giant retinal tear is a very serious problem.
»» Learn more about giant retinal tear
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