RETINAL DISEASES:

The retina is the tissue layer that lines the inner part of the back of the eye. It is the sensory layer of the eye; it has the ability to receive the light rays coming into the eye and convert them to small electrical impulses which are then transmitted to the brain for interpretation. The retina is much like the film in a camera. The light image is recorded onto it.

The retina in actually a multilayered structure which is extremely thin. Because it is so highly sensitive (much more so than any camera film ever produced), it requires a high level of metabolism to do its job. This means that it consumes a lot of oxygen. In fact, the retina has a higher usage of oxygen per unit weight than any other tissue in the body including the brain itself.  For this reason, any disease, injury or other problem that reduces the oxygen level to the retina can, and often will, have an effect on vision.

There are many disorders of the retina itself which can interfere with its ability to see light.  Hemorrhage such as in diabetic retinopathy, swelling from injury, age-related hardening of the arteries and its consequent poor circulation and toxic chemicals or drugs are just a few of the problems that may decrease a person's vision. Just as putting a new lens onto a camera which has an old, outdated roll of film will not improve the picture, changing one's eyeglasses will not improve the vision if it is the retina which is diseased or injured.

The retinal disease that most older patients worry about is macular degeneration.  At the present time, there is no known specific cause for this problem, and there is no known preventive measure to avoid it.  There are many over-the-counter preparations which are heavily advertised as being effective in one way or another, but unfortunately, most of these dietary supplements are not proven to be of real value.  There are different types of macular degeneration, and they are managed differently.  For a more complete discussion of this disease, please click here. 

The retina is the only part of the eye in which we can actually look directly at blood vessels. For this reason, examination of the retina may give some information about one's general health. For example, if you are a diabetic and have been so for at least about 6 years, changes from diabetes might be observable by our looking at the retina. The same is true for high blood pressure. Keep in mind, though, that if the retina appears normal, this does not mean that you do not have diabetes or high blood pressure, only that it hasn't shown up in your eyes. You still need regular medical examinations by your primary care physician.

When ophthalmologists look at the retina, it is often done with the pupils dilated. This simply allows better visibility by making a larger opening through which we examine it. There may be retinal problems that only are present at the very outer edge of the retina, and these often cannot be seen without dilating drops. In addition, a larger opening permits a better three-dimensional view. This is important in evaluating for other diseases such as holes in the retina. Retinal holes and peripheral retinal thinning may lead to retinal detachment, and it is far better to detect problems early when they are more readily treated. Glaucoma, which affects the optic nerve is often detected by the very same type of examination. And retinal tumors, while not very common, may only be visible through a dilated pupil as well.

Our comprehensive eye examination typically includes a retina evaluation with dilating drops. These do take time to work, and that is why your visit to our office might be longer than you have experienced in the past. If you notice the onset of flashing lights or floating spots or "cobwebs" in your vision, please call our office. Often, these sensations are normal, but since they may represent retinal problems, you should be examined.

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