Vision

What is age related macular degeneration (AMD) eye disorder?

Age related macular degeneration (AMD) is a chronic eye disorder that occurs more commonly after age 50. It results primarily in the loss of central vision. It is marked by deterioration of the macula, a spot of densely packed specialized cells centered at the back of the retina. These cells allow you to see color and fine detail. Damage to these cells can leave you with a blind spot in the central portion of your vision.

There are two types of AMD: dry and wet.
With dry AMD, initial changes occur in the retinal pigment epithelium, a thin layer of tissue sandwiched between the photo-sensitive cells of the retina and a layer of blood vessels. The choroids is the nourishing vascular coat of the eye that extends from the iris back to the optic nerve. The choroids lies between the retina and the tough outer shell of the eye called the sclera. The RPE forms the outermost surface of the retina and provides a critical passage way for nutrients and waste products between the retina and the choroids. Dry AMD tends to progress slowly and some people may not be bothered by it unless they live to a very old age. Evidence suggests that certain vitamins and minerals in your diet may help slow the progression of AMD.

The wet form of AMD is characterized by abnormal blood vessels that grow from the choroids into the space underneath the retinal pigment epithelium and the retina. Plasma and blood can leak into tissues and destroy light sensitive cells. Almost all cases of wet AMD start out as the dry form. Wet AMD also progresses much more rapidly than dry form. If dark spots are seen in the center of your vision or wavy visual distortions, these may be signs of wet AMD. One of the most common and effective treatment for wet AMD is the use of anti-angiogenic medications. These medications are injected directly into the eye which will prevent or retard the growth of new abnormal blood vessels by blocking the effects of a growth factor that these blood vessels need to thrive.

Other older therapies for wet AMD include photocoagulation and photodynamic therapy. These destroy the abnormal blood vessels beneath the retina. These procedures have certain drawbacks and are also limited by where and to what extent the vessels have formed.

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How does an image reaches your brain through your eye? What are age related eye problems?

Eyes are far superior to any existing technology because they are made of living tissues. Eyes move and function together in perfect synchronization. Each eyeball makes many rapid adjustments for brightness, focus and internal pressure. The journey of an image to your brain includes five steps:

- Light passes through your cornea.
- Light is directed through your pupil.
- The crystalline lens fine tunes the focus.
- The retina transforms light into electrical impulses.
- The brain “sees” the image.

Some eye problems become common as age increases. There are variety of measures one can take to minimize or even prevent the effects of eye conditions including:
- Presbyopia
It is also called near vision. Wearing corrective eyeglasses is the simplest way to manage presbyopia. Prescription eyeglasses also are a relatively simple way to correct for presbyopia. Another option is to wear bifocal contact lenses or wear a different strength of contact lengths on each eye. Multi-focal intracular lens implants – plastic lenses that are surgically placed inside the eyes may be another option.

- Dry Eyes
Tears are an essential lubricant for eyes and are produced by glands in and around eyelids. Sometimes, tear production and tear quality decreases with age causing dry eyes. Dry eyes make your eyes feel hot and gritty and appear irritated but they seldom cause eye damage. Dry eyes can be treated by using non prescription, preservative free artificial tear solutions, applying ointments that moisten and protect the cornea for longer intervals that can artificial tears alone. Another option is blocking the ducts with tiny removable silicone or gel like plugs, using prescribed eye drops to increase production of tears.

After working for few hours in front of computers, sometimes eyes become red. What causes this and how to avoid it?

There is a condition called Computer Vision Syndrome (CVS). The typical symptoms of CVS are:
- Headaches, especially in front of head.
- Loss of focus.
- Burning, irritable, tired eyes.
- Inability to read for prolonged periods of time.
- Neck and shoulder pain.

CAUSES OF COMPUTER VISION SYNDROME

- Energy respond differently to characters on computer screen as compared to printed characters.
- The characters on a computer screen neither have contrast or sharp edges. These characters have their brightness. maximally at the center and decrease in intensity towards their edges. It makes it difficult for eyes to maintain focus and remain fixed onto the images.
- The continuous flexing of the eyes focusing mechanism leads to fatigue and a burning, irritable, tired-eyes feeling that is so common after sitting long hours at computer.

PREVENTION OF COMPUTER VISION SYNDROME

- Wear proper glasses that will allow you to work comfortably and productively.
- Use proper lighting by eliminating harsh, distracting, exterior light that cause eye strain by closing drapes, shades or blinds. Reduce interior lighting by using fewer light bulbs or fluorescent tubes.
- Minimize glare.
- The computer display screen should be upgraded. New LCD screens are easier on the eyes. Select screen refresh rate of at least 75 Hertz. Maintain the highest resolution possible.
- The display settings should be set so the brightness of screen is about same as work environment.
- The text size should be three times the size of the smallest text you can read from a normal viewing position.
- Do not stare and work at a stretch at the computer. Blink often to avoid dryness and irritation. Tears coating the eye evaporate more rapidly during long non-blinking phases.
- Relax your eyes.
- Modify your workstation. If you need to look back and forth between a printed page and computer screen, it can cause eye strain.
- Stretching is necessary in between the work to prevent neck, back, and shoulder pain.
- Take a 10-min break every hour to stand up, move about and stretch.